Commit Graph

595256 Commits

Author SHA1 Message Date
Andrew Morton 1aa8aea535 mm: uninline page_mapped()
It's huge.  Uninlining it saves 206 bytes per callsite.  Shaves 4924
bytes from the x86_64 allmodconfig vmlinux.

[akpm@linux-foundation.org: coding-style fixes]
Cc: Steve Capper <steve.capper@arm.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Chanho Min 29f9cb53d2 mm/highmem: simplify is_highmem()
is_highmem() can be simplified by use of is_highmem_idx().  This patch
removes redundant code and will make it easier to maintain if the zone
policy is changed or a new zone is added.

(akpm: saves me 25 bytes of text per is_highmem() callsite)

Signed-off-by: Chanho Min <chanho.min@lge.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Vlastimil Babka fdd048e12c mm, compaction: skip blocks where isolation fails in async direct compaction
The goal of direct compaction is to quickly make a high-order page
available for the pending allocation.  Within an aligned block of pages
of desired order, a single allocated page that cannot be isolated for
migration means that the block cannot fully merge to a buddy page that
would satisfy the allocation request.  Therefore we can reduce the
allocation stall by skipping the rest of the block immediately on
isolation failure.  For async compaction, this also means a higher
chance of succeeding until it detects contention.

We however shouldn't completely sacrifice the second objective of
compaction, which is to reduce overal long-term memory fragmentation.
As a compromise, perform the eager skipping only in direct async
compaction, while sync compaction (including kcompactd) remains
thorough.

Testing was done using stress-highalloc from mmtests, configured for
order-4 GFP_KERNEL allocations:

                                 4.6-rc1               4.6-rc1
                                  before                 after
  Success 1 Min         24.00 (  0.00%)       27.00 (-12.50%)
  Success 1 Mean        30.20 (  0.00%)       31.60 ( -4.64%)
  Success 1 Max         37.00 (  0.00%)       35.00 (  5.41%)
  Success 2 Min         42.00 (  0.00%)       32.00 ( 23.81%)
  Success 2 Mean        44.00 (  0.00%)       44.80 ( -1.82%)
  Success 2 Max         48.00 (  0.00%)       52.00 ( -8.33%)
  Success 3 Min         91.00 (  0.00%)       92.00 ( -1.10%)
  Success 3 Mean        92.20 (  0.00%)       92.80 ( -0.65%)
  Success 3 Max         94.00 (  0.00%)       93.00 (  1.06%)

We can see that success rates are unaffected by the skipping.

                4.6-rc1     4.6-rc1
                 before       after
  User         2587.42     2566.53
  System        482.89      471.20
  Elapsed      1395.68     1382.00

Times are not so useful metric for this benchmark as main portion is the
interfering kernel builds, but results do hint at reduced system times.

                                      4.6-rc1     4.6-rc1
                                       before       after
  Direct pages scanned                163614      159608
  Kswapd pages scanned               2070139     2078790
  Kswapd pages reclaimed             2061707     2069757
  Direct pages reclaimed              163354      159505

Reduced direct reclaim was unintended, but could be explained by more
successful first attempt at (async) direct compaction, which is
attempted before the first reclaim attempt in __alloc_pages_slowpath().

  Compaction stalls                    33052       39853
  Compaction success                   12121       19773
  Compaction failures                  20931       20079

Compaction is indeed more successful, and thus less likely to get
deferred, so there are also more direct compaction stalls.

  Page migrate success               3781876     3326819
  Page migrate failure                 45817       41774
  Compaction pages isolated          7868232     6941457
  Compaction migrate scanned       168160492   127269354
  Compaction migrate prescanned            0           0
  Compaction free scanned         2522142582  2326342620
  Compaction free direct alloc             0           0
  Compaction free dir. all. miss           0           0
  Compaction cost                       5252        4476

The patch reduces migration scanned pages by 25% thanks to the eager
skipping.

[hughd@google.com: prevent nr_isolated_* from going negative]
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Vlastimil Babka a34753d275 mm, compaction: reduce spurious pcplist drains
Compaction drains the local pcplists each time migration scanner moves
away from a cc->order aligned block where it isolated pages for
migration, so that the pages freed by migrations can merge into higher
orders.

The detection is currently coarser than it could be.  The
cc->last_migrated_pfn variable should track the lowest pfn that was
isolated for migration.  But it is set to the pfn where
isolate_migratepages_block() starts scanning, which is typically the
first pfn of the pageblock.  There, the scanner might fail to isolate
several order-aligned blocks, and then isolate COMPACT_CLUSTER_MAX in
another block.  This would cause the pcplists drain to be performed,
although the scanner didn't yet finish the block where it isolated from.

This patch thus makes cc->last_migrated_pfn handling more accurate by
setting it to the pfn of an actually isolated page in
isolate_migratepages_block().  Although practical effects of this patch
are likely low, it arguably makes the intent of the code more obvious.
Also the next patch will make async direct compaction skip blocks more
aggressively, and draining pcplists due to skipped blocks is wasteful.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Vlastimil Babka 06b6640a39 mm, compaction: wrap calculating first and last pfn of pageblock
Compaction code has accumulated numerous instances of manual
calculations of the first (inclusive) and last (exclusive) pfn of a
pageblock (or a smaller block of given order), given a pfn within the
pageblock.

Wrap these calculations by introducing pageblock_start_pfn(pfn) and
pageblock_end_pfn(pfn) macros.

[vbabka@suse.cz: fix crash in get_pfnblock_flags_mask() from isolate_freepages():]
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.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>
2016-05-19 19:12:14 -07:00
Konstantin Khlebnikov e4c5800a39 mm/rmap: replace BUG_ON(anon_vma->degree) with VM_WARN_ON
This check effectively catches anon vma hierarchy inconsistence and some
vma corruptions.  It was effective for catching corner cases in anon vma
reusing logic.  For now this code seems stable so check could be hidden
under CONFIG_DEBUG_VM and replaced with WARN because it's not so fatal.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Suggested-by: Vasily Averin <vvs@virtuozzo.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Andrew Morton fee83b3aba mm/mempolicy.c:offset_il_node() document and clarify
This code was pretty obscure and was relying upon obscure side-effects
of next_node(-1, ...) and was relying upon NUMA_NO_NODE being equal to
-1.

Clean that all up and document the function's intent.

Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Andrew Morton 54f18d3526 mm/hugetlb.c: use first_memory_node
Instead of open-coding it.

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Li Zhang 949698a31a mm/page_alloc: Remove useless parameter of __free_pages_boot_core
__free_pages_boot_core has parameter pfn which is not used at all.
Remove it.

Signed-off-by: Li Zhang <zhlcindy@linux.vnet.ibm.com>
Reviewed-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Michal Hocko fda3d69be9 mm/memcontrol.c:mem_cgroup_select_victim_node(): clarify comment
> The comment seems to have not much to do with the code?

I guess the comment tries to say that the code path is triggered when we
charge the page which happens _before_ it is added to the LRU list and
so last_scanned_node might contain the stale data.

Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Yaowei Bai 4ee815be1d mm/mempolicy.c: vma_migratable() can return bool
Make vma_migratable() return bool due to this particular function only
using either one or zero as its return value.

Signed-off-by: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Yaowei Bai bb00a789e5 mm/vmalloc.c: is_vmalloc_addr() can return bool
Make is_vmalloc_addr() return bool to improve readability due to this
particular function only using either one or zero as its return value.

Signed-off-by: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Yaowei Bai c98940f6fa mm/memory_hotplug: is_mem_section_removable() can return bool
Make is_mem_section_removable() return bool to improve readability due
to this particular function only using either one or zero as its return
value.

Signed-off-by: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Yaowei Bai 32f6271dbd mm/hugetlb: is_vm_hugetlb_page() can return bool
Make is_vm_hugetlb_page() return bool to improve readability due to this
particular function only using either one or zero as its return value.

Signed-off-by: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Vaishali Thakkar 2b18e5321f x86: mm: use hugetlb_bad_size()
Update setup_hugepagesz() to call hugetlb_bad_size() when unsupported
hugepage size is found.

Signed-off-by: Vaishali Thakkar <vaishali.thakkar@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Cc: Dominik Dingel <dingel@linux.vnet.ibm.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Vaishali Thakkar b3d424f1a5 tile: mm: use hugetlb_bad_size()
Update setup_hugepagesz() to call hugetlb_bad_size() when unsupported
hugepage size is found.

Signed-off-by: Vaishali Thakkar <vaishali.thakkar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Cc: Dominik Dingel <dingel@linux.vnet.ibm.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Vaishali Thakkar 71bf79cc3f powerpc: mm: use hugetlb_bad_size()
Update setup_hugepagesz() to call hugetlb_bad_size() when unsupported
hugepage size is found.

Signed-off-by: Vaishali Thakkar <vaishali.thakkar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Cc: Dominik Dingel <dingel@linux.vnet.ibm.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Vaishali Thakkar 9cc3387fa2 metag: mm: use hugetlb_bad_size()
Update setup_hugepagesz() to call hugetlb_bad_size() when unsupported
hugepage size is found.

Signed-off-by: Vaishali Thakkar <vaishali.thakkar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Cc: Dominik Dingel <dingel@linux.vnet.ibm.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Vaishali Thakkar d77e20cea7 arm64: mm: use hugetlb_bad_size()
Update setup_hugepagesz() to call hugetlb_bad_size() when unsupported
hugepage size is found.

Signed-off-by: Vaishali Thakkar <vaishali.thakkar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Cc: Dominik Dingel <dingel@linux.vnet.ibm.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Vaishali Thakkar 9fee021d15 mm/hugetlb: introduce hugetlb_bad_size()
When any unsupported hugepage size is specified, 'hugepagesz=' and
'hugepages=' should be ignored during command line parsing until any
supported hugepage size is found.  But currently incorrect number of
hugepages are allocated when unsupported size is specified as it fails
to ignore the 'hugepages=' command.

Test case:

Note that this is specific to x86 architecture.

Boot the kernel with command line option 'hugepagesz=256M hugepages=X'.
After boot, dmesg output shows that X number of hugepages of the size 2M
is pre-allocated instead of 0.

So, to handle such command line options, introduce new routine
hugetlb_bad_size.  The routine hugetlb_bad_size sets the global variable
parsed_valid_hugepagesz.  We are using parsed_valid_hugepagesz to save
the state when unsupported hugepagesize is found so that we can ignore
the 'hugepages=' parameters after that and then reset the variable when
supported hugepage size is found.

The routine hugetlb_bad_size can be called while setting 'hugepagesz='
parameter in an architecture specific code.

Signed-off-by: Vaishali Thakkar <vaishali.thakkar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Cc: Dominik Dingel <dingel@linux.vnet.ibm.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Mike Kravetz 09a95e29cb mm/hugetlb: optimize minimum size (min_size) accounting
It was observed that minimum size accounting associated with the
hugetlbfs min_size mount option may not perform optimally and as
expected.  As huge pages/reservations are released from the filesystem
and given back to the global pools, they are reserved for subsequent
filesystem use as long as the subpool reserved count is less than
subpool minimum size.  It does not take into account used pages within
the filesystem.  The filesystem size limits are not exceeded and this is
technically not a bug.  However, better behavior would be to wait for
the number of used pages/reservations associated with the filesystem to
drop below the minimum size before taking reservations to satisfy
minimum size.

An optimization is also made to the hugepage_subpool_get_pages() routine
which is called when pages/reservations are allocated.  This does not
change behavior, but simply avoids the accounting if all reservations
have already been taken (subpool reserved count == 0).

Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Andrew Morton 0edaf86cf1 include/linux/nodemask.h: create next_node_in() helper
Lots of code does

	node = next_node(node, XXX);
	if (node == MAX_NUMNODES)
		node = first_node(XXX);

so create next_node_in() to do this and use it in various places.

[mhocko@suse.com: use next_node_in() helper]
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Hui Zhu <zhuhui@xiaomi.com>
Cc: Wang Xiaoqiang <wangxq10@lzu.edu.cn>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Rasmus Villemoes 48a270554a include/linux: apply __malloc attribute
Attach the malloc attribute to a few allocation functions.  This helps
gcc generate better code by telling it that the return value doesn't
alias any existing pointers (which is even more valuable given the
pessimizations implied by -fno-strict-aliasing).

A simple example of what this allows gcc to do can be seen by looking at
the last part of drm_atomic_helper_plane_reset:

	plane->state = kzalloc(sizeof(*plane->state), GFP_KERNEL);

	if (plane->state) {
		plane->state->plane = plane;
		plane->state->rotation = BIT(DRM_ROTATE_0);
	}

which compiles to

    e8 99 bf d6 ff          callq  ffffffff8116d540 <kmem_cache_alloc_trace>
    48 85 c0                test   %rax,%rax
    48 89 83 40 02 00 00    mov    %rax,0x240(%rbx)
    74 11                   je     ffffffff814015c4 <drm_atomic_helper_plane_reset+0x64>
    48 89 18                mov    %rbx,(%rax)
    48 8b 83 40 02 00 00    mov    0x240(%rbx),%rax [*]
    c7 40 40 01 00 00 00    movl   $0x1,0x40(%rax)

With this patch applied, the instruction at [*] is elided, since the
store to plane->state->plane is known to not alter the value of
plane->state.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Rasmus Villemoes d64e85d3e1 compiler.h: add support for malloc attribute
gcc as far back as at least 3.04 documents the function attribute
__malloc__.  Add a shorthand for attaching that to a function
declaration.  This was also suggested by Andi Kleen way back in 2002
[1], but didn't get applied, perhaps because gcc at that time generated
the exact same code with and without this attribute.

This attribute tells the compiler that the return value (if non-NULL)
can be assumed not to alias any other valid pointers at the time of the
call.

Please note that the documentation for a range of gcc versions (starting
from around 4.7) contained a somewhat confusing and self-contradicting
text:

  The malloc attribute is used to tell the compiler that a function may
  be treated as if any non-NULL pointer it returns cannot alias any other
  pointer valid when the function returns and *that the memory has
  undefined content*.  [...] Standard functions with this property include
  malloc and *calloc*.

(emphasis mine). The intended meaning has later been clarified [2]:

  This tells the compiler that a function is malloc-like, i.e., that the
  pointer P returned by the function cannot alias any other pointer valid
  when the function returns, and moreover no pointers to valid objects
  occur in any storage addressed by P.

What this means is that we can apply the attribute to kmalloc and
friends, and it is ok for the returned memory to have well-defined
contents (__GFP_ZERO).  But it is not ok to apply it to kmemdup(), nor
to other functions which both allocate and possibly initialize the
memory with existing pointers.  So unless someone is doing something
pretty perverted kstrdup() should also be a fine candidate.

[1] http://thread.gmane.org/gmane.linux.kernel/57172
[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56955

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Joonsoo Kim 0139aa7b7f mm: rename _count, field of the struct page, to _refcount
Many developers already know that field for reference count of the
struct page is _count and atomic type.  They would try to handle it
directly and this could break the purpose of page reference count
tracepoint.  To prevent direct _count modification, this patch rename it
to _refcount and add warning message on the code.  After that, developer
who need to handle reference count will find that field should not be
accessed directly.

[akpm@linux-foundation.org: fix comments, per Vlastimil]
[akpm@linux-foundation.org: Documentation/vm/transhuge.txt too]
[sfr@canb.auug.org.au: sync ethernet driver changes]
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Sunil Goutham <sgoutham@cavium.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Manish Chopra <manish.chopra@qlogic.com>
Cc: Yuval Mintz <yuval.mintz@qlogic.com>
Cc: Tariq Toukan <tariqt@mellanox.com>
Cc: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Joonsoo Kim 6d061f9f61 mm/page_ref: use page_ref helper instead of direct modification of _count
page_reference manipulation functions are introduced to track down
reference count change of the page.  Use it instead of direct
modification of _count.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Sunil Goutham <sgoutham@cavium.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Li Peng 43efd3ea64 mm/slub.c: fix sysfs filename in comment
/sys/kernel/slab/xx/defrag_ratio should be remote_node_defrag_ratio.

Link: http://lkml.kernel.org/r/1463449242-5366-1-git-send-email-lip@dtdream.com
Signed-off-by: Li Peng <lip@dtdream.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>
2016-05-19 19:12:14 -07:00
Yang Shi a3187e438b mm: slab: remove ZONE_DMA_FLAG
Now we have IS_ENABLED helper to check if a Kconfig option is enabled or
not, so ZONE_DMA_FLAG sounds no longer useful.

And, the use of ZONE_DMA_FLAG in slab looks pointless according to the
comment [1] from Johannes Weiner, so remove them and ORing passed in
flags with the cache gfp flags has been done in kmem_getpages().

[1] https://lkml.org/lkml/2014/9/25/553

Link: http://lkml.kernel.org/r/1462381297-11009-1-git-send-email-yang.shi@linaro.org
Signed-off-by: Yang Shi <yang.shi@linaro.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Thomas Garnier c7ce4f60ac mm: SLAB freelist randomization
Provides an optional config (CONFIG_SLAB_FREELIST_RANDOM) to randomize
the SLAB freelist.  The list is randomized during initialization of a
new set of pages.  The order on different freelist sizes is pre-computed
at boot for performance.  Each kmem_cache has its own randomized
freelist.  Before pre-computed lists are available freelists are
generated dynamically.  This security feature reduces the predictability
of the kernel SLAB allocator against heap overflows rendering attacks
much less stable.

For example this attack against SLUB (also applicable against SLAB)
would be affected:

  https://jon.oberheide.org/blog/2010/09/10/linux-kernel-can-slub-overflow/

Also, since v4.6 the freelist was moved at the end of the SLAB.  It
means a controllable heap is opened to new attacks not yet publicly
discussed.  A kernel heap overflow can be transformed to multiple
use-after-free.  This feature makes this type of attack harder too.

To generate entropy, we use get_random_bytes_arch because 0 bits of
entropy is available in the boot stage.  In the worse case this function
will fallback to the get_random_bytes sub API.  We also generate a shift
random number to shift pre-computed freelist for each new set of pages.

The config option name is not specific to the SLAB as this approach will
be extended to other allocators like SLUB.

Performance results highlighted no major changes:

Hackbench (running 90 10 times):

  Before average: 0.0698
  After average: 0.0663 (-5.01%)

slab_test 1 run on boot.  Difference only seen on the 2048 size test
being the worse case scenario covered by freelist randomization.  New
slab pages are constantly being created on the 10000 allocations.
Variance should be mainly due to getting new pages every few
allocations.

Before:

  Single thread testing
  =====================
  1. Kmalloc: Repeatedly allocate then free test
  10000 times kmalloc(8) -> 99 cycles kfree -> 112 cycles
  10000 times kmalloc(16) -> 109 cycles kfree -> 140 cycles
  10000 times kmalloc(32) -> 129 cycles kfree -> 137 cycles
  10000 times kmalloc(64) -> 141 cycles kfree -> 141 cycles
  10000 times kmalloc(128) -> 152 cycles kfree -> 148 cycles
  10000 times kmalloc(256) -> 195 cycles kfree -> 167 cycles
  10000 times kmalloc(512) -> 257 cycles kfree -> 199 cycles
  10000 times kmalloc(1024) -> 393 cycles kfree -> 251 cycles
  10000 times kmalloc(2048) -> 649 cycles kfree -> 228 cycles
  10000 times kmalloc(4096) -> 806 cycles kfree -> 370 cycles
  10000 times kmalloc(8192) -> 814 cycles kfree -> 411 cycles
  10000 times kmalloc(16384) -> 892 cycles kfree -> 455 cycles
  2. Kmalloc: alloc/free test
  10000 times kmalloc(8)/kfree -> 121 cycles
  10000 times kmalloc(16)/kfree -> 121 cycles
  10000 times kmalloc(32)/kfree -> 121 cycles
  10000 times kmalloc(64)/kfree -> 121 cycles
  10000 times kmalloc(128)/kfree -> 121 cycles
  10000 times kmalloc(256)/kfree -> 119 cycles
  10000 times kmalloc(512)/kfree -> 119 cycles
  10000 times kmalloc(1024)/kfree -> 119 cycles
  10000 times kmalloc(2048)/kfree -> 119 cycles
  10000 times kmalloc(4096)/kfree -> 121 cycles
  10000 times kmalloc(8192)/kfree -> 119 cycles
  10000 times kmalloc(16384)/kfree -> 119 cycles

After:

  Single thread testing
  =====================
  1. Kmalloc: Repeatedly allocate then free test
  10000 times kmalloc(8) -> 130 cycles kfree -> 86 cycles
  10000 times kmalloc(16) -> 118 cycles kfree -> 86 cycles
  10000 times kmalloc(32) -> 121 cycles kfree -> 85 cycles
  10000 times kmalloc(64) -> 176 cycles kfree -> 102 cycles
  10000 times kmalloc(128) -> 178 cycles kfree -> 100 cycles
  10000 times kmalloc(256) -> 205 cycles kfree -> 109 cycles
  10000 times kmalloc(512) -> 262 cycles kfree -> 136 cycles
  10000 times kmalloc(1024) -> 342 cycles kfree -> 157 cycles
  10000 times kmalloc(2048) -> 701 cycles kfree -> 238 cycles
  10000 times kmalloc(4096) -> 803 cycles kfree -> 364 cycles
  10000 times kmalloc(8192) -> 835 cycles kfree -> 404 cycles
  10000 times kmalloc(16384) -> 896 cycles kfree -> 441 cycles
  2. Kmalloc: alloc/free test
  10000 times kmalloc(8)/kfree -> 121 cycles
  10000 times kmalloc(16)/kfree -> 121 cycles
  10000 times kmalloc(32)/kfree -> 123 cycles
  10000 times kmalloc(64)/kfree -> 142 cycles
  10000 times kmalloc(128)/kfree -> 121 cycles
  10000 times kmalloc(256)/kfree -> 119 cycles
  10000 times kmalloc(512)/kfree -> 119 cycles
  10000 times kmalloc(1024)/kfree -> 119 cycles
  10000 times kmalloc(2048)/kfree -> 119 cycles
  10000 times kmalloc(4096)/kfree -> 119 cycles
  10000 times kmalloc(8192)/kfree -> 119 cycles
  10000 times kmalloc(16384)/kfree -> 119 cycles

[akpm@linux-foundation.org: propagate gfp_t into cache_random_seq_create()]
Signed-off-by: Thomas Garnier <thgarnie@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Laura Abbott <labbott@fedoraproject.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Vladimir Davydov 81ae6d0395 mm/slub.c: replace kick_all_cpus_sync() with synchronize_sched() in kmem_cache_shrink()
When we call __kmem_cache_shrink on memory cgroup removal, we need to
synchronize kmem_cache->cpu_partial update with put_cpu_partial that
might be running on other cpus.  Currently, we achieve that by using
kick_all_cpus_sync, which works as a system wide memory barrier.  Though
fast it is, this method has a flaw - it issues a lot of IPIs, which
might hurt high performance or real-time workloads.

To fix this, let's replace kick_all_cpus_sync with synchronize_sched.
Although the latter one may take much longer to finish, it shouldn't be
a problem in this particular case, because memory cgroups are destroyed
asynchronously from a workqueue so that no user visible effects should
be introduced.  OTOH, it will save us from excessive IPIs when someone
removes a cgroup.

Anyway, even if using synchronize_sched turns out to take too long, we
can always introduce a kind of __kmem_cache_shrink batching so that this
method would only be called once per one cgroup destruction (not per
each per memcg kmem cache as it is now).

Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Joonsoo Kim 801faf0db8 mm/slab: lockless decision to grow cache
To check whether free objects exist or not precisely, we need to grab a
lock.  But, accuracy isn't that important because race window would be
even small and if there is too much free object, cache reaper would reap
it.  So, this patch makes the check for free object exisistence not to
hold a lock.  This will reduce lock contention in heavily allocation
case.

Note that until now, n->shared can be freed during the processing by
writing slabinfo, but, with some trick in this patch, we can access it
freely within interrupt disabled period.

Below is the result of concurrent allocation/free in slab allocation
benchmark made by Christoph a long time ago.  I make the output simpler.
The number shows cycle count during alloc/free respectively so less is
better.

  * Before
  Kmalloc N*alloc N*free(32): Average=248/966
  Kmalloc N*alloc N*free(64): Average=261/949
  Kmalloc N*alloc N*free(128): Average=314/1016
  Kmalloc N*alloc N*free(256): Average=741/1061
  Kmalloc N*alloc N*free(512): Average=1246/1152
  Kmalloc N*alloc N*free(1024): Average=2437/1259
  Kmalloc N*alloc N*free(2048): Average=4980/1800
  Kmalloc N*alloc N*free(4096): Average=9000/2078

  * After
  Kmalloc N*alloc N*free(32): Average=344/792
  Kmalloc N*alloc N*free(64): Average=347/882
  Kmalloc N*alloc N*free(128): Average=390/959
  Kmalloc N*alloc N*free(256): Average=393/1067
  Kmalloc N*alloc N*free(512): Average=683/1229
  Kmalloc N*alloc N*free(1024): Average=1295/1325
  Kmalloc N*alloc N*free(2048): Average=2513/1664
  Kmalloc N*alloc N*free(4096): Average=4742/2172

It shows that allocation performance decreases for the object size up to
128 and it may be due to extra checks in cache_alloc_refill().  But,
with considering improvement of free performance, net result looks the
same.  Result for other size class looks very promising, roughly, 50%
performance improvement.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.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>
2016-05-19 19:12:14 -07:00
Joonsoo Kim 213b46958c mm/slab: refill cpu cache through a new slab without holding a node lock
Until now, cache growing makes a free slab on node's slab list and then
we can allocate free objects from it.  This necessarily requires to hold
a node lock which is very contended.  If we refill cpu cache before
attaching it to node's slab list, we can avoid holding a node lock as
much as possible because this newly allocated slab is only visible to
the current task.  This will reduce lock contention.

Below is the result of concurrent allocation/free in slab allocation
benchmark made by Christoph a long time ago.  I make the output simpler.
The number shows cycle count during alloc/free respectively so less is
better.

  * Before
  Kmalloc N*alloc N*free(32): Average=355/750
  Kmalloc N*alloc N*free(64): Average=452/812
  Kmalloc N*alloc N*free(128): Average=559/1070
  Kmalloc N*alloc N*free(256): Average=1176/980
  Kmalloc N*alloc N*free(512): Average=1939/1189
  Kmalloc N*alloc N*free(1024): Average=3521/1278
  Kmalloc N*alloc N*free(2048): Average=7152/1838
  Kmalloc N*alloc N*free(4096): Average=13438/2013

  * After
  Kmalloc N*alloc N*free(32): Average=248/966
  Kmalloc N*alloc N*free(64): Average=261/949
  Kmalloc N*alloc N*free(128): Average=314/1016
  Kmalloc N*alloc N*free(256): Average=741/1061
  Kmalloc N*alloc N*free(512): Average=1246/1152
  Kmalloc N*alloc N*free(1024): Average=2437/1259
  Kmalloc N*alloc N*free(2048): Average=4980/1800
  Kmalloc N*alloc N*free(4096): Average=9000/2078

It shows that contention is reduced for all the object sizes and
performance increases by 30 ~ 40%.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.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>
2016-05-19 19:12:14 -07:00
Joonsoo Kim 76b342bdc7 mm/slab: separate cache_grow() to two parts
This is a preparation step to implement lockless allocation path when
there is no free objects in kmem_cache.

What we'd like to do here is to refill cpu cache without holding a node
lock.  To accomplish this purpose, refill should be done after new slab
allocation but before attaching the slab to the management list.  So,
this patch separates cache_grow() to two parts, allocation and attaching
to the list in order to add some code inbetween them in the following
patch.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.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>
2016-05-19 19:12:14 -07:00
Joonsoo Kim 511e3a0588 mm/slab: make cache_grow() handle the page allocated on arbitrary node
Currently, cache_grow() assumes that allocated page's nodeid would be
same with parameter nodeid which is used for allocation request.  If we
discard this assumption, we can handle fallback_alloc() case gracefully.
So, this patch makes cache_grow() handle the page allocated on arbitrary
node and clean-up relevant code.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.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>
2016-05-19 19:12:14 -07:00
Joonsoo Kim 03d1d43a12 mm/slab: racy access/modify the slab color
Slab color isn't needed to be changed strictly.  Because locking for
changing slab color could cause more lock contention so this patch
implements racy access/modify the slab color.  This is a preparation
step to implement lockless allocation path when there is no free objects
in the kmem_cache.

Below is the result of concurrent allocation/free in slab allocation
benchmark made by Christoph a long time ago.  I make the output simpler.
The number shows cycle count during alloc/free respectively so less is
better.

  * Before
  Kmalloc N*alloc N*free(32): Average=365/806
  Kmalloc N*alloc N*free(64): Average=452/690
  Kmalloc N*alloc N*free(128): Average=736/886
  Kmalloc N*alloc N*free(256): Average=1167/985
  Kmalloc N*alloc N*free(512): Average=2088/1125
  Kmalloc N*alloc N*free(1024): Average=4115/1184
  Kmalloc N*alloc N*free(2048): Average=8451/1748
  Kmalloc N*alloc N*free(4096): Average=16024/2048

  * After
  Kmalloc N*alloc N*free(32): Average=355/750
  Kmalloc N*alloc N*free(64): Average=452/812
  Kmalloc N*alloc N*free(128): Average=559/1070
  Kmalloc N*alloc N*free(256): Average=1176/980
  Kmalloc N*alloc N*free(512): Average=1939/1189
  Kmalloc N*alloc N*free(1024): Average=3521/1278
  Kmalloc N*alloc N*free(2048): Average=7152/1838
  Kmalloc N*alloc N*free(4096): Average=13438/2013

It shows that contention is reduced for object size >= 1024 and
performance increases by roughly 15%.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Pekka Enberg <penberg@kernel.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>
2016-05-19 19:12:14 -07:00
Joonsoo Kim 6052b7880a mm/slab: don't keep free slabs if free_objects exceeds free_limit
Currently, determination to free a slab is done whenever each freed
object is put into the slab.  This has a following problem.

Assume free_limit = 10 and nr_free = 9.

Free happens as following sequence and nr_free changes as following.

free(become a free slab) free(not become a free slab) nr_free: 9 -> 10
(at first free) -> 11 (at second free)

If we try to check if we can free current slab or not on each object
free, we can't free any slab in this situation because current slab
isn't a free slab when nr_free exceed free_limit (at second free) even
if there is a free slab.

However, if we check it lastly, we can free 1 free slab.

This problem would cause to keep too much memory in the slab subsystem.
This patch try to fix it by checking number of free object after all
free work is done.  If there is free slab at that time, we can free slab
as much as possible so we keep free slab as minimal.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.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>
2016-05-19 19:12:14 -07:00
Joonsoo Kim c3d332b6b2 mm/slab: clean-up kmem_cache_node setup
There are mostly same code for setting up kmem_cache_node either in
cpuup_prepare() or alloc_kmem_cache_node().  Factor out and clean-up
them.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Tested-by: Nishanth Menon <nm@ti.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Pekka Enberg <penberg@kernel.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>
2016-05-19 19:12:14 -07:00
Joonsoo Kim ded0ecf611 mm/slab: factor out kmem_cache_node initialization code
It can be reused on other place, so factor out it.  Following patch will
use it.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Pekka Enberg <penberg@kernel.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>
2016-05-19 19:12:14 -07:00
Joonsoo Kim a5aa63a5f7 mm/slab: drain the free slab as much as possible
slabs_tofree() implies freeing all free slab.  We can do it with just
providing INT_MAX.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Pekka Enberg <penberg@kernel.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>
2016-05-19 19:12:14 -07:00
Joonsoo Kim 8888177ea1 mm/slab: remove BAD_ALIEN_MAGIC again
Initial attemp to remove BAD_ALIEN_MAGIC is once reverted by 'commit
edcad25095 ("Revert "slab: remove BAD_ALIEN_MAGIC"")' because it
causes a problem on m68k which has many node but !CONFIG_NUMA.  In this
case, although alien cache isn't used at all but to cope with some
initialization path, garbage value is used and that is BAD_ALIEN_MAGIC.
Now, this patch set use_alien_caches to 0 when !CONFIG_NUMA, there is no
initialization path problem so we don't need BAD_ALIEN_MAGIC at all.  So
remove it.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Pekka Enberg <penberg@kernel.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>
2016-05-19 19:12:14 -07:00
Joonsoo Kim 18726ca8b3 mm/slab: fix the theoretical race by holding proper lock
While processing concurrent allocation, SLAB could be contended a lot
because it did a lots of work with holding a lock.  This patchset try to
reduce the number of critical section to reduce lock contention.  Major
changes are lockless decision to allocate more slab and lockless cpu
cache refill from the newly allocated slab.

Below is the result of concurrent allocation/free in slab allocation
benchmark made by Christoph a long time ago.  I make the output simpler.
The number shows cycle count during alloc/free respectively so less is
better.

  * Before
  Kmalloc N*alloc N*free(32): Average=365/806
  Kmalloc N*alloc N*free(64): Average=452/690
  Kmalloc N*alloc N*free(128): Average=736/886
  Kmalloc N*alloc N*free(256): Average=1167/985
  Kmalloc N*alloc N*free(512): Average=2088/1125
  Kmalloc N*alloc N*free(1024): Average=4115/1184
  Kmalloc N*alloc N*free(2048): Average=8451/1748
  Kmalloc N*alloc N*free(4096): Average=16024/2048

  * After
  Kmalloc N*alloc N*free(32): Average=344/792
  Kmalloc N*alloc N*free(64): Average=347/882
  Kmalloc N*alloc N*free(128): Average=390/959
  Kmalloc N*alloc N*free(256): Average=393/1067
  Kmalloc N*alloc N*free(512): Average=683/1229
  Kmalloc N*alloc N*free(1024): Average=1295/1325
  Kmalloc N*alloc N*free(2048): Average=2513/1664
  Kmalloc N*alloc N*free(4096): Average=4742/2172

It shows that performance improves greatly (roughly more than 50%) for
the object class whose size is more than 128 bytes.

This patch (of 11):

If we don't hold neither the slab_mutex nor the node lock, node's shared
array cache could be freed and re-populated.  If __kmem_cache_shrink()
is called at the same time, it will call drain_array() with n->shared
without holding node lock so problem can happen.  This patch fix the
situation by holding the node lock before trying to drain the shared
array.

In addition, add a debug check to confirm that n->shared access race
doesn't exist.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.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>
2016-05-19 19:12:14 -07:00
Arnd Bergmann 19d795b677 kernel/padata.c: hide unused functions
A recent cleanup removed some exported functions that were not used
anywhere, which in turn exposed the fact that some other functions in
the same file are only used in some configurations.

We now get a warning about them when CONFIG_HOTPLUG_CPU is disabled:

  kernel/padata.c:670:12: error: '__padata_remove_cpu' defined but not used [-Werror=unused-function]
   static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
              ^~~~~~~~~~~~~~~~~~~
  kernel/padata.c:650:12: error: '__padata_add_cpu' defined but not used [-Werror=unused-function]
   static int __padata_add_cpu(struct padata_instance *pinst, int cpu)

This rearranges the code so the __padata_remove_cpu/__padata_add_cpu
functions are within the #ifdef that protects the code that calls them.

[akpm@linux-foundation.org: coding-style fixes]
Fixes: 4ba6d78c671e ("kernel/padata.c: removed unused code")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Richard Cochran <rcochran@linutronix.de>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Richard Cochran 815613da6a kernel/padata.c: removed unused code
By accident I stumbled across code that has never been used.  This
driver has EXPORT_SYMBOL functions, and the only user of the code is
pcrypt.c, but this only uses a subset of the exported symbols.

According to 'git log -G', the functions, padata_set_cpumasks,
padata_add_cpu, and padata_remove_cpu have never been used since they
were first introduced.  This patch removes the unused code.

On one 64 bit build, with CRYPTO_PCRYPT built in, the text is more than
4k smaller.

  kbuild_hp> size $KBUILD_OUTPUT/vmlinux
      text    data     bss      dec hex    filename
  10566658 4678360 1122304 16367322 f9beda vmlinux
  10561984 4678360 1122304 16362648 f9ac98 vmlinux

On another config, 32 bit, the saving is about 0.5k bytes.

  kbuild_hp-x86> size $KBUILD_OUTPUT/vmlinux
  6012005 2409513 2785280 11206798 ab008e vmlinux
  6011491 2409513 2785280 11206284 aafe8c vmlinux

Signed-off-by: Richard Cochran <rcochran@linutronix.de>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Guozhonghua 8f9b1802c2 ocfs2: clean up an unneeded goto in ocfs2_put_slot()
The goto is not useful in ocfs2_put_slot(), so delete it.

Signed-off-by: Guozhonghua <guozhonghua@h3c.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <joseph.qi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Jun Piao aa6913dbd2 ocfs2: clean up unused parameter 'count' in o2hb_read_block_input()
Clean up unused parameter 'count' in o2hb_read_block_input().

Signed-off-by: Jun Piao <piaojun@huawei.com>
Reviewed-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
piaojun c14688ea24 ocfs2: clean up an unused variable 'wants_rotate' in ocfs2_truncate_rec
Clean up an unused variable 'wants_rotate' in ocfs2_truncate_rec.

Signed-off-by: Jun Piao <piaojun@huawei.com>
Reviewed-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Guozhonghua 8ba442214c ocfs2: fix comment in struct ocfs2_extended_slot
The comment in ocfs2_extended_slot has the offset wrong.

Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <joseph.qi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Du, Changbin b9fdac7f66 debugobjects: insulate non-fixup logic related to static obj from fixup callbacks
When activating a static object we need make sure that the object is
tracked in the object tracker.  If it is a non-static object then the
activation is illegal.

In previous implementation, each subsystem need take care of this in
their fixup callbacks.  Actually we can put it into debugobjects core.
Thus we can save duplicated code, and have *pure* fixup callbacks.

To achieve this, a new callback "is_static_object" is introduced to let
the type specific code decide whether a object is static or not.  If
yes, we take it into object tracker, otherwise give warning and invoke
fixup callback.

This change has paassed debugobjects selftest, and I also do some test
with all debugobjects supports enabled.

At last, I have a concern about the fixups that can it change the object
which is in incorrect state on fixup? Because the 'addr' may not point
to any valid object if a non-static object is not tracked.  Then Change
such object can overwrite someone's memory and cause unexpected
behaviour.  For example, the timer_fixup_activate bind timer to function
stub_timer.

Link: http://lkml.kernel.org/r/1462576157-14539-1-git-send-email-changbin.du@intel.com
[changbin.du@intel.com: improve code comments where invoke the new is_static_object callback]
  Link: http://lkml.kernel.org/r/1462777431-8171-1-git-send-email-changbin.du@intel.com
Signed-off-by: Du, Changbin <changbin.du@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Triplett <josh@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Du, Changbin 8bad1cd0e1 Documentation: update debugobjects doc
Update documentation creangponding to change(debugobjects: make fixup
functions return bool instead of int).

Signed-off-by: Du, Changbin <changbin.du@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Triplett <josh@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Du, Changbin d99b1d8912 percpu_counter: update debugobjects fixup callbacks return type
Update the return type to use bool instead of int, corresponding to
cheange (debugobjects: make fixup functions return bool instead of int).

Signed-off-by: Du, Changbin <changbin.du@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Triplett <josh@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00