On Tue, 11 Sep 2012, Stephen Rothwell wrote:
> After merging the final tree, today's linux-next build (sparc64 defconfig)
> produced this warning:
>
> mm/slab.c:808:13: warning: '__slab_error' defined but not used [-Wunused-function]
>
> Introduced by commit 945cf2b619 ("mm/sl[aou]b: Extract a common
> function for kmem_cache_destroy"). All uses of slab_error() are now
> guarded by DEBUG.
There is no use case left for slab builds without DEBUG.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
In array cache, there is a object at index 0, check it.
Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Right now, we call ClearSlabPfmemalloc() for first page of slab when we
clear SlabPfmemalloc flag. This is fine for most swap-over-network use
cases as it is expected that order-0 pages are in use. Unfortunately it
is possible that that __ac_put_obj() checks SlabPfmemalloc on a tail
page and while this is harmless, it is sloppy. This patch ensures that
the head page is always used.
This problem was originally identified by Joonsoo Kim.
[js1304@gmail.com: Original implementation and problem identification]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
DEADLOCK will be report while running a kernel with NUMA and LOCKDEP enabled,
the process of this fake report is:
kmem_cache_free() //free obj in cachep
-> cache_free_alien() //acquire cachep's l3 alien lock
-> __drain_alien_cache()
-> free_block()
-> slab_destroy()
-> kmem_cache_free() //free slab in cachep->slabp_cache
-> cache_free_alien() //acquire cachep->slabp_cache's l3 alien lock
Since the cachep and cachep->slabp_cache's l3 alien are in the same lock class,
fake report generated.
This should not happen since we already have init_lock_keys() which will
reassign the lock class for both l3 list and l3 alien.
However, init_lock_keys() was invoked at a wrong position which is before we
invoke enable_cpucache() on each cache.
Since until set slab_state to be FULL, we won't invoke enable_cpucache()
on caches to build their l3 alien while creating them, so although we invoked
init_lock_keys(), the l3 alien lock class won't change since we don't have
them until invoked enable_cpucache() later.
This patch will invoke init_lock_keys() after we done enable_cpucache()
instead of before to avoid the fake DEADLOCK report.
Michael traced the problem back to a commit in release 3.0.0:
commit 30765b92ad
Author: Peter Zijlstra <peterz@infradead.org>
Date: Thu Jul 28 23:22:56 2011 +0200
slab, lockdep: Annotate the locks before using them
Fernando found we hit the regular OFF_SLAB 'recursion' before we
annotate the locks, cure this.
The relevant portion of the stack-trace:
> [ 0.000000] [<c085e24f>] rt_spin_lock+0x50/0x56
> [ 0.000000] [<c04fb406>] __cache_free+0x43/0xc3
> [ 0.000000] [<c04fb23f>] kmem_cache_free+0x6c/0xdc
> [ 0.000000] [<c04fb2fe>] slab_destroy+0x4f/0x53
> [ 0.000000] [<c04fb396>] free_block+0x94/0xc1
> [ 0.000000] [<c04fc551>] do_tune_cpucache+0x10b/0x2bb
> [ 0.000000] [<c04fc8dc>] enable_cpucache+0x7b/0xa7
> [ 0.000000] [<c0bd9d3c>] kmem_cache_init_late+0x1f/0x61
> [ 0.000000] [<c0bba687>] start_kernel+0x24c/0x363
> [ 0.000000] [<c0bba0ba>] i386_start_kernel+0xa9/0xaf
Reported-by: Fernando Lopez-Lezcano <nando@ccrma.Stanford.EDU>
Acked-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1311888176.2617.379.camel@laptop
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The commit moved init_lock_keys() before we build up the alien, so we
failed to reclass it.
Cc: <stable@vger.kernel.org> # 3.0+
Acked-by: Christoph Lameter <cl@linux.com>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Get rid of the refcount stuff in the allocators and do that part of
kmem_cache management in the common code.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Do the initial settings of the fields in common code. This will allow us
to push more processing into common code later and improve readability.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Shift the allocations to common code. That way the allocation and
freeing of the kmem_cache structures is handled by common code.
Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
What is done there can be done in __kmem_cache_shutdown.
This affects RCU handling somewhat. On rcu free all slab allocators do
not refer to other management structures than the kmem_cache structure.
Therefore these other structures can be freed before the rcu deferred
free to the page allocator occurs.
Reviewed-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
The freeing action is basically the same in all slab allocators.
Move to the common kmem_cache_destroy() function.
Reviewed-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Make all allocators use the "kmem_cache" slabname for the "kmem_cache"
structure.
Reviewed-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
kmem_cache_destroy does basically the same in all allocators.
Extract common code which is easy since we already have common mutex
handling.
Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Move the code to append the new kmem_cache to the list of slab caches to
the kmem_cache_create code in the shared code.
This is possible now since the acquisition of the mutex was moved into
kmem_cache_create().
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
cache_grow() can reenable irqs so the cpu (and node) can change, so ensure
that we take list_lock on the correct nodelist.
This fixes an issue with commit 072bb0aa5e ("mm: sl[au]b: add
knowledge of PFMEMALLOC reserve pages") where list_lock for the wrong
node was taken after growing the cache.
Reported-and-tested-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Initalizers for deferrable delayed_work are confused.
* __DEFERRED_WORK_INITIALIZER()
* DECLARE_DEFERRED_WORK()
* INIT_DELAYED_WORK_DEFERRABLE()
Rename them to
* __DEFERRABLE_WORK_INITIALIZER()
* DECLARE_DEFERRABLE_WORK()
* INIT_DEFERRABLE_WORK()
This patch doesn't cause any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
page_get_cache() isn't called from anything, so remove it.
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
page_get_cache() does not need to call compound_head(), as its unique
caller virt_to_slab() already makes sure to return a head page.
Additionally, removing the compound_head() call makes page_get_cache()
consistent with page_get_slab().
Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Getting and putting objects in SLAB currently requires a function call but
the bulk of the work is related to PFMEMALLOC reserves which are only
consumed when network-backed storage is critical. Use an inline function
to determine if the function call is required.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Neil Brown <neilb@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__GFP_MEMALLOC will allow the allocation to disregard the watermarks, much
like PF_MEMALLOC. It allows one to pass along the memalloc state in
object related allocation flags as opposed to task related flags, such as
sk->sk_allocation. This removes the need for ALLOC_PFMEMALLOC as callers
using __GFP_MEMALLOC can get the ALLOC_NO_WATERMARK flag which is now
enough to identify allocations related to page reclaim.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Neil Brown <neilb@suse.de>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When a user or administrator requires swap for their application, they
create a swap partition and file, format it with mkswap and activate it
with swapon. Swap over the network is considered as an option in diskless
systems. The two likely scenarios are when blade servers are used as part
of a cluster where the form factor or maintenance costs do not allow the
use of disks and thin clients.
The Linux Terminal Server Project recommends the use of the Network Block
Device (NBD) for swap according to the manual at
https://sourceforge.net/projects/ltsp/files/Docs-Admin-Guide/LTSPManual.pdf/download
There is also documentation and tutorials on how to setup swap over NBD at
places like https://help.ubuntu.com/community/UbuntuLTSP/EnableNBDSWAP The
nbd-client also documents the use of NBD as swap. Despite this, the fact
is that a machine using NBD for swap can deadlock within minutes if swap
is used intensively. This patch series addresses the problem.
The core issue is that network block devices do not use mempools like
normal block devices do. As the host cannot control where they receive
packets from, they cannot reliably work out in advance how much memory
they might need. Some years ago, Peter Zijlstra developed a series of
patches that supported swap over an NFS that at least one distribution is
carrying within their kernels. This patch series borrows very heavily
from Peter's work to support swapping over NBD as a pre-requisite to
supporting swap-over-NFS. The bulk of the complexity is concerned with
preserving memory that is allocated from the PFMEMALLOC reserves for use
by the network layer which is needed for both NBD and NFS.
Patch 1 adds knowledge of the PFMEMALLOC reserves to SLAB and SLUB to
preserve access to pages allocated under low memory situations
to callers that are freeing memory.
Patch 2 optimises the SLUB fast path to avoid pfmemalloc checks
Patch 3 introduces __GFP_MEMALLOC to allow access to the PFMEMALLOC
reserves without setting PFMEMALLOC.
Patch 4 opens the possibility for softirqs to use PFMEMALLOC reserves
for later use by network packet processing.
Patch 5 only sets page->pfmemalloc when ALLOC_NO_WATERMARKS was required
Patch 6 ignores memory policies when ALLOC_NO_WATERMARKS is set.
Patches 7-12 allows network processing to use PFMEMALLOC reserves when
the socket has been marked as being used by the VM to clean pages. If
packets are received and stored in pages that were allocated under
low-memory situations and are unrelated to the VM, the packets
are dropped.
Patch 11 reintroduces __skb_alloc_page which the networking
folk may object to but is needed in some cases to propogate
pfmemalloc from a newly allocated page to an skb. If there is a
strong objection, this patch can be dropped with the impact being
that swap-over-network will be slower in some cases but it should
not fail.
Patch 13 is a micro-optimisation to avoid a function call in the
common case.
Patch 14 tags NBD sockets as being SOCK_MEMALLOC so they can use
PFMEMALLOC if necessary.
Patch 15 notes that it is still possible for the PFMEMALLOC reserve
to be depleted. To prevent this, direct reclaimers get throttled on
a waitqueue if 50% of the PFMEMALLOC reserves are depleted. It is
expected that kswapd and the direct reclaimers already running
will clean enough pages for the low watermark to be reached and
the throttled processes are woken up.
Patch 16 adds a statistic to track how often processes get throttled
Some basic performance testing was run using kernel builds, netperf on
loopback for UDP and TCP, hackbench (pipes and sockets), iozone and
sysbench. Each of them were expected to use the sl*b allocators
reasonably heavily but there did not appear to be significant performance
variances.
For testing swap-over-NBD, a machine was booted with 2G of RAM with a
swapfile backed by NBD. 8*NUM_CPU processes were started that create
anonymous memory mappings and read them linearly in a loop. The total
size of the mappings were 4*PHYSICAL_MEMORY to use swap heavily under
memory pressure.
Without the patches and using SLUB, the machine locks up within minutes
and runs to completion with them applied. With SLAB, the story is
different as an unpatched kernel run to completion. However, the patched
kernel completed the test 45% faster.
MICRO
3.5.0-rc2 3.5.0-rc2
vanilla swapnbd
Unrecognised test vmscan-anon-mmap-write
MMTests Statistics: duration
Sys Time Running Test (seconds) 197.80 173.07
User+Sys Time Running Test (seconds) 206.96 182.03
Total Elapsed Time (seconds) 3240.70 1762.09
This patch: mm: sl[au]b: add knowledge of PFMEMALLOC reserve pages
Allocations of pages below the min watermark run a risk of the machine
hanging due to a lack of memory. To prevent this, only callers who have
PF_MEMALLOC or TIF_MEMDIE set and are not processing an interrupt are
allowed to allocate with ALLOC_NO_WATERMARKS. Once they are allocated to
a slab though, nothing prevents other callers consuming free objects
within those slabs. This patch limits access to slab pages that were
alloced from the PFMEMALLOC reserves.
When this patch is applied, pages allocated from below the low watermark
are returned with page->pfmemalloc set and it is up to the caller to
determine how the page should be protected. SLAB restricts access to any
page with page->pfmemalloc set to callers which are known to able to
access the PFMEMALLOC reserve. If one is not available, an attempt is
made to allocate a new page rather than use a reserve. SLUB is a bit more
relaxed in that it only records if the current per-CPU page was allocated
from PFMEMALLOC reserve and uses another partial slab if the caller does
not have the necessary GFP or process flags. This was found to be
sufficient in tests to avoid hangs due to SLUB generally maintaining
smaller lists than SLAB.
In low-memory conditions it does mean that !PFMEMALLOC allocators can fail
a slab allocation even though free objects are available because they are
being preserved for callers that are freeing pages.
[a.p.zijlstra@chello.nl: Original implementation]
[sebastian@breakpoint.cc: Correct order of page flag clearing]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Neil Brown <neilb@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the mutex handling into the common kmem_cache_create()
function.
Then we can also move more checks out of SLAB's kmem_cache_create()
into the common code.
Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Use the mutex definition from SLAB and make it the common way to take a sleeping lock.
This has the effect of using a mutex instead of a rw semaphore for SLUB.
SLOB gains the use of a mutex for kmem_cache_create serialization.
Not needed now but SLOB may acquire some more features later (like slabinfo
/ sysfs support) through the expansion of the common code that will
need this.
Reviewed-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
All allocators have some sort of support for the bootstrap status.
Setup a common definition for the boot states and make all slab
allocators use that definition.
Reviewed-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Kmem_cache_create() does a variety of sanity checks but those
vary depending on the allocator. Use the strictest tests and put them into
a slab_common file. Make the tests conditional on CONFIG_DEBUG_VM.
This patch has the effect of adding sanity checks for SLUB and SLOB
under CONFIG_DEBUG_VM and removes the checks in SLAB for !CONFIG_DEBUG_VM.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
During kmem_cache_init_late(), we transition to the LATE state,
and after some more work, to the FULL state, its last state
This is quite different from slub, that will only transition to
its last state (previously SYSFS), in a (late)initcall, after a lot
more of the kernel is ready.
This means that in slab, we have no way to taking actions dependent
on the initialization of other pieces of the kernel that are supposed
to start way after kmem_init_late(), such as cgroups initialization.
To achieve more consistency in this behavior, that patch only
transitions to the UP state in kmem_init_late. In my analysis,
setup_cpu_cache() should be happy to test for >= UP, instead of
== FULL. It also has passed some tests I've made.
We then only mark FULL state after the reap timers are in place,
meaning that no further setup is expected.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Commit 8c138b only sits in Pekka's and linux-next tree now, which tries
to replace obj_size(cachep) with cachep->object_size, but has a typo in
kmem_cache_free() by using "size" instead of "object_size", which casues
some regressions.
Reported-and-tested-by: Fengguang Wu <wfg@linux.intel.com>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Cc: Christoph Lameter <cl@linux.com>
Acked-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Commit 3b0efdf ("mm, sl[aou]b: Extract common fields from struct
kmem_cache") renamed the kmem_cache structure's "next" field to "list"
but forgot to update one instance in leaks_show().
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
A consistent name with slub saves us an acessor function.
In both caches, this field represents the same thing. We would
like to use it from the mem_cgroup code.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
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>
The size of the slab object is frequently needed. Since we now
have a size field directly in the kmem_cache structure there is no
need anymore of the obj_size macro/function.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Define a struct that describes common fields used in all slab allocators.
A slab allocator either uses the common definition (like SLOB) or is
required to provide members of kmem_cache with the definition given.
After that it will be possible to share code that
only operates on those fields of kmem_cache.
The patch basically takes the slob definition of kmem cache and
uses the field namees for the other allocators.
It also standardizes the names used for basic object lengths in
allocators:
object_size Struct size specified at kmem_cache_create. Basically
the payload expected to be used by the subsystem.
size The size of memory allocator for each object. This size
is larger than object_size and includes padding, alignment
and extra metadata for each object (f.e. for debugging
and rcu).
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Those are rather trivial now and its better to see inline what is
really going on.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Add fields to the page struct so that it is properly documented that
slab overlays the lru fields.
This cleans up some casts in slab.
Reviewed-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Pull SLAB changes from Pekka Enberg:
"There's the new kmalloc_array() API, minor fixes and performance
improvements, but quite honestly, nothing terribly exciting."
* 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
mm: SLAB Out-of-memory diagnostics
slab: introduce kmalloc_array()
slub: per cpu partial statistics change
slub: include include for prefetch
slub: Do not hold slub_lock when calling sysfs_slab_add()
slub: prefetch next freelist pointer in slab_alloc()
slab, cleanup: remove unneeded return
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>
Following the example at mm/slub.c, add out-of-memory diagnostics to the
SLAB allocator to help on debugging certain OOM conditions.
An example print out looks like this:
<snip page allocator out-of-memory message>
SLAB: Unable to allocate memory on node 0 (gfp=0x11200)
cache: bio-0, object size: 192, order: 0
node 0: slabs: 3/3, objs: 60/60, free: 0
Signed-off-by: Rafael Aquini <aquini@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
The procedure ends right after the if-statement, so remove ``return''.
Also move the last common statement outside.
Signed-off-by: Zhao Jin <cronozhj@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
* 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
slub: disallow changing cpu_partial from userspace for debug caches
slub: add missed accounting
slub: Extract get_freelist from __slab_alloc
slub: Switch per cpu partial page support off for debugging
slub: fix a possible memleak in __slab_alloc()
slub: fix slub_max_order Documentation
slub: add missed accounting
slab: add taint flag outputting to debug paths.
slub: add taint flag outputting to debug paths
slab: introduce slab_max_order kernel parameter
slab: rename slab_break_gfp_order to slab_max_order
Including trace/events/*.h TRACE_EVENT() macro headers in other headers
can cause strange side effects if another trace/event/*.h header
includes that header. Having trace/events/kmem.h inside slab_def.h
caused a compile error in sparc64 when changes were done to some header
files. Moving the kmem.h trace header out of slab.h and into slab.c
fixes the problem.
Note, both slub.c and slob.c already include the trace/events/kmem.h
file. Only slab.c had it missing.
Link: http://lkml.kernel.org/r/20120105190405.1e3191fb5a43b2a0f1655e1f@canb.auug.org.au
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 30765b92 ("slab, lockdep: Annotate the locks before using
them") moves the init_lock_keys() call from after g_cpucache_up =
FULL, to before it. And overlooks the fact that init_node_lock_keys()
tests for it and ignores everything !FULL.
Introduce a LATE stage and change the lockdep test to be <LATE.
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When we get corruption reports, it's useful to see if the kernel was
tainted, to rule out problems we can't do anything about.
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Introduce new slab_max_order kernel parameter which is the equivalent of
slub_max_order.
For immediate purposes, allows users to override the heuristic that sets
the max order to 1 by default if they have more than 32MB of RAM. This
may result in page allocation failures if there is substantial
fragmentation.
Another usecase would be to increase the max order for better
performance.
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
slab_break_gfp_order is more appropriately named slab_max_order since it
enforces the maximum order size of slabs as long as a single object will
still fit.
Also rename BREAK_GFP_ORDER_{LO,HI} accordingly.
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Historically /proc/slabinfo and files under /sys/kernel/slab/* have
world read permissions and are accessible to the world. slabinfo
contains rather private information related both to the kernel and
userspace tasks. Depending on the situation, it might reveal either
private information per se or information useful to make another
targeted attack. Some examples of what can be learned by
reading/watching for /proc/slabinfo entries:
1) dentry (and different *inode*) number might reveal other processes fs
activity. The number of dentry "active objects" doesn't strictly show
file count opened/touched by a process, however, there is a good
correlation between them. The patch "proc: force dcache drop on
unauthorized access" relies on the privacy of dentry count.
2) different inode entries might reveal the same information as (1), but
these are more fine granted counters. If a filesystem is mounted in a
private mount point (or even a private namespace) and fs type differs from
other mounted fs types, fs activity in this mount point/namespace is
revealed. If there is a single ecryptfs mount point, the whole fs
activity of a single user is revealed. Number of files in ecryptfs
mount point is a private information per se.
3) fuse_* reveals number of files / fs activity of a user in a user
private mount point. It is approx. the same severity as ecryptfs
infoleak in (2).
4) sysfs_dir_cache similar to (2) reveals devices' addition/removal,
which can be otherwise hidden by "chmod 0700 /sys/". With 0444 slabinfo
the precise number of sysfs files is known to the world.
5) buffer_head might reveal some kernel activity. With other
information leaks an attacker might identify what specific kernel
routines generate buffer_head activity.
6) *kmalloc* infoleaks are very situational. Attacker should watch for
the specific kmalloc size entry and filter the noise related to the unrelated
kernel activity. If an attacker has relatively silent victim system, he
might get rather precise counters.
Additional information sources might significantly increase the slabinfo
infoleak benefits. E.g. if an attacker knows that the processes
activity on the system is very low (only core daemons like syslog and
cron), he may run setxid binaries / trigger local daemon activity /
trigger network services activity / await sporadic cron jobs activity
/ etc. and get rather precise counters for fs and network activity of
these privileged tasks, which is unknown otherwise.
Also hiding slabinfo and /sys/kernel/slab/* is a one step to complicate
exploitation of kernel heap overflows (and possibly, other bugs). The
related discussion:
http://thread.gmane.org/gmane.linux.kernel/1108378
To keep compatibility with old permission model where non-root
monitoring daemon could watch for kernel memleaks though slabinfo one
should do:
groupadd slabinfo
usermod -a -G slabinfo $MONITOR_USER
And add the following commands to init scripts (to mountall.conf in
Ubuntu's upstart case):
chmod g+r /proc/slabinfo /sys/kernel/slab/*/*
chgrp slabinfo /proc/slabinfo /sys/kernel/slab/*/*
Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Reviewed-by: Kees Cook <kees@ubuntu.com>
Reviewed-by: Dave Hansen <dave@linux.vnet.ibm.com>
Acked-by: Christoph Lameter <cl@gentwo.org>
Acked-by: David Rientjes <rientjes@google.com>
CC: Valdis.Kletnieks@vt.edu
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Alan Cox <alan@linux.intel.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Lockdep thinks there's lock recursion through:
kmem_cache_free()
cache_flusharray()
spin_lock(&l3->list_lock) <----------------.
free_block() |
slab_destroy() |
call_rcu() |
debug_object_activate() |
debug_object_init() |
__debug_object_init() |
kmem_cache_alloc() |
cache_alloc_refill() |
spin_lock(&l3->list_lock) --'
Now debug objects doesn't use SLAB_DESTROY_BY_RCU and hence there is no
actual possibility of recursing. Luckily debug objects marks it slab
with SLAB_DEBUG_OBJECTS so we can identify the thing.
Mark all SLAB_DEBUG_OBJECTS (all one!) slab caches with a special
lockdep key so that lockdep sees its a different cachep.
Also add a WARN on trying to create a SLAB_DESTROY_BY_RCU |
SLAB_DEBUG_OBJECTS cache, to avoid possible future trouble.
Reported-and-tested-by: Sebastian Siewior <sebastian@breakpoint.cc>
[ fixes to the initial patch ]
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1311341165.27400.58.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Use the nice enumerated constant.
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Reduce high order allocations in do_tune_cpucache() for some setups.
(NR_CPUS=4096 -> we need 64KB)
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
In commit c225150b "slab: fix DEBUG_SLAB build",
"if ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))" is always true if
ARCH_SLAB_MINALIGN == 0. Do not print warning if ARCH_SLAB_MINALIGN == 0.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Reduce high order allocations for some setups.
(NR_CPUS=4096 -> we need 64KB per kmem_cache struct)
We now allocate exact needed size (using nr_cpu_ids and nr_node_ids)
This also makes code a bit smaller on x86_64, since some field offsets
are less than the 127 limit :
Before patch :
# size mm/slab.o
text data bss dec hex filename
22605 361665 32 384302 5dd2e mm/slab.o
After patch :
# size mm/slab.o
text data bss dec hex filename
22349 353473 8224 384046 5dc2e mm/slab.o
CC: Andrew Morton <akpm@linux-foundation.org>
Reported-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Fix CONFIG_SLAB=y CONFIG_DEBUG_SLAB=y build error and warnings.
Now that ARCH_SLAB_MINALIGN defaults to __alignof__(unsigned long long),
it is always defined (when slab.h included), but cannot be used in #if:
mm/slab.c: In function `cache_alloc_debugcheck_after':
mm/slab.c:3156:5: warning: "__alignof__" is not defined
mm/slab.c:3156:5: error: missing binary operator before token "("
make[1]: *** [mm/slab.o] Error 1
So just remove the #if and #endif lines, but then 64-bit build warns:
mm/slab.c: In function `cache_alloc_debugcheck_after':
mm/slab.c:3156:6: warning: cast from pointer to integer of different size
mm/slab.c:3158:10: warning: format `%d' expects type `int', but argument
3 has type `long unsigned int'
Fix those with casts, whatever the actual type of ARCH_SLAB_MINALIGN.
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Currently, when using CONFIG_DEBUG_SLAB, we put in kfree() or
kmem_cache_free() as the last user of free objects, which is not
very useful, so change it to the caller of those functions instead.
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Commit e66eed651f ("list: remove prefetching from regular list
iterators") removed the include of prefetch.h from list.h, which
uncovered several cases that had apparently relied on that rather
obscure header file dependency.
So this fixes things up a bit, using
grep -L linux/prefetch.h $(git grep -l '[^a-z_]prefetchw*(' -- '*.[ch]')
grep -L 'prefetchw*(' $(git grep -l 'linux/prefetch.h' -- '*.[ch]')
to guide us in finding files that either need <linux/prefetch.h>
inclusion, or have it despite not needing it.
There are more of them around (mostly network drivers), but this gets
many core ones.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While looking at some other notifier callbacks I noticed this code could
use a simple cleanup.
notifier_from_errno() no longer needs the if (ret)/else conditional. That
same conditional is now done in notifier_from_errno().
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The size of struct rcu_head may be changed. When it becomes larger,
it may pollute the data after struct slab.
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
The last user was ext4 and Eric Sandeen removed the call in a recent patch. See
the following URL for the discussion:
http://marc.info/?l=linux-ext4&m=129546975702198&w=2
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Local symbols should be static.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
slub: Fix a crash during slabinfo -v
tracing/slab: Move kmalloc tracepoint out of inline code
slub: Fix slub_lock down/up imbalance
slub: Fix build breakage in Documentation/vm
slub tracing: move trace calls out of always inlined functions to reduce kernel code size
slub: move slabinfo.c to tools/slub/slabinfo.c
* 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (30 commits)
gameport: use this_cpu_read instead of lookup
x86: udelay: Use this_cpu_read to avoid address calculation
x86: Use this_cpu_inc_return for nmi counter
x86: Replace uses of current_cpu_data with this_cpu ops
x86: Use this_cpu_ops to optimize code
vmstat: User per cpu atomics to avoid interrupt disable / enable
irq_work: Use per cpu atomics instead of regular atomics
cpuops: Use cmpxchg for xchg to avoid lock semantics
x86: this_cpu_cmpxchg and this_cpu_xchg operations
percpu: Generic this_cpu_cmpxchg() and this_cpu_xchg support
percpu,x86: relocate this_cpu_add_return() and friends
connector: Use this_cpu operations
xen: Use this_cpu_inc_return
taskstats: Use this_cpu_ops
random: Use this_cpu_inc_return
fs: Use this_cpu_inc_return in buffer.c
highmem: Use this_cpu_xx_return() operations
vmstat: Use this_cpu_inc_return for vm statistics
x86: Support for this_cpu_add, sub, dec, inc_return
percpu: Generic support for this_cpu_add, sub, dec, inc_return
...
Fixed up conflicts: in arch/x86/kernel/{apic/nmi.c, apic/x2apic_uv_x.c, process.c}
as per Tejun.
* 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (33 commits)
usb: don't use flush_scheduled_work()
speedtch: don't abuse struct delayed_work
media/video: don't use flush_scheduled_work()
media/video: explicitly flush request_module work
ioc4: use static work_struct for ioc4_load_modules()
init: don't call flush_scheduled_work() from do_initcalls()
s390: don't use flush_scheduled_work()
rtc: don't use flush_scheduled_work()
mmc: update workqueue usages
mfd: update workqueue usages
dvb: don't use flush_scheduled_work()
leds-wm8350: don't use flush_scheduled_work()
mISDN: don't use flush_scheduled_work()
macintosh/ams: don't use flush_scheduled_work()
vmwgfx: don't use flush_scheduled_work()
tpm: don't use flush_scheduled_work()
sonypi: don't use flush_scheduled_work()
hvsi: don't use flush_scheduled_work()
xen: don't use flush_scheduled_work()
gdrom: don't use flush_scheduled_work()
...
Fixed up trivial conflict in drivers/media/video/bt8xx/bttv-input.c
as per Tejun.
__get_cpu_var() can be replaced with this_cpu_read and will then use a
single read instruction with implied address calculation to access the
correct per cpu instance.
However, the address of a per cpu variable passed to __this_cpu_read()
cannot be determined (since it's an implied address conversion through
segment prefixes). Therefore apply this only to uses of __get_cpu_var
where the address of the variable is not used.
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Hugh Dickins <hughd@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
cancel_rearming_delayed_work[queue]() has been superceded by
cancel_delayed_work_sync() quite some time ago. Convert all the
in-kernel users. The conversions are completely equivalent and
trivial.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: "David S. Miller" <davem@davemloft.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: netdev@vger.kernel.org
Cc: Anton Vorontsov <cbou@mail.ru>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Alex Elder <aelder@sgi.com>
Cc: xfs-masters@oss.sgi.com
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: netfilter-devel@vger.kernel.org
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: linux-nfs@vger.kernel.org
The tracepoint for kmalloc is in the slab inlined code which causes
every instance of kmalloc to have the tracepoint.
This patch moves the tracepoint out of the inline code to the
slab C file, which removes a large number of inlined trace
points.
objdump -dr vmlinux.slab| grep 'jmpq.*<trace_kmalloc' |wc -l
213
objdump -dr vmlinux.slab.patched| grep 'jmpq.*<trace_kmalloc' |wc -l
1
This also has a nice impact on size.
text data bss dec hex filename
7023060 2121564 2482432 11627056 b16a30 vmlinux.slab
6970579 2109772 2482432 11562783 b06f1f vmlinux.slab.patched
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Use the new {max,min}3 macros to save some cycles and bytes on the stack.
This patch substitutes trivial nested macros with their counterpart.
Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
Cc: Joe Perches <joe@perches.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Roland Dreier <rolandd@cisco.com>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
No real bugs, just some dead code and some fixups.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch fixes alignment of slab objects in case CONFIG_DEBUG_PAGEALLOC is
active.
Before this spot in kmem_cache_create, we have this situation:
- align contains the required alignment of the object
- cachep->obj_offset is 0 or equals align in case of CONFIG_DEBUG_SLAB
- size equals the size of the object, or object plus trailing redzone in case
of CONFIG_DEBUG_SLAB
This spot tries to fill one page per object if the object is in certain size
limits, however setting obj_offset to PAGE_SIZE - size does break the object
alignment since size may not be aligned with the required alignment.
This patch simply adds an ALIGN(size, align) to the equation and fixes the
object size detection accordingly.
This code in drivers/s390/cio/qdio_setup_init has lead to incorrectly aligned
slab objects (sizeof(struct qdio_q) equals 1792):
qdio_q_cache = kmem_cache_create("qdio_q", sizeof(struct qdio_q),
256, 0, NULL);
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
slub: Allow removal of slab caches during boot
Revert "slub: Allow removal of slab caches during boot"
slub numa: Fix rare allocation from unexpected node
slab: use deferable timers for its periodic housekeeping
slub: Use kmem_cache flags to detect if slab is in debugging mode.
slub: Allow removal of slab caches during boot
slub: Check kasprintf results in kmem_cache_init()
SLUB: Constants need UL
slub: Use a constant for a unspecified node.
SLOB: Free objects to their own list
slab: fix caller tracking on !CONFIG_DEBUG_SLAB && CONFIG_TRACING
slab has a "once every 2 second" timer for its housekeeping.
As the number of logical processors is growing, its more and more
common that this 2 second timer becomes the primary wakeup source.
This patch turns this housekeeping timer into a deferable timer,
which means that the timer does not interrupt idle, but just runs
at the next event that wakes the cpu up.
The impact is that the timer likely runs a bit later, but during the
delay no code is running so there's not all that much reason for
a difference in housekeeping to occur because of this delay.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
We have been resisting new ftrace plugins and removing existing
ones, and kmemtrace has been superseded by kmem trace events
and perf-kmem, so we remove it.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
[ remove kmemtrace from the makefile, handle slob too ]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Example usage of generic "numa_mem_id()":
The mainline slab code, since ~ 2.6.19, does not handle memoryless nodes
well. Specifically, the "fast path"--____cache_alloc()--will never
succeed as slab doesn't cache offnode object on the per cpu queues, and
for memoryless nodes, all memory will be "off node" relative to
numa_node_id(). This adds significant overhead to all kmem cache
allocations, incurring a significant regression relative to earlier
kernels [from before slab.c was reorganized].
This patch uses the generic topology function "numa_mem_id()" to return
the "effective local memory node" for the calling context. This is the
first node in the local node's generic fallback zonelist-- the same node
that "local" mempolicy-based allocations would use. This lets slab cache
these "local" allocations and avoid fallback/refill on every allocation.
N.B.: Slab will need to handle node and memory hotplug events that could
change the value returned by numa_mem_id() for any given node if recent
changes to address memory hotplug don't already address this. E.g., flush
all per cpu slab queues before rebuilding the zonelists while the
"machine" is held in the stopped state.
Performance impact on "hackbench 400 process 200"
2.6.34-rc3-mmotm-100405-1609 no-patch this-patch
ia64 no memoryless nodes [avg of 10]: 11.713 11.637 ~0.65 diff
ia64 cpus all on memless nodes [10]: 228.259 26.484 ~8.6x speedup
The slowdown of the patched kernel from ~12 sec to ~28 seconds when
configured with memoryless nodes is the result of all cpus allocating from
a single node's mm pagepool. The cache lines of the single node are
distributed/interleaved over the memory of the real physical nodes, but
the zone lock, list heads, ... of the single node with memory still each
live in a single cache line that is accessed from all processors.
x86_64 [8x6 AMD] [avg of 40]: 2.883 2.845
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Whitney <eric.whitney@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
By the previous modification, the cpu notifier can return encapsulate
errno value. This converts the cpu notifiers for slab.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We have observed several workloads running on multi-node systems where
memory is assigned unevenly across the nodes in the system. There are
numerous reasons for this but one is the round-robin rotor in
cpuset_mem_spread_node().
For example, a simple test that writes a multi-page file will allocate
pages on nodes 0 2 4 6 ... Odd nodes are skipped. (Sometimes it
allocates on odd nodes & skips even nodes).
An example is shown below. The program "lfile" writes a file consisting
of 10 pages. The program then mmaps the file & uses get_mempolicy(...,
MPOL_F_NODE) to determine the nodes where the file pages were allocated.
The output is shown below:
# ./lfile
allocated on nodes: 2 4 6 0 1 2 6 0 2
There is a single rotor that is used for allocating both file pages & slab
pages. Writing the file allocates both a data page & a slab page
(buffer_head). This advances the RR rotor 2 nodes for each page
allocated.
A quick confirmation seems to confirm this is the cause of the uneven
allocation:
# echo 0 >/dev/cpuset/memory_spread_slab
# ./lfile
allocated on nodes: 6 7 8 9 0 1 2 3 4 5
This patch introduces a second rotor that is used for slab allocations.
Signed-off-by: Jack Steiner <steiner@sgi.com>
Acked-by: 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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Even with SLAB_RED_ZONE and SLAB_STORE_USER enabled, kernel would NOT store
redzone and last user data around allocated memory space if "arch cache line >
sizeof(unsigned long long)". As a result, last user information is unexpectedly
MISSED while dumping slab corruption log.
This fix makes sure that redzone and last user tags get stored unless the
required alignment breaks redzone's.
Signed-off-by: Shiyong Li <shi-yong.li@motorola.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
As suggested by Linus, introduce a kern_ptr_validate() helper that does some
sanity checks to make sure a pointer is a valid kernel pointer. This is a
preparational step for fixing SLUB kmem_ptr_validate().
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Slab lacks any memory hotplug support for nodes that are hotplugged
without cpus being hotplugged. This is possible at least on x86
CONFIG_MEMORY_HOTPLUG_SPARSE kernels where SRAT entries are marked
ACPI_SRAT_MEM_HOT_PLUGGABLE and the regions of RAM represent a seperate
node. It can also be done manually by writing the start address to
/sys/devices/system/memory/probe for kernels that have
CONFIG_ARCH_MEMORY_PROBE set, which is how this patch was tested, and
then onlining the new memory region.
When a node is hotadded, a nodelist for that node is allocated and
initialized for each slab cache. If this isn't completed due to a lack
of memory, the hotadd is aborted: we have a reasonable expectation that
kmalloc_node(nid) will work for all caches if nid is online and memory is
available.
Since nodelists must be allocated and initialized prior to the new node's
memory actually being online, the struct kmem_list3 is allocated off-node
due to kmalloc_node()'s fallback.
When an entire node would be offlined, its nodelists are subsequently
drained. If slab objects still exist and cannot be freed, the offline is
aborted. It is possible that objects will be allocated between this
drain and page isolation, so it's still possible that the offline will
still fail, however.
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
This patch allow to inject faults only for specific slabs.
In order to preserve default behavior cache filter is off by
default (all caches are faulty).
One may define specific set of slabs like this:
# mark skbuff_head_cache as faulty
echo 1 > /sys/kernel/slab/skbuff_head_cache/failslab
# Turn on cache filter (off by default)
echo 1 > /sys/kernel/debug/failslab/cache-filter
# Turn on fault injection
echo 1 > /sys/kernel/debug/failslab/times
echo 1 > /sys/kernel/debug/failslab/probability
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
When factoring common code into transfer_objects in commit 3ded175 ("slab: add
transfer_objects() function"), the 'touched' logic got a bit broken. When
refilling from the shared array (taking objects from the shared array), we are
making use of the shared array so it should be marked as touched.
Subsequently pulling an element from the cpu array and allocating it should
also touch the cpu array, but that is taken care of after the alloc_done label.
(So yes, the cpu array was getting touched = 1 twice).
So revert this logic to how it worked in earlier kernels.
This also affects the behaviour in __drain_alien_cache, which would previously
'touch' the shared array and now does not. I think it is more logical not to
touch there, because we are pushing objects into the shared array rather than
pulling them off. So there is no good reason to postpone reaping them -- if the
shared array is getting utilized, then it will get 'touched' in the alloc path
(where this patch now restores the touch).
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Comparing with existing code, it's a simpler way to use kzalloc_node()
to ensure that each unused alien cache entry is NULL.
CC: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Commit ce79ddc8e2 ("SLAB: Fix lockdep annotations
for CPU hotplug") broke init_node_lock_keys() off-slab logic which causes
lockdep false positives.
Fix that up by reverting the logic back to original while keeping CPU hotplug
fixes intact.
Reported-and-tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reported-and-tested-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
* 'cpumask-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
cpumask: rename tsk_cpumask to tsk_cpus_allowed
cpumask: don't recommend set_cpus_allowed hack in Documentation/cpu-hotplug.txt
cpumask: avoid dereferencing struct cpumask
cpumask: convert drivers/idle/i7300_idle.c to cpumask_var_t
cpumask: use modern cpumask style in drivers/scsi/fcoe/fcoe.c
cpumask: avoid deprecated function in mm/slab.c
cpumask: use cpu_online in kernel/perf_event.c
* 'kmemleak' of git://linux-arm.org/linux-2.6:
kmemleak: fix kconfig for crc32 build error
kmemleak: Reduce the false positives by checking for modified objects
kmemleak: Show the age of an unreferenced object
kmemleak: Release the object lock before calling put_object()
kmemleak: Scan the _ftrace_events section in modules
kmemleak: Simplify the kmemleak_scan_area() function prototype
kmemleak: Do not use off-slab management with SLAB_NOLEAKTRACE
These days we use cpumask_empty() which takes a pointer.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf sched: Fix build failure on sparc
perf bench: Add "all" pseudo subsystem and "all" pseudo suite
perf tools: Introduce perf_session class
perf symbols: Ditch dso->find_symbol
perf symbols: Allow lookups by symbol name too
perf symbols: Add missing "Variables" entry to map_type__name
perf symbols: Add support for 'variable' symtabs
perf symbols: Introduce ELF counterparts to symbol_type__is_a
perf symbols: Introduce symbol_type__is_a
perf symbols: Rename kthreads to kmaps, using another abstraction for it
perf tools: Allow building for ARM
hw-breakpoints: Handle bad modify_user_hw_breakpoint off-case return value
perf tools: Allow cross compiling
tracing, slab: Fix no callsite ifndef CONFIG_KMEMTRACE
tracing, slab: Define kmem_cache_alloc_notrace ifdef CONFIG_TRACING
Trivial conflict due to different fixes to modify_user_hw_breakpoint()
in include/linux/hw_breakpoint.h
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (34 commits)
m68k: rename global variable vmalloc_end to m68k_vmalloc_end
percpu: add missing per_cpu_ptr_to_phys() definition for UP
percpu: Fix kdump failure if booted with percpu_alloc=page
percpu: make misc percpu symbols unique
percpu: make percpu symbols in ia64 unique
percpu: make percpu symbols in powerpc unique
percpu: make percpu symbols in x86 unique
percpu: make percpu symbols in xen unique
percpu: make percpu symbols in cpufreq unique
percpu: make percpu symbols in oprofile unique
percpu: make percpu symbols in tracer unique
percpu: make percpu symbols under kernel/ and mm/ unique
percpu: remove some sparse warnings
percpu: make alloc_percpu() handle array types
vmalloc: fix use of non-existent percpu variable in put_cpu_var()
this_cpu: Use this_cpu_xx in trace_functions_graph.c
this_cpu: Use this_cpu_xx for ftrace
this_cpu: Use this_cpu_xx in nmi handling
this_cpu: Use this_cpu operations in RCU
this_cpu: Use this_cpu ops for VM statistics
...
Fix up trivial (famous last words) global per-cpu naming conflicts in
arch/x86/kvm/svm.c
mm/slab.c
Christoph Lameter