Commit Graph

8627 Commits

Author SHA1 Message Date
Konstantin Khlebnikov
4d88e6f7d5 mm/balloon_compaction: fix deflation when compaction is disabled
If CONFIG_BALLOON_COMPACTION=n balloon_page_insert() does not link pages
with balloon and doesn't set PagePrivate flag, as a result
balloon_page_dequeue() cannot get any pages because it thinks that all
of them are isolated.  Without balloon compaction nobody can isolate
ballooned pages.  It's safe to remove this check.

Fixes: d6d86c0a7f ("mm/balloon_compaction: redesign ballooned pages management").
Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Reported-by: Matt Mullins <mmullins@mmlx.us>
Cc: <stable@vger.kernel.org>	[3.17]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-29 16:33:15 -07:00
Mikulas Patocka
8aba7e0a2c mm/slab_common: don't check for duplicate cache names
The SLUB cache merges caches with the same size and alignment and there
was long standing bug with this behavior:

 - create the cache named "foo"
 - create the cache named "bar" (which is merged with "foo")
 - delete the cache named "foo" (but it stays allocated because "bar"
   uses it)
 - create the cache named "foo" again - it fails because the name "foo"
   is already used

That bug was fixed in commit 694617474e ("slab_common: fix the check
for duplicate slab names") by not warning on duplicate cache names when
the SLUB subsystem is used.

Recently, cache merging was implemented the with SLAB subsystem too, in
12220dea07 ("mm/slab: support slab merge")).  Therefore we need stop
checking for duplicate names even for the SLAB subsystem.

This patch fixes the bug by removing the check.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-29 16:33:15 -07:00
Johannes Weiner
8186eb6a79 mm: rmap: split out page_remove_file_rmap()
page_remove_rmap() has too many branches on PageAnon() and is hard to
follow.  Move the file part into a separate function.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-29 16:33:15 -07:00
Johannes Weiner
d7365e783e mm: memcontrol: fix missed end-writeback page accounting
Commit 0a31bc97c8 ("mm: memcontrol: rewrite uncharge API") changed
page migration to uncharge the old page right away.  The page is locked,
unmapped, truncated, and off the LRU, but it could race with writeback
ending, which then doesn't unaccount the page properly:

test_clear_page_writeback()              migration
                                           wait_on_page_writeback()
  TestClearPageWriteback()
                                           mem_cgroup_migrate()
                                             clear PCG_USED
  mem_cgroup_update_page_stat()
    if (PageCgroupUsed(pc))
      decrease memcg pages under writeback

  release pc->mem_cgroup->move_lock

The per-page statistics interface is heavily optimized to avoid a
function call and a lookup_page_cgroup() in the file unmap fast path,
which means it doesn't verify whether a page is still charged before
clearing PageWriteback() and it has to do it in the stat update later.

Rework it so that it looks up the page's memcg once at the beginning of
the transaction and then uses it throughout.  The charge will be
verified before clearing PageWriteback() and migration can't uncharge
the page as long as that is still set.  The RCU lock will protect the
memcg past uncharge.

As far as losing the optimization goes, the following test results are
from a microbenchmark that maps, faults, and unmaps a 4GB sparse file
three times in a nested fashion, so that there are two negative passes
that don't account but still go through the new transaction overhead.
There is no actual difference:

 old:     33.195102545 seconds time elapsed       ( +-  0.01% )
 new:     33.199231369 seconds time elapsed       ( +-  0.03% )

The time spent in page_remove_rmap()'s callees still adds up to the
same, but the time spent in the function itself seems reduced:

     # Children      Self  Command        Shared Object       Symbol
 old:     0.12%     0.11%  filemapstress  [kernel.kallsyms]   [k] page_remove_rmap
 new:     0.12%     0.08%  filemapstress  [kernel.kallsyms]   [k] page_remove_rmap

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: <stable@vger.kernel.org>	[3.17.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-29 16:33:15 -07:00
Johannes Weiner
3a3c02ecf7 mm: page-writeback: inline account_page_dirtied() into single caller
A follow-up patch would have changed the call signature.  To save the
trouble, just fold it instead.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: <stable@vger.kernel.org>	[3.17.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-29 16:33:14 -07:00
Yasuaki Ishimatsu
35dca71c1f memory-hotplug: clear pgdat which is allocated by bootmem in try_offline_node()
When hot adding the same memory after hot removal, the following
messages are shown:

  WARNING: CPU: 20 PID: 6 at mm/page_alloc.c:4968 free_area_init_node+0x3fe/0x426()
  ...
  Call Trace:
    dump_stack+0x46/0x58
    warn_slowpath_common+0x81/0xa0
    warn_slowpath_null+0x1a/0x20
    free_area_init_node+0x3fe/0x426
    hotadd_new_pgdat+0x90/0x110
    add_memory+0xd4/0x200
    acpi_memory_device_add+0x1aa/0x289
    acpi_bus_attach+0xfd/0x204
    acpi_bus_attach+0x178/0x204
    acpi_bus_scan+0x6a/0x90
    acpi_device_hotplug+0xe8/0x418
    acpi_hotplug_work_fn+0x1f/0x2b
    process_one_work+0x14e/0x3f0
    worker_thread+0x11b/0x510
    kthread+0xe1/0x100
    ret_from_fork+0x7c/0xb0

The detaled explanation is as follows:

When hot removing memory, pgdat is set to 0 in try_offline_node().  But
if the pgdat is allocated by bootmem allocator, the clearing step is
skipped.

And when hot adding the same memory, the uninitialized pgdat is reused.
But free_area_init_node() checks wether pgdat is set to zero.  As a
result, free_area_init_node() hits WARN_ON().

This patch clears pgdat which is allocated by bootmem allocator in
try_offline_node().

Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Zhang Zhen <zhenzhang.zhang@huawei.com>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-29 16:33:14 -07:00
David Rientjes
6d50e60cd2 mm, thp: fix collapsing of hugepages on madvise
If an anonymous mapping is not allowed to fault thp memory and then
madvise(MADV_HUGEPAGE) is used after fault, khugepaged will never
collapse this memory into thp memory.

This occurs because the madvise(2) handler for thp, hugepage_madvise(),
clears VM_NOHUGEPAGE on the stack and it isn't stored in vma->vm_flags
until the final action of madvise_behavior().  This causes the
khugepaged_enter_vma_merge() to be a no-op in hugepage_madvise() when
the vma had previously had VM_NOHUGEPAGE set.

Fix this by passing the correct vma flags to the khugepaged mm slot
handler.  There's no chance khugepaged can run on this vma until after
madvise_behavior() returns since we hold mm->mmap_sem.

It would be possible to clear VM_NOHUGEPAGE directly from vma->vm_flags
in hugepage_advise(), but I didn't want to introduce special case
behavior into madvise_behavior().  I think it's best to just let it
always set vma->vm_flags itself.

Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Suleiman Souhlal <suleiman@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-29 16:33:14 -07:00
Yu Zhao
5ddacbe92b mm: free compound page with correct order
Compound page should be freed by put_page() or free_pages() with correct
order.  Not doing so will cause tail pages leaked.

The compound order can be obtained by compound_order() or use
HPAGE_PMD_ORDER in our case.  Some people would argue the latter is
faster but I prefer the former which is more general.

This bug was observed not just on our servers (the worst case we saw is
11G leaked on a 48G machine) but also on our workstations running Ubuntu
based distro.

  $ cat /proc/vmstat  | grep thp_zero_page_alloc
  thp_zero_page_alloc 55
  thp_zero_page_alloc_failed 0

This means there is (thp_zero_page_alloc - 1) * (2M - 4K) memory leaked.

Fixes: 97ae17497e ("thp: implement refcounting for huge zero page")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: David Rientjes <rientjes@google.com>
Cc: Bob Liu <lliubbo@gmail.com>
Cc: <stable@vger.kernel.org>	[3.8+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-29 16:33:14 -07:00
Joonsoo Kim
6ea41c0c0a mm/compaction.c: avoid premature range skip in isolate_migratepages_range
Commit edc2ca6124 ("mm, compaction: move pageblock checks up from
isolate_migratepages_range()") commonizes isolate_migratepages variants
and make them use isolate_migratepages_block().

isolate_migratepages_block() could stop the execution when enough pages
are isolated, but, there is no code in isolate_migratepages_range() to
handle this case.  In the result, even if isolate_migratepages_block()
returns prematurely without checking all pages in the range,

isolate_migratepages_block() is called repeately on the following
pageblock and some pages in the previous range are skipped to check.
Then, CMA is failed frequently due to this fact.

To fix this problem, this patch let isolate_migratepages_range() know
the situation that enough pages are isolated and stop the isolation in
that case.

Note that isolate_migratepages() has no such problem, because, it always
stops the isolation after just one call of isolate_migratepages_block().

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-29 16:33:13 -07:00
Wang Nan
401507d67d cgroup/kmemleak: add kmemleak_free() for cgroup deallocations.
Commit ff7ee93f47 ("cgroup/kmemleak: Annotate alloc_page() for cgroup
allocations") introduces kmemleak_alloc() for alloc_page_cgroup(), but
corresponding kmemleak_free() is missing, which makes kmemleak be
wrongly disabled after memory offlining.  Log is pasted at the end of
this commit message.

This patch add kmemleak_free() into free_page_cgroup().  During page
offlining, this patch removes corresponding entries in kmemleak rbtree.
After that, the freed memory can be allocated again by other subsystems
without killing kmemleak.

  bash # for x in 1 2 3 4; do echo offline > /sys/devices/system/memory/memory$x/state ; sleep 1; done ; dmesg | grep leak

  Offlined Pages 32768
  kmemleak: Cannot insert 0xffff880016969000 into the object search tree (overlaps existing)
  CPU: 0 PID: 412 Comm: sleep Not tainted 3.17.0-rc5+ #86
  Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
  Call Trace:
    dump_stack+0x46/0x58
    create_object+0x266/0x2c0
    kmemleak_alloc+0x26/0x50
    kmem_cache_alloc+0xd3/0x160
    __sigqueue_alloc+0x49/0xd0
    __send_signal+0xcb/0x410
    send_signal+0x45/0x90
    __group_send_sig_info+0x13/0x20
    do_notify_parent+0x1bb/0x260
    do_exit+0x767/0xa40
    do_group_exit+0x44/0xa0
    SyS_exit_group+0x17/0x20
    system_call_fastpath+0x16/0x1b

  kmemleak: Kernel memory leak detector disabled
  kmemleak: Object 0xffff880016900000 (size 524288):
  kmemleak:   comm "swapper/0", pid 0, jiffies 4294667296
  kmemleak:   min_count = 0
  kmemleak:   count = 0
  kmemleak:   flags = 0x1
  kmemleak:   checksum = 0
  kmemleak:   backtrace:
        log_early+0x63/0x77
        kmemleak_alloc+0x4b/0x50
        init_section_page_cgroup+0x7f/0xf5
        page_cgroup_init+0xc5/0xd0
        start_kernel+0x333/0x408
        x86_64_start_reservations+0x2a/0x2c
        x86_64_start_kernel+0xf5/0xfc

Fixes: ff7ee93f47 (cgroup/kmemleak: Annotate alloc_page() for cgroup allocations)
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: <stable@vger.kernel.org>	[3.2+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-29 16:33:13 -07:00
Will Deacon
ce9ec37bdd zap_pte_range: update addr when forcing flush after TLB batching faiure
When unmapping a range of pages in zap_pte_range, the page being
unmapped is added to an mmu_gather_batch structure for asynchronous
freeing. If we run out of space in the batch structure before the range
has been completely unmapped, then we break out of the loop, force a
TLB flush and free the pages that we have batched so far. If there are
further pages to unmap, then we resume the loop where we left off.

Unfortunately, we forget to update addr when we break out of the loop,
which causes us to truncate the range being invalidated as the end
address is exclusive. When we re-enter the loop at the same address, the
page has already been freed and the pte_present test will fail, meaning
that we do not reconsider the address for invalidation.

This patch fixes the problem by incrementing addr by the PAGE_SIZE
before breaking out of the loop on batch failure.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-28 13:16:28 -07:00
Linus Torvalds
d1e14f1d63 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs updates from Al Viro:
 "overlayfs merge + leak fix for d_splice_alias() failure exits"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  overlayfs: embed middle into overlay_readdir_data
  overlayfs: embed root into overlay_readdir_data
  overlayfs: make ovl_cache_entry->name an array instead of pointer
  overlayfs: don't hold ->i_mutex over opening the real directory
  fix inode leaks on d_splice_alias() failure exits
  fs: limit filesystem stacking depth
  overlay: overlay filesystem documentation
  overlayfs: implement show_options
  overlayfs: add statfs support
  overlay filesystem
  shmem: support RENAME_WHITEOUT
  ext4: support RENAME_WHITEOUT
  vfs: add RENAME_WHITEOUT
  vfs: add whiteout support
  vfs: export check_sticky()
  vfs: introduce clone_private_mount()
  vfs: export __inode_permission() to modules
  vfs: export do_splice_direct() to modules
  vfs: add i_op->dentry_open()
2014-10-26 11:19:18 -07:00
Linus Torvalds
1c45d9a920 ACPI and power management updates for 3.18-rc2
- Fix for a recent PCI power management change that overlooked
    the fact that some IRQ chips might not be able to configure
    PCIe PME for system wakeup from Lucas Stach.
 
  - Fix for a bug introduced in 3.17 where acpi_device_wakeup()
    is called with a wrong ordering of arguments from Zhang Rui.
 
  - A bunch of intel_pstate driver fixes (all -stable candidates)
    from Dirk Brandewie, Gabriele Mazzotta and Pali Rohár.
 
  - Fixes for a rather long-standing problem with the OOM killer
    and the freezer that frozen processes killed by the OOM do
    not actually release any memory until they are thawed, so
    OOM-killing them is rather pointless, with a couple of
    cleanups on top (Michal Hocko, Cong Wang, Rafael J Wysocki).
 
  - ACPICA update to upstream release 20140926, inlcuding mostly
    cleanups reducing differences between the upstream ACPICA and
    the kernel code, tools changes (acpidump, acpiexec) and
    support for the _DDN object (Bob Moore, Lv Zheng).
 
  - New PM QoS class for memory bandwidth from Tomeu Vizoso.
 
  - Default 32-bit DMA mask for platform devices enumerated by ACPI
    (this change is mostly needed for some drivers development in
    progress targeted at 3.19) from Heikki Krogerus.
 
  - ACPI EC driver cleanups, mostly related to debugging, from
    Lv Zheng.
 
  - cpufreq-dt driver updates from Thomas Petazzoni.
 
  - powernv cpuidle driver update from Preeti U Murthy.
 
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Merge tag 'pm+acpi-3.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI and power management updates from Rafael Wysocki:
 "This is material that didn't make it to my 3.18-rc1 pull request for
  various reasons, mostly related to timing and travel (LinuxCon EU /
  LPC) plus a couple of fixes for recent bugs.

  The only really new thing here is the PM QoS class for memory
  bandwidth, but it is simple enough and users of it will be added in
  the next cycle.  One major change in behavior is that platform devices
  enumerated by ACPI will use 32-bit DMA mask by default.  Also included
  is an ACPICA update to a new upstream release, but that's mostly
  cleanups, changes in tools and similar.  The rest is fixes and
  cleanups mostly.

  Specifics:

   - Fix for a recent PCI power management change that overlooked the
     fact that some IRQ chips might not be able to configure PCIe PME
     for system wakeup from Lucas Stach.

   - Fix for a bug introduced in 3.17 where acpi_device_wakeup() is
     called with a wrong ordering of arguments from Zhang Rui.

   - A bunch of intel_pstate driver fixes (all -stable candidates) from
     Dirk Brandewie, Gabriele Mazzotta and Pali Rohár.

   - Fixes for a rather long-standing problem with the OOM killer and
     the freezer that frozen processes killed by the OOM do not actually
     release any memory until they are thawed, so OOM-killing them is
     rather pointless, with a couple of cleanups on top (Michal Hocko,
     Cong Wang, Rafael J Wysocki).

   - ACPICA update to upstream release 20140926, inlcuding mostly
     cleanups reducing differences between the upstream ACPICA and the
     kernel code, tools changes (acpidump, acpiexec) and support for the
     _DDN object (Bob Moore, Lv Zheng).

   - New PM QoS class for memory bandwidth from Tomeu Vizoso.

   - Default 32-bit DMA mask for platform devices enumerated by ACPI
     (this change is mostly needed for some drivers development in
     progress targeted at 3.19) from Heikki Krogerus.

   - ACPI EC driver cleanups, mostly related to debugging, from Lv
     Zheng.

   - cpufreq-dt driver updates from Thomas Petazzoni.

   - powernv cpuidle driver update from Preeti U Murthy"

* tag 'pm+acpi-3.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (34 commits)
  intel_pstate: Correct BYT VID values.
  intel_pstate: Fix BYT frequency reporting
  intel_pstate: Don't lose sysfs settings during cpu offline
  cpufreq: intel_pstate: Reflect current no_turbo state correctly
  cpufreq: expose scaling_cur_freq sysfs file for set_policy() drivers
  cpufreq: intel_pstate: Fix setting max_perf_pct in performance policy
  PCI / PM: handle failure to enable wakeup on PCIe PME
  ACPI: invoke acpi_device_wakeup() with correct parameters
  PM / freezer: Clean up code after recent fixes
  PM: convert do_each_thread to for_each_process_thread
  OOM, PM: OOM killed task shouldn't escape PM suspend
  freezer: remove obsolete comments in __thaw_task()
  freezer: Do not freeze tasks killed by OOM killer
  ACPI / platform: provide default DMA mask
  cpuidle: powernv: Populate cpuidle state details by querying the device-tree
  cpufreq: cpufreq-dt: adjust message related to regulators
  cpufreq: cpufreq-dt: extend with platform_data
  cpufreq: allow driver-specific data
  ACPI / EC: Cleanup coding style.
  ACPI / EC: Refine event/query debugging messages.
  ...
2014-10-24 11:29:31 -07:00
Miklos Szeredi
46fdb794e3 shmem: support RENAME_WHITEOUT
Allocate a dentry, initialize it with a whiteout and hash it in the place
of the old dentry.  Later the old dentry will be moved away and the
whiteout will remain.

i_mutex protects agains concurrent readdir.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
2014-10-24 00:14:37 +02:00
Michal Hocko
5695be142e OOM, PM: OOM killed task shouldn't escape PM suspend
PM freezer relies on having all tasks frozen by the time devices are
getting frozen so that no task will touch them while they are getting
frozen. But OOM killer is allowed to kill an already frozen task in
order to handle OOM situtation. In order to protect from late wake ups
OOM killer is disabled after all tasks are frozen. This, however, still
keeps a window open when a killed task didn't manage to die by the time
freeze_processes finishes.

Reduce the race window by checking all tasks after OOM killer has been
disabled. This is still not race free completely unfortunately because
oom_killer_disable cannot stop an already ongoing OOM killer so a task
might still wake up from the fridge and get killed without
freeze_processes noticing. Full synchronization of OOM and freezer is,
however, too heavy weight for this highly unlikely case.

Introduce and check oom_kills counter which gets incremented early when
the allocator enters __alloc_pages_may_oom path and only check all the
tasks if the counter changes during the freezing attempt. The counter
is updated so early to reduce the race window since allocator checked
oom_killer_disabled which is set by PM-freezing code. A false positive
will push the PM-freezer into a slow path but that is not a big deal.

Changes since v1
- push the re-check loop out of freeze_processes into
  check_frozen_processes and invert the condition to make the code more
  readable as per Rafael

Fixes: f660daac47 (oom: thaw threads if oom killed thread is frozen before deferring)
Cc: 3.2+ <stable@vger.kernel.org> # 3.2+
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-10-21 23:44:21 +02:00
Linus Torvalds
c2661b8060 A large number of cleanups and bug fixes, with some (minor) journal
optimizations.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
 "A large number of cleanups and bug fixes, with some (minor) journal
  optimizations"

[ This got sent to me before -rc1, but was stuck in my spam folder.   - Linus ]

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (67 commits)
  ext4: check s_chksum_driver when looking for bg csum presence
  ext4: move error report out of atomic context in ext4_init_block_bitmap()
  ext4: Replace open coded mdata csum feature to helper function
  ext4: delete useless comments about ext4_move_extents
  ext4: fix reservation overflow in ext4_da_write_begin
  ext4: add ext4_iget_normal() which is to be used for dir tree lookups
  ext4: don't orphan or truncate the boot loader inode
  ext4: grab missed write_count for EXT4_IOC_SWAP_BOOT
  ext4: optimize block allocation on grow indepth
  ext4: get rid of code duplication
  ext4: fix over-defensive complaint after journal abort
  ext4: fix return value of ext4_do_update_inode
  ext4: fix mmap data corruption when blocksize < pagesize
  vfs: fix data corruption when blocksize < pagesize for mmaped data
  ext4: fold ext4_nojournal_sops into ext4_sops
  ext4: support freezing ext2 (nojournal) file systems
  ext4: fold ext4_sync_fs_nojournal() into ext4_sync_fs()
  ext4: don't check quota format when there are no quota files
  jbd2: simplify calling convention around __jbd2_journal_clean_checkpoint_list
  jbd2: avoid pointless scanning of checkpoint lists
  ...
2014-10-20 09:50:11 -07:00
Linus Torvalds
d3dc366bba Merge branch 'for-3.18/core' of git://git.kernel.dk/linux-block
Pull core block layer changes from Jens Axboe:
 "This is the core block IO pull request for 3.18.  Apart from the new
  and improved flush machinery for blk-mq, this is all mostly bug fixes
  and cleanups.

   - blk-mq timeout updates and fixes from Christoph.

   - Removal of REQ_END, also from Christoph.  We pass it through the
     ->queue_rq() hook for blk-mq instead, freeing up one of the request
     bits.  The space was overly tight on 32-bit, so Martin also killed
     REQ_KERNEL since it's no longer used.

   - blk integrity updates and fixes from Martin and Gu Zheng.

   - Update to the flush machinery for blk-mq from Ming Lei.  Now we
     have a per hardware context flush request, which both cleans up the
     code should scale better for flush intensive workloads on blk-mq.

   - Improve the error printing, from Rob Elliott.

   - Backing device improvements and cleanups from Tejun.

   - Fixup of a misplaced rq_complete() tracepoint from Hannes.

   - Make blk_get_request() return error pointers, fixing up issues
     where we NULL deref when a device goes bad or missing.  From Joe
     Lawrence.

   - Prep work for drastically reducing the memory consumption of dm
     devices from Junichi Nomura.  This allows creating clone bio sets
     without preallocating a lot of memory.

   - Fix a blk-mq hang on certain combinations of queue depths and
     hardware queues from me.

   - Limit memory consumption for blk-mq devices for crash dump
     scenarios and drivers that use crazy high depths (certain SCSI
     shared tag setups).  We now just use a single queue and limited
     depth for that"

* 'for-3.18/core' of git://git.kernel.dk/linux-block: (58 commits)
  block: Remove REQ_KERNEL
  blk-mq: allocate cpumask on the home node
  bio-integrity: remove the needless fail handle of bip_slab creating
  block: include func name in __get_request prints
  block: make blk_update_request print prefix match ratelimited prefix
  blk-merge: don't compute bi_phys_segments from bi_vcnt for cloned bio
  block: fix alignment_offset math that assumes io_min is a power-of-2
  blk-mq: Make bt_clear_tag() easier to read
  blk-mq: fix potential hang if rolling wakeup depth is too high
  block: add bioset_create_nobvec()
  block: use bio_clone_fast() in blk_rq_prep_clone()
  block: misplaced rq_complete tracepoint
  sd: Honor block layer integrity handling flags
  block: Replace strnicmp with strncasecmp
  block: Add T10 Protection Information functions
  block: Don't merge requests if integrity flags differ
  block: Integrity checksum flag
  block: Relocate bio integrity flags
  block: Add a disk flag to block integrity profile
  block: Add prefix to block integrity profile flags
  ...
2014-10-18 11:53:51 -07:00
Linus Torvalds
dfe2c6dcc8 Merge branch 'akpm' (patches from Andrew Morton)
Merge second patch-bomb from Andrew Morton:
 - a few hotfixes
 - drivers/dma updates
 - MAINTAINERS updates
 - Quite a lot of lib/ updates
 - checkpatch updates
 - binfmt updates
 - autofs4
 - drivers/rtc/
 - various small tweaks to less used filesystems
 - ipc/ updates
 - kernel/watchdog.c changes

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (135 commits)
  mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared
  kernel/param: consolidate __{start,stop}___param[] in <linux/moduleparam.h>
  ia64: remove duplicate declarations of __per_cpu_start[] and __per_cpu_end[]
  frv: remove unused declarations of __start___ex_table and __stop___ex_table
  kvm: ensure hard lockup detection is disabled by default
  kernel/watchdog.c: control hard lockup detection default
  staging: rtl8192u: use %*pEn to escape buffer
  staging: rtl8192e: use %*pEn to escape buffer
  staging: wlan-ng: use %*pEhp to print SN
  lib80211: remove unused print_ssid()
  wireless: hostap: proc: print properly escaped SSID
  wireless: ipw2x00: print SSID via %*pE
  wireless: libertas: print esaped string via %*pE
  lib/vsprintf: add %*pE[achnops] format specifier
  lib / string_helpers: introduce string_escape_mem()
  lib / string_helpers: refactoring the test suite
  lib / string_helpers: move documentation to c-file
  include/linux: remove strict_strto* definitions
  arch/x86/mm/numa.c: fix boot failure when all nodes are hotpluggable
  fs: check bh blocknr earlier when searching lru
  ...
2014-10-14 03:54:50 +02:00
Linus Torvalds
df133e8fa8 Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 mm updates from Ingo Molnar:
 "This tree includes the following changes:

   - fix memory hotplug
   - fix hibernation bootup memory layout assumptions
   - fix hyperv numa guest kernel messages
   - remove dead code
   - update documentation"

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Update memory map description to list hypervisor-reserved area
  x86/mm, hibernate: Do not assume the first e820 area to be RAM
  x86/mm/numa: Drop dead code and rename setup_node_data() to setup_alloc_data()
  x86/mm/hotplug: Modify PGD entry when removing memory
  x86/mm/hotplug: Pass sync_global_pgds() a correct argument in remove_pagetable()
  x86: Remove set_pmd_pfn
2014-10-14 02:22:41 +02:00
Peter Feiner
64e455079e mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared
For VMAs that don't want write notifications, PTEs created for read faults
have their write bit set.  If the read fault happens after VM_SOFTDIRTY is
cleared, then the PTE's softdirty bit will remain clear after subsequent
writes.

Here's a simple code snippet to demonstrate the bug:

  char* m = mmap(NULL, getpagesize(), PROT_READ | PROT_WRITE,
                 MAP_ANONYMOUS | MAP_SHARED, -1, 0);
  system("echo 4 > /proc/$PPID/clear_refs"); /* clear VM_SOFTDIRTY */
  assert(*m == '\0');     /* new PTE allows write access */
  assert(!soft_dirty(x));
  *m = 'x';               /* should dirty the page */
  assert(soft_dirty(x));  /* fails */

With this patch, write notifications are enabled when VM_SOFTDIRTY is
cleared.  Furthermore, to avoid unnecessary faults, write notifications
are disabled when VM_SOFTDIRTY is set.

As a side effect of enabling and disabling write notifications with
care, this patch fixes a bug in mprotect where vm_page_prot bits set by
drivers were zapped on mprotect.  An analogous bug was fixed in mmap by
commit c9d0bf2414 ("mm: uncached vma support with writenotify").

Signed-off-by: Peter Feiner <pfeiner@google.com>
Reported-by: Peter Feiner <pfeiner@google.com>
Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Jamie Liu <jamieliu@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:18:28 +02:00
Marek Szyprowski
de9e14eebf drivers: dma-contiguous: add initialization from device tree
Add a function to create CMA region from previously reserved memory and
add support for handling 'shared-dma-pool' reserved-memory device tree
nodes.

Based on previous code provided by Josh Cartwright <joshc@codeaurora.org>

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Josh Cartwright <joshc@codeaurora.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:18:12 +02:00
Weijie Yang
68faed630f mm/cma: fix cma bitmap aligned mask computing
The current cma bitmap aligned mask computation is incorrect.  It could
cause an unexpected alignment when using cma_alloc() if the wanted align
order is larger than cma->order_per_bit.

Take kvm for example (PAGE_SHIFT = 12), kvm_cma->order_per_bit is set to
6.  When kvm_alloc_rma() tries to alloc kvm_rma_pages, it will use 15 as
the expected align value.  After using the current implementation however,
we get 0 as cma bitmap aligned mask other than 511.

This patch fixes the cma bitmap aligned mask calculation.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org>	[3.17]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:18:12 +02:00
Joonsoo Kim
85c9f4b04a mm/slab: fix unaligned access on sparc64
Commit bf0dea23a9 ("mm/slab: use percpu allocator for cpu cache")
changed the allocation method for cpu cache array from slab allocator to
percpu allocator.  Alignment should be provided for aligned memory in
percpu allocator case, but, that commit mistakenly set this alignment to
0.  So, percpu allocator returns unaligned memory address.  It doesn't
cause any problem on x86 which permits unaligned access, but, it causes
the problem on sparc64 which needs strong guarantee of alignment.

Following bug report is reported from David Miller.

  I'm getting tons of the following on sparc64:

  [603965.383447] Kernel unaligned access at TPC[546b58] free_block+0x98/0x1a0
  [603965.396987] Kernel unaligned access at TPC[546b60] free_block+0xa0/0x1a0
  ...
  [603970.554394] log_unaligned: 333 callbacks suppressed
  ...

This patch provides a proper alignment parameter when allocating cpu
cache to fix this unaligned memory access problem on sparc64.

Reported-by: David Miller <davem@davemloft.net>
Tested-by: David Miller <davem@davemloft.net>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.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>
2014-10-14 02:18:12 +02:00
Linus Torvalds
d6dd50e07c Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Ingo Molnar:
 "The main changes in this cycle were:

   - changes related to No-CBs CPUs and NO_HZ_FULL

   - RCU-tasks implementation

   - torture-test updates

   - miscellaneous fixes

   - locktorture updates

   - RCU documentation updates"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (81 commits)
  workqueue: Use cond_resched_rcu_qs macro
  workqueue: Add quiescent state between work items
  locktorture: Cleanup header usage
  locktorture: Cannot hold read and write lock
  locktorture: Fix __acquire annotation for spinlock irq
  locktorture: Support rwlocks
  rcu: Eliminate deadlock between CPU hotplug and expedited grace periods
  locktorture: Document boot/module parameters
  rcutorture: Rename rcutorture_runnable parameter
  locktorture: Add test scenario for rwsem_lock
  locktorture: Add test scenario for mutex_lock
  locktorture: Make torture scripting account for new _runnable name
  locktorture: Introduce torture context
  locktorture: Support rwsems
  locktorture: Add infrastructure for torturing read locks
  torture: Address race in module cleanup
  locktorture: Make statistics generic
  locktorture: Teach about lock debugging
  locktorture: Support mutexes
  locktorture: Add documentation
  ...
2014-10-13 15:44:12 +02:00
Linus Torvalds
77c688ac87 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs updates from Al Viro:
 "The big thing in this pile is Eric's unmount-on-rmdir series; we
  finally have everything we need for that.  The final piece of prereqs
  is delayed mntput() - now filesystem shutdown always happens on
  shallow stack.

  Other than that, we have several new primitives for iov_iter (Matt
  Wilcox, culled from his XIP-related series) pushing the conversion to
  ->read_iter()/ ->write_iter() a bit more, a bunch of fs/dcache.c
  cleanups and fixes (including the external name refcounting, which
  gives consistent behaviour of d_move() wrt procfs symlinks for long
  and short names alike) and assorted cleanups and fixes all over the
  place.

  This is just the first pile; there's a lot of stuff from various
  people that ought to go in this window.  Starting with
  unionmount/overlayfs mess...  ;-/"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (60 commits)
  fs/file_table.c: Update alloc_file() comment
  vfs: Deduplicate code shared by xattr system calls operating on paths
  reiserfs: remove pointless forward declaration of struct nameidata
  don't need that forward declaration of struct nameidata in dcache.h anymore
  take dname_external() into fs/dcache.c
  let path_init() failures treated the same way as subsequent link_path_walk()
  fix misuses of f_count() in ppp and netlink
  ncpfs: use list_for_each_entry() for d_subdirs walk
  vfs: move getname() from callers to do_mount()
  gfs2_atomic_open(): skip lookups on hashed dentry
  [infiniband] remove pointless assignments
  gadgetfs: saner API for gadgetfs_create_file()
  f_fs: saner API for ffs_sb_create_file()
  jfs: don't hash direct inode
  [s390] remove pointless assignment of ->f_op in vmlogrdr ->open()
  ecryptfs: ->f_op is never NULL
  android: ->f_op is never NULL
  nouveau: __iomem misannotations
  missing annotation in fs/file.c
  fs: namespace: suppress 'may be used uninitialized' warnings
  ...
2014-10-13 11:28:42 +02:00
Linus Torvalds
ce254b34da Fixup for 3.18: use PATCHv2 of "mm: Support compiling out madvise and fadvise"
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Merge tag 'tiny/no-advice-fixup-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/josh/linux

Pull tinification fix from Josh "Paper Bag" Triplett:
 "Fixup to use PATCHv2 of 'mm: Support compiling out madvise and
  fadvise'"

* tag 'tiny/no-advice-fixup-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/josh/linux:
  mm: Support fadvise without CONFIG_MMU
2014-10-12 09:21:57 -04:00
Josh Triplett
887e7019e3 mm: Support fadvise without CONFIG_MMU
Commit d3ac21cacc ("mm: Support compiling
out madvise and fadvise") incorrectly made fadvise conditional on
CONFIG_MMU.  (The merged branch unintentionally incorporated v1 of the
patch rather than the fixed v2.)  Apply the delta from v1 to v2, to
allow fadvise without CONFIG_MMU.

Reported-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
2014-10-10 13:12:28 -07:00
Linus Torvalds
c798360cd1 Merge branch 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
Pull percpu updates from Tejun Heo:
 "A lot of activities on percpu front.  Notable changes are...

   - percpu allocator now can take @gfp.  If @gfp doesn't contain
     GFP_KERNEL, it tries to allocate from what's already available to
     the allocator and a work item tries to keep the reserve around
     certain level so that these atomic allocations usually succeed.

     This will replace the ad-hoc percpu memory pool used by
     blk-throttle and also be used by the planned blkcg support for
     writeback IOs.

     Please note that I noticed a bug in how @gfp is interpreted while
     preparing this pull request and applied the fix 6ae833c7fe
     ("percpu: fix how @gfp is interpreted by the percpu allocator")
     just now.

   - percpu_ref now uses longs for percpu and global counters instead of
     ints.  It leads to more sparse packing of the percpu counters on
     64bit machines but the overhead should be negligible and this
     allows using percpu_ref for refcnting pages and in-memory objects
     directly.

   - The switching between percpu and single counter modes of a
     percpu_ref is made independent of putting the base ref and a
     percpu_ref can now optionally be initialized in single or killed
     mode.  This allows avoiding percpu shutdown latency for cases where
     the refcounted objects may be synchronously created and destroyed
     in rapid succession with only a fraction of them reaching fully
     operational status (SCSI probing does this when combined with
     blk-mq support).  It's also planned to be used to implement forced
     single mode to detect underflow more timely for debugging.

  There's a separate branch percpu/for-3.18-consistent-ops which cleans
  up the duplicate percpu accessors.  That branch causes a number of
  conflicts with s390 and other trees.  I'll send a separate pull
  request w/ resolutions once other branches are merged"

* 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (33 commits)
  percpu: fix how @gfp is interpreted by the percpu allocator
  blk-mq, percpu_ref: start q->mq_usage_counter in atomic mode
  percpu_ref: make INIT_ATOMIC and switch_to_atomic() sticky
  percpu_ref: add PERCPU_REF_INIT_* flags
  percpu_ref: decouple switching to percpu mode and reinit
  percpu_ref: decouple switching to atomic mode and killing
  percpu_ref: add PCPU_REF_DEAD
  percpu_ref: rename things to prepare for decoupling percpu/atomic mode switch
  percpu_ref: replace pcpu_ prefix with percpu_
  percpu_ref: minor code and comment updates
  percpu_ref: relocate percpu_ref_reinit()
  Revert "blk-mq, percpu_ref: implement a kludge for SCSI blk-mq stall during probe"
  Revert "percpu: free percpu allocation info for uniprocessor system"
  percpu-refcount: make percpu_ref based on longs instead of ints
  percpu-refcount: improve WARN messages
  percpu: fix locking regression in the failure path of pcpu_alloc()
  percpu-refcount: add @gfp to percpu_ref_init()
  proportions: add @gfp to init functions
  percpu_counter: add @gfp to percpu_counter_init()
  percpu_counter: make percpu_counters_lock irq-safe
  ...
2014-10-10 07:26:02 -04:00
Linus Torvalds
b211e9d7c8 Merge branch 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
 "Nothing too interesting.  Just a handful of cleanup patches"

* 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  Revert "cgroup: remove redundant variable in cgroup_mount()"
  cgroup: remove redundant variable in cgroup_mount()
  cgroup: fix missing unlock in cgroup_release_agent()
  cgroup: remove CGRP_RELEASABLE flag
  perf/cgroup: Remove perf_put_cgroup()
  cgroup: remove redundant check in cgroup_ino()
  cpuset: simplify proc_cpuset_show()
  cgroup: simplify proc_cgroup_show()
  cgroup: use a per-cgroup work for release agent
  cgroup: remove bogus comments
  cgroup: remove redundant code in cgroup_rmdir()
  cgroup: remove some useless forward declarations
  cgroup: fix a typo in comment.
2014-10-10 07:24:40 -04:00
Chao Yu
f203c3b33f zbud: avoid accessing last unused freelist
For now, there are NCHUNKS of 64 freelists in zbud_pool, the last
unbuddied[63] freelist linked with all zbud pages which have free chunks
of 63.  Calculating according to context of num_free_chunks(), our max
chunk number of unbuddied zbud page is 62, so none of zbud pages will be
added/removed in last freelist, but still we will try to find an unbuddied
zbud page in the last unused freelist, it is unneeded.

This patch redefines NCHUNKS to 63 as free chunk number in one zbud page,
hence we can decrease size of zpool and avoid accessing the last unused
freelist whenever failing to allocate zbud from freelist in zbud_alloc.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Cc: Seth Jennings <sjennings@variantweb.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:03 -04:00
Dan Streetman
5538c56237 zsmalloc: simplify init_zspage free obj linking
Change zsmalloc init_zspage() logic to iterate through each object on each
of its pages, checking the offset to verify the object is on the current
page before linking it into the zspage.

The current zsmalloc init_zspage free object linking code has logic that
relies on there only being one page per zspage when PAGE_SIZE is a
multiple of class->size.  It calculates the number of objects for the
current page, and iterates through all of them plus one, to account for
the assumed partial object at the end of the page.  While this currently
works, the logic can be simplified to just link the object at each
successive offset until the offset is larger than PAGE_SIZE, which does
not rely on PAGE_SIZE being a multiple of class->size.

Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:03 -04:00
Wang Sheng-Hui
6dd9737e31 mm/zsmalloc.c: correct comment for fullness group computation
The letter 'f' in "n <= N/f" stands for fullness_threshold_frac, not
1/fullness_threshold_frac.

Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:03 -04:00
Minchan Kim
722cdc1723 zsmalloc: change return value unit of zs_get_total_size_bytes
zs_get_total_size_bytes returns a amount of memory zsmalloc consumed with
*byte unit* but zsmalloc operates *page unit* rather than byte unit so
let's change the API so benefit we could get is that reduce unnecessary
overhead (ie, change page unit with byte unit) in zsmalloc.

Since return type is pages, "zs_get_total_pages" is better than
"zs_get_total_size_bytes".

Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Dan Streetman <ddstreet@ieee.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: <juno.choi@lge.com>
Cc: <seungho1.park@lge.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: David Horner <ds2horner@gmail.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>
2014-10-09 22:26:02 -04:00
Minchan Kim
13de8933c9 zsmalloc: move pages_allocated to zs_pool
Currently, zram has no feature to limit memory so theoretically zram can
deplete system memory.  Users have asked for a limit several times as even
without exhaustion zram makes it hard to control memory usage of the
platform.  This patchset adds the feature.

Patch 1 makes zs_get_total_size_bytes faster because it would be used
frequently in later patches for the new feature.

Patch 2 changes zs_get_total_size_bytes's return unit from bytes to page
so that zsmalloc doesn't need unnecessary operation(ie, << PAGE_SHIFT).

Patch 3 adds new feature.  I added the feature into zram layer, not
zsmalloc because limiation is zram's requirement, not zsmalloc so any
other user using zsmalloc(ie, zpool) shouldn't affected by unnecessary
branch of zsmalloc.  In future, if every users of zsmalloc want the
feature, then, we could move the feature from client side to zsmalloc
easily but vice versa would be painful.

Patch 4 adds news facility to report maximum memory usage of zram so that
this avoids user polling frequently via /sys/block/zram0/ mem_used_total
and ensures transient max are not missed.

This patch (of 4):

pages_allocated has counted in size_class structure and when user of
zsmalloc want to see total_size_bytes, it should gather all of count from
each size_class to report the sum.

It's not bad if user don't see the value often but if user start to see
the value frequently, it would be not a good deal for performance pov.

This patch moves the count from size_class to zs_pool so it could reduce
memory footprint (from [255 * 8byte] to [sizeof(atomic_long_t)]).

Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Dan Streetman <ddstreet@ieee.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: <juno.choi@lge.com>
Cc: <seungho1.park@lge.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Reviewed-by: David Horner <ds2horner@gmail.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>
2014-10-09 22:26:02 -04:00
Christoph Lameter
7cc36bbddd vmstat: on-demand vmstat workers V8
vmstat workers are used for folding counter differentials into the zone,
per node and global counters at certain time intervals.  They currently
run at defined intervals on all processors which will cause some holdoff
for processors that need minimal intrusion by the OS.

The current vmstat_update mechanism depends on a deferrable timer firing
every other second by default which registers a work queue item that runs
on the local CPU, with the result that we have 1 interrupt and one
additional schedulable task on each CPU every 2 seconds If a workload
indeed causes VM activity or multiple tasks are running on a CPU, then
there are probably bigger issues to deal with.

However, some workloads dedicate a CPU for a single CPU bound task.  This
is done in high performance computing, in high frequency financial
applications, in networking (Intel DPDK, EZchip NPS) and with the advent
of systems with more and more CPUs over time, this may become more and
more common to do since when one has enough CPUs one cares less about
efficiently sharing a CPU with other tasks and more about efficiently
monopolizing a CPU per task.

The difference of having this timer firing and workqueue kernel thread
scheduled per second can be enormous.  An artificial test measuring the
worst case time to do a simple "i++" in an endless loop on a bare metal
system and under Linux on an isolated CPU with dynticks and with and
without this patch, have Linux match the bare metal performance (~700
cycles) with this patch and loose by couple of orders of magnitude (~200k
cycles) without it[*].  The loss occurs for something that just calculates
statistics.  For networking applications, for example, this could be the
difference between dropping packets or sustaining line rate.

Statistics are important and useful, but it would be great if there would
be a way to not cause statistics gathering produce a huge performance
difference.  This patche does just that.

This patch creates a vmstat shepherd worker that monitors the per cpu
differentials on all processors.  If there are differentials on a
processor then a vmstat worker local to the processors with the
differentials is created.  That worker will then start folding the diffs
in regular intervals.  Should the worker find that there is no work to be
done then it will make the shepherd worker monitor the differentials
again.

With this patch it is possible then to have periods longer than
2 seconds without any OS event on a "cpu" (hardware thread).

The patch shows a very minor increased in system performance.

hackbench -s 512 -l 2000 -g 15 -f 25 -P

Results before the patch:

Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks)
Each sender will pass 2000 messages of 512 bytes
Time: 4.992
Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks)
Each sender will pass 2000 messages of 512 bytes
Time: 4.971
Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks)
Each sender will pass 2000 messages of 512 bytes
Time: 5.063

Hackbench after the patch:

Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks)
Each sender will pass 2000 messages of 512 bytes
Time: 4.973
Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks)
Each sender will pass 2000 messages of 512 bytes
Time: 4.990
Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks)
Each sender will pass 2000 messages of 512 bytes
Time: 4.993

[fengguang.wu@intel.com: cpu_stat_off can be static]
Signed-off-by: Christoph Lameter <cl@linux.com>
Reviewed-by: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Max Krasnyansky <maxk@qti.qualcomm.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:02 -04:00
Mel Gorman
2c0346a36c mm: mempolicy: skip inaccessible VMAs when setting MPOL_MF_LAZY
PROT_NUMA VMAs are skipped to avoid problems distinguishing between
present, prot_none and special entries.  MPOL_MF_LAZY is not visible from
userspace since commit a720094ded ("mm: mempolicy: Hide MPOL_NOOP and
MPOL_MF_LAZY from userspace for now") but it should still skip VMAs the
same way task_numa_work does.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:02 -04:00
Konstantin Khlebnikov
09316c09dd mm/balloon_compaction: add vmstat counters and kpageflags bit
Always mark pages with PageBalloon even if balloon compaction is disabled
and expose this mark in /proc/kpageflags as KPF_BALLOON.

Also this patch adds three counters into /proc/vmstat: "balloon_inflate",
"balloon_deflate" and "balloon_migrate".  They accumulate balloon
activity.  Current size of balloon is (balloon_inflate - balloon_deflate)
pages.

All generic balloon code now gathered under option CONFIG_MEMORY_BALLOON.
It should be selected by ballooning driver which wants use this feature.
Currently virtio-balloon is the only user.

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:01 -04:00
Konstantin Khlebnikov
9d1ba80564 mm/balloon_compaction: remove balloon mapping and flag AS_BALLOON_MAP
Now ballooned pages are detected using PageBalloon().  Fake mapping is no
longer required.  This patch links ballooned pages to balloon device using
field page->private instead of page->mapping.  Also this patch embeds
balloon_dev_info directly into struct virtio_balloon.

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:01 -04:00
Konstantin Khlebnikov
d6d86c0a7f mm/balloon_compaction: redesign ballooned pages management
Sasha Levin reported KASAN splash inside isolate_migratepages_range().
Problem is in the function __is_movable_balloon_page() which tests
AS_BALLOON_MAP in page->mapping->flags.  This function has no protection
against anonymous pages.  As result it tried to check address space flags
inside struct anon_vma.

Further investigation shows more problems in current implementation:

* Special branch in __unmap_and_move() never works:
  balloon_page_movable() checks page flags and page_count.  In
  __unmap_and_move() page is locked, reference counter is elevated, thus
  balloon_page_movable() always fails.  As a result execution goes to the
  normal migration path.  virtballoon_migratepage() returns
  MIGRATEPAGE_BALLOON_SUCCESS instead of MIGRATEPAGE_SUCCESS,
  move_to_new_page() thinks this is an error code and assigns
  newpage->mapping to NULL.  Newly migrated page lose connectivity with
  balloon an all ability for further migration.

* lru_lock erroneously required in isolate_migratepages_range() for
  isolation ballooned page.  This function releases lru_lock periodically,
  this makes migration mostly impossible for some pages.

* balloon_page_dequeue have a tight race with balloon_page_isolate:
  balloon_page_isolate could be executed in parallel with dequeue between
  picking page from list and locking page_lock.  Race is rare because they
  use trylock_page() for locking.

This patch fixes all of them.

Instead of fake mapping with special flag this patch uses special state of
page->_mapcount: PAGE_BALLOON_MAPCOUNT_VALUE = -256.  Buddy allocator uses
PAGE_BUDDY_MAPCOUNT_VALUE = -128 for similar purpose.  Storing mark
directly in struct page makes everything safer and easier.

PagePrivate is used to mark pages present in page list (i.e.  not
isolated, like PageLRU for normal pages).  It replaces special rules for
reference counter and makes balloon migration similar to migration of
normal pages.  This flag is protected by page_lock together with link to
the balloon device.

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Link: http://lkml.kernel.org/p/53E6CEAA.9020105@oracle.com
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: <stable@vger.kernel.org>	[3.8+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:01 -04:00
Steve Capper
2667f50e8b mm: introduce a general RCU get_user_pages_fast()
This series implements general forms of get_user_pages_fast and
__get_user_pages_fast in core code and activates them for arm and arm64.

These are required for Transparent HugePages to function correctly, as a
futex on a THP tail will otherwise result in an infinite loop (due to the
core implementation of __get_user_pages_fast always returning 0).

Unfortunately, a futex on THP tail can be quite common for certain
workloads; thus THP is unreliable without a __get_user_pages_fast
implementation.

This series may also be beneficial for direct-IO heavy workloads and
certain KVM workloads.

This patch (of 6):

get_user_pages_fast() attempts to pin user pages by walking the page
tables directly and avoids taking locks.  Thus the walker needs to be
protected from page table pages being freed from under it, and needs to
block any THP splits.

One way to achieve this is to have the walker disable interrupts, and rely
on IPIs from the TLB flushing code blocking before the page table pages
are freed.

On some platforms we have hardware broadcast of TLB invalidations, thus
the TLB flushing code doesn't necessarily need to broadcast IPIs; and
spuriously broadcasting IPIs can hurt system performance if done too
often.

This problem has been solved on PowerPC and Sparc by batching up page
table pages belonging to more than one mm_user, then scheduling an
rcu_sched callback to free the pages.  This RCU page table free logic has
been promoted to core code and is activated when one enables
HAVE_RCU_TABLE_FREE.  Unfortunately, these architectures implement their
own get_user_pages_fast routines.

The RCU page table free logic coupled with an IPI broadcast on THP split
(which is a rare event), allows one to protect a page table walker by
merely disabling the interrupts during the walk.

This patch provides a general RCU implementation of get_user_pages_fast
that can be used by architectures that perform hardware broadcast of TLB
invalidations.

It is based heavily on the PowerPC implementation by Nick Piggin.

[akpm@linux-foundation.org: various comment fixes]
Signed-off-by: Steve Capper <steve.capper@linaro.org>
Tested-by: Dann Frazier <dann.frazier@canonical.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:00 -04:00
Paul McQuade
baa2ef8398 mm/dmapool.c: fixed a brace coding style issue
Remove 3 brace coding style for any arm of this statement

Signed-off-by: Paul McQuade <paulmcquad@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:00 -04:00
Paul McQuade
25acde3173 mm: ksm use pr_err instead of printk
WARNING: Prefer: pr_err(...  to printk(KERN_ERR ...

[akpm@linux-foundation.org: remove KERN_ERR]
Signed-off-by: Paul McQuade <paulmcquad@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:00 -04:00
Paul McQuade
d85fbee89f mm/bootmem.c: use include/linux/ headers
Replace asm. headers with linux/headers:

<linux/bug.h>
<linux/io.h>

Signed-off-by: Paul McQuade <paulmcquad@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:00 -04:00
Paul McQuade
99dadfdde0 mm/filemap.c: remove trailing whitespace
Signed-off-by: Paul McQuade <paulmcquad@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:00 -04:00
Paul McQuade
2581d20237 mm/mremap.c: use linux headers
"WARNING: Use #include <linux/uaccess.h> instead of <asm/uaccess.h>"

Signed-off-by: Paul McQuade <paulmcquad@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:00 -04:00
Vladimir Davydov
cf2b8fbf1d memcg: zap memcg_can_account_kmem
memcg_can_account_kmem() returns true iff

    !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) &&
                                   memcg_kmem_is_active(memcg);

To begin with the !mem_cgroup_is_root(memcg) check is useless, because one
can't enable kmem accounting for the root cgroup (mem_cgroup_write()
returns EINVAL on an attempt to set the limit on the root cgroup).

Furthermore, the !mem_cgroup_disabled() check also seems to be redundant.
The point is memcg_can_account_kmem() is called from three places:
mem_cgroup_salbinfo_read(), __memcg_kmem_get_cache(), and
__memcg_kmem_newpage_charge().  The latter two functions are only invoked
if memcg_kmem_enabled() returns true, which implies that the memory cgroup
subsystem is enabled.  And mem_cgroup_slabinfo_read() shows the output of
memory.kmem.slabinfo, which won't exist if the memory cgroup is completely
disabled.

So let's substitute all the calls to memcg_can_account_kmem() with plain
memcg_kmem_is_active(), and kill the former.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:00 -04:00
Johannes Weiner
b70a2a21dc mm: memcontrol: fix transparent huge page allocations under pressure
In a memcg with even just moderate cache pressure, success rates for
transparent huge page allocations drop to zero, wasting a lot of effort
that the allocator puts into assembling these pages.

The reason for this is that the memcg reclaim code was never designed for
higher-order charges.  It reclaims in small batches until there is room
for at least one page.  Huge page charges only succeed when these batches
add up over a series of huge faults, which is unlikely under any
significant load involving order-0 allocations in the group.

Remove that loop on the memcg side in favor of passing the actual reclaim
goal to direct reclaim, which is already set up and optimized to meet
higher-order goals efficiently.

This brings memcg's THP policy in line with the system policy: if the
allocator painstakingly assembles a hugepage, memcg will at least make an
honest effort to charge it.  As a result, transparent hugepage allocation
rates amid cache activity are drastically improved:

                                      vanilla                 patched
pgalloc                 4717530.80 (  +0.00%)   4451376.40 (  -5.64%)
pgfault                  491370.60 (  +0.00%)    225477.40 ( -54.11%)
pgmajfault                    2.00 (  +0.00%)         1.80 (  -6.67%)
thp_fault_alloc               0.00 (  +0.00%)       531.60 (+100.00%)
thp_fault_fallback          749.00 (  +0.00%)       217.40 ( -70.88%)

[ Note: this may in turn increase memory consumption from internal
  fragmentation, which is an inherent risk of transparent hugepages.
  Some setups may have to adjust the memcg limits accordingly to
  accomodate this - or, if the machine is already packed to capacity,
  disable the transparent huge page feature. ]

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Dave Hansen <dave@sr71.net>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:59 -04:00
Johannes Weiner
3fbe724424 mm: memcontrol: simplify detecting when the memory+swap limit is hit
When attempting to charge pages, we first charge the memory counter and
then the memory+swap counter.  If one of the counters is at its limit, we
enter reclaim, but if it's the memory+swap counter, reclaim shouldn't swap
because that wouldn't change the situation.  However, if the counters have
the same limits, we never get to the memory+swap limit.  To know whether
reclaim should swap or not, there is a state flag that indicates whether
the limits are equal and whether hitting the memory limit implies hitting
the memory+swap limit.

Just try the memory+swap counter first.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Dave Hansen <dave@sr71.net>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:59 -04:00
Michal Hocko
aabfb57296 mm: memcontrol: do not kill uncharge batching in free_pages_and_swap_cache
free_pages_and_swap_cache limits release_pages to PAGEVEC_SIZE chunks.
This is not a big deal for the normal release path but it completely kills
memcg uncharge batching which reduces res_counter spin_lock contention.
Dave has noticed this with his page fault scalability test case on a large
machine when the lock was basically dominating on all CPUs:

    80.18%    80.18%  [kernel]               [k] _raw_spin_lock
                  |
                  --- _raw_spin_lock
                     |
                     |--66.59%-- res_counter_uncharge_until
                     |          res_counter_uncharge
                     |          uncharge_batch
                     |          uncharge_list
                     |          mem_cgroup_uncharge_list
                     |          release_pages
                     |          free_pages_and_swap_cache
                     |          tlb_flush_mmu_free
                     |          |
                     |          |--90.12%-- unmap_single_vma
                     |          |          unmap_vmas
                     |          |          unmap_region
                     |          |          do_munmap
                     |          |          vm_munmap
                     |          |          sys_munmap
                     |          |          system_call_fastpath
                     |          |          __GI___munmap
                     |          |
                     |           --9.88%-- tlb_flush_mmu
                     |                     tlb_finish_mmu
                     |                     unmap_region
                     |                     do_munmap
                     |                     vm_munmap
                     |                     sys_munmap
                     |                     system_call_fastpath
                     |                     __GI___munmap

In his case the load was running in the root memcg and that part has been
handled by reverting 05b8430123 ("mm: memcontrol: use root_mem_cgroup
res_counter") because this is a clear regression, but the problem remains
inside dedicated memcgs.

There is no reason to limit release_pages to PAGEVEC_SIZE batches other
than lru_lock held times.  This logic, however, can be moved inside the
function.  mem_cgroup_uncharge_list and free_hot_cold_page_list do not
hold any lock for the whole pages_to_free list so it is safe to call them
in a single run.

The release_pages() code was previously breaking the lru_lock each
PAGEVEC_SIZE pages (ie, 14 pages).  However this code has no usage of
pagevecs so switch to breaking the lock at least every SWAP_CLUSTER_MAX
(32) pages.  This means that the lock acquisition frequency is
approximately halved and the max hold times are approximately doubled.

The now unneeded batching is removed from free_pages_and_swap_cache().

Also update the grossly out-of-date release_pages documentation.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Dave Hansen <dave@sr71.net>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:59 -04:00
Sebastian Andrzej Siewior
01c2965f07 mm: dmapool: add/remove sysfs file outside of the pool lock lock
cat /sys/.../pools followed by removal the device leads to:

|======================================================
|[ INFO: possible circular locking dependency detected ]
|3.17.0-rc4+ #1498 Not tainted
|-------------------------------------------------------
|rmmod/2505 is trying to acquire lock:
| (s_active#28){++++.+}, at: [<c017f754>] kernfs_remove_by_name_ns+0x3c/0x88
|
|but task is already holding lock:
| (pools_lock){+.+.+.}, at: [<c011494c>] dma_pool_destroy+0x18/0x17c
|
|which lock already depends on the new lock.
|the existing dependency chain (in reverse order) is:
|
|-> #1 (pools_lock){+.+.+.}:
|   [<c0114ae8>] show_pools+0x30/0xf8
|   [<c0313210>] dev_attr_show+0x1c/0x48
|   [<c0180e84>] sysfs_kf_seq_show+0x88/0x10c
|   [<c017f960>] kernfs_seq_show+0x24/0x28
|   [<c013efc4>] seq_read+0x1b8/0x480
|   [<c011e820>] vfs_read+0x8c/0x148
|   [<c011ea10>] SyS_read+0x40/0x8c
|   [<c000e960>] ret_fast_syscall+0x0/0x48
|
|-> #0 (s_active#28){++++.+}:
|   [<c017e9ac>] __kernfs_remove+0x258/0x2ec
|   [<c017f754>] kernfs_remove_by_name_ns+0x3c/0x88
|   [<c0114a7c>] dma_pool_destroy+0x148/0x17c
|   [<c03ad288>] hcd_buffer_destroy+0x20/0x34
|   [<c03a4780>] usb_remove_hcd+0x110/0x1a4

The problem is the lock order of pools_lock and kernfs_mutex in
dma_pool_destroy() vs show_pools() call path.

This patch breaks out the creation of the sysfs file outside of the
pools_lock mutex.  The newly added pools_reg_lock ensures that there is no
race of create vs destroy code path in terms whether or not the sysfs file
has to be deleted (and was it deleted before we try to create a new one)
and what to do if device_create_file() failed.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:59 -04:00