Commit Graph

435 Commits

Author SHA1 Message Date
Mel Gorman a720094ded mm: mempolicy: Hide MPOL_NOOP and MPOL_MF_LAZY from userspace for now
The use of MPOL_NOOP and MPOL_MF_LAZY to allow an application to
explicitly request lazy migration is a good idea but the actual
API has not been well reviewed and once released we have to support it.
For now this patch prevents an application using the services. This
will need to be revisited.

Signed-off-by: Mel Gorman <mgorman@suse.de>
2012-12-11 14:42:44 +00:00
Mel Gorman 4b10e7d562 mm: mempolicy: Implement change_prot_numa() in terms of change_protection()
This patch converts change_prot_numa() to use change_protection(). As
pte_numa and friends check the PTE bits directly it is necessary for
change_protection() to use pmd_mknuma(). Hence the required
modifications to change_protection() are a little clumsy but the
end result is that most of the numa page table helpers are just one or
two instructions.

Signed-off-by: Mel Gorman <mgorman@suse.de>
2012-12-11 14:42:44 +00:00
Lee Schermerhorn b24f53a0be mm: mempolicy: Add MPOL_MF_LAZY
NOTE: Once again there is a lot of patch stealing and the end result
	is sufficiently different that I had to drop the signed-offs.
	Will re-add if the original authors are ok with that.

This patch adds another mbind() flag to request "lazy migration".  The
flag, MPOL_MF_LAZY, modifies MPOL_MF_MOVE* such that the selected
pages are marked PROT_NONE. The pages will be migrated in the fault
path on "first touch", if the policy dictates at that time.

"Lazy Migration" will allow testing of migrate-on-fault via mbind().
Also allows applications to specify that only subsequently touched
pages be migrated to obey new policy, instead of all pages in range.
This can be useful for multi-threaded applications working on a
large shared data area that is initialized by an initial thread
resulting in all pages on one [or a few, if overflowed] nodes.
After PROT_NONE, the pages in regions assigned to the worker threads
will be automatically migrated local to the threads on 1st touch.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
2012-12-11 14:42:43 +00:00
Lee Schermerhorn 771fb4d806 mm: mempolicy: Check for misplaced page
This patch provides a new function to test whether a page resides
on a node that is appropriate for the mempolicy for the vma and
address where the page is supposed to be mapped.  This involves
looking up the node where the page belongs.  So, the function
returns that node so that it may be used to allocated the page
without consulting the policy again.

A subsequent patch will call this function from the fault path.
Because of this, I don't want to go ahead and allocate the page, e.g.,
via alloc_page_vma() only to have to free it if it has the correct
policy.  So, I just mimic the alloc_page_vma() node computation
logic--sort of.

Note:  we could use this function to implement a MPOL_MF_STRICT
behavior when migrating pages to match mbind() mempolicy--e.g.,
to ensure that pages in an interleaved range are reinterleaved
rather than left where they are when they reside on any page in
the interleave nodemask.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
[ Added MPOL_F_LAZY to trigger migrate-on-fault;
  simplified code now that we don't have to bother
  with special crap for interleaved ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
2012-12-11 14:42:41 +00:00
Lee Schermerhorn d3a710337b mm: mempolicy: Add MPOL_NOOP
This patch augments the MPOL_MF_LAZY feature by adding a "NOOP" policy
to mbind().  When the NOOP policy is used with the 'MOVE and 'LAZY
flags, mbind() will map the pages PROT_NONE so that they will be
migrated on the next touch.

This allows an application to prepare for a new phase of operation
where different regions of shared storage will be assigned to
worker threads, w/o changing policy.  Note that we could just use
"default" policy in this case.  However, this also allows an
application to request that pages be migrated, only if necessary,
to follow any arbitrary policy that might currently apply to a
range of pages, without knowing the policy, or without specifying
multiple mbind()s for ranges with different policies.

[ Bug in early version of mpol_parse_str() reported by Fengguang Wu. ]

Bug-Reported-by: Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
2012-12-11 14:42:40 +00:00
Peter Zijlstra 479e2802d0 mm: mempolicy: Make MPOL_LOCAL a real policy
Make MPOL_LOCAL a real and exposed policy such that applications that
relied on the previous default behaviour can explicitly request it.

Requested-by: Christoph Lameter <cl@linux.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
2012-12-11 14:42:39 +00:00
Mel Gorman 7b2a2d4a18 mm: migrate: Add a tracepoint for migrate_pages
The pgmigrate_success and pgmigrate_fail vmstat counters tells the user
about migration activity but not the type or the reason. This patch adds
a tracepoint to identify the type of page migration and why the page is
being migrated.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
2012-12-11 14:28:35 +00:00
Mel Gorman 18a2f371f5 tmpfs: fix shared mempolicy leak
This fixes a regression in 3.7-rc, which has since gone into stable.

Commit 00442ad04a ("mempolicy: fix a memory corruption by refcount
imbalance in alloc_pages_vma()") changed get_vma_policy() to raise the
refcount on a shmem shared mempolicy; whereas shmem_alloc_page() went
on expecting alloc_page_vma() to drop the refcount it had acquired.
This deserves a rework: but for now fix the leak in shmem_alloc_page().

Hugh: shmem_swapin() did not need a fix, but surely it's clearer to use
the same refcounting there as in shmem_alloc_page(), delete its onstack
mempolicy, and the strange mpol_cond_copy() and __mpol_cond_copy() -
those were invented to let swapin_readahead() make an unknown number of
calls to alloc_pages_vma() with one mempolicy; but since 00442ad04a,
alloc_pages_vma() has kept refcount in balance, so now no problem.

Reported-and-tested-by: Tommi Rantala <tt.rantala@gmail.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-06 11:56:43 -08:00
David Rientjes 32f8516a8c mm, mempolicy: fix printing stack contents in numa_maps
When reading /proc/pid/numa_maps, it's possible to return the contents of
the stack where the mempolicy string should be printed if the policy gets
freed from beneath us.

This happens because mpol_to_str() may return an error the
stack-allocated buffer is then printed without ever being stored.

There are two possible error conditions in mpol_to_str():

 - if the buffer allocated is insufficient for the string to be stored,
   and

 - if the mempolicy has an invalid mode.

The first error condition is not triggered in any of the callers to
mpol_to_str(): at least 50 bytes is always allocated on the stack and this
is sufficient for the string to be written.  A future patch should convert
this into BUILD_BUG_ON() since we know the maximum strlen possible, but
that's not -rc material.

The second error condition is possible if a race occurs in dropping a
reference to a task's mempolicy causing it to be freed during the read().
The slab poison value is then used for the mode and mpol_to_str() returns
-EINVAL.

This race is only possible because get_vma_policy() believes that
mm->mmap_sem protects task->mempolicy, which isn't true.  The exit path
does not hold mm->mmap_sem when dropping the reference or setting
task->mempolicy to NULL: it uses task_lock(task) instead.

Thus, it's required for the caller of a task mempolicy to hold
task_lock(task) while grabbing the mempolicy and reading it.  Callers with
a vma policy store their mempolicy earlier and can simply increment the
reference count so it's guaranteed not to be freed.

Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-16 18:00:50 -07:00
Minchan Kim 082708072a mm: revert 0def08e3 ("mm/mempolicy.c: check return code of check_range")
Revert commit 0def08e3ac because check_range can't fail in
migrate_to_node with considering current usecases.

Quote from Johannes

: I think it makes sense to revert.  Not because of the semantics, but I
: just don't see how check_range() could even fail for this callsite:
:
: 1. we pass mm->mmap->vm_start in there, so we should not fail due to
:    find_vma()
:
: 2. we pass MPOL_MF_DISCONTIG_OK, so the discontig checks do not apply
:    and so can not fail
:
: 3. we pass MPOL_MF_MOVE | MPOL_MF_MOVE_ALL, the page table loops will
:    continue until addr == end, so we never fail with -EIO

And I added a new VM_BUG_ON for checking migrate_to_node's future usecase
which might pass to MPOL_MF_STRICT.

Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vasiliy Kulikov <segooon@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:58 +09:00
Mel Gorman 00442ad04a mempolicy: fix a memory corruption by refcount imbalance in alloc_pages_vma()
Commit cc9a6c8776 ("cpuset: mm: reduce large amounts of memory barrier
related damage v3") introduced a potential memory corruption.
shmem_alloc_page() uses a pseudo vma and it has one significant unique
combination, vma->vm_ops=NULL and vma->policy->flags & MPOL_F_SHARED.

get_vma_policy() does NOT increase a policy ref when vma->vm_ops=NULL
and mpol_cond_put() DOES decrease a policy ref when a policy has
MPOL_F_SHARED.  Therefore, when a cpuset update race occurs,
alloc_pages_vma() falls in 'goto retry_cpuset' path, decrements the
reference count and frees the policy prematurely.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Christoph Lameter <cl@linux.com>
Cc: Josh Boyer <jwboyer@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:22 +09:00
KOSAKI Motohiro 63f74ca21f mempolicy: fix refcount leak in mpol_set_shared_policy()
When shared_policy_replace() fails to allocate new->policy is not freed
correctly by mpol_set_shared_policy().  The problem is that shared
mempolicy code directly call kmem_cache_free() in multiple places where
it is easy to make a mistake.

This patch creates an sp_free wrapper function and uses it. The bug was
introduced pre-git age (IOW, before 2.6.12-rc2).

[mgorman@suse.de: Editted changelog]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Christoph Lameter <cl@linux.com>
Cc: Josh Boyer <jwboyer@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:22 +09:00
Mel Gorman b22d127a39 mempolicy: fix a race in shared_policy_replace()
shared_policy_replace() use of sp_alloc() is unsafe.  1) sp_node cannot
be dereferenced if sp->lock is not held and 2) another thread can modify
sp_node between spin_unlock for allocating a new sp node and next
spin_lock.  The bug was introduced before 2.6.12-rc2.

Kosaki's original patch for this problem was to allocate an sp node and
policy within shared_policy_replace and initialise it when the lock is
reacquired.  I was not keen on this approach because it partially
duplicates sp_alloc().  As the paths were sp->lock is taken are not that
performance critical this patch converts sp->lock to sp->mutex so it can
sleep when calling sp_alloc().

[kosaki.motohiro@jp.fujitsu.com: Original patch]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Cc: Josh Boyer <jwboyer@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:22 +09:00
KOSAKI Motohiro 869833f2c5 mempolicy: remove mempolicy sharing
Dave Jones' system call fuzz testing tool "trinity" triggered the
following bug error with slab debugging enabled

    =============================================================================
    BUG numa_policy (Not tainted): Poison overwritten
    -----------------------------------------------------------------------------

    INFO: 0xffff880146498250-0xffff880146498250. First byte 0x6a instead of 0x6b
    INFO: Allocated in mpol_new+0xa3/0x140 age=46310 cpu=6 pid=32154
     __slab_alloc+0x3d3/0x445
     kmem_cache_alloc+0x29d/0x2b0
     mpol_new+0xa3/0x140
     sys_mbind+0x142/0x620
     system_call_fastpath+0x16/0x1b

    INFO: Freed in __mpol_put+0x27/0x30 age=46268 cpu=6 pid=32154
     __slab_free+0x2e/0x1de
     kmem_cache_free+0x25a/0x260
     __mpol_put+0x27/0x30
     remove_vma+0x68/0x90
     exit_mmap+0x118/0x140
     mmput+0x73/0x110
     exit_mm+0x108/0x130
     do_exit+0x162/0xb90
     do_group_exit+0x4f/0xc0
     sys_exit_group+0x17/0x20
     system_call_fastpath+0x16/0x1b

    INFO: Slab 0xffffea0005192600 objects=27 used=27 fp=0x          (null) flags=0x20000000004080
    INFO: Object 0xffff880146498250 @offset=592 fp=0xffff88014649b9d0

The problem is that the structure is being prematurely freed due to a
reference count imbalance. In the following case mbind(addr, len) should
replace the memory policies of both vma1 and vma2 and thus they will
become to share the same mempolicy and the new mempolicy will have the
MPOL_F_SHARED flag.

  +-------------------+-------------------+
  |     vma1          |     vma2(shmem)   |
  +-------------------+-------------------+
  |                                       |
 addr                                 addr+len

alloc_pages_vma() uses get_vma_policy() and mpol_cond_put() pair for
maintaining the mempolicy reference count.  The current rule is that
get_vma_policy() only increments refcount for shmem VMA and
mpol_conf_put() only decrements refcount if the policy has
MPOL_F_SHARED.

In above case, vma1 is not shmem vma and vma->policy has MPOL_F_SHARED!
The reference count will be decreased even though was not increased
whenever alloc_page_vma() is called.  This has been broken since commit
[52cd3b07: mempolicy: rework mempolicy Reference Counting] in 2008.

There is another serious bug with the sharing of memory policies.
Currently, mempolicy rebind logic (it is called from cpuset rebinding)
ignores a refcount of mempolicy and override it forcibly.  Thus, any
mempolicy sharing may cause mempolicy corruption.  The bug was
introduced by commit [68860ec1: cpusets: automatic numa mempolicy
rebinding].

Ideally, the shared policy handling would be rewritten to either
properly handle COW of the policy structures or at least reference count
MPOL_F_SHARED based exclusively on information within the policy.
However, this patch takes the easier approach of disabling any policy
sharing between VMAs.  Each new range allocated with sp_alloc will
allocate a new policy, set the reference count to 1 and drop the
reference count of the old policy.  This increases the memory footprint
but is not expected to be a major problem as mbind() is unlikely to be
used for fine-grained ranges.  It is also inefficient because it means
we allocate a new policy even in cases where mbind_range() could use the
new_policy passed to it.  However, it is more straight-forward and the
change should be invisible to the user.

[mgorman@suse.de: Edited changelog]
Reported-by: Dave Jones <davej@redhat.com>,
Cc: Christoph Lameter <cl@linux.com>,
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Josh Boyer <jwboyer@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:21 +09:00
KOSAKI Motohiro 8d34694c1a revert "mm: mempolicy: Let vma_merge and vma_split handle vma->vm_policy linkages"
Commit 05f144a0d5 ("mm: mempolicy: Let vma_merge and vma_split handle
vma->vm_policy linkages") removed vma->vm_policy updates code but it is
the purpose of mbind_range().  Now, mbind_range() is virtually a no-op
and while it does not allow memory corruption it is not the right fix.
This patch is a revert.

[mgorman@suse.de: Edited changelog]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: Josh Boyer <jwboyer@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:21 +09:00
Dave Jones 80de7c3138 Remove user-triggerable BUG from mpol_to_str
Trivially triggerable, found by trinity:

  kernel BUG at mm/mempolicy.c:2546!
  Process trinity-child2 (pid: 23988, threadinfo ffff88010197e000, task ffff88007821a670)
  Call Trace:
    show_numa_map+0xd5/0x450
    show_pid_numa_map+0x13/0x20
    traverse+0xf2/0x230
    seq_read+0x34b/0x3e0
    vfs_read+0xac/0x180
    sys_pread64+0xa2/0xc0
    system_call_fastpath+0x1a/0x1f
  RIP: mpol_to_str+0x156/0x360

Cc: stable@vger.kernel.org
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-09-06 09:37:58 -07:00
Linus Torvalds 720d85075b Merge branch 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux
Pull SLAB changes from Pekka Enberg:
 "Most of the changes included are from Christoph Lameter's "common
  slab" patch series that unifies common parts of SLUB, SLAB, and SLOB
  allocators.  The unification is needed for Glauber Costa's "kmem
  memcg" work that will hopefully appear for v3.7.

  The rest of the changes are fixes and speedups by various people."

* 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux: (32 commits)
  mm: Fix build warning in kmem_cache_create()
  slob: Fix early boot kernel crash
  mm, slub: ensure irqs are enabled for kmemcheck
  mm, sl[aou]b: Move kmem_cache_create mutex handling to common code
  mm, sl[aou]b: Use a common mutex definition
  mm, sl[aou]b: Common definition for boot state of the slab allocators
  mm, sl[aou]b: Extract common code for kmem_cache_create()
  slub: remove invalid reference to list iterator variable
  mm: Fix signal SIGFPE in slabinfo.c.
  slab: move FULL state transition to an initcall
  slab: Fix a typo in commit 8c138b "slab: Get rid of obj_size macro"
  mm, slab: Build fix for recent kmem_cache changes
  slab: rename gfpflags to allocflags
  slub: refactoring unfreeze_partials()
  slub: use __cmpxchg_double_slab() at interrupt disabled place
  slab/mempolicy: always use local policy from interrupt context
  slab: Get rid of obj_size macro
  mm, sl[aou]b: Extract common fields from struct kmem_cache
  slab: Remove some accessors
  slab: Use page struct fields instead of casting
  ...
2012-07-30 11:32:24 -07:00
David Rientjes c4c0e9e544 mm, mempolicy: fix mbind() to do synchronous migration
If the range passed to mbind() is not allocated on nodes set in the
nodemask, it migrates the pages to respect the constraint.

The final formal of migrate_pages() is a mode of type enum migrate_mode,
not a boolean.  do_mbind() is currently passing "true" which is the
equivalent of MIGRATE_SYNC_LIGHT.  This should instead be MIGRATE_SYNC
for synchronous page migration.

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-20 22:10:42 -07:00
Andi Kleen e7b691b085 slab/mempolicy: always use local policy from interrupt context
slab_node() could access current->mempolicy from interrupt context.
However there's a race condition during exit where the mempolicy
is first freed and then the pointer zeroed.

Using this from interrupts seems bogus anyways. The interrupt
will interrupt a random process and therefore get a random
mempolicy. Many times, this will be idle's, which noone can change.

Just disable this here and always use local for slab
from interrupts. I also cleaned up the callers of slab_node a bit
which always passed the same argument.

I believe the original mempolicy code did that in fact,
so it's likely a regression.

v2: send version with correct logic
v3: simplify. fix typo.
Reported-by: Arun Sharma <asharma@fb.com>
Cc: penberg@kernel.org
Cc: cl@linux.com
Signed-off-by: Andi Kleen <ak@linux.intel.com>
[tdmackey@twitter.com: Rework control flow based on feedback from
cl@linux.com, fix logic, and cleanup current task_struct reference]
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: David Mackey <tdmackey@twitter.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-06-20 10:01:04 +03:00
Andrew Morton 0ce72d4f73 mm: do_migrate_pages(): rename arguments
s/from_nodes/from and s/to_nodes/to/.  The "_nodes" is redundant - it
duplicates the argument's type.

Done in a fit of irritation over 80-col issues :(

Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <mkosaki@redhat.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:20 -07:00
Larry Woodman 4a5b18cc19 mm: do_migrate_pages() calls migrate_to_node() even if task is already on a correct node
While running an application that moves tasks from one cpuset to another
I noticed that it takes much longer and moves many more pages than
expected.

The reason for this is do_migrate_pages() does its best to preserve the
relative node differential from the first node of the cpuset because the
application may have been written with that in mind.  If memory was
interleaved on the nodes of the source cpuset by an application
do_migrate_pages() will try its best to maintain that interleaving on
the nodes of the destination cpuset.  This means copying the memory from
all source nodes to the destination nodes even if the source and
destination nodes overlap.

This is a problem for userspace NUMA placement tools.  The amount of
time spent doing extra memory moves cancels out some of the NUMA
performance improvements.  Furthermore, if the number of source and
destination nodes are to maintain the previous interleaving layout
anyway.

This patch changes do_migrate_pages() to only preserve the relative
layout inside the program if the number of NUMA nodes in the source and
destination mask are the same.  If the number is different, we do a much
more efficient migration by not touching memory that is in an allowed
node.

This preserves the old behaviour for programs that want it, while
allowing a userspace NUMA placement tool to use the new, faster
migration.  This improves performance in our tests by up to a factor of
7.

Without this change migrating tasks from a cpuset containing nodes 0-7
to a cpuset containing nodes 3-4, we migrate from ALL the nodes even if
they are in the both the source and destination nodesets:

   Migrating 7 to 4
   Migrating 6 to 3
   Migrating 5 to 4
   Migrating 4 to 3
   Migrating 1 to 4
   Migrating 3 to 4
   Migrating 0 to 3
   Migrating 2 to 3

With this change we only migrate from nodes that are not in the
destination nodesets:

   Migrating 7 to 4
   Migrating 6 to 3
   Migrating 5 to 4
   Migrating 2 to 3
   Migrating 1 to 4
   Migrating 0 to 3

Yet if we move from a cpuset containing nodes 2,3,4 to a cpuset
containing 3,4,5 we still do move everything so that we preserve the
desired NUMA offsets:

   Migrating 4 to 5
   Migrating 3 to 4
   Migrating 2 to 3

As far as performance is concerned this simple patch improves the time
it takes to move 14, 20 and 26 large tasks from a cpuset containing
nodes 0-7 to a cpuset containing nodes 1 & 3 by up to a factor of 7.
Here are the timings with and without the patch:

BEFORE PATCH -- Move times: 59, 140, 651 seconds
============

  Moving 14 tasks from nodes (0-7) to nodes (1,3)
  numad(8780) do_migrate_pages (mm=0xffff88081d414400
  from_nodes=0xffff880818c81d28 to_nodes=0xffff880818c81ce8 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d414400 source=0x7 dest=0x3 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d414400 source=0x6 dest=0x1 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d414400 source=0x5 dest=0x3 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d414400 source=0x4 dest=0x1 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d414400 source=0x2 dest=0x1 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d414400 source=0x1 dest=0x3 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d414400 source=0x0 dest=0x1 flags=0x4)
  (Above moves repeated for each of the 14 tasks...)
  PID 8890 moved to node(s) 1,3 in 59.2 seconds

  Moving 20 tasks from nodes (0-7) to nodes (1,4-5)
  numad(8780) do_migrate_pages (mm=0xffff88081d88c700
  from_nodes=0xffff880818c81d28 to_nodes=0xffff880818c81ce8 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d88c700 source=0x7 dest=0x4 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d88c700 source=0x6 dest=0x1 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d88c700 source=0x3 dest=0x1 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d88c700 source=0x2 dest=0x5 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d88c700 source=0x1 dest=0x4 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d88c700 source=0x0 dest=0x1 flags=0x4)
  (Above moves repeated for each of the 20 tasks...)
  PID 8962 moved to node(s) 1,4-5 in 139.88 seconds

  Moving 26 tasks from nodes (0-7) to nodes (1-3,5)
  numad(8780) do_migrate_pages (mm=0xffff88081d5bc740
  from_nodes=0xffff880818c81d28 to_nodes=0xffff880818c81ce8 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d5bc740 source=0x7 dest=0x5 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d5bc740 source=0x6 dest=0x3 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d5bc740 source=0x5 dest=0x2 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d5bc740 source=0x3 dest=0x5 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d5bc740 source=0x2 dest=0x3 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d5bc740 source=0x1 dest=0x2 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d5bc740 source=0x0 dest=0x1 flags=0x4)
  numad(8780) migrate_to_node (mm=0xffff88081d5bc740 source=0x4 dest=0x1 flags=0x4)
  (Above moves repeated for each of the 26 tasks...)
  PID 9058 moved to node(s) 1-3,5 in 651.45 seconds

AFTER PATCH -- Move times: 42, 56, 93 seconds
===========

  Moving 14 tasks from nodes (0-7) to nodes (5,7)
  numad(33209) do_migrate_pages (mm=0xffff88101d5ff140
  from_nodes=0xffff88101e7b5d28 to_nodes=0xffff88101e7b5ce8 flags=0x4)
  numad(33209) migrate_to_node (mm=0xffff88101d5ff140 source=0x6 dest=0x5 flags=0x4)
  numad(33209) migrate_to_node (mm=0xffff88101d5ff140 source=0x4 dest=0x5 flags=0x4)
  numad(33209) migrate_to_node (mm=0xffff88101d5ff140 source=0x3 dest=0x7 flags=0x4)
  numad(33209) migrate_to_node (mm=0xffff88101d5ff140 source=0x2 dest=0x5 flags=0x4)
  numad(33209) migrate_to_node (mm=0xffff88101d5ff140 source=0x1 dest=0x7 flags=0x4)
  numad(33209) migrate_to_node (mm=0xffff88101d5ff140 source=0x0 dest=0x5 flags=0x4)
  (Above moves repeated for each of the 14 tasks...)
  PID 33221 moved to node(s) 5,7 in 41.67 seconds

  Moving 20 tasks from nodes (0-7) to nodes (1,3,5)
  numad(33209) do_migrate_pages (mm=0xffff88101d6c37c0
  from_nodes=0xffff88101e7b5d28 to_nodes=0xffff88101e7b5ce8 flags=0x4)
  numad(33209) migrate_to_node (mm=0xffff88101d6c37c0 source=0x7 dest=0x3 flags=0x4)
  numad(33209) migrate_to_node (mm=0xffff88101d6c37c0 source=0x6 dest=0x1 flags=0x4)
  numad(33209) migrate_to_node (mm=0xffff88101d6c37c0 source=0x4 dest=0x3 flags=0x4)
  numad(33209) migrate_to_node (mm=0xffff88101d6c37c0 source=0x2 dest=0x5 flags=0x4)
  numad(33209) migrate_to_node (mm=0xffff88101d6c37c0 source=0x0 dest=0x1 flags=0x4)
  (Above moves repeated for each of the 20 tasks...)
  PID 33289 moved to node(s) 1,3,5 in 56.3 seconds

  Moving 26 tasks from nodes (0-7) to nodes (1,3,5,7)
  numad(33209) do_migrate_pages (mm=0xffff88101d924400
  from_nodes=0xffff88101e7b5d28 to_nodes=0xffff88101e7b5ce8 flags=0x4)
  numad(33209) migrate_to_node (mm=0xffff88101d924400 source=0x6 dest=0x5 flags=0x4)
  numad(33209) migrate_to_node (mm=0xffff88101d924400 source=0x4 dest=0x1 flags=0x4)
  numad(33209) migrate_to_node (mm=0xffff88101d924400 source=0x2 dest=0x5 flags=0x4)
  numad(33209) migrate_to_node (mm=0xffff88101d924400 source=0x0 dest=0x1 flags=0x4)
  (Above moves repeated for each of the 26 tasks...)
  PID 33372 moved to node(s) 1,3,5,7 in 92.67 seconds

[akpm@linux-foundation.org: clean up comment layout]
Signed-off-by: Larry Woodman <lwoodman@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:20 -07:00
Wang Sheng-Hui 89c522c78a mm/mempolicy.c: use enum value MPOL_REBIND_ONCE in mpol_rebind_policy()
We have enum definition in mempolicy.h: MPOL_REBIND_ONCE.  It should
replace the magic number 0 for step comparison in function
mpol_rebind_policy.

Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:18 -07:00
Mel Gorman 05f144a0d5 mm: mempolicy: Let vma_merge and vma_split handle vma->vm_policy linkages
Dave Jones' system call fuzz testing tool "trinity" triggered the
following bug error with slab debugging enabled

    =============================================================================
    BUG numa_policy (Not tainted): Poison overwritten
    -----------------------------------------------------------------------------

    INFO: 0xffff880146498250-0xffff880146498250. First byte 0x6a instead of 0x6b
    INFO: Allocated in mpol_new+0xa3/0x140 age=46310 cpu=6 pid=32154
     __slab_alloc+0x3d3/0x445
     kmem_cache_alloc+0x29d/0x2b0
     mpol_new+0xa3/0x140
     sys_mbind+0x142/0x620
     system_call_fastpath+0x16/0x1b
    INFO: Freed in __mpol_put+0x27/0x30 age=46268 cpu=6 pid=32154
     __slab_free+0x2e/0x1de
     kmem_cache_free+0x25a/0x260
     __mpol_put+0x27/0x30
     remove_vma+0x68/0x90
     exit_mmap+0x118/0x140
     mmput+0x73/0x110
     exit_mm+0x108/0x130
     do_exit+0x162/0xb90
     do_group_exit+0x4f/0xc0
     sys_exit_group+0x17/0x20
     system_call_fastpath+0x16/0x1b
    INFO: Slab 0xffffea0005192600 objects=27 used=27 fp=0x          (null) flags=0x20000000004080
    INFO: Object 0xffff880146498250 @offset=592 fp=0xffff88014649b9d0

This implied a reference counting bug and the problem happened during
mbind().

mbind() applies a new memory policy to a range and uses mbind_range() to
merge existing VMAs or split them as necessary.  In the event of splits,
mpol_dup() will allocate a new struct mempolicy and maintain existing
reference counts whose rules are documented in
Documentation/vm/numa_memory_policy.txt .

The problem occurs with shared memory policies.  The vm_op->set_policy
increments the reference count if necessary and split_vma() and
vma_merge() have already handled the existing reference counts.
However, policy_vma() screws it up by replacing an existing
vma->vm_policy with one that potentially has the wrong reference count
leading to a premature free.  This patch removes the damage caused by
policy_vma().

With this patch applied Dave's trinity tool runs an mbind test for 5
minutes without error.  /proc/slabinfo reported that there are no
numa_policy or shared_policy_node objects allocated after the test
completed and the shared memory region was deleted.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Dave Jones <davej@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Stephen Wilson <wilsons@start.ca>
Cc: Christoph Lameter <cl@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-23 17:57:33 -07:00
Linus Torvalds 644473e9c6 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull user namespace enhancements from Eric Biederman:
 "This is a course correction for the user namespace, so that we can
  reach an inexpensive, maintainable, and reasonably complete
  implementation.

  Highlights:
   - Config guards make it impossible to enable the user namespace and
     code that has not been converted to be user namespace safe.

   - Use of the new kuid_t type ensures the if you somehow get past the
     config guards the kernel will encounter type errors if you enable
     user namespaces and attempt to compile in code whose permission
     checks have not been updated to be user namespace safe.

   - All uids from child user namespaces are mapped into the initial
     user namespace before they are processed.  Removing the need to add
     an additional check to see if the user namespace of the compared
     uids remains the same.

   - With the user namespaces compiled out the performance is as good or
     better than it is today.

   - For most operations absolutely nothing changes performance or
     operationally with the user namespace enabled.

   - The worst case performance I could come up with was timing 1
     billion cache cold stat operations with the user namespace code
     enabled.  This went from 156s to 164s on my laptop (or 156ns to
     164ns per stat operation).

   - (uid_t)-1 and (gid_t)-1 are reserved as an internal error value.
     Most uid/gid setting system calls treat these value specially
     anyway so attempting to use -1 as a uid would likely cause
     entertaining failures in userspace.

   - If setuid is called with a uid that can not be mapped setuid fails.
     I have looked at sendmail, login, ssh and every other program I
     could think of that would call setuid and they all check for and
     handle the case where setuid fails.

   - If stat or a similar system call is called from a context in which
     we can not map a uid we lie and return overflowuid.  The LFS
     experience suggests not lying and returning an error code might be
     better, but the historical precedent with uids is different and I
     can not think of anything that would break by lying about a uid we
     can't map.

   - Capabilities are localized to the current user namespace making it
     safe to give the initial user in a user namespace all capabilities.

  My git tree covers all of the modifications needed to convert the core
  kernel and enough changes to make a system bootable to runlevel 1."

Fix up trivial conflicts due to nearby independent changes in fs/stat.c

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (46 commits)
  userns:  Silence silly gcc warning.
  cred: use correct cred accessor with regards to rcu read lock
  userns: Convert the move_pages, and migrate_pages permission checks to use uid_eq
  userns: Convert cgroup permission checks to use uid_eq
  userns: Convert tmpfs to use kuid and kgid where appropriate
  userns: Convert sysfs to use kgid/kuid where appropriate
  userns: Convert sysctl permission checks to use kuid and kgids.
  userns: Convert proc to use kuid/kgid where appropriate
  userns: Convert ext4 to user kuid/kgid where appropriate
  userns: Convert ext3 to use kuid/kgid where appropriate
  userns: Convert ext2 to use kuid/kgid where appropriate.
  userns: Convert devpts to use kuid/kgid where appropriate
  userns: Convert binary formats to use kuid/kgid where appropriate
  userns: Add negative depends on entries to avoid building code that is userns unsafe
  userns: signal remove unnecessary map_cred_ns
  userns: Teach inode_capable to understand inodes whose uids map to other namespaces.
  userns: Fail exec for suid and sgid binaries with ids outside our user namespace.
  userns: Convert stat to return values mapped from kuids and kgids
  userns: Convert user specfied uids and gids in chown into kuids and kgid
  userns: Use uid_eq gid_eq helpers when comparing kuids and kgids in the vfs
  ...
2012-05-23 17:42:39 -07:00
Eric W. Biederman b38a86eb19 userns: Convert the move_pages, and migrate_pages permission checks to use uid_eq
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-05-15 14:59:30 -07:00
Sasha Levin f2a9ef8807 mm: fix NULL ptr dereference in migrate_pages
Commit 3268c63 ("mm: fix move/migrate_pages() race on task struct") has
added an odd construct where 'mm' is checked for being NULL, and if it is,
it would get dereferenced anyways by mput()ing it.

This would lead to the following NULL ptr deref and BUG() when calling
migrate_pages() with a pid that has no mm struct:

[25904.193704] BUG: unable to handle kernel NULL pointer dereference at 0000000000000050
[25904.194235] IP: [<ffffffff810b0de7>] mmput+0x27/0xf0
[25904.194235] PGD 773e6067 PUD 77da0067 PMD 0
[25904.194235] Oops: 0002 [#1] PREEMPT SMP
[25904.194235] CPU 2
[25904.194235] Pid: 31608, comm: trinity Tainted: G        W    3.4.0-rc2-next-20120412-sasha #69
[25904.194235] RIP: 0010:[<ffffffff810b0de7>]  [<ffffffff810b0de7>] mmput+0x27/0xf0
[25904.194235] RSP: 0018:ffff880077d49e08  EFLAGS: 00010202
[25904.194235] RAX: 0000000000000286 RBX: 0000000000000000 RCX: 0000000000000000
[25904.194235] RDX: ffff880075ef8000 RSI: 000000000000023d RDI: 0000000000000286
[25904.194235] RBP: ffff880077d49e18 R08: 0000000000000001 R09: 0000000000000001
[25904.194235] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[25904.194235] R13: 00000000ffffffea R14: ffff880034287740 R15: ffff8800218d3010
[25904.194235] FS:  00007fc8b244c700(0000) GS:ffff880029800000(0000) knlGS:0000000000000000
[25904.194235] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[25904.194235] CR2: 0000000000000050 CR3: 00000000767c6000 CR4: 00000000000406e0
[25904.194235] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[25904.194235] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[25904.194235] Process trinity (pid: 31608, threadinfo ffff880077d48000, task ffff880075ef8000)
[25904.194235] Stack:
[25904.194235]  ffff8800342876c0 0000000000000000 ffff880077d49f78 ffffffff811b8020
[25904.194235]  ffffffff811b7d91 ffff880075ef8000 ffff88002256d200 0000000000000000
[25904.194235]  00000000000003ff 0000000000000000 0000000000000000 0000000000000000
[25904.194235] Call Trace:
[25904.194235]  [<ffffffff811b8020>] sys_migrate_pages+0x340/0x3a0
[25904.194235]  [<ffffffff811b7d91>] ? sys_migrate_pages+0xb1/0x3a0
[25904.194235]  [<ffffffff8266cbb9>] system_call_fastpath+0x16/0x1b
[25904.194235] Code: c9 c3 66 90 55 31 d2 48 89 e5 be 3d 02 00 00 48 83 ec 10 48 89 1c 24 4c 89 64 24 08 48 89 fb 48 c7 c7 cf 0e e1 82 e8 69 18 03 00 <f0> ff 4b 50 0f 94 c0 84 c0 0f 84 aa 00 00 00 48 89 df e8 72 f1
[25904.194235] RIP  [<ffffffff810b0de7>] mmput+0x27/0xf0
[25904.194235]  RSP <ffff880077d49e08>
[25904.194235] CR2: 0000000000000050
[25904.348999] ---[ end trace a307b3ed40206b4b ]---

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-25 21:26:34 -07:00
Mel Gorman cc9a6c8776 cpuset: mm: reduce large amounts of memory barrier related damage v3
Commit c0ff7453bb ("cpuset,mm: fix no node to alloc memory when
changing cpuset's mems") wins a super prize for the largest number of
memory barriers entered into fast paths for one commit.

[get|put]_mems_allowed is incredibly heavy with pairs of full memory
barriers inserted into a number of hot paths.  This was detected while
investigating at large page allocator slowdown introduced some time
after 2.6.32.  The largest portion of this overhead was shown by
oprofile to be at an mfence introduced by this commit into the page
allocator hot path.

For extra style points, the commit introduced the use of yield() in an
implementation of what looks like a spinning mutex.

This patch replaces the full memory barriers on both read and write
sides with a sequence counter with just read barriers on the fast path
side.  This is much cheaper on some architectures, including x86.  The
main bulk of the patch is the retry logic if the nodemask changes in a
manner that can cause a false failure.

While updating the nodemask, a check is made to see if a false failure
is a risk.  If it is, the sequence number gets bumped and parallel
allocators will briefly stall while the nodemask update takes place.

In a page fault test microbenchmark, oprofile samples from
__alloc_pages_nodemask went from 4.53% of all samples to 1.15%.  The
actual results were

                             3.3.0-rc3          3.3.0-rc3
                             rc3-vanilla        nobarrier-v2r1
    Clients   1 UserTime       0.07 (  0.00%)   0.08 (-14.19%)
    Clients   2 UserTime       0.07 (  0.00%)   0.07 (  2.72%)
    Clients   4 UserTime       0.08 (  0.00%)   0.07 (  3.29%)
    Clients   1 SysTime        0.70 (  0.00%)   0.65 (  6.65%)
    Clients   2 SysTime        0.85 (  0.00%)   0.82 (  3.65%)
    Clients   4 SysTime        1.41 (  0.00%)   1.41 (  0.32%)
    Clients   1 WallTime       0.77 (  0.00%)   0.74 (  4.19%)
    Clients   2 WallTime       0.47 (  0.00%)   0.45 (  3.73%)
    Clients   4 WallTime       0.38 (  0.00%)   0.37 (  1.58%)
    Clients   1 Flt/sec/cpu  497620.28 (  0.00%) 520294.53 (  4.56%)
    Clients   2 Flt/sec/cpu  414639.05 (  0.00%) 429882.01 (  3.68%)
    Clients   4 Flt/sec/cpu  257959.16 (  0.00%) 258761.48 (  0.31%)
    Clients   1 Flt/sec      495161.39 (  0.00%) 517292.87 (  4.47%)
    Clients   2 Flt/sec      820325.95 (  0.00%) 850289.77 (  3.65%)
    Clients   4 Flt/sec      1020068.93 (  0.00%) 1022674.06 (  0.26%)
    MMTests Statistics: duration
    Sys Time Running Test (seconds)             135.68    132.17
    User+Sys Time Running Test (seconds)         164.2    160.13
    Total Elapsed Time (seconds)                123.46    120.87

The overall improvement is small but the System CPU time is much
improved and roughly in correlation to what oprofile reported (these
performance figures are without profiling so skew is expected).  The
actual number of page faults is noticeably improved.

For benchmarks like kernel builds, the overall benefit is marginal but
the system CPU time is slightly reduced.

To test the actual bug the commit fixed I opened two terminals.  The
first ran within a cpuset and continually ran a small program that
faulted 100M of anonymous data.  In a second window, the nodemask of the
cpuset was continually randomised in a loop.

Without the commit, the program would fail every so often (usually
within 10 seconds) and obviously with the commit everything worked fine.
With this patch applied, it also worked fine so the fix should be
functionally equivalent.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-21 17:54:59 -07:00
Christoph Lameter 3268c63ede mm: fix move/migrate_pages() race on task struct
Migration functions perform the rcu_read_unlock too early.  As a result
the task pointed to may change from under us.  This can result in an oops,
as reported by Dave Hansen in https://lkml.org/lkml/2012/2/23/302.

The following patch extend the period of the rcu_read_lock until after the
permissions checks are done.  We also take a refcount so that the task
reference is stable when calling security check functions and performing
cpuset node validation (which takes a mutex).

The refcount is dropped before actual page migration occurs so there is no
change to the refcounts held during page migration.

Also move the determination of the mm of the task struct to immediately
before the do_migrate*() calls so that it is clear that we switch from
handling the task during permission checks to the mm for the actual
migration.  Since the determination is only done once and we then no
longer use the task_struct we can be sure that we operate on a specific
address space that will not change from under us.

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Christoph Lameter <cl@linux.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Reported-by: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-21 17:54:58 -07:00
Andrea Arcangeli 1a5a9906d4 mm: thp: fix pmd_bad() triggering in code paths holding mmap_sem read mode
In some cases it may happen that pmd_none_or_clear_bad() is called with
the mmap_sem hold in read mode.  In those cases the huge page faults can
allocate hugepmds under pmd_none_or_clear_bad() and that can trigger a
false positive from pmd_bad() that will not like to see a pmd
materializing as trans huge.

It's not khugepaged causing the problem, khugepaged holds the mmap_sem
in write mode (and all those sites must hold the mmap_sem in read mode
to prevent pagetables to go away from under them, during code review it
seems vm86 mode on 32bit kernels requires that too unless it's
restricted to 1 thread per process or UP builds).  The race is only with
the huge pagefaults that can convert a pmd_none() into a
pmd_trans_huge().

Effectively all these pmd_none_or_clear_bad() sites running with
mmap_sem in read mode are somewhat speculative with the page faults, and
the result is always undefined when they run simultaneously.  This is
probably why it wasn't common to run into this.  For example if the
madvise(MADV_DONTNEED) runs zap_page_range() shortly before the page
fault, the hugepage will not be zapped, if the page fault runs first it
will be zapped.

Altering pmd_bad() not to error out if it finds hugepmds won't be enough
to fix this, because zap_pmd_range would then proceed to call
zap_pte_range (which would be incorrect if the pmd become a
pmd_trans_huge()).

The simplest way to fix this is to read the pmd in the local stack
(regardless of what we read, no need of actual CPU barriers, only
compiler barrier needed), and be sure it is not changing under the code
that computes its value.  Even if the real pmd is changing under the
value we hold on the stack, we don't care.  If we actually end up in
zap_pte_range it means the pmd was not none already and it was not huge,
and it can't become huge from under us (khugepaged locking explained
above).

All we need is to enforce that there is no way anymore that in a code
path like below, pmd_trans_huge can be false, but pmd_none_or_clear_bad
can run into a hugepmd.  The overhead of a barrier() is just a compiler
tweak and should not be measurable (I only added it for THP builds).  I
don't exclude different compiler versions may have prevented the race
too by caching the value of *pmd on the stack (that hasn't been
verified, but it wouldn't be impossible considering
pmd_none_or_clear_bad, pmd_bad, pmd_trans_huge, pmd_none are all inlines
and there's no external function called in between pmd_trans_huge and
pmd_none_or_clear_bad).

		if (pmd_trans_huge(*pmd)) {
			if (next-addr != HPAGE_PMD_SIZE) {
				VM_BUG_ON(!rwsem_is_locked(&tlb->mm->mmap_sem));
				split_huge_page_pmd(vma->vm_mm, pmd);
			} else if (zap_huge_pmd(tlb, vma, pmd, addr))
				continue;
			/* fall through */
		}
		if (pmd_none_or_clear_bad(pmd))

Because this race condition could be exercised without special
privileges this was reported in CVE-2012-1179.

The race was identified and fully explained by Ulrich who debugged it.
I'm quoting his accurate explanation below, for reference.

====== start quote =======
      mapcount 0 page_mapcount 1
      kernel BUG at mm/huge_memory.c:1384!

    At some point prior to the panic, a "bad pmd ..." message similar to the
    following is logged on the console:

      mm/memory.c:145: bad pmd ffff8800376e1f98(80000000314000e7).

    The "bad pmd ..." message is logged by pmd_clear_bad() before it clears
    the page's PMD table entry.

        143 void pmd_clear_bad(pmd_t *pmd)
        144 {
    ->  145         pmd_ERROR(*pmd);
        146         pmd_clear(pmd);
        147 }

    After the PMD table entry has been cleared, there is an inconsistency
    between the actual number of PMD table entries that are mapping the page
    and the page's map count (_mapcount field in struct page). When the page
    is subsequently reclaimed, __split_huge_page() detects this inconsistency.

       1381         if (mapcount != page_mapcount(page))
       1382                 printk(KERN_ERR "mapcount %d page_mapcount %d\n",
       1383                        mapcount, page_mapcount(page));
    -> 1384         BUG_ON(mapcount != page_mapcount(page));

    The root cause of the problem is a race of two threads in a multithreaded
    process. Thread B incurs a page fault on a virtual address that has never
    been accessed (PMD entry is zero) while Thread A is executing an madvise()
    system call on a virtual address within the same 2 MB (huge page) range.

               virtual address space
              .---------------------.
              |                     |
              |                     |
            .-|---------------------|
            | |                     |
            | |                     |<-- B(fault)
            | |                     |
      2 MB  | |/////////////////////|-.
      huge <  |/////////////////////|  > A(range)
      page  | |/////////////////////|-'
            | |                     |
            | |                     |
            '-|---------------------|
              |                     |
              |                     |
              '---------------------'

    - Thread A is executing an madvise(..., MADV_DONTNEED) system call
      on the virtual address range "A(range)" shown in the picture.

    sys_madvise
      // Acquire the semaphore in shared mode.
      down_read(&current->mm->mmap_sem)
      ...
      madvise_vma
        switch (behavior)
        case MADV_DONTNEED:
             madvise_dontneed
               zap_page_range
                 unmap_vmas
                   unmap_page_range
                     zap_pud_range
                       zap_pmd_range
                         //
                         // Assume that this huge page has never been accessed.
                         // I.e. content of the PMD entry is zero (not mapped).
                         //
                         if (pmd_trans_huge(*pmd)) {
                             // We don't get here due to the above assumption.
                         }
                         //
                         // Assume that Thread B incurred a page fault and
             .---------> // sneaks in here as shown below.
             |           //
             |           if (pmd_none_or_clear_bad(pmd))
             |               {
             |                 if (unlikely(pmd_bad(*pmd)))
             |                     pmd_clear_bad
             |                     {
             |                       pmd_ERROR
             |                         // Log "bad pmd ..." message here.
             |                       pmd_clear
             |                         // Clear the page's PMD entry.
             |                         // Thread B incremented the map count
             |                         // in page_add_new_anon_rmap(), but
             |                         // now the page is no longer mapped
             |                         // by a PMD entry (-> inconsistency).
             |                     }
             |               }
             |
             v
    - Thread B is handling a page fault on virtual address "B(fault)" shown
      in the picture.

    ...
    do_page_fault
      __do_page_fault
        // Acquire the semaphore in shared mode.
        down_read_trylock(&mm->mmap_sem)
        ...
        handle_mm_fault
          if (pmd_none(*pmd) && transparent_hugepage_enabled(vma))
              // We get here due to the above assumption (PMD entry is zero).
              do_huge_pmd_anonymous_page
                alloc_hugepage_vma
                  // Allocate a new transparent huge page here.
                ...
                __do_huge_pmd_anonymous_page
                  ...
                  spin_lock(&mm->page_table_lock)
                  ...
                  page_add_new_anon_rmap
                    // Here we increment the page's map count (starts at -1).
                    atomic_set(&page->_mapcount, 0)
                  set_pmd_at
                    // Here we set the page's PMD entry which will be cleared
                    // when Thread A calls pmd_clear_bad().
                  ...
                  spin_unlock(&mm->page_table_lock)

    The mmap_sem does not prevent the race because both threads are acquiring
    it in shared mode (down_read).  Thread B holds the page_table_lock while
    the page's map count and PMD table entry are updated.  However, Thread A
    does not synchronize on that lock.

====== end quote =======

[akpm@linux-foundation.org: checkpatch fixes]
Reported-by: Ulrich Obergfell <uobergfe@redhat.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Jones <davej@redhat.com>
Acked-by: Larry Woodman <lwoodman@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: <stable@vger.kernel.org>		[2.6.38+]
Cc: Mark Salter <msalter@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-21 17:54:54 -07:00
Linus Torvalds 097d59106a vm: avoid using find_vma_prev() unnecessarily
Several users of "find_vma_prev()" were not in fact interested in the
previous vma if there was no primary vma to be found either.  And in
those cases, we're much better off just using the regular "find_vma()",
and then "prev" can be looked up by just checking vma->vm_prev.

The find_vma_prev() semantics are fairly subtle (see Mikulas' recent
commit 83cd904d271b: "mm: fix find_vma_prev"), and the whole "return
prev by reference" means that it generates worse code too.

Thus this "let's avoid using this inconvenient and clearly too subtle
interface when we don't really have to" patch.

Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-06 18:23:36 -08:00
Mel Gorman a6bc32b899 mm: compaction: introduce sync-light migration for use by compaction
This patch adds a lightweight sync migrate operation MIGRATE_SYNC_LIGHT
mode that avoids writing back pages to backing storage.  Async compaction
maps to MIGRATE_ASYNC while sync compaction maps to MIGRATE_SYNC_LIGHT.
For other migrate_pages users such as memory hotplug, MIGRATE_SYNC is
used.

This avoids sync compaction stalling for an excessive length of time,
particularly when copying files to a USB stick where there might be a
large number of dirty pages backed by a filesystem that does not support
->writepages.

[aarcange@redhat.com: This patch is heavily based on Andrea's work]
[akpm@linux-foundation.org: fix fs/nfs/write.c build]
[akpm@linux-foundation.org: fix fs/btrfs/disk-io.c build]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andy Isaacson <adi@hexapodia.org>
Cc: Nai Xia <nai.xia@gmail.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:09 -08:00
KOSAKI Motohiro fcfb4dcc96 mm/mempolicy.c: mpol_equal(): use bool
mpol_equal() logically returns a boolean.  Use a bool type to slightly
improve readability.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Stephen Wilson <wilsons@start.ca>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:45 -08:00
KOSAKI Motohiro e26a51148f mm/mempolicy.c: refix mbind_range() vma issue
commit 8aacc9f550 ("mm/mempolicy.c: fix pgoff in mbind vma merge") is the
slightly incorrect fix.

Why? Think following case.

1. map 4 pages of a file at offset 0

   [0123]

2. map 2 pages just after the first mapping of the same file but with
   page offset 2

   [0123][23]

3. mbind() 2 pages from the first mapping at offset 2.
   mbind_range() should treat new vma is,

   [0123][23]
     |23|
     mbind vma

   but it does

   [0123][23]
     |01|
     mbind vma

   Oops. then, it makes wrong vma merge and splitting ([01][0123] or similar).

This patch fixes it.

[testcase]
  test result - before the patch

	case4: 126: test failed. expect '2,4', actual '2,2,2'
       	case5: passed
	case6: passed
	case7: passed
	case8: passed
	case_n: 246: test failed. expect '4,2', actual '1,4'

	------------[ cut here ]------------
	kernel BUG at mm/filemap.c:135!
	invalid opcode: 0000 [#4] SMP DEBUG_PAGEALLOC

	(snip long bug on messages)

  test result - after the patch

	case4: passed
       	case5: passed
	case6: passed
	case7: passed
	case8: passed
	case_n: passed

  source:  mbind_vma_test.c
============================================================
 #include <numaif.h>
 #include <numa.h>
 #include <sys/mman.h>
 #include <stdio.h>
 #include <unistd.h>
 #include <stdlib.h>
 #include <string.h>

static unsigned long pagesize;
void* mmap_addr;
struct bitmask *nmask;
char buf[1024];
FILE *file;
char retbuf[10240] = "";
int mapped_fd;

char *rubysrc = "ruby -e '\
  pid = %d; \
  vstart = 0x%llx; \
  vend = 0x%llx; \
  s = `pmap -q #{pid}`; \
  rary = []; \
  s.each_line {|line|; \
    ary=line.split(\" \"); \
    addr = ary[0].to_i(16); \
    if(vstart <= addr && addr < vend) then \
      rary.push(ary[1].to_i()/4); \
    end; \
  }; \
  print rary.join(\",\"); \
'";

void init(void)
{
	void* addr;
	char buf[128];

	nmask = numa_allocate_nodemask();
	numa_bitmask_setbit(nmask, 0);

	pagesize = getpagesize();

	sprintf(buf, "%s", "mbind_vma_XXXXXX");
	mapped_fd = mkstemp(buf);
	if (mapped_fd == -1)
		perror("mkstemp "), exit(1);
	unlink(buf);

	if (lseek(mapped_fd, pagesize*8, SEEK_SET) < 0)
		perror("lseek "), exit(1);
	if (write(mapped_fd, "\0", 1) < 0)
		perror("write "), exit(1);

	addr = mmap(NULL, pagesize*8, PROT_NONE,
		    MAP_SHARED, mapped_fd, 0);
	if (addr == MAP_FAILED)
		perror("mmap "), exit(1);

	if (mprotect(addr+pagesize, pagesize*6, PROT_READ|PROT_WRITE) < 0)
		perror("mprotect "), exit(1);

	mmap_addr = addr + pagesize;

	/* make page populate */
	memset(mmap_addr, 0, pagesize*6);
}

void fin(void)
{
	void* addr = mmap_addr - pagesize;
	munmap(addr, pagesize*8);

	memset(buf, 0, sizeof(buf));
	memset(retbuf, 0, sizeof(retbuf));
}

void mem_bind(int index, int len)
{
	int err;

	err = mbind(mmap_addr+pagesize*index, pagesize*len,
		    MPOL_BIND, nmask->maskp, nmask->size, 0);
	if (err)
		perror("mbind "), exit(err);
}

void mem_interleave(int index, int len)
{
	int err;

	err = mbind(mmap_addr+pagesize*index, pagesize*len,
		    MPOL_INTERLEAVE, nmask->maskp, nmask->size, 0);
	if (err)
		perror("mbind "), exit(err);
}

void mem_unbind(int index, int len)
{
	int err;

	err = mbind(mmap_addr+pagesize*index, pagesize*len,
		    MPOL_DEFAULT, NULL, 0, 0);
	if (err)
		perror("mbind "), exit(err);
}

void Assert(char *expected, char *value, char *name, int line)
{
	if (strcmp(expected, value) == 0) {
		fprintf(stderr, "%s: passed\n", name);
		return;
	}
	else {
		fprintf(stderr, "%s: %d: test failed. expect '%s', actual '%s'\n",
			name, line,
			expected, value);
//		exit(1);
	}
}

/*
      AAAA
    PPPPPPNNNNNN
    might become
    PPNNNNNNNNNN
    case 4 below
*/
void case4(void)
{
	init();
	sprintf(buf, rubysrc, getpid(), mmap_addr, mmap_addr+pagesize*6);

	mem_bind(0, 4);
	mem_unbind(2, 2);

	file = popen(buf, "r");
	fread(retbuf, sizeof(retbuf), 1, file);
	Assert("2,4", retbuf, "case4", __LINE__);

	fin();
}

/*
       AAAA
 PPPPPPNNNNNN
 might become
 PPPPPPPPPPNN
 case 5 below
*/
void case5(void)
{
	init();
	sprintf(buf, rubysrc, getpid(), mmap_addr, mmap_addr+pagesize*6);

	mem_bind(0, 2);
	mem_bind(2, 2);

	file = popen(buf, "r");
	fread(retbuf, sizeof(retbuf), 1, file);
	Assert("4,2", retbuf, "case5", __LINE__);

	fin();
}

/*
	    AAAA
	PPPPNNNNXXXX
	might become
	PPPPPPPPPPPP 6
*/
void case6(void)
{
	init();
	sprintf(buf, rubysrc, getpid(), mmap_addr, mmap_addr+pagesize*6);

	mem_bind(0, 2);
	mem_bind(4, 2);
	mem_bind(2, 2);

	file = popen(buf, "r");
	fread(retbuf, sizeof(retbuf), 1, file);
	Assert("6", retbuf, "case6", __LINE__);

	fin();
}

/*
    AAAA
PPPPNNNNXXXX
might become
PPPPPPPPXXXX 7
*/
void case7(void)
{
	init();
	sprintf(buf, rubysrc, getpid(), mmap_addr, mmap_addr+pagesize*6);

	mem_bind(0, 2);
	mem_interleave(4, 2);
	mem_bind(2, 2);

	file = popen(buf, "r");
	fread(retbuf, sizeof(retbuf), 1, file);
	Assert("4,2", retbuf, "case7", __LINE__);

	fin();
}

/*
    AAAA
PPPPNNNNXXXX
might become
PPPPNNNNNNNN 8
*/
void case8(void)
{
	init();
	sprintf(buf, rubysrc, getpid(), mmap_addr, mmap_addr+pagesize*6);

	mem_bind(0, 2);
	mem_interleave(4, 2);
	mem_interleave(2, 2);

	file = popen(buf, "r");
	fread(retbuf, sizeof(retbuf), 1, file);
	Assert("2,4", retbuf, "case8", __LINE__);

	fin();
}

void case_n(void)
{
	init();
	sprintf(buf, rubysrc, getpid(), mmap_addr, mmap_addr+pagesize*6);

	/* make redundunt mappings [0][1234][34][7] */
	mmap(mmap_addr + pagesize*4, pagesize*2, PROT_READ|PROT_WRITE,
	     MAP_FIXED|MAP_SHARED, mapped_fd, pagesize*3);

	/* Expect to do nothing. */
	mem_unbind(2, 2);

	file = popen(buf, "r");
	fread(retbuf, sizeof(retbuf), 1, file);
	Assert("4,2", retbuf, "case_n", __LINE__);

	fin();
}

int main(int argc, char** argv)
{
	case4();
	case5();
	case6();
	case7();
	case8();
	case_n();

	return 0;
}
=============================================================

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Caspar Zhang <caspar@casparzhang.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: <stable@vger.kernel.org>		[3.1.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-12-29 16:31:57 -08:00
Linus Torvalds 32aaeffbd4 Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
  Revert "tracing: Include module.h in define_trace.h"
  irq: don't put module.h into irq.h for tracking irqgen modules.
  bluetooth: macroize two small inlines to avoid module.h
  ip_vs.h: fix implicit use of module_get/module_put from module.h
  nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
  include: replace linux/module.h with "struct module" wherever possible
  include: convert various register fcns to macros to avoid include chaining
  crypto.h: remove unused crypto_tfm_alg_modname() inline
  uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
  pm_runtime.h: explicitly requires notifier.h
  linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
  miscdevice.h: fix up implicit use of lists and types
  stop_machine.h: fix implicit use of smp.h for smp_processor_id
  of: fix implicit use of errno.h in include/linux/of.h
  of_platform.h: delete needless include <linux/module.h>
  acpi: remove module.h include from platform/aclinux.h
  miscdevice.h: delete unnecessary inclusion of module.h
  device_cgroup.h: delete needless include <linux/module.h>
  net: sch_generic remove redundant use of <linux/module.h>
  net: inet_timewait_sock doesnt need <linux/module.h>
  ...

Fix up trivial conflicts (other header files, and  removal of the ab3550 mfd driver) in
 - drivers/media/dvb/frontends/dibx000_common.c
 - drivers/media/video/{mt9m111.c,ov6650.c}
 - drivers/mfd/ab3550-core.c
 - include/linux/dmaengine.h
2011-11-06 19:44:47 -08:00
H Hartley Sweeten e754d79d35 mm/mempolicy.c: quiet sparse noise
Quiet the spares noise:

warning: symbol 'default_policy' was not declared. Should it be static?

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Stephen Wilson <wilsons@start.ca>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-10-31 17:30:50 -07:00
Paul Gortmaker b95f1b31b7 mm: Map most files to use export.h instead of module.h
The files changed within are only using the EXPORT_SYMBOL
macro variants.  They are not using core modular infrastructure
and hence don't need module.h but only the export.h header.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 09:20:12 -04:00
KAMEZAWA Hiroyuki 2bbff6c761 mm/mempolicy.c: make copy_from_user() provably correct
When compiling mm/mempolicy.c with struct user copy checks the following
warning is shown:

  In file included from arch/x86/include/asm/uaccess.h:572,
                   from include/linux/uaccess.h:5,
                   from include/linux/highmem.h:7,
                   from include/linux/pagemap.h:10,
                   from include/linux/mempolicy.h:70,
                   from mm/mempolicy.c:68:
  In function `copy_from_user',
      inlined from `compat_sys_get_mempolicy' at mm/mempolicy.c:1415:
  arch/x86/include/asm/uaccess_64.h:64: warning: call to `copy_from_user_overflow' declared with attribute warning: copy_from_user() buffer size is not provably correct
    LD      mm/built-in.o

Fix this by passing correct buffer size value.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-09-14 18:09:36 -07:00
Caspar Zhang 8aacc9f550 mm/mempolicy.c: fix pgoff in mbind vma merge
commit 9d8cebd4bc ("mm: fix mbind vma merge problem") didn't really
fix the mbind vma merge problem due to wrong pgoff value passing to
vma_merge(), which made vma_merge() always return NULL.

Before the patch applied, we are getting a result like:

  addr = 0x7fa58f00c000
  [snip]
  7fa58f00c000-7fa58f00d000 rw-p 00000000 00:00 0
  7fa58f00d000-7fa58f00e000 rw-p 00000000 00:00 0
  7fa58f00e000-7fa58f00f000 rw-p 00000000 00:00 0

here 7fa58f00c000->7fa58f00f000 we get 3 VMAs which are expected to be
merged described as described in commit 9d8cebd.

Re-testing the patched kernel with the reproducer provided in commit
9d8cebd, we get the correct result:

  addr = 0x7ffa5aaa2000
  [snip]
  7ffa5aaa2000-7ffa5aaa6000 rw-p 00000000 00:00 0
  7fffd556f000-7fffd5584000 rw-p 00000000 00:00 0                          [stack]

Signed-off-by: Caspar Zhang <caspar@casparzhang.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-09-14 18:09:36 -07:00
Michal Hocko 778d3b0ff0 cpusets: randomize node rotor used in cpuset_mem_spread_node()
[ This patch has already been accepted as commit 0ac0c0d0f8 but later
  reverted (commit 35926ff5fb) because it itroduced arch specific
  __node_random which was defined only for x86 code so it broke other
  archs.  This is a followup without any arch specific code.  Other than
  that there are no functional changes.]

Some workloads that create a large number of small files tend to assign
too many pages to node 0 (multi-node systems).  Part of the reason is
that the rotor (in cpuset_mem_spread_node()) used to assign nodes starts
at node 0 for newly created tasks.

This patch changes the rotor to be initialized to a random node number
of the cpuset.

[akpm@linux-foundation.org: fix layout]
[Lee.Schermerhorn@hp.com: Define stub numa_random() for !NUMA configuration]
[mhocko@suse.cz: Make it arch independent]
[akpm@linux-foundation.org: fix CONFIG_NUMA=y, MAX_NUMNODES>1 build]
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Paul Menage <menage@google.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Robin Holt <holt@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Paul Menage <menage@google.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Robin Holt <holt@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-26 16:49:43 -07:00
Stephen Wilson f69ff943df mm: proc: move show_numa_map() to fs/proc/task_mmu.c
Moving show_numa_map() from mempolicy.c to task_mmu.c solves several
issues.

  - Having the show() operation "miles away" from the corresponding
    seq_file iteration operations is a maintenance burden.

  - The need to export ad hoc info like struct proc_maps_private is
    eliminated.

  - The implementation of show_numa_map() can be improved in a simple
    manner by cooperating with the other seq_file operations (start,
    stop, etc) -- something that would be messy to do without this
    change.

Signed-off-by: Stephen Wilson <wilsons@start.ca>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:34 -07:00
Stephen Wilson 9840e37239 mm: remove check_huge_range()
This function has been superseded by gather_hugetbl_stats() and is no
longer needed.

Signed-off-by: Stephen Wilson <wilsons@start.ca>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:33 -07:00
Stephen Wilson 722e2ee09b mm: make gather_stats() type-safe and remove forward declaration
Improve the prototype of gather_stats() to take a struct numa_maps as
argument instead of a generic void *.  Update all callers to make the
required type explicit.

Since gather_stats() is not needed before its definition and is scheduled
to be moved out of mempolicy.c the declaration is removed as well.

Signed-off-by: Stephen Wilson <wilsons@start.ca>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:33 -07:00
Stephen Wilson b1f72d1857 mm: remove MPOL_MF_STATS
Mapping statistics in a NUMA environment is now computed using the generic
walk_page_range() logic.  Remove the old/equivalent functionality.

Signed-off-by: Stephen Wilson <wilsons@start.ca>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:33 -07:00
Stephen Wilson 29ea2f6982 mm: use walk_page_range() instead of custom page table walking code
Converting show_numa_map() to use the generic routine decouples the
function from mempolicy.c, allowing it to be moved out of the mm subsystem
and into fs/proc.

Also, include KSM pages in /proc/pid/numa_maps statistics.  The pagewalk
logic implemented by check_pte_range() failed to account for such pages as
they were not applicable to the page migration case.

Signed-off-by: Stephen Wilson <wilsons@start.ca>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:32 -07:00
Stephen Wilson d98f6cb67f mm: export get_vma_policy()
In commit 48fce3429d ("mempolicies: unexport get_vma_policy()")
get_vma_policy() was marked static as all clients were local to
mempolicy.c.

However, the decision to generate /proc/pid/numa_maps in the numa memory
policy code and outside the procfs subsystem introduces an artificial
interdependency between the two systems.  Exporting get_vma_policy() once
again is the first step to clean up this interdependency.

Signed-off-by: Stephen Wilson <wilsons@start.ca>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:32 -07:00
Namhyung Kim 7571966189 mempolicy: remove redundant check in __mpol_equal()
The 'flags' field is already checked, no need to do it again.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Cc: Bob Liu <lliubbo@gmail.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:04 -07:00
Linus Torvalds e16b396ce3 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (47 commits)
  doc: CONFIG_UNEVICTABLE_LRU doesn't exist anymore
  Update cpuset info & webiste for cgroups
  dcdbas: force SMI to happen when expected
  arch/arm/Kconfig: remove one to many l's in the word.
  asm-generic/user.h: Fix spelling in comment
  drm: fix printk typo 'sracth'
  Remove one to many n's in a word
  Documentation/filesystems/romfs.txt: fixing link to genromfs
  drivers:scsi Change printk typo initate -> initiate
  serial, pch uart: Remove duplicate inclusion of linux/pci.h header
  fs/eventpoll.c: fix spelling
  mm: Fix out-of-date comments which refers non-existent functions
  drm: Fix printk typo 'failled'
  coh901318.c: Change initate to initiate.
  mbox-db5500.c Change initate to initiate.
  edac: correct i82975x error-info reported
  edac: correct i82975x mci initialisation
  edac: correct commented info
  fs: update comments to point correct document
  target: remove duplicate include of target/target_core_device.h from drivers/target/target_core_hba.c
  ...

Trivial conflict in fs/eventpoll.c (spelling vs addition)
2011-03-18 10:37:40 -07:00
Andi Kleen 5c4b4be3b6 mm: use correct numa policy node for transparent hugepages
Pass down the correct node for a transparent hugepage allocation.  Most
callers continue to use the current node, however the hugepaged daemon
now uses the previous node of the first to be collapsed page instead.
This ensures that khugepaged does not mess up local memory for an
existing process which uses local policy.

The choice of node is somewhat primitive currently: it just uses the
node of the first page in the pmd range.  An alternative would be to
look at multiple pages and use the most popular node.  I used the
simplest variant for now which should work well enough for the case of
all pages being on the same node.

[akpm@linux-foundation.org: coding-style fixes]
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-04 17:53:39 -08:00
Andi Kleen 2f5f9486f8 mm: change alloc_pages_vma to pass down the policy node for local policy
Currently alloc_pages_vma() always uses the local node as policy node for
the LOCAL policy.  Pass this node down as an argument instead.

No behaviour change from this patch, but will be needed for followons.

Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-04 17:53:39 -08:00
Justin P. Mattock ae0e47f02a Remove one to many n's in a word
Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-03-01 15:47:58 +01:00
Andi Kleen 8eac563c1c thp: fix interleaving for transparent hugepages
The THP code didn't pass the correct interleaving shift to the memory
policy code.  Fix this here by adjusting for the order.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-25 15:07:37 -08:00
Andrea Arcangeli 0bbbc0b33d thp: add numa awareness to hugepage allocations
It's mostly a matter of replacing alloc_pages with alloc_pages_vma after
introducing alloc_pages_vma.  khugepaged needs special handling as the
allocation has to happen inside collapse_huge_page where the vma is known
and an error has to be returned to the outer loop to sleep
alloc_sleep_millisecs in case of failure.  But it retains the more
efficient logic of handling allocation failures in khugepaged in case of
CONFIG_NUMA=n.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 17:32:45 -08:00
Andrea Arcangeli bae9c19bf1 thp: split_huge_page_mm/vma
split_huge_page_pmd compat code.  Each one of those would need to be
expanded to hundred of lines of complex code without a fully reliable
split_huge_page_pmd design.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 17:32:41 -08:00
KOSAKI Motohiro 1e50df39f6 mempolicy: remove tasklist_lock from migrate_pages
Today, tasklist_lock in migrate_pages doesn't protect anything.
rcu_read_lock() provide enough protection from pid hash walk.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 17:32:36 -08:00
Mel Gorman 7f0f24967b mm: migration: cleanup migrate_pages API by matching types for offlining and sync
With the introduction of the boolean sync parameter, the API looks a
little inconsistent as offlining is still an int.  Convert offlining to a
bool for the sake of being tidy.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 17:32:34 -08:00
Mel Gorman 77f1fe6b08 mm: migration: allow migration to operate asynchronously and avoid synchronous compaction in the faster path
Migration synchronously waits for writeback if the initial passes fails.
Callers of memory compaction do not necessarily want this behaviour if the
caller is latency sensitive or expects that synchronous migration is not
going to have a significantly better success rate.

This patch adds a sync parameter to migrate_pages() allowing the caller to
indicate if wait_on_page_writeback() is allowed within migration or not.
For reclaim/compaction, try_to_compact_pages() is first called
asynchronously, direct reclaim runs and then try_to_compact_pages() is
called synchronously as there is a greater expectation that it'll succeed.

[akpm@linux-foundation.org: build/merge fix]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 17:32:34 -08:00
Zeng Zhaoming 55cfaa3cbd mm/mempolicy.c: add rcu read lock to protect pid structure
find_task_by_vpid() should be protected by rcu_read_lock(), to prevent
free_pid() reclaiming pid.

Signed-off-by: Zeng Zhaoming <zengzm.kernel@gmail.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-12-02 14:51:14 -08:00
Eric Dumazet 800416f799 numa: fix slab_node(MPOL_BIND)
When a node contains only HighMem memory, slab_node(MPOL_BIND)
dereferences a NULL pointer.

[ This code seems to go back all the way to commit 19770b32609b: "mm:
  filter based on a nodemask as well as a gfp_mask".  Which was back in
  April 2008, and it got merged into 2.6.26.  - Linus ]

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-28 10:04:30 -07:00
Vasiliy Kulikov 0def08e3ac mm/mempolicy.c: check return code of check_range
Function check_range may return ERR_PTR(...). Check for it.

Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:06 -07:00
Minchan Kim cf608ac19c mm: compaction: fix COMPACTPAGEFAILED counting
Presently update_nr_listpages() doesn't have a role.  That's because lists
passed is always empty just after calling migrate_pages.  The
migrate_pages cleans up page list which have failed to migrate before
returning by aaa994b3.

 [PATCH] page migration: handle freeing of pages in migrate_pages()

 Do not leave pages on the lists passed to migrate_pages().  Seems that we will
 not need any postprocessing of pages.  This will simplify the handling of
 pages by the callers of migrate_pages().

At that time, we thought we don't need any postprocessing of pages.  But
the situation is changed.  The compaction need to know the number of
failed to migrate for COMPACTPAGEFAILED stat

This patch makes new rule for caller of migrate_pages to call
putback_lru_pages.  So caller need to clean up the lists so it has a
chance to postprocess the pages.  [suggested by Christoph Lameter]

Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andi Kleen <andi@firstfloor.org>
Reviewed-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:06 -07:00
KOSAKI Motohiro 596d7cfa2b mempolicy: reduce stack size of migrate_pages()
migrate_pages() is using >500 bytes stack. Reduce it.

   mm/mempolicy.c: In function 'sys_migrate_pages':
   mm/mempolicy.c:1344: warning: the frame size of 528 bytes is larger than 512 bytes

[akpm@linux-foundation.org: don't play with a might-be-NULL pointer]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-09 20:44:58 -07:00
David Rientjes 6f48d0ebd9 oom: select task from tasklist for mempolicy ooms
The oom killer presently kills current whenever there is no more memory
free or reclaimable on its mempolicy's nodes.  There is no guarantee that
current is a memory-hogging task or that killing it will free any
substantial amount of memory, however.

In such situations, it is better to scan the tasklist for nodes that are
allowed to allocate on current's set of nodes and kill the task with the
highest badness() score.  This ensures that the most memory-hogging task,
or the one configured by the user with /proc/pid/oom_adj, is always
selected in such scenarios.

Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-09 20:44:56 -07:00
Lee Schermerhorn 5c0c165490 mempolicy: fix dangling reference to tmpfs superblock mpol
My patch to "Factor out duplicate put/frees in mpol_shared_policy_init()
to a common return path"; and Dan Carpenter's fix thereto both left a
dangling reference to the incoming tmpfs superblock mempolicy structure.
A similar leak was introduced earlier when the nodemask was moved offstack
to the scratch area despite the note in the comment block regarding the
incoming ref.

Move the remaining 'put of the incoming "mpol" to the common exit path to
drop the reference.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Dan Carpenter <error27@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-06-29 15:29:31 -07:00
Dan Carpenter 0cae3457b1 mempolicy: ERR_PTR dereference in mpol_shared_policy_init()
The original code called mpol_put(new) while "new" was an ERR_PTR.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-26 08:19:23 -07:00
Greg Thelen 6ec3a12712 mm: consider the entire user address space during node migration
Use mm->task_size instead of TASK_SIZE to ensure that the entire user
address space is migrated.  mm->task_size is independent of the calling
task context.  TASK SIZE may be dependant on the address space size of the
calling process.  Usage of TASK_SIZE can lead to partial address space
migration if the calling process was 32 bit and the migrating process was
64 bit.

Here is the test script used on 64 system with a 32 bit echo process:

  mount -t cgroup none /cgroup -o cpuset
  cd /cgroup

  mkdir 0
  echo 1 > 0/cpuset.cpus
  echo 0 > 0/cpuset.mems
  echo 1 > 0/cpuset.memory_migrate

  mkdir 1
  echo 1 > 1/cpuset.cpus
  echo 1 > 1/cpuset.mems
  echo 1 > 1/cpuset.memory_migrate

  echo $$ > 0/tasks
  64_bit_process &
  pid=$!

  echo $pid > 1/tasks   # This does not migrate all process pages without
                        # this patch.  If 64 bit echo is used or this patch is
                        # applied, then the full address space of $pid is
                        # migrated.

To check memory migration, I watched:
  grep MemUsed /sys/devices/system/node/node*/meminfo

Signed-off-by: Greg Thelen <gthelen@google.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:07:00 -07:00
Miao Xie c0ff7453bb cpuset,mm: fix no node to alloc memory when changing cpuset's mems
Before applying this patch, cpuset updates task->mems_allowed and
mempolicy by setting all new bits in the nodemask first, and clearing all
old unallowed bits later.  But in the way, the allocator may find that
there is no node to alloc memory.

The reason is that cpuset rebinds the task's mempolicy, it cleans the
nodes which the allocater can alloc pages on, for example:

(mpol: mempolicy)
	task1			task1's mpol	task2
	alloc page		1
	  alloc on node0? NO	1
				1		change mems from 1 to 0
				1		rebind task1's mpol
				0-1		  set new bits
				0	  	  clear disallowed bits
	  alloc on node1? NO	0
	  ...
	can't alloc page
	  goto oom

This patch fixes this problem by expanding the nodes range first(set newly
allowed bits) and shrink it lazily(clear newly disallowed bits).  So we
use a variable to tell the write-side task that read-side task is reading
nodemask, and the write-side task clears newly disallowed nodes after
read-side task ends the current memory allocation.

[akpm@linux-foundation.org: fix spello]
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Paul Menage <menage@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:06:57 -07:00
Miao Xie 708c1bbc9d mempolicy: restructure rebinding-mempolicy functions
Nick Piggin reported that the allocator may see an empty nodemask when
changing cpuset's mems[1].  It happens only on the kernel that do not do
atomic nodemask_t stores.  (MAX_NUMNODES > BITS_PER_LONG)

But I found that there is also a problem on the kernel that can do atomic
nodemask_t stores.  The problem is that the allocator can't find a node to
alloc page when changing cpuset's mems though there is a lot of free
memory.  The reason is like this:

(mpol: mempolicy)
	task1			task1's mpol	task2
	alloc page		1
	  alloc on node0? NO	1
				1		change mems from 1 to 0
				1		rebind task1's mpol
				0-1		  set new bits
				0	  	  clear disallowed bits
	  alloc on node1? NO	0
	  ...
	can't alloc page
	  goto oom

I can use the attached program reproduce it by the following step:

# mkdir /dev/cpuset
# mount -t cpuset cpuset /dev/cpuset
# mkdir /dev/cpuset/1
# echo `cat /dev/cpuset/cpus` > /dev/cpuset/1/cpus
# echo `cat /dev/cpuset/mems` > /dev/cpuset/1/mems
# echo $$ > /dev/cpuset/1/tasks
# numactl --membind=`cat /dev/cpuset/mems` ./cpuset_mem_hog <nr_tasks> &
   <nr_tasks> = max(nr_cpus - 1, 1)
# killall -s SIGUSR1 cpuset_mem_hog
# ./change_mems.sh

several hours later, oom will happen though there is a lot of free memory.

This patchset fixes this problem by expanding the nodes range first(set
newly allowed bits) and shrink it lazily(clear newly disallowed bits).  So
we use a variable to tell the write-side task that read-side task is
reading nodemask, and the write-side task clears newly disallowed nodes
after read-side task ends the current memory allocation.

This patch:

In order to fix no node to alloc memory, when we want to update mempolicy
and mems_allowed, we expand the set of nodes first (set all the newly
nodes) and shrink the set of nodes lazily(clean disallowed nodes), But the
mempolicy's rebind functions may breaks the expanding.

So we restructure the mempolicy's rebind functions and split the rebind
work to two steps, just like the update of cpuset's mems: The 1st step:
expand the set of the mempolicy's nodes.  The 2nd step: shrink the set of
the mempolicy's nodes.  It is used when there is no real lock to protect
the mempolicy in the read-side.  Otherwise we can do rebind work at once.

In order to implement it, we define

	enum mpol_rebind_step {
		MPOL_REBIND_ONCE,
		MPOL_REBIND_STEP1,
		MPOL_REBIND_STEP2,
		MPOL_REBIND_NSTEP,
	};

If the mempolicy needn't be updated by two steps, we can pass
MPOL_REBIND_ONCE to the rebind functions.  Or we can pass
MPOL_REBIND_STEP1 to do the first step of the rebind work and pass
MPOL_REBIND_STEP2 to do the second step work.

Besides that, it maybe long time between these two step and we have to
release the lock that protects mempolicy and mems_allowed.  If we hold the
lock once again, we must check whether the current mempolicy is under the
rebinding (the first step has been done) or not, because the task may
alloc a new mempolicy when we don't hold the lock.  So we defined the
following flag to identify it:

#define MPOL_F_REBINDING (1 << 2)

The new functions will be used in the next patch.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Paul Menage <menage@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:06:57 -07:00
Lee Schermerhorn 15d77835ac mempolicy: factor mpol_shared_policy_init() return paths
Factor out duplicate put/frees in mpol_shared_policy_init() to a common
return path.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:06:57 -07:00
Lee Schermerhorn 345ace9c79 mempolicy: rename policy_types and cleanup initialization
Rename 'policy_types[]' to 'policy_modes[]' to better match the array
contents.

Use designated intializer syntax for policy_modes[].

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:06:57 -07:00
Lee Schermerhorn b4652e8429 mempolicy: lose unnecessary loop variable in mpol_parse_str()
We don't really need the extra variable 'i' in mpol_parse_str().  The only
use is as the the loop variable.  Then, it's assigned to 'mode'.  Just use
mode, and loose the 'uninitialized_var()' macro.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:06:57 -07:00
Lee Schermerhorn e17f74af35 mempolicy: don't call mpol_set_nodemask() when no_context
No need to call mpol_set_nodemask() when we have no context for the
mempolicy.  This can occur when we're parsing a tmpfs 'mpol' mount option.
 Just save the raw nodemask in the mempolicy's w.user_nodemask member for
use when a tmpfs/shmem file is created.  mpol_shared_policy_init() will
"contextualize" the policy for the new file based on the creating task's
context.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:06:57 -07:00
Bob Liu 1980050250 mempolicy: remove redundant check
Lee's patch "mempolicy: use MPOL_PREFERRED for system-wide default policy"
has made the MPOL_DEFAULT only used in the memory policy APIs.  So, no
need to check in __mpol_equal also.  Also get rid of mpol_match_intent()
and move its logic directly into __mpol_equal().

Signed-off-by: Bob Liu <lliubbo@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:06:57 -07:00
Bob Liu 6eb27e1fdf mempolicy: remove case MPOL_INTERLEAVE from policy_zonelist()
In policy_zonelist() mode MPOL_INTERLEAVE shouldn't happen, so fall
through to BUG() instead of break to return.  I also fixed the comment.

Signed-off-by: Bob Liu <lliubbo@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:06:57 -07:00
Bob Liu 6d556294d5 mempolicy: remove redundant code
1.  In funtion is_valid_nodemask(), varibable k will be inited to 0 in
   the following loop, needn't init to policy_zone anymore.

2. (MPOL_F_STATIC_NODES | MPOL_F_RELATIVE_NODES) has already defined
   to MPOL_MODE_FLAGS in mempolicy.h.

Signed-off-by: Bob Liu <lliubbo@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:06:57 -07:00
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
Lee Schermerhorn c6b6ef8bb0 mempolicy: fix get_mempolicy() for relative and static nodes
Discovered while testing other mempolicy changes:

get_mempolicy() does not handle static/relative mode flags correctly.
Return the value that the user specified so that it can be restored
via set_mempolicy() if desired.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-24 16:31:22 -07:00
KOSAKI Motohiro 926f2ae04f tmpfs: cleanup mpol_parse_str()
mpol_parse_str() made lots 'err' variable related bug.  Because it is ugly
and reviewing unfriendly.

This patch simplifies it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Acked-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-24 16:31:21 -07:00
KOSAKI Motohiro 12821f5fb9 tmpfs: handle MPOL_LOCAL mount option properly
commit 71fe804b6d (mempolicy: use struct mempolicy pointer in
shmem_sb_info) added mpol=local mount option.  but its feature is broken
since it was born.  because such code always return 1 (i.e.  mount
failure).

This patch fixes it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Acked-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-24 16:31:21 -07:00
KOSAKI Motohiro d69b2e63e9 tmpfs: mpol=bind:0 don't cause mount error.
Currently, following mount operation cause mount error.

% mount -t tmpfs -ompol=bind:0 none /tmp

Because commit 71fe804b6d (mempolicy: use struct mempolicy pointer in
shmem_sb_info) corrupted MPOL_BIND parse code.

This patch restore the needed one.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Acked-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-24 16:31:21 -07:00
Ravikiran G Thirumalai 413b43deab tmpfs: fix oops on mounts with mpol=default
Fix an 'oops' when a tmpfs mount point is mounted with the mpol=default
mempolicy.

Upon remounting a tmpfs mount point with 'mpol=default' option, the mount
code crashed with a null pointer dereference.  The initial problem report
was on 2.6.27, but the problem exists in mainline 2.6.34-rc as well.  On
examining the code, we see that mpol_new returns NULL if default mempolicy
was requested.  This 'NULL' mempolicy is accessed to store the node mask
resulting in oops.

The following patch fixes it.

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Acked-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-24 16:31:21 -07:00
Linus Torvalds 4e3eaddd14 Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  locking: Make sparse work with inline spinlocks and rwlocks
  x86/mce: Fix RCU lockdep splats
  rcu: Increase RCU CPU stall timeouts if PROVE_RCU
  ftrace: Replace read_barrier_depends() with rcu_dereference_raw()
  rcu: Suppress RCU lockdep warnings during early boot
  rcu, ftrace: Fix RCU lockdep splat in ftrace_perf_buf_prepare()
  rcu: Suppress __mpol_dup() false positive from RCU lockdep
  rcu: Make rcu_read_lock_sched_held() handle !PREEMPT
  rcu: Add control variables to lockdep_rcu_dereference() diagnostics
  rcu, cgroup: Relax the check in task_subsys_state() as early boot is now handled by lockdep-RCU
  rcu: Use wrapper function instead of exporting tasklist_lock
  sched, rcu: Fix rcu_dereference() for RCU-lockdep
  rcu: Make task_subsys_state() RCU-lockdep checks handle boot-time use
  rcu: Fix holdoff for accelerated GPs for last non-dynticked CPU
  x86/gart: Unexport gart_iommu_aperture

Fix trivial conflicts in kernel/trace/ftrace.c
2010-03-13 14:43:01 -08:00
KOSAKI Motohiro da0aa13894 mm/mempolicy.c: fix indentation of the comments of do_migrate_pages
Currently, do_migrate_pages() have very long comment and this is not
indent properly.  I often misunderstand it is function starting commnents
and confused it.

this patch fixes it.

note: this patch doesn't break 80 column rule. I guess original
      author intended this indentaion, but an accident corrupted it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 11:26:25 -08:00
KOSAKI Motohiro 9d8cebd4bc mm: fix mbind vma merge problem
Strangely, current mbind() doesn't merge vma with neighbor vma although it's possible.
Unfortunately, many vma can reduce performance...

This patch fixes it.

    reproduced program
    ----------------------------------------------------------------
     #include <numaif.h>
     #include <numa.h>
     #include <sys/mman.h>
     #include <stdio.h>
     #include <unistd.h>
     #include <stdlib.h>
     #include <string.h>

    static unsigned long pagesize;

    int main(int argc, char** argv)
    {
    	void* addr;
    	int ch;
    	int node;
    	struct bitmask *nmask = numa_allocate_nodemask();
    	int err;
    	int node_set = 0;
    	char buf[128];

    	while ((ch = getopt(argc, argv, "n:")) != -1){
    		switch (ch){
    		case 'n':
    			node = strtol(optarg, NULL, 0);
    			numa_bitmask_setbit(nmask, node);
    			node_set = 1;
    			break;
    		default:
    			;
    		}
    	}
    	argc -= optind;
    	argv += optind;

    	if (!node_set)
    		numa_bitmask_setbit(nmask, 0);

    	pagesize = getpagesize();

    	addr = mmap(NULL, pagesize*3, PROT_READ|PROT_WRITE,
    		    MAP_ANON|MAP_PRIVATE, 0, 0);
    	if (addr == MAP_FAILED)
    		perror("mmap "), exit(1);

    	fprintf(stderr, "pid = %d \n" "addr = %p\n", getpid(), addr);

    	/* make page populate */
    	memset(addr, 0, pagesize*3);

    	/* first mbind */
    	err = mbind(addr+pagesize, pagesize, MPOL_BIND, nmask->maskp,
    		    nmask->size, MPOL_MF_MOVE_ALL);
    	if (err)
    		error("mbind1 ");

    	/* second mbind */
    	err = mbind(addr, pagesize*3, MPOL_DEFAULT, NULL, 0, 0);
    	if (err)
    		error("mbind2 ");

    	sprintf(buf, "cat /proc/%d/maps", getpid());
    	system(buf);

    	return 0;
    }
    ----------------------------------------------------------------

result without this patch

	addr = 0x7fe26ef09000
	[snip]
	7fe26ef09000-7fe26ef0a000 rw-p 00000000 00:00 0
	7fe26ef0a000-7fe26ef0b000 rw-p 00000000 00:00 0
	7fe26ef0b000-7fe26ef0c000 rw-p 00000000 00:00 0
	7fe26ef0c000-7fe26ef0d000 rw-p 00000000 00:00 0

	=> 0x7fe26ef09000-0x7fe26ef0c000 have three vmas.

result with this patch

	addr = 0x7fc9ebc76000
	[snip]
	7fc9ebc76000-7fc9ebc7a000 rw-p 00000000 00:00 0
	7fffbe690000-7fffbe6a5000 rw-p 00000000	00:00 0	[stack]

	=> 0x7fc9ebc76000-0x7fc9ebc7a000 have only one vma.

[minchan.kim@gmail.com: fix file offset passed to vma_merge()]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 11:26:25 -08:00
Paul E. McKenney 99ee4ca746 rcu: Suppress __mpol_dup() false positive from RCU lockdep
Common code is used during task creation and after the task has
started running.  RCU protection is not needed during task
creation because no other CPU has access to the
under-construction task.  Provide the RCU protection anyway to
suppress the false positive, as there does not appear to be a
good way for the common code to recognize that the task is only
accessible to the CPU creating it.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1267667418-32233-2-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-04 12:07:34 +01:00
Hugh Dickins 62b61f611e ksm: memory hotremove migration only
The previous patch enables page migration of ksm pages, but that soon gets
into trouble: not surprising, since we're using the ksm page lock to lock
operations on its stable_node, but page migration switches the page whose
lock is to be used for that.  Another layer of locking would fix it, but
do we need that yet?

Do we actually need page migration of ksm pages?  Yes, memory hotremove
needs to offline sections of memory: and since we stopped allocating ksm
pages with GFP_HIGHUSER, they will tend to be GFP_HIGHUSER_MOVABLE
candidates for migration.

But KSM is currently unconscious of NUMA issues, happily merging pages
from different NUMA nodes: at present the rule must be, not to use
MADV_MERGEABLE where you care about NUMA.  So no, NUMA page migration of
ksm pages does not make sense yet.

So, to complete support for ksm swapping we need to make hotremove safe.
ksm_memory_callback() take ksm_thread_mutex when MEM_GOING_OFFLINE and
release it when MEM_OFFLINE or MEM_CANCEL_OFFLINE.  But if mapped pages
are freed before migration reaches them, stable_nodes may be left still
pointing to struct pages which have been removed from the system: the
stable_node needs to identify a page by pfn rather than page pointer, then
it can safely prune them when MEM_OFFLINE.

And make NUMA migration skip PageKsm pages where it skips PageReserved.
But it's only when we reach unmap_and_move() that the page lock is taken
and we can be sure that raised pagecount has prevented a PageAnon from
being upgraded: so add offlining arg to migrate_pages(), to migrate ksm
page when offlining (has sufficient locking) but reject it otherwise.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Chris Wright <chrisw@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 08:53:20 -08:00
Lee Schermerhorn 06808b0827 hugetlb: derive huge pages nodes allowed from task mempolicy
This patch derives a "nodes_allowed" node mask from the numa mempolicy of
the task modifying the number of persistent huge pages to control the
allocation, freeing and adjusting of surplus huge pages when the pool page
count is modified via the new sysctl or sysfs attribute
"nr_hugepages_mempolicy".  The nodes_allowed mask is derived as follows:

* For "default" [NULL] task mempolicy, a NULL nodemask_t pointer
  is produced.  This will cause the hugetlb subsystem to use
  node_online_map as the "nodes_allowed".  This preserves the
  behavior before this patch.
* For "preferred" mempolicy, including explicit local allocation,
  a nodemask with the single preferred node will be produced.
  "local" policy will NOT track any internode migrations of the
  task adjusting nr_hugepages.
* For "bind" and "interleave" policy, the mempolicy's nodemask
  will be used.
* Other than to inform the construction of the nodes_allowed node
  mask, the actual mempolicy mode is ignored.  That is, all modes
  behave like interleave over the resulting nodes_allowed mask
  with no "fallback".

See the updated documentation [next patch] for more information
about the implications of this patch.

Examples:

Starting with:

	Node 0 HugePages_Total:     0
	Node 1 HugePages_Total:     0
	Node 2 HugePages_Total:     0
	Node 3 HugePages_Total:     0

Default behavior [with or without this patch] balances persistent
hugepage allocation across nodes [with sufficient contiguous memory]:

	sysctl vm.nr_hugepages[_mempolicy]=32

yields:

	Node 0 HugePages_Total:     8
	Node 1 HugePages_Total:     8
	Node 2 HugePages_Total:     8
	Node 3 HugePages_Total:     8

Of course, we only have nr_hugepages_mempolicy with the patch,
but with default mempolicy, nr_hugepages_mempolicy behaves the
same as nr_hugepages.

Applying mempolicy--e.g., with numactl [using '-m' a.k.a.
'--membind' because it allows multiple nodes to be specified
and it's easy to type]--we can allocate huge pages on
individual nodes or sets of nodes.  So, starting from the
condition above, with 8 huge pages per node, add 8 more to
node 2 using:

	numactl -m 2 sysctl vm.nr_hugepages_mempolicy=40

This yields:

	Node 0 HugePages_Total:     8
	Node 1 HugePages_Total:     8
	Node 2 HugePages_Total:    16
	Node 3 HugePages_Total:     8

The incremental 8 huge pages were restricted to node 2 by the
specified mempolicy.

Similarly, we can use mempolicy to free persistent huge pages
from specified nodes:

	numactl -m 0,1 sysctl vm.nr_hugepages_mempolicy=32

yields:

	Node 0 HugePages_Total:     4
	Node 1 HugePages_Total:     4
	Node 2 HugePages_Total:    16
	Node 3 HugePages_Total:     8

The 8 huge pages freed were balanced over nodes 0 and 1.

[rientjes@google.com: accomodate reworked NODEMASK_ALLOC]
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Andi Kleen <andi@firstfloor.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Nishanth Aravamudan <nacc@us.ibm.com>
Cc: Adam Litke <agl@us.ibm.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Eric Whitney <eric.whitney@hp.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 08:53:12 -08:00
KOSAKI Motohiro 6d9c285a63 mm: move inc_zone_page_state(NR_ISOLATED) to just isolated place
Christoph pointed out inc_zone_page_state(NR_ISOLATED) should be placed
in right after isolate_page().

This patch does it.

Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 08:53:12 -08:00
KOSAKI Motohiro b05ca7385a do_mbind(): fix memory leak
If migrate_prep is failed, new variable is leaked.  This patch fixes it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-29 07:39:29 -07:00
KOSAKI Motohiro ab8a3e14e6 mbind(): fix leak of never putback pages
If mbind() receives an invalid address, do_mbind leaks a page.  The
following test program detects this leak.

This patch fixes it.

migrate_efault.c
=======================================
 #include <numaif.h>
 #include <numa.h>
 #include <sys/mman.h>
 #include <stdio.h>
 #include <unistd.h>
 #include <stdlib.h>
 #include <string.h>

static unsigned long pagesize;

static void* make_hole_mapping(void)
{

	void* addr;

	addr = mmap(NULL, pagesize*3, PROT_READ|PROT_WRITE,
		    MAP_ANON|MAP_PRIVATE, 0, 0);
	if (addr == MAP_FAILED)
		return NULL;

	/* make page populate */
	memset(addr, 0, pagesize*3);

	/* make memory hole */
	munmap(addr+pagesize, pagesize);

	return addr;
}

int main(int argc, char** argv)
{
	void* addr;
	int ch;
	int node;
	struct bitmask *nmask = numa_allocate_nodemask();
	int err;
	int node_set = 0;

	while ((ch = getopt(argc, argv, "n:")) != -1){
		switch (ch){
		case 'n':
			node = strtol(optarg, NULL, 0);
			numa_bitmask_setbit(nmask, node);
			node_set = 1;
			break;
		default:
			;
		}
	}
	argc -= optind;
	argv += optind;

	if (!node_set)
		numa_bitmask_setbit(nmask, 0);

	pagesize = getpagesize();

	addr = make_hole_mapping();

	err = mbind(addr, pagesize*3, MPOL_BIND, nmask->maskp, nmask->size, MPOL_MF_MOVE_ALL);
	if (err)
		perror("mbind ");

	return 0;
}
=======================================

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-29 07:39:29 -07:00
KAMEZAWA Hiroyuki 4bfc44958e mm: make set_mempolicy(MPOL_INTERLEAV) N_HIGH_MEMORY aware
At first, init_task's mems_allowed is initialized as this.
 init_task->mems_allowed == node_state[N_POSSIBLE]

And cpuset's top_cpuset mask is initialized as this
 top_cpuset->mems_allowed = node_state[N_HIGH_MEMORY]

Before 2.6.29:
policy's mems_allowed is initialized as this.

  1. update tasks->mems_allowed by its cpuset->mems_allowed.
  2. policy->mems_allowed = nodes_and(tasks->mems_allowed, user's mask)

Updating task's mems_allowed in reference to top_cpuset's one.
cpuset's mems_allowed is aware of N_HIGH_MEMORY, always.

In 2.6.30: After commit 58568d2a82
("cpuset,mm: update tasks' mems_allowed in time"), policy's mems_allowed
is initialized as this.

  1. policy->mems_allowd = nodes_and(task->mems_allowed, user's mask)

Here, if task is in top_cpuset, task->mems_allowed is not updated from
init's one.  Assume user excutes command as #numactrl --interleave=all
,....

  policy->mems_allowd = nodes_and(N_POSSIBLE, ALL_SET_MASK)

Then, policy's mems_allowd can includes a possible node, which has no pgdat.

MPOL's INTERLEAVE just scans nodemask of task->mems_allowd and access this
directly.

  NODE_DATA(nid)->zonelist even if NODE_DATA(nid)==NULL

Then, what's we need is making policy->mems_allowed be aware of
N_HIGH_MEMORY.  This patch does that.  But to do so, extra nodemask will
be on statck.  Because I know cpumask has a new interface of
CPUMASK_ALLOC(), I added it to node.

This patch stands on old behavior.  But I feel this fix itself is just a
Band-Aid.  But to do fundametal fix, we have to take care of memory
hotplug and it takes time.  (task->mems_allowd should be N_HIGH_MEMORY, I
think.)

mpol_set_nodemask() should be aware of N_HIGH_MEMORY and policy's nodemask
should be includes only online nodes.

In old behavior, this is guaranteed by frequent reference to cpuset's
code.  Now, most of them are removed and mempolicy has to check it by
itself.

To do check, a few nodemask_t will be used for calculating nodemask.  But,
size of nodemask_t can be big and it's not good to allocate them on stack.

Now, cpumask_t has CPUMASK_ALLOC/FREE an easy code for get scratch area.
NODEMASK_ALLOC/FREE shoudl be there.

[akpm@linux-foundation.org: cleanups & tweaks]
Tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Paul Menage <menage@google.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: David Rientjes <rientjes@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-08-07 10:39:55 -07:00
Mel Gorman 6484eb3e2a page allocator: do not check NUMA node ID when the caller knows the node is valid
Callers of alloc_pages_node() can optionally specify -1 as a node to mean
"allocate from the current node".  However, a number of the callers in
fast paths know for a fact their node is valid.  To avoid a comparison and
branch, this patch adds alloc_pages_exact_node() that only checks the nid
with VM_BUG_ON().  Callers that know their node is valid are then
converted.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Paul Mundt <lethal@linux-sh.org>	[for the SLOB NUMA bits]
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16 19:47:32 -07:00
Miao Xie 58568d2a82 cpuset,mm: update tasks' mems_allowed in time
Fix allocating page cache/slab object on the unallowed node when memory
spread is set by updating tasks' mems_allowed after its cpuset's mems is
changed.

In order to update tasks' mems_allowed in time, we must modify the code of
memory policy.  Because the memory policy is applied in the process's
context originally.  After applying this patch, one task directly
manipulates anothers mems_allowed, and we use alloc_lock in the
task_struct to protect mems_allowed and memory policy of the task.

But in the fast path, we didn't use lock to protect them, because adding a
lock may lead to performance regression.  But if we don't add a lock,the
task might see no nodes when changing cpuset's mems_allowed to some
non-overlapping set.  In order to avoid it, we set all new allowed nodes,
then clear newly disallowed ones.

[lee.schermerhorn@hp.com:
  The rework of mpol_new() to extract the adjusting of the node mask to
  apply cpuset and mpol flags "context" breaks set_mempolicy() and mbind()
  with MPOL_PREFERRED and a NULL nodemask--i.e., explicit local
  allocation.  Fix this by adding the check for MPOL_PREFERRED and empty
  node mask to mpol_new_mpolicy().

  Remove the now unneeded 'nodes = NULL' from mpol_new().

  Note that mpol_new_mempolicy() is always called with a non-NULL
  'nodes' parameter now that it has been removed from mpol_new().
  Therefore, we don't need to test nodes for NULL before testing it for
  'empty'.  However, just to be extra paranoid, add a VM_BUG_ON() to
  verify this assumption.]
[lee.schermerhorn@hp.com:

  I don't think the function name 'mpol_new_mempolicy' is descriptive
  enough to differentiate it from mpol_new().

  This function applies cpuset set context, usually constraining nodes
  to those allowed by the cpuset.  However, when the 'RELATIVE_NODES flag
  is set, it also translates the nodes.  So I settled on
  'mpol_set_nodemask()', because the comment block for mpol_new() mentions
  that we need to call this function to "set nodes".

  Some additional minor line length, whitespace and typo cleanup.]
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Paul Menage <menage@google.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16 19:47:31 -07:00
Heiko Carstens 938bb9f5e8 [CVE-2009-0029] System call wrappers part 28
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:30 +01:00
James Morris 2b82892565 Merge branch 'master' into next
Conflicts:
	security/keys/internal.h
	security/keys/process_keys.c
	security/keys/request_key.c

Fixed conflicts above by using the non 'tsk' versions.

Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 11:29:12 +11:00
David Howells c69e8d9c01 CRED: Use RCU to access another task's creds and to release a task's own creds
Use RCU to access another task's creds and to release a task's own creds.
This means that it will be possible for the credentials of a task to be
replaced without another task (a) requiring a full lock to read them, and (b)
seeing deallocated memory.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:19 +11:00
David Howells b6dff3ec5e CRED: Separate task security context from task_struct
Separate the task security context from task_struct.  At this point, the
security data is temporarily embedded in the task_struct with two pointers
pointing to it.

Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
entry.S via asm-offsets.

With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:16 +11:00
David Howells 76aac0e9a1 CRED: Wrap task credential accesses in the core kernel
Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-audit@redhat.com
Cc: containers@lists.linux-foundation.org
Cc: linux-mm@kvack.org
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:12 +11:00
Christoph Lameter 0aedadf91a mm: move migrate_prep out from under mmap_sem
Move the migrate_prep outside the mmap_sem for the following system calls

1. sys_move_pages
2. sys_migrate_pages
3. sys_mbind()

It really does not matter when we flush the lru.  The system is free to
add pages onto the lru even during migration which will make the page
migration either skip the page (mbind, migrate_pages) or return a busy
state (move_pages).

Fixes this lockdep warning (and potential deadlock):

Some VM place has
      mmap_sem -> kevent_wq via lru_add_drain_all()

net/core/dev.c::dev_ioctl()  has
     rtnl_lock  ->  mmap_sem        (*) the ioctl has copy_from_user() and it can do page fault.

linkwatch_event has
     kevent_wq -> rtnl_lock

Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-06 15:41:18 -08:00
Lee Schermerhorn 894bc31041 Unevictable LRU Infrastructure
When the system contains lots of mlocked or otherwise unevictable pages,
the pageout code (kswapd) can spend lots of time scanning over these
pages.  Worse still, the presence of lots of unevictable pages can confuse
kswapd into thinking that more aggressive pageout modes are required,
resulting in all kinds of bad behaviour.

Infrastructure to manage pages excluded from reclaim--i.e., hidden from
vmscan.  Based on a patch by Larry Woodman of Red Hat.  Reworked to
maintain "unevictable" pages on a separate per-zone LRU list, to "hide"
them from vmscan.

Kosaki Motohiro added the support for the memory controller unevictable
lru list.

Pages on the unevictable list have both PG_unevictable and PG_lru set.
Thus, PG_unevictable is analogous to and mutually exclusive with
PG_active--it specifies which LRU list the page is on.

The unevictable infrastructure is enabled by a new mm Kconfig option
[CONFIG_]UNEVICTABLE_LRU.

A new function 'page_evictable(page, vma)' in vmscan.c tests whether or
not a page may be evictable.  Subsequent patches will add the various
!evictable tests.  We'll want to keep these tests light-weight for use in
shrink_active_list() and, possibly, the fault path.

To avoid races between tasks putting pages [back] onto an LRU list and
tasks that might be moving the page from non-evictable to evictable state,
the new function 'putback_lru_page()' -- inverse to 'isolate_lru_page()'
-- tests the "evictability" of a page after placing it on the LRU, before
dropping the reference.  If the page has become unevictable,
putback_lru_page() will redo the 'putback', thus moving the page to the
unevictable list.  This way, we avoid "stranding" evictable pages on the
unevictable list.

[akpm@linux-foundation.org: fix fallout from out-of-order merge]
[riel@redhat.com: fix UNEVICTABLE_LRU and !PROC_PAGE_MONITOR build]
[nishimura@mxp.nes.nec.co.jp: remove redundant mapping check]
[kosaki.motohiro@jp.fujitsu.com: unevictable-lru-infrastructure: putback_lru_page()/unevictable page handling rework]
[kosaki.motohiro@jp.fujitsu.com: kill unnecessary lock_page() in vmscan.c]
[kosaki.motohiro@jp.fujitsu.com: revert migration change of unevictable lru infrastructure]
[kosaki.motohiro@jp.fujitsu.com: revert to unevictable-lru-infrastructure-kconfig-fix.patch]
[kosaki.motohiro@jp.fujitsu.com: restore patch failure of vmstat-unevictable-and-mlocked-pages-vm-events.patch]
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Debugged-by: Benjamin Kidwell <benjkidwell@yahoo.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:50:26 -07:00
Nick Piggin 62695a84eb vmscan: move isolate_lru_page() to vmscan.c
On large memory systems, the VM can spend way too much time scanning
through pages that it cannot (or should not) evict from memory.  Not only
does it use up CPU time, but it also provokes lock contention and can
leave large systems under memory presure in a catatonic state.

This patch series improves VM scalability by:

1) putting filesystem backed, swap backed and unevictable pages
   onto their own LRUs, so the system only scans the pages that it
   can/should evict from memory

2) switching to two handed clock replacement for the anonymous LRUs,
   so the number of pages that need to be scanned when the system
   starts swapping is bound to a reasonable number

3) keeping unevictable pages off the LRU completely, so the
   VM does not waste CPU time scanning them. ramfs, ramdisk,
   SHM_LOCKED shared memory segments and mlock()ed VMA pages
   are keept on the unevictable list.

This patch:

isolate_lru_page logically belongs to be in vmscan.c than migrate.c.

It is tough, because we don't need that function without memory migration
so there is a valid argument to have it in migrate.c.  However a
subsequent patch needs to make use of it in the core mm, so we can happily
move it to vmscan.c.

Also, make the function a little more generic by not requiring that it
adds an isolated page to a given list.  Callers can do that.

	Note that we now have '__isolate_lru_page()', that does
	something quite different, visible outside of vmscan.c
	for use with memory controller.  Methinks we need to
	rationalize these names/purposes.	--lts

[akpm@linux-foundation.org: fix mm/memory_hotplug.c build]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:50:25 -07:00
MinChan Kim d6bf73e434 do_migrate_pages(): remove unused variable
Signed-off-by: MinChan Kim <minchan.kim@gmail.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-12 16:07:29 -07:00
Andi Kleen a551643895 hugetlb: modular state for hugetlb page size
The goal of this patchset is to support multiple hugetlb page sizes.  This
is achieved by introducing a new struct hstate structure, which
encapsulates the important hugetlb state and constants (eg.  huge page
size, number of huge pages currently allocated, etc).

The hstate structure is then passed around the code which requires these
fields, they will do the right thing regardless of the exact hstate they
are operating on.

This patch adds the hstate structure, with a single global instance of it
(default_hstate), and does the basic work of converting hugetlb to use the
hstate.

Future patches will add more hstate structures to allow for different
hugetlbfs mounts to have different page sizes.

[akpm@linux-foundation.org: coding-style fixes]
Acked-by: Adam Litke <agl@us.ibm.com>
Acked-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24 10:47:17 -07:00
David Rientjes d79df630f6 mempolicy: mask off internal flags for userspace API
Flags considered internal to the mempolicy kernel code are stored as part
of the "flags" member of struct mempolicy.

Before exposing a policy type to userspace via get_mempolicy(), these
internal flags must be masked.  Flags exposed to userspace, however,
should still be returned to the user.

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-04 13:03:05 -07:00
Lee Schermerhorn 71fe804b6d mempolicy: use struct mempolicy pointer in shmem_sb_info
This patch replaces the mempolicy mode, mode_flags, and nodemask in the
shmem_sb_info struct with a struct mempolicy pointer, initialized to NULL.
This removes dependency on the details of mempolicy from shmem.c and hugetlbfs
inode.c and simplifies the interfaces.

mpol_parse_str() in mempolicy.c is changed to return, via a pointer to a
pointer arg, a struct mempolicy pointer on success.  For MPOL_DEFAULT, the
returned pointer is NULL.  Further, mpol_parse_str() now takes a 'no_context'
argument that causes the input nodemask to be stored in the w.user_nodemask of
the created mempolicy for use when the mempolicy is installed in a tmpfs inode
shared policy tree.  At that time, any cpuset contextualization is applied to
the original input nodemask.  This preserves the previous behavior where the
input nodemask was stored in the superblock.  We can think of the returned
mempolicy as "context free".

Because mpol_parse_str() is now calling mpol_new(), we can remove from
mpol_to_str() the semantic checks that mpol_new() already performs.

Add 'no_context' parameter to mpol_to_str() to specify that it should format
the nodemask in w.user_nodemask for 'bind' and 'interleave' policies.

Change mpol_shared_policy_init() to take a pointer to a "context free" struct
mempolicy and to create a new, "contextualized" mempolicy using the mode,
mode_flags and user_nodemask from the input mempolicy.

  Note: we know that the mempolicy passed to mpol_to_str() or
  mpol_shared_policy_init() from a tmpfs superblock is "context free".  This
  is currently the only instance thereof.  However, if we found more uses for
  this concept, and introduced any ambiguity as to whether a mempolicy was
  context free or not, we could add another internal mode flag to identify
  context free mempolicies.  Then, we could remove the 'no_context' argument
  from mpol_to_str().

Added shmem_get_sbmpol() to return a reference counted superblock mempolicy,
if one exists, to pass to mpol_shared_policy_init().  We must add the
reference under the sb stat_lock to prevent races with replacement of the mpol
by remount.  This reference is removed in mpol_shared_policy_init().

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: another build fix]
[akpm@linux-foundation.org: yet another build fix]
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:25 -07:00
Lee Schermerhorn 3f226aa1cb mempolicy: support mpol=local tmpfs mount option
For tmpfs/shmem shared policies, MPOL_DEFAULT is not necessarily equivalent to
"local allocation".  Because shared policies are at the same "scope" level
[see Documentation/vm/numa_memory_policy.txt], as vma policies MPOL_DEFAULT
means "fall back to current task policy".

This patch extends the memory policy string parsing function to display
"local" for MPOL_PREFERRED + MPOL_F_LOCAL.  This allows one to specify local
allocation as the default policy for shared memory areas via the tmpfs mpol
mount option, regardless of the current task's policy.

Also, "local" is now displayed for this policy.  This patch allows us to
accept the same input format as the display.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:25 -07:00
Lee Schermerhorn 095f1fc4eb mempolicy: rework shmem mpol parsing and display
mm/shmem.c currently contains functions to parse and display memory policy
strings for the tmpfs 'mpol' mount option.  Move this to mm/mempolicy.c with
the rest of the mempolicy support.  With subsequent patches, we'll be able to
remove knowledge of the details [mode, flags, policy, ...] completely from
shmem.c

1) replace shmem_parse_mpol() in mm/shmem.c with mpol_parse_str() in
   mm/mempolicy.c.  Rework to use the policy_types[] array [used by
   mpol_to_str()] to look up mode by name.

2) use mpol_to_str() to format policy for shmem_show_mpol().  mpol_to_str()
   expects a pointer to a struct mempolicy, so temporarily construct one.
   This will be replaced with a reference to a struct mempolicy in the tmpfs
   superblock in a subsequent patch.

   NOTE 1: I changed mpol_to_str() to use a colon ':' rather than an equal
   sign '=' as the nodemask delimiter to match mpol_parse_str() and the
   tmpfs/shmem mpol mount option formatting that now uses mpol_to_str().  This
   is a user visible change to numa_maps, but then the addition of the mode
   flags already changed the display.  It makes sense to me to have the mounts
   and numa_maps display the policy in the same format.  However, if anyone
   objects strongly, I can pass the desired nodemask delimeter as an arg to
   mpol_to_str().

   Note 2: Like show_numa_map(), I don't check the return code from
   mpol_to_str().  I do use a longer buffer than the one provided by
   show_numa_map(), which seems to have sufficed so far.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:24 -07:00
Lee Schermerhorn 2291990ab3 mempolicy: clean-up mpol-to-str() mempolicy formatting
mpol-to-str() formats memory policies into printable strings.  Currently this
is only used to display "numa_maps".  A subsequent patch will use
mpol_to_str() for formatting tmpfs [shmem] mpol mount options, allowing us to
remove essentially duplicate code in mm/shmem.c.  This patch cleans up
mpol_to_str() generally and in preparation for that patch.

1) show_numa_maps() is not checking the return code from mpol_to_str().
   There's not a lot we can do in this context if mpol_to_str() did return the
   error [insufficient space in buffer].  Proposed "solution": just check,
   under DEBUG_VM, that callers are providing sufficient buffer space for the
   policy, flags, and a few nodes.  This way, we'll get some display.
   show_numa_maps() is providing a 50-byte buffer, so it won't trip this
   check.  50-bytes should be sufficient unless one has a large number of
   nodes in a very sparse nodemask.

2) The display of the new mode flags ["static" & "relative"] was set up to
   display multiple flags, separated by a "bar" '|'.  However, this support is
   incomplete--e.g., need_bar was never incremented; and currently, these two
   flags are mutually exclusive.  So remove the "bar" support, for now, and
   only display one flag.

3) Use snprint() to format flags, so as not to overflow the buffer.  Not
   that it's ever happed, AFAIK.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:24 -07:00
Lee Schermerhorn fc36b8d3d8 mempolicy: use MPOL_F_LOCAL to Indicate Preferred Local Policy
Now that we're using "preferred local" policy for system default, we need to
make this as fast as possible.  Because of the variable size of the mempolicy
structure [based on size of nodemasks], the preferred_node may be in a
different cacheline from the mode.  This can result in accessing an extra
cacheline in the normal case of system default policy.  Suspect this is the
cause of an observed 2-3% slowdown in page fault testing relative to kernel
without this patch series.

To alleviate this, use an internal mode flag, MPOL_F_LOCAL in the mempolicy
flags member which is guaranteed [?] to be in the same cacheline as the mode
itself.

Verified that reworked mempolicy now performs slightly better on 25-rc8-mm1
for both anon and shmem segments with system default and vma [preferred local]
policy.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:24 -07:00
Lee Schermerhorn 53f2556b67 mempolicy: mPOL_PREFERRED cleanups for "local allocation"
Here are a couple of "cleanups" for MPOL_PREFERRED behavior when
v.preferred_node < 0 -- i.e., "local allocation":

1)  [do_]get_mempolicy() calls the now renamed get_policy_nodemask()
    to fetch the nodemask associated with a policy.  Currently,
    get_policy_nodemask() returns the set of nodes with memory, when
    the policy 'mode' is 'PREFERRED, and the preferred_node is < 0.
    Change to return an empty nodemask, as this is what was specified
    to achieve "local allocation".

2)  When a task is moved into a [new] cpuset, mpol_rebind_policy() is
    called to adjust any task and vma policy nodes to be valid in the
    new cpuset.  However, when the policy is MPOL_PREFERRED, and the
    preferred_node is <0, no rebind is necessary.  The "local allocation"
    indication is valid in any cpuset.  Existing code will "do the right
    thing" because node_remap() will just return the argument node when
    it is outside of the valid range of node ids.  However, I think it is
    clearer and cleaner to skip the remap explicitly in this case.

3)  mpol_to_str() produces a printable, "human readable" string from a
    struct mempolicy.  For MPOL_PREFERRED with preferred_node <0,  show
    "local", as this indicates local allocation, as the task migrates
    among nodes.  Note that this matches the usage of "local allocation"
    in libnuma() and numactl.  Without this change, I believe that node_set()
    [via set_bit()] will set bit 31, resulting in a misleading display.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:24 -07:00
Lee Schermerhorn bea904d54d mempolicy: use MPOL_PREFERRED for system-wide default policy
Currently, when one specifies MPOL_DEFAULT via a NUMA memory policy API
[set_mempolicy(), mbind() and internal versions], the kernel simply installs a
NULL struct mempolicy pointer in the appropriate context: task policy, vma
policy, or shared policy.  This causes any use of that policy to "fall back"
to the next most specific policy scope.

The only use of MPOL_DEFAULT to mean "local allocation" is in the system
default policy.  This requires extra checks/cases for MPOL_DEFAULT in many
mempolicy.c functions.

There is another, "preferred" way to specify local allocation via the APIs.
That is using the MPOL_PREFERRED policy mode with an empty nodemask.
Internally, the empty nodemask gets converted to a preferred_node id of '-1'.
All internal usage of MPOL_PREFERRED will convert the '-1' to the id of the
node local to the cpu where the allocation occurs.

System default policy, except during boot, is hard-coded to "local
allocation".  By using the MPOL_PREFERRED mode with a negative value of
preferred node for system default policy, MPOL_DEFAULT will never occur in the
'policy' member of a struct mempolicy.  Thus, we can remove all checks for
MPOL_DEFAULT when converting policy to a node id/zonelist in the allocation
paths.

In slab_node() return local node id when policy pointer is NULL.  No need to
set a pol value to take the switch default.  Replace switch default with
BUG()--i.e., shouldn't happen.

With this patch MPOL_DEFAULT is only used in the APIs, including internal
calls to do_set_mempolicy() and in the display of policy in
/proc/<pid>/numa_maps.  It always means "fall back" to the the next most
specific policy scope.  This simplifies the description of memory policies
quite a bit, with no visible change in behavior.

get_mempolicy() continues to return MPOL_DEFAULT and an empty nodemask when
the requested policy [task or vma/shared] is NULL.  These are the values one
would supply via set_mempolicy() or mbind() to achieve that condition--default
behavior.

This patch updates Documentation to reflect this change.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:24 -07:00
Lee Schermerhorn 52cd3b0740 mempolicy: rework mempolicy Reference Counting [yet again]
After further discussion with Christoph Lameter, it has become clear that my
earlier attempts to clean up the mempolicy reference counting were a bit of
overkill in some areas, resulting in superflous ref/unref in what are usually
fast paths.  In other areas, further inspection reveals that I botched the
unref for interleave policies.

A separate patch, suitable for upstream/stable trees, fixes up the known
errors in the previous attempt to fix reference counting.

This patch reworks the memory policy referencing counting and, one hopes,
simplifies the code.  Maybe I'll get it right this time.

See the update to the numa_memory_policy.txt document for a discussion of
memory policy reference counting that motivates this patch.

Summary:

Lookup of mempolicy, based on (vma, address) need only add a reference for
shared policy, and we need only unref the policy when finished for shared
policies.  So, this patch backs out all of the unneeded extra reference
counting added by my previous attempt.  It then unrefs only shared policies
when we're finished with them, using the mpol_cond_put() [conditional put]
helper function introduced by this patch.

Note that shmem_swapin() calls read_swap_cache_async() with a dummy vma
containing just the policy.  read_swap_cache_async() can call alloc_page_vma()
multiple times, so we can't let alloc_page_vma() unref the shared policy in
this case.  To avoid this, we make a copy of any non-null shared policy and
remove the MPOL_F_SHARED flag from the copy.  This copy occurs before reading
a page [or multiple pages] from swap, so the overhead should not be an issue
here.

I introduced a new static inline function "mpol_cond_copy()" to copy the
shared policy to an on-stack policy and remove the flags that would require a
conditional free.  The current implementation of mpol_cond_copy() assumes that
the struct mempolicy contains no pointers to dynamically allocated structures
that must be duplicated or reference counted during copy.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:24 -07:00
Lee Schermerhorn aab0b1029f mempolicy: mark shared policies for unref
As part of yet another rework of mempolicy reference counting, we want to be
able to identify shared policies efficiently, because they have an extra ref
taken on lookup that needs to be removed when we're finished using the policy.

  Note:  the extra ref is required because the policies are
  shared between tasks/processes and can be changed/freed
  by one task while another task is using them--e.g., for
  page allocation.

Building on David Rientjes mempolicy "mode flags" enhancement, this patch
indicates a "shared" policy by setting a new MPOL_F_SHARED flag in the flags
member of the struct mempolicy added by David.  MPOL_F_SHARED, and any future
"internal mode flags" are reserved from bit zero up, as they will never be
passed in the upper bits of the mode argument of a mempolicy API.

I set the MPOL_F_SHARED flag when the policy is installed in the shared policy
rb-tree.  Don't need/want to clear the flag when removing from the tree as the
mempolicy is freed [unref'd] internally to the sp_delete() function.  However,
a task could hold another reference on this mempolicy from a prior lookup.  We
need the MPOL_F_SHARED flag to stay put so that any tasks holding a ref will
unref, eventually freeing, the mempolicy.

A later patch in this series will introduce a function to conditionally unref
[mpol_free] a policy.  The MPOL_F_SHARED flag is one reason [currently the
only reason] to unref/free a policy via the conditional free.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:24 -07:00
Lee Schermerhorn 45c4745af3 mempolicy: rename struct mempolicy 'policy' member to 'mode'
The terms 'policy' and 'mode' are both used in various places to describe the
semantics of the value stored in the 'policy' member of struct mempolicy.
Furthermore, the term 'policy' is used to refer to that member, to the entire
struct mempolicy and to the more abstract concept of the tuple consisting of a
"mode" and an optional node or set of nodes.  Recently, we have added "mode
flags" that are passed in the upper bits of the 'mode' [or sometimes,
'policy'] member of the numa APIs.

I'd like to resolve this confusion, which perhaps only exists in my mind, by
renaming the 'policy' member to 'mode' throughout, and fixing up the
Documentation.  Man pages will be updated separately.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:24 -07:00
Lee Schermerhorn ae4d8c16aa mempolicy: fixup Fallback for Default Shmem Policy
get_vma_policy() is not handling fallback to task policy correctly when the
get_policy() vm_op returns NULL.  The NULL overwrites the 'pol' variable that
was holding the fallback task mempolicy.  So, it was falling back directly to
system default policy.

Fix get_vma_policy() to use only non-NULL policy returned from the vma
get_policy op.

shm_get_policy() was falling back to current task's mempolicy if the "backing
file system" [tmpfs vs hugetlbfs] does not support the get_policy vm_op and
the vma policy is null.  This is incorrect for show_numa_maps() which is
likely querying the numa_maps of some task other than current.  Remove this
fallback.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:24 -07:00
Lee Schermerhorn f4e53d910b mempolicy: write lock mmap_sem while changing task mempolicy
A read of /proc/<pid>/numa_maps holds the target task's mmap_sem for read
while examining each vma's mempolicy.  A vma's mempolicy can fall back to the
task's policy.  However, the task could be changing it's task policy and free
the one that the show_numa_maps() is examining.

To prevent this, grab the mmap_sem for write when updating task mempolicy.
Pointed out to me by Christoph Lameter and extracted and reworked from
Christoph's alternative mempol reference counting patch.

This is analogous to the way that do_mbind() and do_get_mempolicy() prevent
races between task's sharing an mm_struct [a.k.a.  threads] setting and
querying a mempolicy for a particular address.

Note: this is necessary, but not sufficient, to allow us to stop taking an
extra reference on "other task's mempolicy" in get_vma_policy.  Subsequent
patches will complete this update, allowing us to simplify the tests for
whether we need to unref a mempolicy at various points in the code.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:23 -07:00
Lee Schermerhorn 846a16bf0f mempolicy: rename mpol_copy to mpol_dup
This patch renames mpol_copy() to mpol_dup() because, well, that's what it
does.  Like, e.g., strdup() for strings, mpol_dup() takes a pointer to an
existing mempolicy, allocates a new one and copies the contents.

In a later patch, I want to use the name mpol_copy() to copy the contents from
one mempolicy to another like, e.g., strcpy() does for strings.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:23 -07:00
Lee Schermerhorn f0be3d32b0 mempolicy: rename mpol_free to mpol_put
This is a change that was requested some time ago by Mel Gorman.  Makes sense
to me, so here it is.

Note: I retain the name "mpol_free_shared_policy()" because it actually does
free the shared_policy, which is NOT a reference counted object.  However, ...

The mempolicy object[s] referenced by the shared_policy are reference counted,
so mpol_put() is used to release the reference held by the shared_policy.  The
mempolicy might not be freed at this time, because some task attached to the
shared object associated with the shared policy may be in the process of
allocating a page based on the mempolicy.  In that case, the task performing
the allocation will hold a reference on the mempolicy, obtained via
mpol_shared_policy_lookup().  The mempolicy will be freed when all tasks
holding such a reference have called mpol_put() for the mempolicy.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:23 -07:00
David Rientjes 3e1f064562 mempolicy: disallow static or relative flags for local preferred mode
MPOL_F_STATIC_NODES and MPOL_F_RELATIVE_NODES don't mean anything for
MPOL_PREFERRED policies that were created with an empty nodemask (for purely
local allocations).  They'll never be invalidated because the allowed mems of
a task changes or need to be rebound relative to a cpuset's placement.

Also fixes a bug identified by Lee Schermerhorn that disallowed empty
nodemasks to be passed to MPOL_PREFERRED to specify local allocations.  [A
different, somewhat incomplete, patch already existed in 25-rc5-mm1.]

Cc: Paul Jackson <pj@sgi.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:20 -07:00
David Rientjes 37012946da mempolicy: create mempolicy_operations structure
Create a mempolicy_operations structure that currently points to two
functions[*] for the various modes:

	int (*create)(struct mempolicy *, const nodemask_t *);
	void (*rebind)(struct mempolicy *, const nodemask_t *);

This splits the implementation for the various modes out of two large
functions, mpol_new() and mpol_rebind_policy().  Eventually it may be
beneficial to add additional functions to accomodate the existing switch()
statements in mm/mempolicy.c.

 [*] The ->create() function for MPOL_DEFAULT is currently NULL since no
     struct mempolicy is dynamically allocated.

[Lee.Schermerhorn@hp.com: fix regression in the package mempolicy regression tests]
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Eric Whitney <eric.whitney@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:20 -07:00
David Rientjes 1d0d2680a0 mempolicy: move rebind functions
Move the mpol_rebind_{policy,task,mm}() functions after mpol_new() to avoid
having to declare function prototypes.

Cc: Paul Jackson <pj@sgi.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:20 -07:00
David Rientjes 4c50bc0116 mempolicy: add MPOL_F_RELATIVE_NODES flag
Adds another optional mode flag, MPOL_F_RELATIVE_NODES, that specifies
nodemasks passed via set_mempolicy() or mbind() should be considered relative
to the current task's mems_allowed.

When the mempolicy is created, the passed nodemask is folded and mapped onto
the current task's mems_allowed.  For example, consider a task using
set_mempolicy() to pass MPOL_INTERLEAVE | MPOL_F_RELATIVE_NODES with a
nodemask of 1-3.  If current's mems_allowed is 4-7, the effected nodemask is
5-7 (the second, third, and fourth node of mems_allowed).

If the same task is attached to a cpuset, the mempolicy nodemask is rebound
each time the mems are changed.  Some possible rebinds and results are:

	mems			result
	1-3			1-3
	1-7			2-4
	1,5-6			1,5-6
	1,5-7			5-7

Likewise, the zonelist built for MPOL_BIND acts on the set of zones assigned
to the resultant nodemask from the relative remap.

In the MPOL_PREFERRED case, the preferred node is remapped from the currently
effected nodemask to the relative nodemask.

This mempolicy mode flag was conceived of by Paul Jackson <pj@sgi.com>.

Cc: Paul Jackson <pj@sgi.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:19 -07:00
David Rientjes f5b087b52f mempolicy: add MPOL_F_STATIC_NODES flag
Add an optional mempolicy mode flag, MPOL_F_STATIC_NODES, that suppresses the
node remap when the policy is rebound.

Adds another member to struct mempolicy, nodemask_t user_nodemask, as part of
a union with cpuset_mems_allowed:

	struct mempolicy {
		...
		union {
			nodemask_t cpuset_mems_allowed;
			nodemask_t user_nodemask;
		} w;
	}

that stores the the nodemask that the user passed when he or she created the
mempolicy via set_mempolicy() or mbind().  When using MPOL_F_STATIC_NODES,
which is passed with any mempolicy mode, the user's passed nodemask
intersected with the VMA or task's allowed nodes is always used when
determining the preferred node, setting the MPOL_BIND zonelist, or creating
the interleave nodemask.  This happens whenever the policy is rebound,
including when a task's cpuset assignment changes or the cpuset's mems are
changed.

This creates an interesting side-effect in that it allows the mempolicy
"intent" to lie dormant and uneffected until it has access to the node(s) that
it desires.  For example, if you currently ask for an interleaved policy over
a set of nodes that you do not have access to, the mempolicy is not created
and the task continues to use the previous policy.  With this change, however,
it is possible to create the same mempolicy; it is only effected when access
to nodes in the nodemask is acquired.

It is also possible to mount tmpfs with the static nodemask behavior when
specifying a node or nodemask.  To do this, simply add "=static" immediately
following the mempolicy mode at mount time:

	mount -o remount mpol=interleave=static:1-3

Also removes mpol_check_policy() and folds its logic into mpol_new() since it
is now obsoleted.  The unused vma_mpol_equal() is also removed.

Cc: Paul Jackson <pj@sgi.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:19 -07:00
David Rientjes 028fec414d mempolicy: support optional mode flags
With the evolution of mempolicies, it is necessary to support mempolicy mode
flags that specify how the policy shall behave in certain circumstances.  The
most immediate need for mode flag support is to suppress remapping the
nodemask of a policy at the time of rebind.

Both the mempolicy mode and flags are passed by the user in the 'int policy'
formal of either the set_mempolicy() or mbind() syscall.  A new constant,
MPOL_MODE_FLAGS, represents the union of legal optional flags that may be
passed as part of this int.  Mempolicies that include illegal flags as part of
their policy are rejected as invalid.

An additional member to struct mempolicy is added to support the mode flags:

	struct mempolicy {
		...
		unsigned short policy;
		unsigned short flags;
	}

The splitting of the 'int' actual passed by the user is done in
sys_set_mempolicy() and sys_mbind() for their respective syscalls.  This is
done by intersecting the actual with MPOL_MODE_FLAGS, rejecting the syscall of
there are additional flags, and storing it in the new 'flags' member of struct
mempolicy.  The intersection of the actual with ~MPOL_MODE_FLAGS is stored in
the 'policy' member of the struct and all current users of pol->policy remain
unchanged.

The union of the policy mode and optional mode flags is passed back to the
user in get_mempolicy().

This combination of mode and flags within the same actual does not break
userspace code that relies on get_mempolicy(&policy, ...) and either

	switch (policy) {
	case MPOL_BIND:
		...
	case MPOL_INTERLEAVE:
		...
	};

statements or

	if (policy == MPOL_INTERLEAVE) {
		...
	}

statements.  Such applications would need to use optional mode flags when
calling set_mempolicy() or mbind() for these previously implemented statements
to stop working.  If an application does start using optional mode flags, it
will need to mask the optional flags off the policy in switch and conditional
statements that only test mode.

An additional member is also added to struct shmem_sb_info to store the
optional mode flags.

[hugh@veritas.com: shmem mpol: fix build warning]
Cc: Paul Jackson <pj@sgi.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:19 -07:00
David Rientjes a3b51e0142 mempolicy: convert MPOL constants to enum
The mempolicy mode constants, MPOL_DEFAULT, MPOL_PREFERRED, MPOL_BIND, and
MPOL_INTERLEAVE, are better declared as part of an enum since they are
sequentially numbered and cannot be combined.

The policy member of struct mempolicy is also converted from type short to
type unsigned short.  A negative policy does not have any legitimate meaning,
so it is possible to change its type in preparation for adding optional mode
flags later.

The equivalent member of struct shmem_sb_info is also changed from int to
unsigned short.

For compatibility, the policy formal to get_mempolicy() remains as a pointer
to an int:

	int get_mempolicy(int *policy, unsigned long *nmask,
			  unsigned long maxnode, unsigned long addr,
			  unsigned long flags);

although the only possible values is the range of type unsigned short.

Cc: Paul Jackson <pj@sgi.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:19 -07:00
Mel Gorman 19770b3260 mm: filter based on a nodemask as well as a gfp_mask
The MPOL_BIND policy creates a zonelist that is used for allocations
controlled by that mempolicy.  As the per-node zonelist is already being
filtered based on a zone id, this patch adds a version of __alloc_pages() that
takes a nodemask for further filtering.  This eliminates the need for
MPOL_BIND to create a custom zonelist.

A positive benefit of this is that allocations using MPOL_BIND now use the
local node's distance-ordered zonelist instead of a custom node-id-ordered
zonelist.  I.e., pages will be allocated from the closest allowed node with
available memory.

[Lee.Schermerhorn@hp.com: Mempolicy: update stale documentation and comments]
[Lee.Schermerhorn@hp.com: Mempolicy: make dequeue_huge_page_vma() obey MPOL_BIND nodemask]
[Lee.Schermerhorn@hp.com: Mempolicy: make dequeue_huge_page_vma() obey MPOL_BIND nodemask rework]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:19 -07:00
Mel Gorman dd1a239f6f mm: have zonelist contains structs with both a zone pointer and zone_idx
Filtering zonelists requires very frequent use of zone_idx().  This is costly
as it involves a lookup of another structure and a substraction operation.  As
the zone_idx is often required, it should be quickly accessible.  The node idx
could also be stored here if it was found that accessing zone->node is
significant which may be the case on workloads where nodemasks are heavily
used.

This patch introduces a struct zoneref to store a zone pointer and a zone
index.  The zonelist then consists of an array of these struct zonerefs which
are looked up as necessary.  Helpers are given for accessing the zone index as
well as the node index.

[kamezawa.hiroyu@jp.fujitsu.com: Suggested struct zoneref instead of embedding information in pointers]
[hugh@veritas.com: mm-have-zonelist: fix memcg ooms]
[hugh@veritas.com: just return do_try_to_free_pages]
[hugh@veritas.com: do_try_to_free_pages gfp_mask redundant]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Christoph Lameter <clameter@sgi.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:18 -07:00
Mel Gorman 0e88460da6 mm: introduce node_zonelist() for accessing the zonelist for a GFP mask
Introduce a node_zonelist() helper function.  It is used to lookup the
appropriate zonelist given a node and a GFP mask.  The patch on its own is a
cleanup but it helps clarify parts of the two-zonelist-per-node patchset.  If
necessary, it can be merged with the next patch in this set without problems.

Reviewed-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 08:58:18 -07:00
Lee Schermerhorn 69682d852f mempolicy: fix reference counting bugs
Address 3 known bugs in the current memory policy reference counting method.
I have a series of patches to rework the reference counting to reduce overhead
in the allocation path.  However, that series will require testing in -mm once
I repost it.

1) alloc_page_vma() does not release the extra reference taken for
   vma/shared mempolicy when the mode == MPOL_INTERLEAVE.  This can result in
   leaking mempolicy structures.  This is probably occurring, but not being
   noticed.

   Fix:  add the conditional release of the reference.

2) hugezonelist unconditionally releases a reference on the mempolicy when
   mode == MPOL_INTERLEAVE.  This can result in decrementing the reference
   count for system default policy [should have no ill effect] or premature
   freeing of task policy.  If this occurred, the next allocation using task
   mempolicy would use the freed structure and probably BUG out.

   Fix:  add the necessary check to the release.

3) The current reference counting method assumes that vma 'get_policy()'
   methods automatically add an extra reference a non-NULL returned mempolicy.
    This is true for shmem_get_policy() used by tmpfs mappings, including
   regular page shm segments.  However, SHM_HUGETLB shm's, backed by
   hugetlbfs, just use the vma policy without the extra reference.  This
   results in freeing of the vma policy on the first allocation, with reuse of
   the freed mempolicy structure on subsequent allocations.

   Fix: Rather than add another condition to the conditional reference
   release, which occur in the allocation path, just add a reference when
   returning the vma policy in shm_get_policy() to match the assumptions.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Greg KH <greg@kroah.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: David Rientjes <rientjes@google.com>
Cc: <eric.whitney@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-10 18:01:19 -07:00
Jan Blunck c32c2f63a9 d_path: Make seq_path() use a struct path argument
seq_path() is always called with a dentry and a vfsmount from a struct path.
Make seq_path() take it directly as an argument.

Signed-off-by: Jan Blunck <jblunck@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-14 21:17:08 -08:00
KOSAKI Motohiro 31f1de46b9 mempolicy: silently restrict nodemask to allowed nodes
Kosaki Motohito noted that "numactl --interleave=all ..." failed in the
presence of memoryless nodes.  This patch attempts to fix that problem.

Some background:

numactl --interleave=all calls set_mempolicy(2) with a fully populated
[out to MAXNUMNODES] nodemask.  set_mempolicy() [in do_set_mempolicy()]
calls contextualize_policy() which requires that the nodemask be a
subset of the current task's mems_allowed; else EINVAL will be returned.

A task's mems_allowed will always be a subset of node_states[N_HIGH_MEMORY]
i.e., nodes with memory.  So, a fully populated nodemask will be
declared invalid if it includes memoryless nodes.

  NOTE:  the same thing will occur when running in a cpuset
         with restricted mem_allowed--for the same reason:
         node mask contains dis-allowed nodes.

mbind(2), on the other hand, just masks off any nodes in the nodemask
that are not included in the caller's mems_allowed.

In each case [mbind() and set_mempolicy()], mpol_check_policy() will
complain [again, resulting in EINVAL] if the nodemask contains any
memoryless nodes.  This is somewhat redundant as mpol_new() will remove
memoryless nodes for interleave policy, as will bind_zonelist()--called
by mpol_new() for BIND policy.

Proposed fix:

1) modify contextualize_policy logic to:
   a) remember whether the incoming node mask is empty.
   b) if not, restrict the nodemask to allowed nodes, as is
      currently done in-line for mbind().  This guarantees
      that the resulting mask includes only nodes with memory.

      NOTE:  this is a [benign, IMO] change in behavior for
             set_mempolicy().  Dis-allowed nodes will be
             silently ignored, rather than returning an error.

   c) fold this code into mpol_check_policy(), replace 2 calls to
      contextualize_policy() to call mpol_check_policy() directly
      and remove contextualize_policy().

2) In existing mpol_check_policy() logic, after "contextualization":
   a) MPOL_DEFAULT:  require that in coming mask "was_empty"
   b) MPOL_{BIND|INTERLEAVE}:  require that contextualized nodemask
      contains at least one node.
   c) add a case for MPOL_PREFERRED:  if in coming was not empty
      and resulting mask IS empty, user specified invalid nodes.
      Return EINVAL.
   c) remove the now redundant check for memoryless nodes

3) remove the now redundant masking of policy nodes for interleave
   policy from mpol_new().

4) Now that mpol_check_policy() contextualizes the nodemask, remove
   the in-line nodes_and() from sys_mbind().  I believe that this
   restores mbind() to the behavior before the memoryless-nodes
   patch series.  E.g., we'll no longer treat an invalid nodemask
   with MPOL_PREFERRED as local allocation.

[ Patch history:

  v1 -> v2:
   - Communicate whether or not incoming node mask was empty to
     mpol_check_policy() for better error checking.
   - As suggested by David Rientjes, remove the now unused
     cpuset_nodes_subset_current_mems_allowed() from cpuset.h

  v2 -> v3:
   - As suggested by Kosaki Motohito, fold the "contextualization"
     of policy nodemask into mpol_check_policy().  Looks a little
     cleaner. ]

Signed-off-by:  Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by:  KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Tested-by:      KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by:       David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-11 20:48:29 -08:00
Lee Schermerhorn 3ad33b2436 Migration: find correct vma in new_vma_page()
We hit the BUG_ON() in mm/rmap.c:vma_address() when trying to migrate via
mbind(MPOL_MF_MOVE) a non-anon region that spans multiple vmas.  For
anon-regions, we just fail to migrate any pages beyond the 1st vma in the
range.

This occurs because do_mbind() collects a list of pages to migrate by
calling check_range().  check_range() walks the task's mm, spanning vmas as
necessary, to collect the migratable pages into a list.  Then, do_mbind()
calls migrate_pages() passing the list of pages, a function to allocate new
pages based on vma policy [new_vma_page()], and a pointer to the first vma
of the range.

For each page in the list, new_vma_page() calls page_address_in_vma()
passing the page and the vma [first in range] to obtain the address to get
for alloc_page_vma().  The page address is needed to get interleaving
policy correct.  If the pages in the list come from multiple vmas,
eventually, new_page_address() will pass that page to page_address_in_vma()
with the incorrect vma.  For !PageAnon pages, this will result in a bug
check in rmap.c:vma_address().  For anon pages, vma_address() will just
return EFAULT and fail the migration.

This patch modifies new_vma_page() to check the return value from
page_address_in_vma().  If the return value is EFAULT, new_vma_page()
searchs forward via vm_next for the vma that maps the page--i.e., that does
not return EFAULT.  This assumes that the pages in the list handed to
migrate_pages() is in address order.  This is currently case.  The patch
documents this assumption in a new comment block for new_vma_page().

If new_vma_page() cannot locate the vma mapping the page in a forward
search in the mm, it will pass a NULL vma to alloc_page_vma().  This will
result in the allocation using the task policy, if any, else system default
policy.  This situation is unlikely, but the patch documents this behavior
with a comment.

Note, this patch results in restarting from the first vma in a multi-vma
range each time new_vma_page() is called.  If this is not acceptable, we
can make the vma argument a pointer, both in new_vma_page() and it's caller
unmap_and_move() so that the value held by the loop in migrate_pages()
always passes down the last vma in which a page was found.  This will
require changes to all new_page_t functions passed to migrate_pages().  Is
this necessary?

For this patch to work, we can't bug check in vma_address() for pages
outside the argument vma.  This patch removes the BUG_ON().  All other
callers [besides new_vma_page()] already check the return status.

Tested on x86_64, 4 node NUMA platform.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-11-14 18:45:38 -08:00
Pavel Emelyanov 228ebcbe63 Uninline find_task_by_xxx set of functions
The find_task_by_something is a set of macros are used to find task by pid
depending on what kind of pid is proposed - global or virtual one.  All of
them are wrappers above the most generic one - find_task_by_pid_type_ns() -
and just substitute some args for it.

It turned out, that dereferencing the current->nsproxy->pid_ns construction
and pushing one more argument on the stack inline cause kernel text size to
grow.

This patch moves all this stuff out-of-line into kernel/pid.c.  Together
with the next patch it saves a bit less than 400 bytes from the .text
section.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:40 -07:00
Pavel Emelyanov b488893a39 pid namespaces: changes to show virtual ids to user
This is the largest patch in the set. Make all (I hope) the places where
the pid is shown to or get from user operate on the virtual pids.

The idea is:
 - all in-kernel data structures must store either struct pid itself
   or the pid's global nr, obtained with pid_nr() call;
 - when seeking the task from kernel code with the stored id one
   should use find_task_by_pid() call that works with global pids;
 - when showing pid's numerical value to the user the virtual one
   should be used, but however when one shows task's pid outside this
   task's namespace the global one is to be used;
 - when getting the pid from userspace one need to consider this as
   the virtual one and use appropriate task/pid-searching functions.

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: nuther build fix]
[akpm@linux-foundation.org: yet nuther build fix]
[akpm@linux-foundation.org: remove unneeded casts]
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:40 -07:00
Paul Menage 8793d854ed Task Control Groups: make cpusets a client of cgroups
Remove the filesystem support logic from the cpusets system and makes cpusets
a cgroup subsystem

The "cpuset" filesystem becomes a dummy filesystem; attempts to mount it get
passed through to the cgroup filesystem with the appropriate options to
emulate the old cpuset filesystem behaviour.

Signed-off-by: Paul Menage <menage@google.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:36 -07:00
Adrian Bunk dbcb0f19c8 mm/mempolicy.c: cleanups
This patch contains the following cleanups:
- every file should include the headers containing the prototypes for
  its global functions
- make the follosing needlessly global functions static:
  - migrate_to_node()
  - do_mbind()
  - sp_alloc()
  - mpol_rebind_policy()

[akpm@linux-foundation.org: fix uninitialised var warning]
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 09:43:03 -07:00
Lee Schermerhorn 37b07e4163 memoryless nodes: fixup uses of node_online_map in generic code
Here's a cut at fixing up uses of the online node map in generic code.

mm/shmem.c:shmem_parse_mpol()

	Ensure nodelist is subset of nodes with memory.
	Use node_states[N_HIGH_MEMORY] as default for missing
	nodelist for interleave policy.

mm/shmem.c:shmem_fill_super()

	initialize policy_nodes to node_states[N_HIGH_MEMORY]

mm/page-writeback.c:highmem_dirtyable_memory()

	sum over nodes with memory

mm/page_alloc.c:zlc_setup()

	allowednodes - use nodes with memory.

mm/page_alloc.c:default_zonelist_order()

	average over nodes with memory.

mm/page_alloc.c:find_next_best_node()

	skip nodes w/o memory.
	N_HIGH_MEMORY state mask may not be initialized at this time,
	unless we want to depend on early_calculate_totalpages() [see
	below].  Will ZONE_MOVABLE ever be configurable?

mm/page_alloc.c:find_zone_movable_pfns_for_nodes()

	spread kernelcore over nodes with memory.

	This required calling early_calculate_totalpages()
	unconditionally, and populating N_HIGH_MEMORY node
	state therein from nodes in the early_node_map[].
	If we can depend on this, we can eliminate the
	population of N_HIGH_MEMORY mask from __build_all_zonelists()
	and use the N_HIGH_MEMORY mask in find_next_best_node().

mm/mempolicy.c:mpol_check_policy()

	Ensure nodes specified for policy are subset of
	nodes with memory.

[akpm@linux-foundation.org: fix warnings]
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Christoph Lameter <clameter@sgi.com>
Cc: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 09:42:59 -07:00
Christoph Lameter 56bbd65df0 Memoryless nodes: Update memory policy and page migration
Online nodes now may have no memory.  The checks and initialization must
therefore be changed to no longer use the online functions.

This will correctly initialize the interleave on bootup to only target nodes
with memory and will make sys_move_pages return an error when a page is to be
moved to a memoryless node.  Similarly we will get an error if MPOL_BIND and
MPOL_INTERLEAVE is used on a memoryless node.

These are somewhat new semantics.  So far one could specify memoryless nodes
and we would maybe do the right thing and just ignore the node (or we'd do
something strange like with MPOL_INTERLEAVE).  If we want to allow the
specification of memoryless nodes via memory policies then we need to keep
checking for online nodes.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Acked-by: Nishanth Aravamudan <nacc@us.ibm.com>
Tested-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Bob Picco <bob.picco@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@skynet.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 09:42:58 -07:00
Christoph Lameter 6eaf806a22 Memoryless nodes: Fix interleave behavior for memoryless nodes
MPOL_INTERLEAVE currently simply loops over all nodes.  Allocations on
memoryless nodes will be redirected to nodes with memory.  This results in an
imbalance because the neighboring nodes to memoryless nodes will get
significantly more interleave hits that the rest of the nodes on the system.

We can avoid this imbalance by clearing the nodes in the interleave node set
that have no memory.  If we use the node map of the memory nodes instead of
the online nodes then we have only the nodes we want.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Tested-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Bob Picco <bob.picco@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@skynet.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 09:42:58 -07:00
Lee Schermerhorn 754af6f5a8 Mem Policy: add MPOL_F_MEMS_ALLOWED get_mempolicy() flag
Allow an application to query the memories allowed by its context.

Updated numa_memory_policy.txt to mention that applications can use this to
obtain allowed memories for constructing valid policies.

TODO:  update out-of-tree libnuma wrapper[s], or maybe add a new
wrapper--e.g.,  numa_get_mems_allowed() ?

Also, update numa syscall man pages.

Tested with memtoy V>=0.13.

Signed-off-by:  Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 09:42:54 -07:00
Jesper Juhl 43fac94dd6 Clean up duplicate includes in mm/
This patch cleans up duplicate includes in
	mm/

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 09:42:52 -07:00
Lee Schermerhorn 480eccf9ae Fix NUMA Memory Policy Reference Counting
This patch proposes fixes to the reference counting of memory policy in the
page allocation paths and in show_numa_map().  Extracted from my "Memory
Policy Cleanups and Enhancements" series as stand-alone.

Shared policy lookup [shmem] has always added a reference to the policy,
but this was never unrefed after page allocation or after formatting the
numa map data.

Default system policy should not require additional ref counting, nor
should the current task's task policy.  However, show_numa_map() calls
get_vma_policy() to examine what may be [likely is] another task's policy.
The latter case needs protection against freeing of the policy.

This patch adds a reference count to a mempolicy returned by
get_vma_policy() when the policy is a vma policy or another task's
mempolicy.  Again, shared policy is already reference counted on lookup.  A
matching "unref" [__mpol_free()] is performed in alloc_page_vma() for
shared and vma policies, and in show_numa_map() for shared and another
task's mempolicy.  We can call __mpol_free() directly, saving an admittedly
inexpensive inline NULL test, because we know we have a non-NULL policy.

Handling policy ref counts for hugepages is a bit trickier.
huge_zonelist() returns a zone list that might come from a shared or vma
'BIND policy.  In this case, we should hold the reference until after the
huge page allocation in dequeue_hugepage().  The patch modifies
huge_zonelist() to return a pointer to the mempolicy if it needs to be
unref'd after allocation.

Kernel Build [16cpu, 32GB, ia64] - average of 10 runs:

		w/o patch	w/ refcount patch
	    Avg	  Std Devn	   Avg	  Std Devn
Real:	 100.59	    0.38	 100.63	    0.43
User:	1209.60	    0.37	1209.91	    0.31
System:   81.52	    0.42	  81.64	    0.34

Signed-off-by:  Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Andi Kleen <ak@suse.de>
Cc: Christoph Lameter <clameter@sgi.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-09-19 11:24:18 -07:00
Christoph Lameter 3b42d28b2a Page migration: Do not accept invalid nodes in the target nodeset
Page migration currently does not check if the target of the move contains
nodes that that are invalid (if root attempts to migrate pages)
and may try to allocate from invalid nodes if these are specified
leading to oopses.

Return -EINVAL if an offline node is specified.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-31 01:42:23 -07:00
Mel Gorman b377fd3982 Apply memory policies to top two highest zones when highest zone is ZONE_MOVABLE
The NUMA layer only supports NUMA policies for the highest zone.  When
ZONE_MOVABLE is configured with kernelcore=, the the highest zone becomes
ZONE_MOVABLE.  The result is that policies are only applied to allocations
like anonymous pages and page cache allocated from ZONE_MOVABLE when the
zone is used.

This patch applies policies to the two highest zones when the highest zone
is ZONE_MOVABLE.  As ZONE_MOVABLE consists of pages from the highest "real"
zone, it's always functionally equivalent.

The patch has been tested on a variety of machines both NUMA and non-NUMA
covering x86, x86_64 and ppc64.  No abnormal results were seen in
kernbench, tbench, dbench or hackbench.  It passes regression tests from
the numactl package with and without kernelcore= once numactl tests are
patched to wait for vmstat counters to update.

akpm: this is the nasty hack to fix NUMA mempolicies in the presence of
ZONE_MOVABLE and kernelcore= in 2.6.23.  Christoph says "For .24 either merge
the mobility or get the other solution that Mel is working on.  That solution
would only use a single zonelist per node and filter on the fly.  That may
help performance and also help to make memory policies work better."

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by:  Lee Schermerhorn <lee.schermerhorn@hp.com>
Tested-by:  Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-22 19:52:47 -07:00
Paul Mundt 20c2df83d2 mm: Remove slab destructors from kmem_cache_create().
Slab destructors were no longer supported after Christoph's
c59def9f22 change. They've been
BUGs for both slab and slub, and slob never supported them
either.

This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-07-20 10:11:58 +09:00
Mel Gorman 396faf0303 Allow huge page allocations to use GFP_HIGH_MOVABLE
Huge pages are not movable so are not allocated from ZONE_MOVABLE.  However,
as ZONE_MOVABLE will always have pages that can be migrated or reclaimed, it
can be used to satisfy hugepage allocations even when the system has been
running a long time.  This allows an administrator to resize the hugepage pool
at runtime depending on the size of ZONE_MOVABLE.

This patch adds a new sysctl called hugepages_treat_as_movable.  When a
non-zero value is written to it, future allocations for the huge page pool
will use ZONE_MOVABLE.  Despite huge pages being non-movable, we do not
introduce additional external fragmentation of note as huge pages are always
the largest contiguous block we care about.

[akpm@linux-foundation.org: various fixes]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 10:22:59 -07:00
Mel Gorman 769848c038 Add __GFP_MOVABLE for callers to flag allocations from high memory that may be migrated
It is often known at allocation time whether a page may be migrated or not.
This patch adds a flag called __GFP_MOVABLE and a new mask called
GFP_HIGH_MOVABLE.  Allocations using the __GFP_MOVABLE can be either migrated
using the page migration mechanism or reclaimed by syncing with backing
storage and discarding.

An API function very similar to alloc_zeroed_user_highpage() is added for
__GFP_MOVABLE allocations called alloc_zeroed_user_highpage_movable().  The
flags used by alloc_zeroed_user_highpage() are not changed because it would
change the semantics of an existing API.  After this patch is applied there
are no in-kernel users of alloc_zeroed_user_highpage() so it probably should
be marked deprecated if this patch is merged.

Note that this patch includes a minor cleanup to the use of __GFP_ZERO in
shmem.c to keep all flag modifications to inode->mapping in the
shmem_dir_alloc() helper function.  This clean-up suggestion is courtesy of
Hugh Dickens.

Additional credit goes to Christoph Lameter and Linus Torvalds for shaping the
concept.  Credit to Hugh Dickens for catching issues with shmem swap vector
and ramfs allocations.

[akpm@linux-foundation.org: build fix]
[hugh@veritas.com: __GFP_ZERO cleanup]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 10:22:59 -07:00
Paul Mundt 140d5a4904 numa: mempolicy: trivial debug fixes.
Enabling debugging fails to build due to the nodemask variable in
do_mbind() having changed names, and then oopses on boot due to the
assumption that the nodemask can be dereferenced -- which doesn't work out
so well when the policy is changed to MPOL_DEFAULT with a NULL nodemask by
numa_default_policy().

This fixes it up, and switches from PDprintk() to pr_debug() while
we're at it.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:36 -07:00
Paul Mundt b71636e298 numa: mempolicy: dynamic interleave map for system init
This converts the default system init memory policy to use a dynamically
created node map instead of defaulting to all online nodes.  Nodes of a
certain size (>= 16MB) are judged to be suitable for interleave, and are added
to the map.  If all nodes are smaller in size, the largest one is
automatically selected.

Without this, tiny nodes find themselves out of memory before we even make it
to userspace.  Systems with large nodes will notice no change.

Only the system init policy is effected by this change, the regular
MPOL_DEFAULT policy is still switched to later on in the boot process as
normal.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Cc: Andi Kleen <ak@suse.de>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:36 -07:00
Christoph Lameter 0dc952dc3e [PATCH] Page migration: Fix vma flag checking
Currently we do not check for vma flags if sys_move_pages is called to move
individual pages.  If sys_migrate_pages is called to move pages then we
check for vm_flags that indicate a non migratable vma but that still
includes VM_LOCKED and we can migrate mlocked pages.

Extract the vma_migratable check from mm/mempolicy.c, fix it and put it
into migrate.h so that is can be used from both locations.

Problem was spotted by Lee Schermerhorn

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-05 07:57:51 -08:00
KAMEZAWA Hiroyuki 8af5e2eb3c [PATCH] fix mempolicy's check on a system with memory-less-node
bind_zonelist() can create zero-length zonelist if there is a
memory-less-node.  This patch checks the length of zonelist.  If length is
0, returns -EINVAL.

tested on ia64/NUMA with memory-less-node.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Andi Kleen <ak@suse.de>
Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-20 17:10:13 -08:00
Christoph Lameter 6267276f3f [PATCH] optional ZONE_DMA: deal with cases of ZONE_DMA meaning the first zone
This patchset follows up on the earlier work in Andrew's tree to reduce the
number of zones.  The patches allow to go to a minimum of 2 zones.  This one
allows also to make ZONE_DMA optional and therefore the number of zones can be
reduced to one.

ZONE_DMA is usually used for ISA DMA devices.  There are a number of reasons
why we would not want to have ZONE_DMA

1. Some arches do not need ZONE_DMA at all.

2. With the advent of IOMMUs DMA zones are no longer needed.
   The necessity of DMA zones may drastically be reduced
   in the future. This patchset allows a compilation of
   a kernel without that overhead.

3. Devices that require ISA DMA get rare these days. All
   my systems do not have any need for ISA DMA.

4. The presence of an additional zone unecessarily complicates
   VM operations because it must be scanned and balancing
   logic must operate on its.

5. With only ZONE_NORMAL one can reach the situation where
   we have only one zone. This will allow the unrolling of many
   loops in the VM and allows the optimization of varous
   code paths in the VM.

6. Having only a single zone in a NUMA system results in a
   1-1 correspondence between nodes and zones. Various additional
   optimizations to critical VM paths become possible.

Many systems today can operate just fine with a single zone.  If you look at
what is in ZONE_DMA then one usually sees that nothing uses it.  The DMA slabs
are empty (Some arches use ZONE_DMA instead of ZONE_NORMAL, then ZONE_NORMAL
will be empty instead).

On all of my systems (i386, x86_64, ia64) ZONE_DMA is completely empty.  Why
constantly look at an empty zone in /proc/zoneinfo and empty slab in
/proc/slabinfo?  Non i386 also frequently have no need for ZONE_DMA and zones
stay empty.

The patchset was tested on i386 (UP / SMP), x86_64 (UP, NUMA) and ia64 (NUMA).

The RFC posted earlier (see
http://marc.theaimsgroup.com/?l=linux-kernel&m=115231723513008&w=2) had lots
of #ifdefs in them.  An effort has been made to minize the number of #ifdefs
and make this as compact as possible.  The job was made much easier by the
ongoing efforts of others to extract common arch specific functionality.

I have been running this for awhile now on my desktop and finally Linux is
using all my available RAM instead of leaving the 16MB in ZONE_DMA untouched:

christoph@pentium940:~$ cat /proc/zoneinfo
Node 0, zone   Normal
  pages free     4435
        min      1448
        low      1810
        high     2172
        active   241786
        inactive 210170
        scanned  0 (a: 0 i: 0)
        spanned  524224
        present  524224
    nr_anon_pages 61680
    nr_mapped    14271
    nr_file_pages 390264
    nr_slab_reclaimable 27564
    nr_slab_unreclaimable 1793
    nr_page_table_pages 449
    nr_dirty     39
    nr_writeback 0
    nr_unstable  0
    nr_bounce    0
    cpu: 0 pcp: 0
              count: 156
              high:  186
              batch: 31
    cpu: 0 pcp: 1
              count: 9
              high:  62
              batch: 15
  vm stats threshold: 20
    cpu: 1 pcp: 0
              count: 177
              high:  186
              batch: 31
    cpu: 1 pcp: 1
              count: 12
              high:  62
              batch: 15
  vm stats threshold: 20
  all_unreclaimable: 0
  prev_priority:     12
  temp_priority:     12
  start_pfn:         0

This patch:

In two places in the VM we use ZONE_DMA to refer to the first zone.  If
ZONE_DMA is optional then other zones may be first.  So simply replace
ZONE_DMA with zone 0.

This also fixes ZONETABLE_PGSHIFT.  If we have only a single zone then
ZONES_PGSHIFT may become 0 because there is no need anymore to encode the zone
number related to a pgdat.  However, we still need a zonetable to index all
the zones for each node if this is a NUMA system.  Therefore define
ZONETABLE_SHIFT unconditionally as the offset of the ZONE field in page flags.

[apw@shadowen.org: fix mismerge]
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@suse.de>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Matthew Wilcox <willy@debian.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11 10:51:18 -08:00
Christoph Lameter 30150f8d7b [PATCH] mbind: restrict nodes to the currently allowed cpuset
Currently one can specify an arbitrary node mask to mbind that includes
nodes not allowed.  If that is done with an interleave policy then we will
go around all the nodes.  Those outside of the currently allowed cpuset
will be redirected to the border nodes.  Interleave will then create
imbalances at the borders of the cpuset.

This patch restricts the nodes to the currently allowed cpuset.

The RFC for this patch was discussed at
http://marc.theaimsgroup.com/?t=116793842100004&r=1&w=2

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-01-23 07:52:06 -08:00
Josef Sipek e9536ae720 [PATCH] struct path: convert mm
Signed-off-by: Josef Sipek <jsipek@fsl.cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:47 -08:00
Helge Deller 15ad7cdcfd [PATCH] struct seq_operations and struct file_operations constification
- move some file_operations structs into the .rodata section

 - move static strings from policy_types[] array into the .rodata section

 - fix generic seq_operations usages, so that those structs may be defined
   as "const" as well

[akpm@osdl.org: couple of fixes]
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:46 -08:00
Christoph Lameter e94b176609 [PATCH] slab: remove SLAB_KERNEL
SLAB_KERNEL is an alias of GFP_KERNEL.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:24 -08:00
Andy Whitcroft 25ba77c141 [PATCH] numa node ids are int, page_to_nid and zone_to_nid should return int
NUMA node ids are passed as either int or unsigned int almost exclusivly
page_to_nid and zone_to_nid both return unsigned long.  This is a throw
back to when page_to_nid was a #define and was thus exposing the real type
of the page flags field.

In addition to fixing up the definitions of page_to_nid and zone_to_nid I
audited the users of these functions identifying the following incorrect
uses:

1) mm/page_alloc.c show_node() -- printk dumping the node id,
2) include/asm-ia64/pgalloc.h pgtable_quicklist_free() -- comparison
   against numa_node_id() which returns an int from cpu_to_node(), and
3) mm/mpolicy.c check_pte_range -- used as an index in node_isset which
   uses bit_set which in generic code takes an int.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:23 -08:00
Paul Jackson 9276b1bc96 [PATCH] memory page_alloc zonelist caching speedup
Optimize the critical zonelist scanning for free pages in the kernel memory
allocator by caching the zones that were found to be full recently, and
skipping them.

Remembers the zones in a zonelist that were short of free memory in the
last second.  And it stashes a zone-to-node table in the zonelist struct,
to optimize that conversion (minimize its cache footprint.)

Recent changes:

    This differs in a significant way from a similar patch that I
    posted a week ago.  Now, instead of having a nodemask_t of
    recently full nodes, I have a bitmask of recently full zones.
    This solves a problem that last weeks patch had, which on
    systems with multiple zones per node (such as DMA zone) would
    take seeing any of these zones full as meaning that all zones
    on that node were full.

    Also I changed names - from "zonelist faster" to "zonelist cache",
    as that seemed to better convey what we're doing here - caching
    some of the key zonelist state (for faster access.)

    See below for some performance benchmark results.  After all that
    discussion with David on why I didn't need them, I went and got
    some ;).  I wanted to verify that I had not hurt the normal case
    of memory allocation noticeably.  At least for my one little
    microbenchmark, I found (1) the normal case wasn't affected, and
    (2) workloads that forced scanning across multiple nodes for
    memory improved up to 10% fewer System CPU cycles and lower
    elapsed clock time ('sys' and 'real').  Good.  See details, below.

    I didn't have the logic in get_page_from_freelist() for various
    full nodes and zone reclaim failures correct.  That should be
    fixed up now - notice the new goto labels zonelist_scan,
    this_zone_full, and try_next_zone, in get_page_from_freelist().

There are two reasons I persued this alternative, over some earlier
proposals that would have focused on optimizing the fake numa
emulation case by caching the last useful zone:

 1) Contrary to what I said before, we (SGI, on large ia64 sn2 systems)
    have seen real customer loads where the cost to scan the zonelist
    was a problem, due to many nodes being full of memory before
    we got to a node we could use.  Or at least, I think we have.
    This was related to me by another engineer, based on experiences
    from some time past.  So this is not guaranteed.  Most likely, though.

    The following approach should help such real numa systems just as
    much as it helps fake numa systems, or any combination thereof.

 2) The effort to distinguish fake from real numa, using node_distance,
    so that we could cache a fake numa node and optimize choosing
    it over equivalent distance fake nodes, while continuing to
    properly scan all real nodes in distance order, was going to
    require a nasty blob of zonelist and node distance munging.

    The following approach has no new dependency on node distances or
    zone sorting.

See comment in the patch below for a description of what it actually does.

Technical details of note (or controversy):

 - See the use of "zlc_active" and "did_zlc_setup" below, to delay
   adding any work for this new mechanism until we've looked at the
   first zone in zonelist.  I figured the odds of the first zone
   having the memory we needed were high enough that we should just
   look there, first, then get fancy only if we need to keep looking.

 - Some odd hackery was needed to add items to struct zonelist, while
   not tripping up the custom zonelists built by the mm/mempolicy.c
   code for MPOL_BIND.  My usual wordy comments below explain this.
   Search for "MPOL_BIND".

 - Some per-node data in the struct zonelist is now modified frequently,
   with no locking.  Multiple CPU cores on a node could hit and mangle
   this data.  The theory is that this is just performance hint data,
   and the memory allocator will work just fine despite any such mangling.
   The fields at risk are the struct 'zonelist_cache' fields 'fullzones'
   (a bitmask) and 'last_full_zap' (unsigned long jiffies).  It should
   all be self correcting after at most a one second delay.

 - This still does a linear scan of the same lengths as before.  All
   I've optimized is making the scan faster, not algorithmically
   shorter.  It is now able to scan a compact array of 'unsigned
   short' in the case of many full nodes, so one cache line should
   cover quite a few nodes, rather than each node hitting another
   one or two new and distinct cache lines.

 - If both Andi and Nick don't find this too complicated, I will be
   (pleasantly) flabbergasted.

 - I removed the comment claiming we only use one cachline's worth of
   zonelist.  We seem, at least in the fake numa case, to have put the
   lie to that claim.

 - I pay no attention to the various watermarks and such in this performance
   hint.  A node could be marked full for one watermark, and then skipped
   over when searching for a page using a different watermark.  I think
   that's actually quite ok, as it will tend to slightly increase the
   spreading of memory over other nodes, away from a memory stressed node.

===============

Performance - some benchmark results and analysis:

This benchmark runs a memory hog program that uses multiple
threads to touch alot of memory as quickly as it can.

Multiple runs were made, touching 12, 38, 64 or 90 GBytes out of
the total 96 GBytes on the system, and using 1, 19, 37, or 55
threads (on a 56 CPU system.)  System, user and real (elapsed)
timings were recorded for each run, shown in units of seconds,
in the table below.

Two kernels were tested - 2.6.18-mm3 and the same kernel with
this zonelist caching patch added.  The table also shows the
percentage improvement the zonelist caching sys time is over
(lower than) the stock *-mm kernel.

      number     2.6.18-mm3	   zonelist-cache    delta (< 0 good)	percent
 GBs    N  	------------	   --------------    ----------------	systime
 mem threads   sys user  real	  sys  user  real     sys  user  real	 better
  12	 1     153   24   177	  151	 24   176      -2     0    -1	   1%
  12	19	99   22     8	   99	 22	8	0     0     0	   0%
  12	37     111   25     6	  112	 25	6	1     0     0	  -0%
  12	55     115   25     5	  110	 23	5      -5    -2     0	   4%
  38	 1     502   74   576	  497	 73   570      -5    -1    -6	   0%
  38	19     426   78    48	  373	 76    39     -53    -2    -9	  12%
  38	37     544   83    36	  547	 82    36	3    -1     0	  -0%
  38	55     501   77    23	  511	 80    24      10     3     1	  -1%
  64	 1     917  125  1042	  890	124  1014     -27    -1   -28	   2%
  64	19    1118  138   119	  965	141   103    -153     3   -16	  13%
  64	37    1202  151    94	 1136	150    81     -66    -1   -13	   5%
  64	55    1118  141    61	 1072	140    58     -46    -1    -3	   4%
  90	 1    1342  177  1519	 1275	174  1450     -67    -3   -69	   4%
  90	19    2392  199   192	 2116	189   176    -276   -10   -16	  11%
  90	37    3313  238   175	 2972	225   145    -341   -13   -30	  10%
  90	55    1948  210   104	 1843	213   100    -105     3    -4	   5%

Notes:
 1) This test ran a memory hog program that started a specified number N of
    threads, and had each thread allocate and touch 1/N'th of
    the total memory to be used in the test run in a single loop,
    writing a constant word to memory, one store every 4096 bytes.
    Watching this test during some earlier trial runs, I would see
    each of these threads sit down on one CPU and stay there, for
    the remainder of the pass, a different CPU for each thread.

 2) The 'real' column is not comparable to the 'sys' or 'user' columns.
    The 'real' column is seconds wall clock time elapsed, from beginning
    to end of that test pass.  The 'sys' and 'user' columns are total
    CPU seconds spent on that test pass.  For a 19 thread test run,
    for example, the sum of 'sys' and 'user' could be up to 19 times the
    number of 'real' elapsed wall clock seconds.

 3) Tests were run on a fresh, single-user boot, to minimize the amount
    of memory already in use at the start of the test, and to minimize
    the amount of background activity that might interfere.

 4) Tests were done on a 56 CPU, 28 Node system with 96 GBytes of RAM.

 5) Notice that the 'real' time gets large for the single thread runs, even
    though the measured 'sys' and 'user' times are modest.  I'm not sure what
    that means - probably something to do with it being slow for one thread to
    be accessing memory along ways away.  Perhaps the fake numa system, running
    ostensibly the same workload, would not show this substantial degradation
    of 'real' time for one thread on many nodes -- lets hope not.

 6) The high thread count passes (one thread per CPU - on 55 of 56 CPUs)
    ran quite efficiently, as one might expect.  Each pair of threads needed
    to allocate and touch the memory on the node the two threads shared, a
    pleasantly parallizable workload.

 7) The intermediate thread count passes, when asking for alot of memory forcing
    them to go to a few neighboring nodes, improved the most with this zonelist
    caching patch.

Conclusions:
 * This zonelist cache patch probably makes little difference one way or the
   other for most workloads on real numa hardware, if those workloads avoid
   heavy off node allocations.
 * For memory intensive workloads requiring substantial off-node allocations
   on real numa hardware, this patch improves both kernel and elapsed timings
   up to ten per-cent.
 * For fake numa systems, I'm optimistic, but will have to leave that up to
   Rohit Seth to actually test (once I get him a 2.6.18 backport.)

Signed-off-by: Paul Jackson <pj@sgi.com>
Cc: Rohit Seth <rohitseth@google.com>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: David Rientjes <rientjes@cs.washington.edu>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:20 -08:00
Keith Owens 6993974997 [PATCH] Fix do_mbind warning with CONFIG_MIGRATION=n
With CONFIG_MIGRATION=n

mm/mempolicy.c: In function 'do_mbind':
mm/mempolicy.c:796: warning: passing argument 2 of 'migrate_pages' from incompatible pointer type

Signed-off-by: Keith Owens <kaos@ocs.com.au>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11 11:14:19 -07:00
Alexey Dobriyan 52978be636 [PATCH] kmemdup: some users
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-01 00:39:19 -07:00
Christoph Lameter 765c4507af [PATCH] GFP_THISNODE for the slab allocator
This patch insures that the slab node lists in the NUMA case only contain
slabs that belong to that specific node.  All slab allocations use
GFP_THISNODE when calling into the page allocator.  If an allocation fails
then we fall back in the slab allocator according to the zonelists appropriate
for a certain context.

This allows a replication of the behavior of alloc_pages and alloc_pages node
in the slab layer.

Currently allocations requested from the page allocator may be redirected via
cpusets to other nodes.  This results in remote pages on nodelists and that in
turn results in interrupt latency issues during cache draining.  Plus the slab
is handing out memory as local when it is really remote.

Fallback for slab memory allocations will occur within the slab allocator and
not in the page allocator.  This is necessary in order to be able to use the
existing pools of objects on the nodes that we fall back to before adding more
pages to a slab.

The fallback function insures that the nodes we fall back to obey cpuset
restrictions of the current context.  We do not allocate objects from outside
of the current cpuset context like before.

Note that the implementation of locality constraints within the slab allocator
requires importing logic from the page allocator.  This is a mischmash that is
not that great.  Other allocators (uncached allocator, vmalloc, huge pages)
face similar problems and have similar minimal reimplementations of the basic
fallback logic of the page allocator.  There is another way of implementing a
slab by avoiding per node lists (see modular slab) but this wont work within
the existing slab.

V1->V2:
- Use NUMA_BUILD to avoid #ifdef CONFIG_NUMA
- Exploit GFP_THISNODE being 0 in the NON_NUMA case to avoid another
  #ifdef

[akpm@osdl.org: build fix]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-27 08:26:12 -07:00
Christoph Lameter 89fa30242f [PATCH] NUMA: Add zone_to_nid function
There are many places where we need to determine the node of a zone.
Currently we use a difficult to read sequence of pointer dereferencing.
Put that into an inline function and use throughout VM.  Maybe we can find
a way to optimize the lookup in the future.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-26 08:48:52 -07:00
Christoph Lameter 9b819d204c [PATCH] Add __GFP_THISNODE to avoid fallback to other nodes and ignore cpuset/memory policy restrictions
Add a new gfp flag __GFP_THISNODE to avoid fallback to other nodes.  This
flag is essential if a kernel component requires memory to be located on a
certain node.  It will be needed for alloc_pages_node() to force allocation
on the indicated node and for alloc_pages() to force allocation on the
current node.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-26 08:48:50 -07:00
Christoph Lameter 19655d3487 [PATCH] linearly index zone->node_zonelists[]
I wonder why we need this bitmask indexing into zone->node_zonelists[]?

We always start with the highest zone and then include all lower zones
if we build zonelists.

Are there really cases where we need allocation from ZONE_DMA or
ZONE_HIGHMEM but not ZONE_NORMAL? It seems that the current implementation
of highest_zone() makes that already impossible.

If we go linear on the index then gfp_zone() == highest_zone() and a lot
of definitions fall by the wayside.

We can now revert back to the use of gfp_zone() in mempolicy.c ;-)

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-26 08:48:47 -07:00
Christoph Lameter 2f6726e54a [PATCH] Apply type enum zone_type
After we have done this we can now do some typing cleanup.

The memory policy layer keeps a policy_zone that specifies
the zone that gets memory policies applied. This variable
can now be of type enum zone_type.

The check_highest_zone function and the build_zonelists funnctionm must
then also take a enum zone_type parameter.

Plus there are a number of loops over zones that also should use
zone_type.

We run into some troubles at some points with functions that need a
zone_type variable to become -1. Fix that up.

[pj@sgi.com: fix set_mempolicy() crash]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-26 08:48:47 -07:00
Christoph Lameter 4e4785bcf0 [PATCH] mempolicies: fix policy_zone check
There is a check in zonelist_policy that compares pieces of the bitmap
obtained from a gfp mask via GFP_ZONETYPES with a zone number in function
zonelist_policy().

The bitmap is an ORed mask of __GFP_DMA, __GFP_DMA32 and __GFP_HIGHMEM.
The policy_zone is a zone number with the possible values of ZONE_DMA,
ZONE_DMA32, ZONE_HIGHMEM and ZONE_NORMAL. These are two different domains
of values.

For some reason seemed to work before the zone reduction patchset (It
definitely works on SGI boxes since we just have one zone and the check
cannot fail).

With the zone reduction patchset this check definitely fails on systems
with two zones if the system actually has memory in both zones.

This is because ZONE_NORMAL is selected using no __GFP flag at
all and thus gfp_zone(gfpmask) == 0. ZONE_DMA is selected when __GFP_DMA
is set. __GFP_DMA is 0x01.  So gfp_zone(gfpmask) == 1.

policy_zone is set to ZONE_NORMAL (==1) if ZONE_NORMAL and ZONE_DMA are
populated.

For ZONE_NORMAL gfp_zone(<no _GFP_DMA>) yields 0 which is <
policy_zone(ZONE_NORMAL) and so policy is not applied to regular memory
allocations!

Instead gfp_zone(__GFP_DMA) == 1 which results in policy being applied
to DMA allocations!

What we realy want in that place is to establish the highest allowable
zone for a given gfp_mask. If the highest zone is higher or equal to the
policy_zone then memory policies need to be applied. We have such
a highest_zone() function in page_alloc.c.

So move the highest_zone() function from mm/page_alloc.c into
include/linux/gfp.h.  On the way we simplify the function and use the new
zone_type that was also introduced with the zone reduction patchset plus we
also specify the right type for the gfp flags parameter.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-26 08:48:47 -07:00
Nishanth Aravamudan 3b98b087fc [PATCH] fix NUMA interleaving for huge pages
Since vma->vm_pgoff is in units of smallpages, VMAs for huge pages have the
lower HPAGE_SHIFT - PAGE_SHIFT bits always cleared, which results in badd
offsets to the interleave functions.  Take this difference from small pages
into account when calculating the offset.  This does add a 0-bit shift into
the small-page path (via alloc_page_vma()), but I think that is negligible.
 Also add a BUG_ON to prevent the offset from growing due to a negative
right-shift, which probably shouldn't be allowed anyways.

Tested on an 8-memory node ppc64 NUMA box and got the interleaving I
expected.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Adam Litke <agl@us.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Acked-by: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-01 11:39:10 -07:00
Christoph Lameter ca889e6c45 [PATCH] Use Zoned VM Counters for NUMA statistics
The numa statistics are really event counters.  But they are per node and
so we have had special treatment for these counters through additional
fields on the pcp structure.  We can now use the per zone nature of the
zoned VM counters to realize these.

This will shrink the size of the pcp structure on NUMA systems.  We will
have some room to add additional per zone counters that will all still fit
in the same cacheline.

 Bits	Prior pcp size	  	Size after patch	We can add
 ------------------------------------------------------------------
 64	128 bytes (16 words)	80 bytes (10 words)	48
 32	 76 bytes (19 words)	56 bytes (14 words)	8 (64 byte cacheline)
							72 (128 byte)

Remove the special statistics for numa and replace them with zoned vm
counters.  This has the side effect that global sums of these events now
show up in /proc/vmstat.

Also take the opportunity to move the zone_statistics() function from
page_alloc.c into vmstat.c.

Discussions:
V2 http://marc.theaimsgroup.com/?t=115048227000002&r=1&w=2

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Acked-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-30 11:25:36 -07:00
Eric W. Biederman 99f8955183 [PATCH] proc: don't lock task_structs indefinitely
Every inode in /proc holds a reference to a struct task_struct.  If a
directory or file is opened and remains open after the the task exits this
pinning continues.  With 8K stacks on a 32bit machine the amount pinned per
file descriptor is about 10K.

Normally I would figure a reasonable per user process limit is about 100
processes.  With 80 processes, with a 1000 file descriptors each I can trigger
the 00M killer on a 32bit kernel, because I have pinned about 800MB of useless
data.

This patch replaces the struct task_struct pointer with a pointer to a struct
task_ref which has a struct task_struct pointer.  The so the pinning of dead
tasks does not happen.

The code now has to contend with the fact that the task may now exit at any
time.  Which is a little but not muh more complicated.

With this change it takes about 1000 processes each opening up 1000 file
descriptors before I can trigger the OOM killer.  Much better.

[mlp@google.com: task_mmu small fixes]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Paul Jackson <pj@sgi.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Albert Cahalan <acahalan@gmail.com>
Signed-off-by: Prasanna Meda <mlp@google.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:25 -07:00
Christoph Lameter 7b2259b3e5 [PATCH] page migration: Support a vma migration function
Hooks for calling vma specific migration functions

With this patch a vma may define a vma->vm_ops->migrate function.  That
function may perform page migration on its own (some vmas may not contain page
structs and therefore cannot be handled by regular page migration.  Pages in a
vma may require special preparatory treatment before migration is possible
etc) .  Only mmap_sem is held when the migration function is called.  The
migrate() function gets passed two sets of nodemasks describing the source and
the target of the migration.  The flags parameter either contains

MPOL_MF_MOVE	which means that only pages used exclusively by
		the specified mm should be moved

or

MPOL_MF_MOVE_ALL which means that pages shared with other processes
		should also be moved.

The migration function returns 0 on success or an error condition.  An error
condition will prevent regular page migration from occurring.

On its own this patch cannot be included since there are no users for this
functionality.  But it seems that the uncached allocator will need this
functionality at some point.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-25 10:00:55 -07:00
David Quigley 86c3a7645c [PATCH] SELinux: add security_task_movememory calls to mm code
This patch inserts security_task_movememory hook calls into memory management
code to enable security modules to mediate this operation between tasks.

Since the last posting, the hook has been renamed following feedback from
Christoph Lameter.

Signed-off-by: David Quigley <dpquigl@tycho.nsa.gov>
Acked-by:  Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
Cc: Andi Kleen <ak@muc.de>
Acked-by: Christoph Lameter <clameter@sgi.com>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 07:42:54 -07:00
Christoph Lameter 742755a1d8 [PATCH] page migration: sys_move_pages(): support moving of individual pages
move_pages() is used to move individual pages of a process. The function can
be used to determine the location of pages and to move them onto the desired
node. move_pages() returns status information for each page.

long move_pages(pid, number_of_pages_to_move,
		addresses_of_pages[],
		nodes[] or NULL,
		status[],
		flags);

The addresses of pages is an array of void * pointing to the
pages to be moved.

The nodes array contains the node numbers that the pages should be moved
to. If a NULL is passed instead of an array then no pages are moved but
the status array is updated. The status request may be used to determine
the page state before issuing another move_pages() to move pages.

The status array will contain the state of all individual page migration
attempts when the function terminates. The status array is only valid if
move_pages() completed successfullly.

Possible page states in status[]:

0..MAX_NUMNODES	The page is now on the indicated node.

-ENOENT		Page is not present

-EACCES		Page is mapped by multiple processes and can only
		be moved if MPOL_MF_MOVE_ALL is specified.

-EPERM		The page has been mlocked by a process/driver and
		cannot be moved.

-EBUSY		Page is busy and cannot be moved. Try again later.

-EFAULT		Invalid address (no VMA or zero page).

-ENOMEM		Unable to allocate memory on target node.

-EIO		Unable to write back page. The page must be written
		back in order to move it since the page is dirty and the
		filesystem does not provide a migration function that
		would allow the moving of dirty pages.

-EINVAL		A dirty page cannot be moved. The filesystem does not provide
		a migration function and has no ability to write back pages.

The flags parameter indicates what types of pages to move:

MPOL_MF_MOVE	Move pages that are only mapped by the process.

MPOL_MF_MOVE_ALL Also move pages that are mapped by multiple processes.
		Requires sufficient capabilities.

Possible return codes from move_pages()

-ENOENT		No pages found that would require moving. All pages
		are either already on the target node, not present, had an
		invalid address or could not be moved because they were
		mapped by multiple processes.

-EINVAL		Flags other than MPOL_MF_MOVE(_ALL) specified or an attempt
		to migrate pages in a kernel thread.

-EPERM		MPOL_MF_MOVE_ALL specified without sufficient priviledges.
		or an attempt to move a process belonging to another user.

-EACCES		One of the target nodes is not allowed by the current cpuset.

-ENODEV		One of the target nodes is not online.

-ESRCH		Process does not exist.

-E2BIG		Too many pages to move.

-ENOMEM		Not enough memory to allocate control array.

-EFAULT		Parameters could not be accessed.

A test program for move_pages() may be found with the patches
on ftp.kernel.org:/pub/linux/kernel/people/christoph/pmig/patches-2.6.17-rc4-mm3

From: Christoph Lameter <clameter@sgi.com>

  Detailed results for sys_move_pages()

  Pass a pointer to an integer to get_new_page() that may be used to
  indicate where the completion status of a migration operation should be
  placed.  This allows sys_move_pags() to report back exactly what happened to
  each page.

  Wish there would be a better way to do this. Looks a bit hacky.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Jes Sorensen <jes@trained-monkey.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 07:42:53 -07:00
Christoph Lameter 95a402c384 [PATCH] page migration: use allocator function for migrate_pages()
Instead of passing a list of new pages, pass a function to allocate a new
page.  This allows the correct placement of MPOL_INTERLEAVE pages during page
migration.  It also further simplifies the callers of migrate pages.
migrate_pages() becomes similar to migrate_pages_to() so drop
migrate_pages_to().  The batching of new page allocations becomes unnecessary.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Jes Sorensen <jes@trained-monkey.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 07:42:53 -07:00
Christoph Lameter aaa994b300 [PATCH] page migration: handle freeing of pages in migrate_pages()
Do not leave pages on the lists passed to migrate_pages().  Seems that we will
not need any postprocessing of pages.  This will simplify the handling of
pages by the callers of migrate_pages().

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Jes Sorensen <jes@trained-monkey.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 07:42:53 -07:00
Christoph Lameter 6d472be378 [PATCH] Remove cond_resched in gather_stats()
gather_stats() is called with a spinlock held from check_pte_range.  We
cannot reschedule with a lock held.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-20 07:54:03 -07:00
Alexey Dobriyan 7f927fcc2f [PATCH] Typo fixes
Fix a lot of typos.  Eyeballed by jmc@ in OpenBSD.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 09:16:08 -08:00
Paul Jackson c61afb181c [PATCH] cpuset memory spread slab cache optimizations
The hooks in the slab cache allocator code path for support of NUMA
mempolicies and cpuset memory spreading are in an important code path.  Many
systems will use neither feature.

This patch optimizes those hooks down to a single check of some bits in the
current tasks task_struct flags.  For non NUMA systems, this hook and related
code is already ifdef'd out.

The optimization is done by using another task flag, set if the task is using
a non-default NUMA mempolicy.  Taking this flag bit along with the
PF_SPREAD_PAGE and PF_SPREAD_SLAB flag bits added earlier in this 'cpuset
memory spreading' patch set, one can check for the combination of any of these
special case memory placement mechanisms with a single test of the current
tasks task_struct flags.

This patch also tightens up the code, to save a few bytes of kernel text
space, and moves some of it out of line.  Due to the nested inlines called
from multiple places, we were ending up with three copies of this code, which
once we get off the main code path (for local node allocation) seems a bit
wasteful of instruction memory.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-24 07:33:23 -08:00
Christoph Lameter b20a35035f [PATCH] page migration reorg
Centralize the page migration functions in anticipation of additional
tinkering.  Creates a new file mm/migrate.c

1. Extract buffer_migrate_page() from fs/buffer.c

2. Extract central migration code from vmscan.c

3. Extract some components from mempolicy.c

4. Export pageout() and remove_from_swap() from vmscan.c

5. Make it possible to configure NUMA systems without page migration
   and non-NUMA systems with page migration.

I had to so some #ifdeffing in mempolicy.c that may need a cleanup.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-22 07:54:06 -08:00
Pekka Enberg fcc234f888 [PATCH] mm: kill kmem_cache_t usage
We have struct kmem_cache now so use it instead of the old typedef.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-22 07:53:58 -08:00
Christoph Lameter 90036ee593 [PATCH] page migration: Fail with error if swap not setup
Currently the migration of anonymous pages will silently fail if no swap is
setup.  This patch makes page migration functions check for available swap
and fail with -ENODEV if no swap space is available.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-17 07:51:25 -08:00
Christoph Lameter 74c0024105 [PATCH] Consistent capabilites associated with MPOL_MOVE_ALL
It seems that setting scheduling policy and priorities is also the kind of
thing that might be performed in apps that also use the NUMA API, so it
would seem consistent to use CAP_SYS_NICE for NUMA also.

So use CAP_SYS_NICE for controlling migration permissions.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-14 21:43:02 -08:00
Andrew Morton 7f709ed0e3 [PATCH] numa_maps-update fix
Fix the mm/mempolicy.c build for !CONFIG_HUGETLB_PAGE.

Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: Martin Bligh <mbligh@google.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-08 14:14:00 -08:00
Christoph Lameter 397874dfe9 [PATCH] numa_maps update
Change the format of numa_maps to be more compact and contain additional
information that is useful for managing and troubleshooting memory on a
NUMA system.  Numa_maps can now also support huge pages.

Fixes:

1. More compact format. Only display fields if they contain additional
	information.

2. Always display information for all vmas. The old numa_maps did not display
	vma with no mapped entries. This was a bit confusing because page
	migration removes ptes for file backed vmas. After page migration
	a part of the vmas vanished.

3. Rename maxref to maxmap. This is the maximum mapcount of all the pages
	in a vma and may be used as an indicator as to how many processes
	may be using a certain vma.

4. Include the ability to scan over huge page vmas.

New items shown:

dirty
	Number of pages in a vma that have either the dirty bit set in the
	page_struct or in the pte.

file=<filename>
	The file backing the pages if any

stack
	Stack area

heap
	Heap area

huge
	Huge page area. The number of pages shows is the number of huge
	pages not the regular sized pages.

swapcache
	Number of pages with swap references. Must be >0 in order to
	be shown.

active
	Number of active pages. Only displayed if different from the number
	of pages mapped.

writeback
	Number of pages under writeback. Only displayed if >0.

Sample ouput of a process using huge pages:

00000000 default
2000000000000000 default file=/lib/ld-2.3.90.so mapped=13 mapmax=30 N0=13
2000000000044000 default file=/lib/ld-2.3.90.so anon=2 dirty=2 swapcache=2 N2=2
2000000000064000 default file=/lib/librt-2.3.90.so mapped=2 active=1 N1=1 N3=1
2000000000074000 default file=/lib/librt-2.3.90.so
2000000000080000 default file=/lib/librt-2.3.90.so anon=1 swapcache=1 N2=1
2000000000084000 default
2000000000088000 default file=/lib/libc-2.3.90.so mapped=52 mapmax=32 active=48 N0=52
20000000002bc000 default file=/lib/libc-2.3.90.so
20000000002c8000 default file=/lib/libc-2.3.90.so anon=3 dirty=2 swapcache=3 active=2 N1=1 N2=2
20000000002d4000 default anon=1 swapcache=1 N1=1
20000000002d8000 default file=/lib/libpthread-2.3.90.so mapped=8 mapmax=3 active=7 N2=2 N3=6
20000000002fc000 default file=/lib/libpthread-2.3.90.so
2000000000308000 default file=/lib/libpthread-2.3.90.so anon=1 dirty=1 swapcache=1 N1=1
200000000030c000 default anon=1 dirty=1 swapcache=1 N1=1
2000000000320000 default anon=1 dirty=1 N1=1
200000000071c000 default
2000000000720000 default anon=2 dirty=2 swapcache=1 N1=1 N2=1
2000000000f1c000 default
2000000000f20000 default anon=2 dirty=2 swapcache=1 active=1 N2=1 N3=1
200000000171c000 default
2000000001720000 default anon=1 dirty=1 swapcache=1 N1=1
2000000001b20000 default
2000000001b38000 default file=/lib/libgcc_s.so.1 mapped=2 N1=2
2000000001b48000 default file=/lib/libgcc_s.so.1
2000000001b54000 default file=/lib/libgcc_s.so.1 anon=1 dirty=1 active=0 N1=1
2000000001b58000 default file=/lib/libunwind.so.7.0.0 mapped=2 active=1 N1=2
2000000001b74000 default file=/lib/libunwind.so.7.0.0
2000000001b80000 default file=/lib/libunwind.so.7.0.0
2000000001b84000 default
4000000000000000 default file=/media/huge/test9 mapped=1 N1=1
6000000000000000 default file=/media/huge/test9 anon=1 dirty=1 active=0 N1=1
6000000000004000 default heap
607fffff7fffc000 default anon=1 dirty=1 swapcache=1 N2=1
607fffffff06c000 default stack anon=1 dirty=1 active=0 N1=1
8000000060000000 default file=/mnt/huge/test0 huge dirty=3 N1=3
8000000090000000 default file=/mnt/huge/test1 huge dirty=3 N0=1 N2=2
80000000c0000000 default file=/mnt/huge/test2 huge dirty=3 N1=1 N3=2

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-06 18:40:45 -08:00
Christoph Lameter a57ebfdb2c [PATCH] numa_maps: Fix potential crash on non IA64 platforms
numa_maps should not scan over huge vmas in order not to cause problems for
non IA64 platforms that may have pte entries pointing to huge pages in a
variety of ways in their page tables.  Add a simple check to ignore vmas
containing huge pages.

Signed-off-by: Christoph Lameter <clameter@engr.sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-02 08:33:07 -08:00
Christoph Lameter 511030bcd2 [PATCH] Fix sys_migrate_pages: Move all pages when invoked from root
Currently sys_migrate_pages only moves pages belonging to a process.  This
is okay when invoked from a regular user.  But if invoked from root it
should move all pages as documented in the migrate_pages manpage.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-28 20:53:43 -08:00
Christoph Lameter 1e275d406b [PATCH] page migration: Fix MPOL_INTERLEAVE behavior for migration via mbind()
migrate_pages_to() allocates a list of new pages on the intended target
node or with the intended policy and then uses the list of new pages as
targets for the migration of a list of pages out of place.

When the pages are allocated it is not clear which of the out of place
pages will be moved to the new pages.  So we cannot specify an address as
needed by alloc_page_vma().  This causes problem for MPOL_INTERLEAVE which
will currently allocate the pages on the first node of the set.  If mbind
is used with vma that has the policy of MPOL_INTERLEAVE then the
interleaving of pages may be destroyed.

This patch fixes that by generating a fake address for each alloc_page_vma
which will result is a distribution of pages as prescribed by
MPOL_INTERLEAVE.

Lee also noted that the sequence of nodes for the new pages seems to be
inverted.  So we also invert the way the lists of pages for migration are
build.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Looks-ok-to: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-24 14:31:38 -08:00
Alexey Dobriyan fcab6f3513 [PATCH] mm/mempolicy.c: fix 'if ();' typo
[akpm; it happens that the code was still correct, only inefficient ]

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-20 20:00:11 -08:00
Andi Kleen a9c930bac1 [PATCH] Fix units in mbind check
maxnode is a bit index and can't be directly compared against a byte length
like PAGE_SIZE

Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-20 20:00:10 -08:00
Chris Wright 636f13c174 [PATCH] sys_mbind sanity checking
Make sure maxnodes is safe size before calculating nlongs in
get_nodes().

Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-17 14:09:22 -08:00
Andi Kleen dd942ae331 [PATCH] Handle all and empty zones when setting up custom zonelists for mbind
The memory allocator doesn't like empty zones (which have an
uninitialized freelist), so a x86-64 system with a node fully
in GFP_DMA32 only would crash on mbind.

Fix that up by putting all possible zones as fallback into the zonelist
and skipping the empty ones.

In fact the code always enough allocated space for all zones,
but only used it for the highest. This change just uses all the
memory that was allocated before.

This should work fine for now, but whoever implements node hot removal
needs to fix this somewhere else too (or make sure zone datastructures
by itself never go away, only their memory)

Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-17 08:18:14 -08:00
Chen, Kenneth W 00ac59adfc [PATCH] x86_64: Fix memory policy build without CONFIG_HUGETLBFS
> mm/mempolicy.c: In function `huge_zonelist':
> mm/mempolicy.c:1045: error: `HPAGE_SHIFT' undeclared (first use in this function)
> mm/mempolicy.c:1045: error: (Each undeclared identifier is reported only once
> mm/mempolicy.c:1045: error: for each function it appears in.)
> make[1]: *** [mm/mempolicy.o] Error 1

Need to wrap huge_zonelist function with CONFIG_HUGETLBFS.

Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-04 16:43:14 -08:00
Christoph Lameter 7e2ab150d1 [PATCH] Direct Migration V9: upgrade MPOL_MF_MOVE and sys_migrate_pages()
Modify policy layer to support direct page migration

- Add migrate_pages_to() allowing the migration of a list of pages to a a
  specified node or to vma with a specific allocation policy in sets of
  MIGRATE_CHUNK_SIZE pages

- Modify do_migrate_pages() to do a staged move of pages from the source
  nodes to the target nodes.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-01 08:53:16 -08:00
Christoph Lameter 86c562a9d6 [PATCH] mm: optimize numa policy handling in slab allocator
Move the interrupt check from slab_node into ___cache_alloc and adds an
"unlikely()" to avoid pipeline stalls on some architectures.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-18 19:20:18 -08:00
Christoph Lameter dc85da15d4 [PATCH] NUMA policies in the slab allocator V2
This patch fixes a regression in 2.6.14 against 2.6.13 that causes an
imbalance in memory allocation during bootup.

The slab allocator in 2.6.13 is not numa aware and simply calls
alloc_pages().  This means that memory policies may control the behavior of
alloc_pages().  During bootup the memory policy is set to MPOL_INTERLEAVE
resulting in the spreading out of allocations during bootup over all
available nodes.  The slab allocator in 2.6.13 has only a single list of
slab pages.  As a result the per cpu slab cache and the spinlock controlled
page lists may contain slab entries from off node memory.  The slab
allocator in 2.6.13 makes no effort to discern the locality of an entry on
its lists.

The NUMA aware slab allocator in 2.6.14 controls locality of the slab pages
explicitly by calling alloc_pages_node().  The NUMA slab allocator manages
slab entries by having lists of available slab pages for each node.  The
per cpu slab cache can only contain slab entries associated with the node
local to the processor.  This guarantees that the default allocation mode
of the slab allocator always assigns local memory if available.

Setting MPOL_INTERLEAVE as a default policy during bootup has no effect
anymore.  In 2.6.14 all node unspecific slab allocations are performed on
the boot processor.  This means that most of key data structures are
allocated on one node.  Most processors will have to refer to these
structures making the boot node a potential bottleneck.  This may reduce
performance and cause unnecessary memory pressure on the boot node.

This patch implements NUMA policies in the slab layer.  There is the need
of explicit application of NUMA memory policies by the slab allcator itself
since the NUMA slab allocator does no longer let the page_allocator control
locality.

The check for policies is made directly at the beginning of __cache_alloc
using current->mempolicy.  The memory policy is already frequently checked
by the page allocator (alloc_page_vma() and alloc_page_current()).  So it
is highly likely that the cacheline is present.  For MPOL_INTERLEAVE
kmalloc() will spread out each request to one node after another so that an
equal distribution of allocations can be obtained during bootup.

It is not possible to push the policy check to lower layers of the NUMA
slab allocator since the per cpu caches are now only containing slab
entries from the current node.  If the policy says that the local node is
not to be preferred or forbidden then there is no point in checking the
slab cache or local list of slab pages.  The allocation better be directed
immediately to the lists containing slab entries for the allowed set of
nodes.

This way of applying policy also fixes another strange behavior in 2.6.13.
alloc_pages() is controlled by the memory allocation policy of the current
process.  It could therefore be that one process is running with
MPOL_INTERLEAVE and would f.e.  obtain a new page following that policy
since no slab entries are in the lists anymore.  A page can typically be
used for multiple slab entries but lets say that the current process is
only using one.  The other entries are then added to the slab lists.  These
are now non local entries in the slab lists despite of the possible
availability of local pages that would provide faster access and increase
the performance of the application.

Another process without MPOL_INTERLEAVE may now run and expect a local slab
entry from kmalloc().  However, there are still these free slab entries
from the off node page obtained from the other process via MPOL_INTERLEAVE
in the cache.  The process will then get an off node slab entry although
other slab entries may be available that are local to that process.  This
means that the policy if one process may contaminate the locality of the
slab caches for other processes.

This patch in effect insures that a per process policy is followed for the
allocation of slab entries and that there cannot be a memory policy
influence from one process to another.  A process with default policy will
always get a local slab entry if one is available.  And the process using
memory policies will get its memory arranged as requested.  Off-node slab
allocation will require the use of spinlocks and will make the use of per
cpu caches not possible.  A process using memory policies to redirect
allocations offnode will have to cope with additional lock overhead in
addition to the latency added by the need to access a remote slab entry.

Changes V1->V2
- Remove #ifdef CONFIG_NUMA by moving forward declaration into
  prior #ifdef CONFIG_NUMA section.

- Give the function determining the node number to use a saner
  name.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-18 19:20:18 -08:00
Christoph Lameter fc30128963 [PATCH] Simplify migrate_page_add
Simplify migrate_page_add after feedback from Hugh.  This also allows us to
drop one parameter from migrate_page_add.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-18 19:20:17 -08:00
Nick Piggin 053837fce7 [PATCH] mm: migration page refcounting fix
Migration code currently does not take a reference to target page
properly, so between unlocking the pte and trying to take a new
reference to the page with isolate_lru_page, anything could happen to
it.

Fix this by holding the pte lock until we get a chance to elevate the
refcount.

Other small cleanups while we're here.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-18 19:20:17 -08:00
Robin Holt 7339ff8302 [PATCH] Add tmpfs options for memory placement policies
Anything that writes into a tmpfs filesystem is liable to disproportionately
decrease the available memory on a particular node.  Since there's no telling
what sort of application (e.g.  dd/cp/cat) might be dropping large files
there, this lets the admin choose the appropriate default behavior for their
site's situation.

Introduce a tmpfs mount option which allows specifying a memory policy and
a second option to specify the nodelist for that policy.  With the default
policy, tmpfs will behave as it does today.  This patch adds support for
preferred, bind, and interleave policies.

The default policy will cause pages to be added to tmpfs files on the node
which is doing the writing.  Some jobs expect a single process to create
and manage the tmpfs files.  This results in a node which has a
significantly reduced number of free pages.

With this patch, the administrator can specify the policy and nodes for
that policy where they would prefer allocations.

This patch was originally written by Brent Casavant and Hugh Dickins.  I
added support for the bind and preferred policies and the mpol_nodelist
mount option.

Signed-off-by: Brent Casavant <bcasavan@sgi.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-14 18:27:07 -08:00
Christoph Lameter f4598c8b36 [PATCH] migration: make sure there is no attempt to migrate reserved pages.
This ensures that reserved pages are not migrated.  Reserved pages
currently cause the WARN_ON to trigger in migrate_page_add()

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-12 09:08:48 -08:00
Paul Jackson 4225399a66 [PATCH] cpuset: rebind vma mempolicies fix
Fix more of longstanding bug in cpuset/mempolicy interaction.

NUMA mempolicies (mm/mempolicy.c) are constrained by the current tasks cpuset
to just the Memory Nodes allowed by that cpuset.  The kernel maintains
internal state for each mempolicy, tracking what nodes are used for the
MPOL_INTERLEAVE, MPOL_BIND or MPOL_PREFERRED policies.

When a tasks cpuset memory placement changes, whether because the cpuset
changed, or because the task was attached to a different cpuset, then the
tasks mempolicies have to be rebound to the new cpuset placement, so as to
preserve the cpuset-relative numbering of the nodes in that policy.

An earlier fix handled such mempolicy rebinding for mempolicies attached to a
task.

This fix rebinds mempolicies attached to vma's (address ranges in a tasks
address space.) Due to the need to hold the task->mm->mmap_sem semaphore while
updating vma's, the rebinding of vma mempolicies has to be done when the
cpuset memory placement is changed, at which time mmap_sem can be safely
acquired.  The tasks mempolicy is rebound later, when the task next attempts
to allocate memory and notices that its task->cpuset_mems_generation is
out-of-date with its cpusets mems_generation.

Because walking the tasklist to find all tasks attached to a changing cpuset
requires holding tasklist_lock, a spinlock, one cannot update the vma's of the
affected tasks while doing the tasklist scan.  In general, one cannot acquire
a semaphore (which can sleep) while already holding a spinlock (such as
tasklist_lock).  So a list of mm references has to be built up during the
tasklist scan, then the tasklist lock dropped, then for each mm, its mmap_sem
acquired, and the vma's in that mm rebound.

Once the tasklist lock is dropped, affected tasks may fork new tasks, before
their mm's are rebound.  A kernel global 'cpuset_being_rebound' is set to
point to the cpuset being rebound (there can only be one; cpuset modifications
are done under a global 'manage_sem' semaphore), and the mpol_copy code that
is used to copy a tasks mempolicies during fork catches such forking tasks,
and ensures their children are also rebound.

When a task is moved to a different cpuset, it is easier, as there is only one
task involved.  It's mm->vma's are scanned, using the same
mpol_rebind_policy() as used above.

It may happen that both the mpol_copy hook and the update done via the
tasklist scan update the same mm twice.  This is ok, as the mempolicies of
each vma in an mm keep track of what mems_allowed they are relative to, and
safely no-op a second request to rebind to the same nodes.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:44 -08:00
Paul Jackson 74cb21553f [PATCH] cpuset: numa_policy_rebind cleanup
Cleanup, reorganize and make more robust the mempolicy.c code to rebind
mempolicies relative to the containing cpuset after a tasks memory placement
changes.

The real motivator for this cleanup patch is to lay more groundwork for the
upcoming patch to correctly rebind NUMA mempolicies that are attached to vma's
after the containing cpuset memory placement changes.

NUMA mempolicies are constrained by the cpuset their task is a member of.
When either (1) a task is moved to a different cpuset, or (2) the 'mems'
mems_allowed of a cpuset is changed, then the NUMA mempolicies have embedded
node numbers (for MPOL_BIND, MPOL_INTERLEAVE and MPOL_PREFERRED) that need to
be recalculated, relative to their new cpuset placement.

The old code used an unreliable method of determining what was the old
mems_allowed constraining the mempolicy.  It just looked at the tasks
mems_allowed value.  This sort of worked with the present code, that just
rebinds the -task- mempolicy, and leaves any -vma- mempolicies broken,
referring to the old nodes.  But in an upcoming patch, the vma mempolicies
will be rebound as well.  Then the order in which the various task and vma
mempolicies are updated will no longer be deterministic, and one can no longer
count on the task->mems_allowed holding the old value for as long as needed.
It's not even clear if the current code was guaranteed to work reliably for
task mempolicies.

So I added a mems_allowed field to each mempolicy, stating exactly what
mems_allowed the policy is relative to, and updated synchronously and reliably
anytime that the mempolicy is rebound.

Also removed a useless wrapper routine, numa_policy_rebind(), and had its
caller, cpuset_update_task_memory_state(), call directly to the rewritten
policy_rebind() routine, and made that rebind routine extern instead of
static, and added a "mpol_" prefix to its name, making it
mpol_rebind_policy().

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:44 -08:00
Paul Jackson 909d75a3b7 [PATCH] cpuset: implement cpuset_mems_allowed
Provide a cpuset_mems_allowed() method, which the sys_migrate_pages() code
needed, to obtain the mems_allowed vector of a cpuset, and replaced the
workaround in sys_migrate_pages() to call this new method.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:44 -08:00
Paul Jackson cf2a473c40 [PATCH] cpuset: combine refresh_mems and update_mems
The important code paths through alloc_pages_current() and alloc_page_vma(),
by which most kernel page allocations go, both called
cpuset_update_current_mems_allowed(), which in turn called refresh_mems().
-Both- of these latter two routines did a tasklock, got the tasks cpuset
pointer, and checked for out of date cpuset->mems_generation.

That was a silly duplication of code and waste of CPU cycles on an important
code path.

Consolidated those two routines into a single routine, called
cpuset_update_task_memory_state(), since it updates more than just
mems_allowed.

Changed all callers of either routine to call the new consolidated routine.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:43 -08:00
Paul Jackson 5966514db6 [PATCH] cpuset: mempolicy one more nodemask conversion
Finish converting mm/mempolicy.c from bitmaps to nodemasks.  The previous
conversion had left one routine using bitmaps, since it involved a
corresponding change to kernel/cpuset.c

Fix that interface by replacing with a simple macro that calls nodes_subset(),
or if !CONFIG_CPUSET, returns (1).

Signed-off-by: Paul Jackson <pj@sgi.com>
Cc: Christoph Lameter <christoph@lameter.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:42 -08:00
Christoph Lameter 6ce3c4c0ff [PATCH] Move page migration related functions near do_migrate_pages()
Group page migration functions in mempolicy.c

Add a forward declaration for migrate_page_add (like gather_stats()) and use
our new found mobility to group all page migration related function around
do_migrate_pages().

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:12:44 -08:00
Christoph Lameter 48fce3429d [PATCH] mempolicies: unexport get_vma_policy()
Since the numa_maps functionality is now in mempolicy.c we no longer need to
export get_vma_policy().

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:12:44 -08:00
Christoph Lameter 132beacf97 [PATCH] Drop page table lock before calling migrate_page_add()
migrate_page_add cannot be called with a spinlock held (calls
isolate_lru_page which calles schedule_on_each_cpu).  Drop ptl lock in
check_pte_range before calling migrate_page_add().

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:12:44 -08:00
Christoph Lameter 1a75a6c825 [PATCH] Fold numa_maps into mempolicies.c
First discussed at http://marc.theaimsgroup.com/?t=113149255100001&r=1&w=2

- Use the check_range() in mempolicy.c to gather statistics.

- Improve the numa_maps code in general and fix some comments.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:12:44 -08:00
Christoph Lameter 38e35860db [PATCH] mempolicies: private pointer in check_range and MPOL_MF_INVERT
This was was first posted at
http://marc.theaimsgroup.com/?l=linux-mm&m=113149240227584&w=2

(Part of this functionality is also contained in the direct migration
pathset. The functionality here is more generic and independent of that
patchset.)

- Add internal flags MPOL_MF_INVERT to control check_range() behavior.

- Replace the pagelist passed through by check_range by a general
  private pointer that may be used for other purposes.
  (The following patches will use that to merge numa_maps into
  mempolicy.c and to better group the page migration code in
  the policy layer)

- Improve some comments.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:12:44 -08:00
Christoph Lameter d498471133 [PATCH] SwapMig: Extend parameters for migrate_pages()
Extend the parameters of migrate_pages() to allow the caller control over the
fate of successfully migrated or impossible to migrate pages.

Swap migration and direct migration will have the same interface after this
patch so that patches can be independently applied to the policy layer and the
core migration code.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:12:42 -08:00
Christoph Lameter 39743889aa [PATCH] Swap Migration V5: sys_migrate_pages interface
sys_migrate_pages implementation using swap based page migration

This is the original API proposed by Ray Bryant in his posts during the first
half of 2005 on linux-mm@kvack.org and linux-kernel@vger.kernel.org.

The intent of sys_migrate is to migrate memory of a process.  A process may
have migrated to another node.  Memory was allocated optimally for the prior
context.  sys_migrate_pages allows to shift the memory to the new node.

sys_migrate_pages is also useful if the processes available memory nodes have
changed through cpuset operations to manually move the processes memory.  Paul
Jackson is working on an automated mechanism that will allow an automatic
migration if the cpuset of a process is changed.  However, a user may decide
to manually control the migration.

This implementation is put into the policy layer since it uses concepts and
functions that are also needed for mbind and friends.  The patch also provides
a do_migrate_pages function that may be useful for cpusets to automatically
move memory.  sys_migrate_pages does not modify policies in contrast to Ray's
implementation.

The current code here is based on the swap based page migration capability and
thus is not able to preserve the physical layout relative to it containing
nodeset (which may be a cpuset).  When direct page migration becomes available
then the implementation needs to be changed to do a isomorphic move of pages
between different nodesets.  The current implementation simply evicts all
pages in source nodeset that are not in the target nodeset.

Patch supports ia64, i386 and x86_64.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:12:42 -08:00
Christoph Lameter dc9aa5b9d6 [PATCH] Swap Migration V5: MPOL_MF_MOVE interface
Add page migration support via swap to the NUMA policy layer

This patch adds page migration support to the NUMA policy layer.  An
additional flag MPOL_MF_MOVE is introduced for mbind.  If MPOL_MF_MOVE is
specified then pages that do not conform to the memory policy will be evicted
from memory.  When they get pages back in new pages will be allocated
following the numa policy.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:12:41 -08:00
Christoph Lameter 4be38e351c [PATCH] mm: move determination of policy_zone into page allocator
Currently the function to build a zonelist for a BIND policy has the side
effect to set the policy_zone.  This seems to be a bit strange.  policy
zone seems to not be initialized elsewhere and therefore 0.  Do we police
ZONE_DMA if no bind policy has been used yet?

This patch moves the determination of the zone to apply policies to into
the page allocator.  We determine the zone while building the zonelist for
nodes.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:28 -08:00
Christoph Lameter 21abb1478a [PATCH] Remove old node based policy interface from mempolicy.c
mempolicy.c contains provisional interface for huge page allocation based on
node numbers.  This is in use in SLES9 but was never used (AFAIK) in upstream
versions of Linux.

Huge page allocations now use zonelists to figure out where to allocate pages.
 The use of zonelists allows us to find the closest hugepage which was the
consideration of the NUMA distance for huge page allocations.

Remove the obsolete functions.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Acked-by: William Lee Irwin III <wli@holomorphy.com>
Cc: Adam Litke <agl@us.ibm.com>
Acked-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:23 -08:00
Christoph Lameter 5da7ca8607 [PATCH] Add NUMA policy support for huge pages.
The huge_zonelist() function in the memory policy layer provides an list of
zones ordered by NUMA distance.  The hugetlb layer will walk that list looking
for a zone that has available huge pages but is also in the nodeset of the
current cpuset.

This patch does not contain the folding of find_or_alloc_huge_page() that was
controversial in the earlier discussion.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Acked-by: William Lee Irwin III <wli@holomorphy.com>
Cc: Adam Litke <agl@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:23 -08:00
Andi Kleen 8f493d797b [PATCH] Make sure interleave masks have at least one node set
Otherwise a bad mem policy system call can confuse the interleaving
code into referencing undefined nodes.

Originally reported by Doug Chapman

I was told it's CVE-2005-3358
(one has to love these security people - they make everything sound important)

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-02 17:01:42 -08:00
Linus Torvalds 6aab341e0a mm: re-architect the VM_UNPAGED logic
This replaces the (in my opinion horrible) VM_UNMAPPED logic with very
explicit support for a "remapped page range" aka VM_PFNMAP.  It allows a
VM area to contain an arbitrary range of page table entries that the VM
never touches, and never considers to be normal pages.

Any user of "remap_pfn_range()" automatically gets this new
functionality, and doesn't even have to mark the pages reserved or
indeed mark them any other way.  It just works.  As a side effect, doing
mmap() on /dev/mem works for arbitrary ranges.

Sparc update from David in the next commit.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-28 14:34:23 -08:00
Hugh Dickins 0b14c179a4 [PATCH] unpaged: VM_UNPAGED
Although we tend to associate VM_RESERVED with remap_pfn_range, quite a few
drivers set VM_RESERVED on areas which are then populated by nopage.  The
PageReserved removal in 2.6.15-rc1 changed VM_RESERVED not to free pages in
zap_pte_range, without changing those drivers not to set it: so their pages
just leak away.

Let's not change miscellaneous drivers now: introduce VM_UNPAGED at the core,
to flag the special areas where the ptes may have no struct page, or if they
have then it's not to be touched.  Replace most instances of VM_RESERVED in
core mm by VM_UNPAGED.  Force it on in remap_pfn_range, and the sparc and
sparc64 io_remap_pfn_range.

Revert addition of VM_RESERVED to powerpc vdso, it's not needed there.  Is it
needed anywhere?  It still governs the mm->reserved_vm statistic, and special
vmas not to be merged, and areas not to be core dumped; but could probably be
eliminated later (the drivers are probably specifying it because in 2.4 it
kept swapout off the vma, but in 2.6 we work from the LRU, which these pages
don't get on).

Use the VM_SHM slot for VM_UNPAGED, and define VM_SHM to 0: it serves no
purpose whatsoever, and should be removed from drivers when we clean up.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Acked-by: William Irwin <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-22 09:13:42 -08:00
Paul Jackson 68860ec10b [PATCH] cpusets: automatic numa mempolicy rebinding
This patch automatically updates a tasks NUMA mempolicy when its cpuset
memory placement changes.  It does so within the context of the task,
without any need to support low level external mempolicy manipulation.

If a system is not using cpusets, or if running on a system with just the
root (all-encompassing) cpuset, then this remap is a no-op.  Only when a
task is moved between cpusets, or a cpusets memory placement is changed
does the following apply.  Otherwise, the main routine below,
rebind_policy() is not even called.

When mixing cpusets, scheduler affinity, and NUMA mempolicies, the
essential role of cpusets is to place jobs (several related tasks) on a set
of CPUs and Memory Nodes, the essential role of sched_setaffinity is to
manage a jobs processor placement within its allowed cpuset, and the
essential role of NUMA mempolicy (mbind, set_mempolicy) is to manage a jobs
memory placement within its allowed cpuset.

However, CPU affinity and NUMA memory placement are managed within the
kernel using absolute system wide numbering, not cpuset relative numbering.

This is ok until a job is migrated to a different cpuset, or what's the
same, a jobs cpuset is moved to different CPUs and Memory Nodes.

Then the CPU affinity and NUMA memory placement of the tasks in the job
need to be updated, to preserve their cpuset-relative position.  This can
be done for CPU affinity using sched_setaffinity() from user code, as one
task can modify anothers CPU affinity.  This cannot be done from an
external task for NUMA memory placement, as that can only be modified in
the context of the task using it.

However, it easy enough to remap a tasks NUMA mempolicy automatically when
a task is migrated, using the existing cpuset mechanism to trigger a
refresh of a tasks memory placement after its cpuset has changed.  All that
is needed is the old and new nodemask, and notice to the task that it needs
to rebind its mempolicy.  The tasks mems_allowed has the old mask, the
tasks cpuset has the new mask, and the existing
cpuset_update_current_mems_allowed() mechanism provides the notice.  The
bitmap/cpumask/nodemask remap operators provide the cpuset relative
calculations.

This patch leaves open a couple of issues:

 1) Updating vma and shmfs/tmpfs/hugetlbfs memory policies:

    These mempolicies may reference nodes outside of those allowed to
    the current task by its cpuset.  Tasks are migrated as part of jobs,
    which reside on what might be several cpusets in a subtree.  When such
    a job is migrated, all NUMA memory policy references to nodes within
    that cpuset subtree should be translated, and references to any nodes
    outside that subtree should be left untouched.  A future patch will
    provide the cpuset mechanism needed to mark such subtrees.  With that
    patch, we will be able to correctly migrate these other memory policies
    across a job migration.

 2) Updating cpuset, affinity and memory policies in user space:

    This is harder.  Any placement state stored in user space using
    system-wide numbering will be invalidated across a migration.  More
    work will be required to provide user code with a migration-safe means
    to manage its cpuset relative placement, while preserving the current
    API's that pass system wide numbers, not cpuset relative numbers across
    the kernel-user boundary.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:22 -08:00
Christoph Lameter 5fcbb23050 [PATCH] Remove policy contextualization from mbind
Policy contextualization is only useful for task based policies and not for
vma based policies.  It may be useful to define allowed nodes that are not
accessible from this thread because other threads may have access to these
nodes.  Without this patch strange memory policy situations may cause an
application to fail with out of memory.

Example:

Let's say we have two threads A and B that share the same address space and
a huge array computational array X.

Thread A is restricted by its cpuset to nodes 0 and 1 and thread B is
restricted by its cpuset to nodes 2 and 3.

Thread A now wants to restrict allocations to the first node and thus
applies a BIND policy on X to node 0 and 2.  The cpuset limits this to node
0.  Thus pages for X must be allocated on node 0 now.

Thread B now touches a page that has never been used in X and faults in a
page.  According to the BIND policy of the vma for X the page must be
allocated on page 0.  However, the cpuset of B does not allow allocation on
0 and 1.  Now the application fails in alloc_pages with out of memory.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:45 -07:00
Christoph Lameter 8bccd85ffb [PATCH] Implement sys_* do_* layering in the memory policy layer.
- Do a separation between do_xxx and sys_xxx functions. sys_xxx functions
  take variable sized bitmaps from user space as arguments. do_xxx functions
  take fixed sized nodemask_t as arguments and may be used from inside the
  kernel. Doing so simplifies the initialization code. There is no
  fs = kernel_ds assumption anymore.

- Split up get_nodes into get_nodes (which gets the node list) and
  contextualize_policy which restricts the nodes to those accessible
  to the task and updates cpusets.

- Add comments explaining limitations of bind policy

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:45 -07:00
Hugh Dickins 705e87c0c3 [PATCH] mm: pte_offset_map_lock loops
Convert those common loops using page_table_lock on the outside and
pte_offset_map within to use just pte_offset_map_lock within instead.

These all hold mmap_sem (some exclusively, some not), so at no level can a
page table be whipped away from beneath them.  But whereas pte_alloc loops
tested with the "atomic" pmd_present, these loops are testing with pmd_none,
which on i386 PAE tests both lower and upper halves.

That's now unsafe, so add a cast into pmd_none to test only the vital lower
half: we lose a little sensitivity to a corrupt middle directory, but not
enough to worry about.  It appears that i386 and UML were the only
architectures vulnerable in this way, and pgd and pud no problem.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:40 -07:00
Nick Piggin b5810039a5 [PATCH] core remove PageReserved
Remove PageReserved() calls from core code by tightening VM_RESERVED
handling in mm/ to cover PageReserved functionality.

PageReserved special casing is removed from get_page and put_page.

All setting and clearing of PageReserved is retained, and it is now flagged
in the page_alloc checks to help ensure we don't introduce any refcount
based freeing of Reserved pages.

MAP_PRIVATE, PROT_WRITE of VM_RESERVED regions is tentatively being
deprecated.  We never completely handled it correctly anyway, and is be
reintroduced in future if required (Hugh has a proof of concept).

Once PageReserved() calls are removed from kernel/power/swsusp.c, and all
arch/ and driver code, the Set and Clear calls, and the PG_reserved bit can
be trivially removed.

Last real user of PageReserved is swsusp, which uses PageReserved to
determine whether a struct page points to valid memory or not.  This still
needs to be addressed (a generic page_is_ram() should work).

A last caveat: the ZERO_PAGE is now refcounted and managed with rmap (and
thus mapcounted and count towards shared rss).  These writes to the struct
page could cause excessive cacheline bouncing on big systems.  There are a
number of ways this could be addressed if it is an issue.

Signed-off-by: Nick Piggin <npiggin@suse.de>

Refcount bug fix for filemap_xip.c

Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:39 -07:00
Andi Kleen 662f3a0b94 [PATCH] Remove near all BUGs in mm/mempolicy.c
Most of them can never be triggered and were only for development.

Signed-off-by: "Andi Kleen" <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:35 -07:00
Andi Kleen dfcd3c0dc4 [PATCH] Convert mempolicies to nodemask_t
The NUMA policy code predated nodemask_t so it used open coded bitmaps.
Convert everything to nodemask_t.  Big patch, but shouldn't have any actual
behaviour changes (except I removed one unnecessary check against
node_online_map and one unnecessary BUG_ON)

Signed-off-by: "Andi Kleen" <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:35 -07:00
Al Viro af4ca457ea [PATCH] gfp_t: infrastructure
Beginning of gfp_t annotations:

 - -Wbitwise added to CHECKFLAGS
 - old __bitwise renamed to __bitwise__
 - __bitwise defined to either __bitwise__ or nothing, depending on
   __CHECK_ENDIAN__ being defined
 - gfp_t switched from __nocast to __bitwise__
 - force cast to gfp_t added to __GFP_... constants
 - new helper - gfp_zone(); extracts zone bits out of gfp_t value and casts
   the result to int

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-28 08:16:46 -07:00
Al Viro dd0fc66fb3 [PATCH] gfp flags annotations - part 1
- added typedef unsigned int __nocast gfp_t;

 - replaced __nocast uses for gfp flags with gfp_t - it gives exactly
   the same warnings as far as sparse is concerned, doesn't change
   generated code (from gcc point of view we replaced unsigned int with
   typedef) and documents what's going on far better.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-08 15:00:57 -07:00
Andi Kleen 5b952b3c14 [PATCH] Fix MPOL_F_VERIFY
There was a pretty bad bug in there that the code would always check the full
VMA, not the range the user requested.

When the VMA to be checked was merged with the previous VMA this could lead to
spurious failures.

Signed-off-by: "Andi Kleen" <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-13 08:22:28 -07:00
Andi Kleen d42c69972b [PATCH] PCI: Run PCI driver initialization on local node
Run PCI driver initialization on local node

Instead of adding messy kmalloc_node()s everywhere run the
PCI driver probe on the node local to the device.

This would not have helped for IDE, but should for
other more clean drivers that do more initialization in probe().
It won't help for drivers that do most of the work
on first open (like many network drivers)

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-09-08 14:57:23 -07:00
Christoph Lameter 6e21c8f145 [PATCH] /proc/<pid>/numa_maps to show on which nodes pages reside
This patch was recently discussed on linux-mm:
http://marc.theaimsgroup.com/?t=112085728500002&r=1&w=2

I inherited a large code base from Ray for page migration.  There was a
small patch in there that I find to be very useful since it allows the
display of the locality of the pages in use by a process.  I reworked that
patch and came up with a /proc/<pid>/numa_maps that gives more information
about the vma's of a process.  numa_maps is indexes by the start address
found in /proc/<pid>/maps.  F.e.  with this patch you can see the page use
of the "getty" process:

margin:/proc/12008 # cat maps
00000000-00004000 r--p 00000000 00:00 0
2000000000000000-200000000002c000 r-xp 00000000 08:04 516                /lib/ld-2.3.3.so
2000000000038000-2000000000040000 rw-p 00028000 08:04 516                /lib/ld-2.3.3.so
2000000000040000-2000000000044000 rw-p 2000000000040000 00:00 0
2000000000058000-2000000000260000 r-xp 00000000 08:04 54707842           /lib/tls/libc.so.6.1
2000000000260000-2000000000268000 ---p 00208000 08:04 54707842           /lib/tls/libc.so.6.1
2000000000268000-2000000000274000 rw-p 00200000 08:04 54707842           /lib/tls/libc.so.6.1
2000000000274000-2000000000280000 rw-p 2000000000274000 00:00 0
2000000000280000-20000000002b4000 r--p 00000000 08:04 9126923            /usr/lib/locale/en_US.utf8/LC_CTYPE
2000000000300000-2000000000308000 r--s 00000000 08:04 60071467           /usr/lib/gconv/gconv-modules.cache
2000000000318000-2000000000328000 rw-p 2000000000318000 00:00 0
4000000000000000-4000000000008000 r-xp 00000000 08:04 29576399           /sbin/mingetty
6000000000004000-6000000000008000 rw-p 00004000 08:04 29576399           /sbin/mingetty
6000000000008000-600000000002c000 rw-p 6000000000008000 00:00 0          [heap]
60000fff7fffc000-60000fff80000000 rw-p 60000fff7fffc000 00:00 0
60000ffffff44000-60000ffffff98000 rw-p 60000ffffff44000 00:00 0          [stack]
a000000000000000-a000000000020000 ---p 00000000 00:00 0                  [vdso]

cat numa_maps
2000000000000000 default MaxRef=43 Pages=11 Mapped=11 N0=4 N1=3 N2=2 N3=2
2000000000038000 default MaxRef=1 Pages=2 Mapped=2 Anon=2 N0=2
2000000000040000 default MaxRef=1 Pages=1 Mapped=1 Anon=1 N0=1
2000000000058000 default MaxRef=43 Pages=61 Mapped=61 N0=14 N1=15 N2=16 N3=16
2000000000268000 default MaxRef=1 Pages=2 Mapped=2 Anon=2 N0=2
2000000000274000 default MaxRef=1 Pages=3 Mapped=3 Anon=3 N0=3
2000000000280000 default MaxRef=8 Pages=3 Mapped=3 N0=3
2000000000300000 default MaxRef=8 Pages=2 Mapped=2 N0=2
2000000000318000 default MaxRef=1 Pages=1 Mapped=1 Anon=1 N2=1
4000000000000000 default MaxRef=6 Pages=2 Mapped=2 N1=2
6000000000004000 default MaxRef=1 Pages=1 Mapped=1 Anon=1 N0=1
6000000000008000 default MaxRef=1 Pages=1 Mapped=1 Anon=1 N0=1
60000fff7fffc000 default MaxRef=1 Pages=1 Mapped=1 Anon=1 N0=1
60000ffffff44000 default MaxRef=1 Pages=1 Mapped=1 Anon=1 N0=1

getty uses ld.so.  The first vma is the code segment which is used by 43
other processes and the pages are evenly distributed over the 4 nodes.

The second vma is the process specific data portion for ld.so.  This is
only one page.

The display format is:

<startaddress>	 Links to information in /proc/<pid>/map
<memory policy>  This can be "default" "interleave={}", "prefer=<node>" or "bind={<zones>}"
MaxRef=		<maximum reference to a page in this vma>
Pages=		<Nr of pages in use>
Mapped=		<Nr of pages with mapcount >
Anon=		<nr of anonymous pages>
Nx=		<Nr of pages on Node x>

The content of the proc-file is self-evident.  If this would be tied into
the sparsemem system then the contents of this file would not be too
useful.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-05 00:05:43 -07:00
Eric Dumazet ba17101b41 [PATCH] sys_set_mempolicy() doesnt check if mode < 0
A kernel BUG() is triggered by a call to set_mempolicy() with a negative
first argument.  This is because the mode is declared as an int, and the
validity check doesnt check < 0 values.  Alternatively, mode could be
declared as unsigned int or unsigned long.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-08-01 21:38:00 -07:00
Andi Kleen 90c5029e47 [PATCH] Undo mempolicy shared policy rbtree microoptimization
All mempolicy changes must be inside the spinlock and readding the rb_erase
prevents a crash while doing:

> echo "1" > /tmp/numatest
> numactl --length=0x4000 --shm /tmp/numatest --localalloc
> numactl --length=0x2000 --offset=0 --shm /tmp/numatest --membind=0
> numactl --length=0x2000 --offset=0x2000 --shm /tmp/numatest --membind=1
> ipcs
> ipcrm -M "the_key_value_of_this_shm_area"

Based on a patch by John Blackwood

Cc: <john.blackwood@ccur.com>
Cc: <andrea@suse.de>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-27 16:25:52 -07:00
Hugh Dickins 91612e0df2 [PATCH] mbind: check_range use standard ptwalk
Strict mbind's check for currently mapped pages being on node has been
using a slow loop which re-evaluates pgd, pud, pmd, pte for each entry:
replace that by a standard four-level page table walk like others in mm.
Since mmap_sem is held for writing, page_table_lock can be taken at the
inner level to limit latency.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-21 18:46:19 -07:00
Hugh Dickins 941150a326 [PATCH] mbind: fix verify_pages pte_page
Strict mbind's check that pages already mapped are on right node has been
using pte_page without checking if pfn_valid, and without page_table_lock
to prevent spurious failures when try_to_unmap_one intervenes between the
pte_present and the pte_page.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-21 18:46:19 -07:00
Christoph Lameter e7c8d5c995 [PATCH] node local per-cpu-pages
This patch modifies the way pagesets in struct zone are managed.

Each zone has a per-cpu array of pagesets.  So any particular CPU has some
memory in each zone structure which belongs to itself.  Even if that CPU is
not local to that zone.

So the patch relocates the pagesets for each cpu to the node that is nearest
to the cpu instead of allocating the pagesets in the (possibly remote) target
zone.  This means that the operations to manage pages on remote zone can be
done with information available locally.

We play a macro trick so that non-NUMA pmachines avoid the additional
pointer chase on the page allocator fastpath.

AIM7 benchmark on a 32 CPU SGI Altix

w/o patches:
Tasks    jobs/min  jti  jobs/min/task      real       cpu
    1      484.68  100       484.6769     12.01      1.97   Fri Mar 25 11:01:42 2005
  100    27140.46   89       271.4046     21.44    148.71   Fri Mar 25 11:02:04 2005
  200    30792.02   82       153.9601     37.80    296.72   Fri Mar 25 11:02:42 2005
  300    32209.27   81       107.3642     54.21    451.34   Fri Mar 25 11:03:37 2005
  400    34962.83   78        87.4071     66.59    588.97   Fri Mar 25 11:04:44 2005
  500    31676.92   75        63.3538     91.87    742.71   Fri Mar 25 11:06:16 2005
  600    36032.69   73        60.0545     96.91    885.44   Fri Mar 25 11:07:54 2005
  700    35540.43   77        50.7720    114.63   1024.28   Fri Mar 25 11:09:49 2005
  800    33906.70   74        42.3834    137.32   1181.65   Fri Mar 25 11:12:06 2005
  900    34120.67   73        37.9119    153.51   1325.26   Fri Mar 25 11:14:41 2005
 1000    34802.37   74        34.8024    167.23   1465.26   Fri Mar 25 11:17:28 2005

with slab API changes and pageset patch:

Tasks    jobs/min  jti  jobs/min/task      real       cpu
    1      485.00  100       485.0000     12.00      1.96   Fri Mar 25 11:46:18 2005
  100    28000.96   89       280.0096     20.79    150.45   Fri Mar 25 11:46:39 2005
  200    32285.80   79       161.4290     36.05    293.37   Fri Mar 25 11:47:16 2005
  300    40424.15   84       134.7472     43.19    438.42   Fri Mar 25 11:47:59 2005
  400    39155.01   79        97.8875     59.46    590.05   Fri Mar 25 11:48:59 2005
  500    37881.25   82        75.7625     76.82    730.19   Fri Mar 25 11:50:16 2005
  600    39083.14   78        65.1386     89.35    872.79   Fri Mar 25 11:51:46 2005
  700    38627.83   77        55.1826    105.47   1022.46   Fri Mar 25 11:53:32 2005
  800    39631.94   78        49.5399    117.48   1169.94   Fri Mar 25 11:55:30 2005
  900    36903.70   79        41.0041    141.94   1310.78   Fri Mar 25 11:57:53 2005
 1000    36201.23   77        36.2012    160.77   1458.31   Fri Mar 25 12:00:34 2005

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Shobhit Dayal <shobhit@calsoftinc.com>
Signed-off-by: Shai Fultheim <Shai@Scalex86.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-21 18:46:16 -07:00
Al Viro 01424961e6 [PATCH] mempolicy.c GFP fix
zonelist_policy() forgot to mask non-zone bits from gfp when comparing
zone number with policy_zone. 

ACKed-by: Andi Kleen <ak@suse.de>
Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-24 12:28:34 -07:00
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00