1. 15 Mar, 2016 40 commits
    • Joonsoo Kim's avatar
      mm/slab: avoid returning values by reference · 70f75067
      Joonsoo Kim authored
      
      
      Returing values by reference is bad practice.  Instead, just use
      function return value.
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
      Suggested-by: default avatarChristoph Lameter <cl@linux.com>
      Acked-by: default avatarChristoph Lameter <cl@linux.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      70f75067
    • Joonsoo Kim's avatar
      mm/slab: introduce new slab management type, OBJFREELIST_SLAB · b03a017b
      Joonsoo Kim authored
      
      
      SLAB needs an array to manage freed objects in a slab.  It is only used
      if some objects are freed so we can use free object itself as this
      array.  This requires additional branch in somewhat critical lock path
      to check if it is first freed object or not but that's all we need.
      Benefits is that we can save extra memory usage and reduce some
      computational overhead by allocating a management array when new slab is
      created.
      
      Code change is rather complex than what we can expect from the idea, in
      order to handle debugging feature efficiently.  If you want to see core
      idea only, please remove '#if DEBUG' block in the patch.
      
      Although this idea can apply to all caches whose size is larger than
      management array size, it isn't applied to caches which have a
      constructor.  If such cache's object is used for management array,
      constructor should be called for it before that object is returned to
      user.  I guess that overhead overwhelm benefit in that case so this idea
      doesn't applied to them at least now.
      
      For summary, from now on, slab management type is determined by
      following logic.
      
      1) if management array size is smaller than object size and no ctor, it
         becomes OBJFREELIST_SLAB.
      
      2) if management array size is smaller than leftover, it becomes
         NORMAL_SLAB which uses leftover as a array.
      
      3) if OFF_SLAB help to save memory than way 4), it becomes OFF_SLAB.
         It allocate a management array from the other cache so memory waste
         happens.
      
      4) others become NORMAL_SLAB.  It uses dedicated internal memory in a
         slab as a management array so it causes memory waste.
      
      In my system, without enabling CONFIG_DEBUG_SLAB, Almost caches become
      OBJFREELIST_SLAB and NORMAL_SLAB (using leftover) which doesn't waste
      memory.  Following is the result of number of caches with specific slab
      management type.
      
      TOTAL = OBJFREELIST + NORMAL(leftover) + NORMAL + OFF
      
      /Before/
      126 = 0 + 60 + 25 + 41
      
      /After/
      126 = 97 + 12 + 15 + 2
      
      Result shows that number of caches that doesn't waste memory increase
      from 60 to 109.
      
      I did some benchmarking and it looks that benefit are more than loss.
      
      Kmalloc: Repeatedly allocate then free test
      
      /Before/
      [    0.286809] 1. Kmalloc: Repeatedly allocate then free test
      [    1.143674] 100000 times kmalloc(32) -> 116 cycles kfree -> 78 cycles
      [    1.441726] 100000 times kmalloc(64) -> 121 cycles kfree -> 80 cycles
      [    1.815734] 100000 times kmalloc(128) -> 168 cycles kfree -> 85 cycles
      [    2.380709] 100000 times kmalloc(256) -> 287 cycles kfree -> 95 cycles
      [    3.101153] 100000 times kmalloc(512) -> 370 cycles kfree -> 117 cycles
      [    3.942432] 100000 times kmalloc(1024) -> 413 cycles kfree -> 156 cycles
      [    5.227396] 100000 times kmalloc(2048) -> 622 cycles kfree -> 248 cycles
      [    7.519793] 100000 times kmalloc(4096) -> 1102 cycles kfree -> 452 cycles
      
      /After/
      [    1.205313] 100000 times kmalloc(32) -> 117 cycles kfree -> 78 cycles
      [    1.510526] 100000 times kmalloc(64) -> 124 cycles kfree -> 81 cycles
      [    1.827382] 100000 times kmalloc(128) -> 130 cycles kfree -> 84 cycles
      [    2.226073] 100000 times kmalloc(256) -> 177 cycles kfree -> 92 cycles
      [    2.814747] 100000 times kmalloc(512) -> 286 cycles kfree -> 112 cycles
      [    3.532952] 100000 times kmalloc(1024) -> 344 cycles kfree -> 141 cycles
      [    4.608777] 100000 times kmalloc(2048) -> 519 cycles kfree -> 210 cycles
      [    6.350105] 100000 times kmalloc(4096) -> 789 cycles kfree -> 391 cycles
      
      In fact, I tested another idea implementing OBJFREELIST_SLAB with
      extendable linked array through another freed object.  It can remove
      memory waste completely but it causes more computational overhead in
      critical lock path and it seems that overhead outweigh benefit.  So, this
      patch doesn't include it.
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.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>
      Cc: Jesper Dangaard Brouer <brouer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b03a017b
    • Joonsoo Kim's avatar
      mm/slab: factor out debugging initialization in cache_init_objs() · 10b2e9e8
      Joonsoo Kim authored
      
      
      cache_init_objs() will be changed in following patch and current form
      doesn't fit well for that change.  So, before doing it, this patch
      separates debugging initialization.  This would cause two loop iteration
      when debugging is enabled, but, this overhead seems too light than debug
      feature itself so effect may not be visible.  This patch will greatly
      simplify changes in cache_init_objs() in following patch.
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.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>
      Cc: Jesper Dangaard Brouer <brouer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      10b2e9e8
    • Joonsoo Kim's avatar
      mm/slab: factor out slab list fixup code · d8410234
      Joonsoo Kim authored
      
      
      Slab list should be fixed up after object is detached from the slab and
      this happens at two places.  They do exactly same thing.  They will be
      changed in the following patch, so, to reduce code duplication, this
      patch factor out them and make it common function.
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.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>
      Cc: Jesper Dangaard Brouer <brouer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d8410234
    • Joonsoo Kim's avatar
      mm/slab: make criteria for off slab determination robust and simple · 3217fd9b
      Joonsoo Kim authored
      
      
      To become an off slab, there are some constraints to avoid bootstrapping
      problem and recursive call.  This can be avoided differently by simply
      checking that corresponding kmalloc cache is ready and it's not a off
      slab.  It would be more robust because static size checking can be
      affected by cache size change or architecture type but dynamic checking
      isn't.
      
      One check 'freelist_cache->size > cachep->size / 2' is added to check
      benefit of choosing off slab, because, now, there is no size constraint
      which ensures enough advantage when selecting off slab.
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.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>
      Cc: Jesper Dangaard Brouer <brouer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3217fd9b
    • Joonsoo Kim's avatar
      mm/slab: do not change cache size if debug pagealloc isn't possible · f3a3c320
      Joonsoo Kim authored
      
      
      We can fail to setup off slab in some conditions.  Even in this case,
      debug pagealloc increases cache size to PAGE_SIZE in advance and it is
      waste because debug pagealloc cannot work for it when it isn't the off
      slab.  To improve this situation, this patch checks first that this
      cache with increased size is suitable for off slab.  It actually
      increases cache size when it is suitable for off-slab, so possible waste
      is removed.
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.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>
      Cc: Jesper Dangaard Brouer <brouer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f3a3c320
    • Joonsoo Kim's avatar
      mm/slab: clean up cache type determination · 158e319b
      Joonsoo Kim authored
      
      
      Current cache type determination code is open-code and looks not
      understandable.  Following patch will introduce one more cache type and
      it would make code more complex.  So, before it happens, this patch
      abstracts these codes.
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.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>
      Cc: Jesper Dangaard Brouer <brouer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      158e319b
    • Joonsoo Kim's avatar
      mm/slab: align cache size first before determination of OFF_SLAB candidate · 832a15d2
      Joonsoo Kim authored
      
      
      Finding suitable OFF_SLAB candidate is more related to aligned cache
      size rather than original size.  Same reasoning can be applied to the
      debug pagealloc candidate.  So, this patch moves up alignment fixup to
      proper position.  From that point, size is aligned so we can remove some
      alignment fixups.
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.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>
      Cc: Jesper Dangaard Brouer <brouer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      832a15d2
    • Joonsoo Kim's avatar
      mm/slab: put the freelist at the end of slab page · 2e6b3602
      Joonsoo Kim authored
      
      
      Currently, the freelist is at the front of slab page.  This requires
      extra space to meet object alignment requirement.  If we put the
      freelist at the end of a slab page, objects could start at page boundary
      and will be at correct alignment.  This is possible because freelist has
      no alignment constraint itself.
      
      This gives us two benefits: It removes extra memory space for the
      freelist alignment and remove complex calculation at cache
      initialization step.  I can't think notable drawback here.
      
      I mentioned that this would reduce extra memory space, but, this benefit
      is rather theoretical because it can be applied to very few cases.
      Following is the example cache type that can get benefit from this
      change.
      
        size align num before after
          32    8  124  4100  4092
          64    8   63  4103  4095
          88    8   46  4102  4094
         272    8   15  4103  4095
         408    8   10  4098  4090
          32   16  124  4108  4092
          64   16   63  4111  4095
          32   32  124  4124  4092
          64   32   63  4127  4095
          96   32   42  4106  4074
      
      before means whole size for objects and aligned freelist before applying
      patch and after shows the result of this patch.
      
      Since before is more than 4096, number of object should decrease and
      memory waste happens.
      
      Anyway, this patch removes complex calculation so looks beneficial to
      me.
      
      [akpm@linux-foundation.org: fix kerneldoc]
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
      Acked-by: default avatarChristoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Jesper Dangaard Brouer <brouer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2e6b3602
    • Joonsoo Kim's avatar
      mm/slab: remove object status buffer for DEBUG_SLAB_LEAK · 249247b6
      Joonsoo Kim authored
      
      
      Now, we don't use object status buffer in any setup. Remove it.
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.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>
      Cc: Jesper Dangaard Brouer <brouer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      249247b6
    • Joonsoo Kim's avatar
      mm/slab: alternative implementation for DEBUG_SLAB_LEAK · d31676df
      Joonsoo Kim authored
      
      
      DEBUG_SLAB_LEAK is a debug option.  It's current implementation requires
      status buffer so we need more memory to use it.  And, it cause
      kmem_cache initialization step more complex.
      
      To remove this extra memory usage and to simplify initialization step,
      this patch implement this feature with another way.
      
      When user requests to get slab object owner information, it marks that
      getting information is started.  And then, all free objects in caches
      are flushed to corresponding slab page.  Now, we can distinguish all
      freed object so we can know all allocated objects, too.  After
      collecting slab object owner information on allocated objects, mark is
      checked that there is no free during the processing.  If true, we can be
      sure that our information is correct so information is returned to user.
      
      Although this way is rather complex, it has two important benefits
      mentioned above.  So, I think it is worth changing.
      
      There is one drawback that it takes more time to get slab object owner
      information but it is just a debug option so it doesn't matter at all.
      
      To help review, this patch implements new way only.  Following patch
      will remove useless code.
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.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>
      Cc: Jesper Dangaard Brouer <brouer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d31676df
    • Joonsoo Kim's avatar
      mm/slab: clean up DEBUG_PAGEALLOC processing code · 40b44137
      Joonsoo Kim authored
      
      
      Currently, open code for checking DEBUG_PAGEALLOC cache is spread to
      some sites.  It makes code unreadable and hard to change.
      
      This patch cleans up this code.  The following patch will change the
      criteria for DEBUG_PAGEALLOC cache so this clean-up will help it, too.
      
      [akpm@linux-foundation.org: fix build with CONFIG_DEBUG_PAGEALLOC=n]
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.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>
      Cc: Jesper Dangaard Brouer <brouer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      40b44137
    • Joonsoo Kim's avatar
      mm/slab: use more appropriate condition check for debug_pagealloc · 40323278
      Joonsoo Kim authored
      
      
      debug_pagealloc debugging is related to SLAB_POISON flag rather than
      FORCED_DEBUG option, although FORCED_DEBUG option will enable
      SLAB_POISON.  Fix it.
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
      Acked-by: default avatarChristoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Jesper Dangaard Brouer <brouer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      40323278
    • Joonsoo Kim's avatar
      mm/slab: activate debug_pagealloc in SLAB when it is actually enabled · a307ebd4
      Joonsoo Kim authored
      
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
      Acked-by: default avatarChristoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Jesper Dangaard Brouer <brouer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a307ebd4
    • Joonsoo Kim's avatar
      mm/slab: remove the checks for slab implementation bug · 260b61dd
      Joonsoo Kim authored
      
      
      Some of "#if DEBUG" are for reporting slab implementation bug rather
      than user usecase bug.  It's not really needed because slab is stable
      for a quite long time and it makes code too dirty.  This patch remove
      it.
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
      Acked-by: default avatarChristoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Jesper Dangaard Brouer <brouer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      260b61dd
    • Joonsoo Kim's avatar
      mm/slab: remove useless structure define · 6fb92430
      Joonsoo Kim authored
      
      
      It is obsolete so remove it.
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
      Acked-by: default avatarChristoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Jesper Dangaard Brouer <brouer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6fb92430
    • Joonsoo Kim's avatar
      mm/slab: fix stale code comment · 12c61fe9
      Joonsoo Kim authored
      
      
      This patchset implements a new freed object management way, that is,
      OBJFREELIST_SLAB.  Purpose of it is to reduce memory overhead in SLAB.
      
      SLAB needs a array to manage freed objects in a slab.  If there is
      leftover after objects are packed into a slab, we can use it as a
      management array, and, in this case, there is no memory waste.  But, in
      the other cases, we need to allocate extra memory for a management array
      or utilize dedicated internal memory in a slab for it.  Both cases
      causes memory waste so it's not good.
      
      With this patchset, freed object itself can be used for a management
      array.  So, memory waste could be reduced.  Detailed idea and numbers
      are described in last patch's commit description.  Please refer it.
      
      In fact, I tested another idea implementing OBJFREELIST_SLAB with
      extendable linked array through another freed object.  It can remove
      memory waste completely but it causes more computational overhead in
      critical lock path and it seems that overhead outweigh benefit.  So,
      this patchset doesn't include it.  I will attach prototype just for a
      reference.
      
      This patch (of 16):
      
      We use freelist_idx_t type for free object management whose size would be
      smaller than size of unsigned int.  Fix it.
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.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>
      Cc: Jesper Dangaard Brouer <brouer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      12c61fe9
    • Jesper Dangaard Brouer's avatar
      mm: fix some spelling · 9f706d68
      Jesper Dangaard Brouer authored
      
      
      Fix up trivial spelling errors, noticed while reading the code.
      
      Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.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>
      Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9f706d68
    • Jesper Dangaard Brouer's avatar
      mm: new API kfree_bulk() for SLAB+SLUB allocators · ca257195
      Jesper Dangaard Brouer authored
      
      
      This patch introduce a new API call kfree_bulk() for bulk freeing memory
      objects not bound to a single kmem_cache.
      
      Christoph pointed out that it is possible to implement freeing of
      objects, without knowing the kmem_cache pointer as that information is
      available from the object's page->slab_cache.  Proposing to remove the
      kmem_cache argument from the bulk free API.
      
      Jesper demonstrated that these extra steps per object comes at a
      performance cost.  It is only in the case CONFIG_MEMCG_KMEM is compiled
      in and activated runtime that these steps are done anyhow.  The extra
      cost is most visible for SLAB allocator, because the SLUB allocator does
      the page lookup (virt_to_head_page()) anyhow.
      
      Thus, the conclusion was to keep the kmem_cache free bulk API with a
      kmem_cache pointer, but we can still implement a kfree_bulk() API fairly
      easily.  Simply by handling if kmem_cache_free_bulk() gets called with a
      kmem_cache NULL pointer.
      
      This does increase the code size a bit, but implementing a separate
      kfree_bulk() call would likely increase code size even more.
      
      Below benchmarks cost of alloc+free (obj size 256 bytes) on CPU i7-4790K
      @ 4.00GHz, no PREEMPT and CONFIG_MEMCG_KMEM=y.
      
      Code size increase for SLAB:
      
       add/remove: 0/0 grow/shrink: 1/0 up/down: 74/0 (74)
       function                                     old     new   delta
       kmem_cache_free_bulk                         660     734     +74
      
      SLAB fastpath: 87 cycles(tsc) 21.814
        sz - fallback             - kmem_cache_free_bulk - kfree_bulk
         1 - 103 cycles 25.878 ns -  41 cycles 10.498 ns - 81 cycles 20.312 ns
         2 -  94 cycles 23.673 ns -  26 cycles  6.682 ns - 42 cycles 10.649 ns
         3 -  92 cycles 23.181 ns -  21 cycles  5.325 ns - 39 cycles 9.950 ns
         4 -  90 cycles 22.727 ns -  18 cycles  4.673 ns - 26 cycles 6.693 ns
         8 -  89 cycles 22.270 ns -  14 cycles  3.664 ns - 23 cycles 5.835 ns
        16 -  88 cycles 22.038 ns -  14 cycles  3.503 ns - 22 cycles 5.543 ns
        30 -  89 cycles 22.284 ns -  13 cycles  3.310 ns - 20 cycles 5.197 ns
        32 -  88 cycles 22.249 ns -  13 cycles  3.420 ns - 20 cycles 5.166 ns
        34 -  88 cycles 22.224 ns -  14 cycles  3.643 ns - 20 cycles 5.170 ns
        48 -  88 cycles 22.088 ns -  14 cycles  3.507 ns - 20 cycles 5.203 ns
        64 -  88 cycles 22.063 ns -  13 cycles  3.428 ns - 20 cycles 5.152 ns
       128 -  89 cycles 22.483 ns -  15 cycles  3.891 ns - 23 cycles 5.885 ns
       158 -  89 cycles 22.381 ns -  15 cycles  3.779 ns - 22 cycles 5.548 ns
       250 -  91 cycles 22.798 ns -  16 cycles  4.152 ns - 23 cycles 5.967 ns
      
      SLAB when enabling MEMCG_KMEM runtime:
       - kmemcg fastpath: 130 cycles(tsc) 32.684 ns (step:0)
       1 - 148 cycles 37.220 ns -  66 cycles 16.622 ns - 66 cycles 16.583 ns
       2 - 141 cycles 35.510 ns -  51 cycles 12.820 ns - 58 cycles 14.625 ns
       3 - 140 cycles 35.017 ns -  37 cycles 9.326 ns - 33 cycles 8.474 ns
       4 - 137 cycles 34.507 ns -  31 cycles 7.888 ns - 33 cycles 8.300 ns
       8 - 140 cycles 35.069 ns -  25 cycles 6.461 ns - 25 cycles 6.436 ns
       16 - 138 cycles 34.542 ns -  23 cycles 5.945 ns - 22 cycles 5.670 ns
       30 - 136 cycles 34.227 ns -  22 cycles 5.502 ns - 22 cycles 5.587 ns
       32 - 136 cycles 34.253 ns -  21 cycles 5.475 ns - 21 cycles 5.324 ns
       34 - 136 cycles 34.254 ns -  21 cycles 5.448 ns - 20 cycles 5.194 ns
       48 - 136 cycles 34.075 ns -  21 cycles 5.458 ns - 21 cycles 5.367 ns
       64 - 135 cycles 33.994 ns -  21 cycles 5.350 ns - 21 cycles 5.259 ns
       128 - 137 cycles 34.446 ns -  23 cycles 5.816 ns - 22 cycles 5.688 ns
       158 - 137 cycles 34.379 ns -  22 cycles 5.727 ns - 22 cycles 5.602 ns
       250 - 138 cycles 34.755 ns -  24 cycles 6.093 ns - 23 cycles 5.986 ns
      
      Code size increase for SLUB:
       function                                     old     new   delta
       kmem_cache_free_bulk                         717     799     +82
      
      SLUB benchmark:
       SLUB fastpath: 46 cycles(tsc) 11.691 ns (step:0)
        sz - fallback             - kmem_cache_free_bulk - kfree_bulk
         1 -  61 cycles 15.486 ns -  53 cycles 13.364 ns - 57 cycles 14.464 ns
         2 -  54 cycles 13.703 ns -  32 cycles  8.110 ns - 33 cycles 8.482 ns
         3 -  53 cycles 13.272 ns -  25 cycles  6.362 ns - 27 cycles 6.947 ns
         4 -  51 cycles 12.994 ns -  24 cycles  6.087 ns - 24 cycles 6.078 ns
         8 -  50 cycles 12.576 ns -  21 cycles  5.354 ns - 22 cycles 5.513 ns
        16 -  49 cycles 12.368 ns -  20 cycles  5.054 ns - 20 cycles 5.042 ns
        30 -  49 cycles 12.273 ns -  18 cycles  4.748 ns - 19 cycles 4.758 ns
        32 -  49 cycles 12.401 ns -  19 cycles  4.821 ns - 19 cycles 4.810 ns
        34 -  98 cycles 24.519 ns -  24 cycles  6.154 ns - 24 cycles 6.157 ns
        48 -  83 cycles 20.833 ns -  21 cycles  5.446 ns - 21 cycles 5.429 ns
        64 -  75 cycles 18.891 ns -  20 cycles  5.247 ns - 20 cycles 5.238 ns
       128 -  93 cycles 23.271 ns -  27 cycles  6.856 ns - 27 cycles 6.823 ns
       158 - 102 cycles 25.581 ns -  30 cycles  7.714 ns - 30 cycles 7.695 ns
       250 - 107 cycles 26.917 ns -  38 cycles  9.514 ns - 38 cycles 9.506 ns
      
      SLUB when enabling MEMCG_KMEM runtime:
       - kmemcg fastpath: 71 cycles(tsc) 17.897 ns (step:0)
       1 - 85 cycles 21.484 ns -  78 cycles 19.569 ns - 75 cycles 18.938 ns
       2 - 81 cycles 20.363 ns -  45 cycles 11.258 ns - 44 cycles 11.076 ns
       3 - 78 cycles 19.709 ns -  33 cycles 8.354 ns - 32 cycles 8.044 ns
       4 - 77 cycles 19.430 ns -  28 cycles 7.216 ns - 28 cycles 7.003 ns
       8 - 101 cycles 25.288 ns -  23 cycles 5.849 ns - 23 cycles 5.787 ns
       16 - 76 cycles 19.148 ns -  20 cycles 5.162 ns - 20 cycles 5.081 ns
       30 - 76 cycles 19.067 ns -  19 cycles 4.868 ns - 19 cycles 4.821 ns
       32 - 76 cycles 19.052 ns -  19 cycles 4.857 ns - 19 cycles 4.815 ns
       34 - 121 cycles 30.291 ns -  25 cycles 6.333 ns - 25 cycles 6.268 ns
       48 - 108 cycles 27.111 ns -  21 cycles 5.498 ns - 21 cycles 5.458 ns
       64 - 100 cycles 25.164 ns -  20 cycles 5.242 ns - 20 cycles 5.229 ns
       128 - 155 cycles 38.976 ns -  27 cycles 6.886 ns - 27 cycles 6.892 ns
       158 - 132 cycles 33.034 ns -  30 cycles 7.711 ns - 30 cycles 7.728 ns
       250 - 130 cycles 32.612 ns -  38 cycles 9.560 ns - 38 cycles 9.549 ns
      
      Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.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>
      Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ca257195
    • Jesper Dangaard Brouer's avatar
      slab: implement bulk free in SLAB allocator · e6cdb58d
      Jesper Dangaard Brouer authored
      This patch implements the free side of bulk API for the SLAB allocator
      kmem_cache_free_bulk(), and concludes the implementation of optimized
      bulk API for SLAB allocator.
      
      Benchmarked[1] cost of alloc+free (obj size 256 bytes) on CPU i7-4790K @
      4.00GHz, with no debug options, no PREEMPT and CONFIG_MEMCG_KMEM=y but
      no active user of kmemcg.
      
      SLAB single alloc+free cost: 87 cycles(tsc) 21.814 ns with this
      optimized config.
      
      bulk- Current fallback          - optimized SLAB bulk
        1 - 102 cycles(tsc) 25.747 ns - 41 cycles(tsc) 10.490 ns - improved 59.8%
        2 -  94 cycles(tsc) 23.546 ns - 26 cycles(tsc)  6.567 ns - improved 72.3%
        3 -  92 cycles(tsc) 23.127 ns - 20 cycles(tsc)  5.244 ns - improved 78.3%
        4 -  90 cycles(tsc) 22.663 ns - 18 cycles(tsc)  4.588 ns - improved 80.0%
        8 -  88 cycles(tsc) 22.242 ns - 14 cycles(tsc)  3.656 ns - improved 84.1%
       16 -  88 cycles(tsc) 22.010 ns - 13 cycles(tsc)  3.480 ns - improved 85.2%
       30 -  89 cycles(tsc) 22.305 ns - 13 cycles(tsc)  3.303 ns - improved 85.4%
       32 -  89 cycles(tsc) 22.277 ns - 13 cycles(tsc)  3.309 ns - improved 85.4%
       34 -  88 cycles(tsc) 22.246 ns - 13 cycles(tsc)  3.294 ns - improved 85.2%
       48 -  88 cycles(tsc) 22.121 ns - 13 cycles(tsc)  3.492 ns - improved 85.2%
       64 -  88 cycles(tsc) 22.052 ns - 13 cycles(tsc)  3.411 ns - improved 85.2%
      128 -  89 cycles(tsc) 22.452 ns - 15 cycles(tsc)  3.841 ns - improved 83.1%
      158 -  89 cycles(tsc) 22.403 ns - 14 cycles(tsc)  3.746 ns - improved 84.3%
      250 -  91 cycles(tsc) 22.775 ns - 16 cycles(tsc)  4.111 ns - improved 82.4%
      
      Notice it is not recommended to do very large bulk operation with
      this bulk API, because local IRQs are disabled in this period.
      
      [1] https://github.com/netoptimizer/prototype-kernel/blob/master/kernel/mm/slab_bulk_test01.c
      
      
      
      Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.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>
      Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e6cdb58d
    • Jesper Dangaard Brouer's avatar
      slab: avoid running debug SLAB code with IRQs disabled for alloc_bulk · 7b0501dd
      Jesper Dangaard Brouer authored
      
      
      Move the call to cache_alloc_debugcheck_after() outside the IRQ disabled
      section in kmem_cache_alloc_bulk().
      
      When CONFIG_DEBUG_SLAB is disabled the compiler should remove this code.
      
      Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.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>
      Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7b0501dd
    • Jesper Dangaard Brouer's avatar
      slab: implement bulk alloc in SLAB allocator · 2a777eac
      Jesper Dangaard Brouer authored
      
      
      This patch implements the alloc side of bulk API for the SLAB allocator.
      
      Further optimization are still possible by changing the call to
      __do_cache_alloc() into something that can return multiple objects.
      This optimization is left for later, given end results already show in
      the area of 80% speedup.
      
      Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.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>
      Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2a777eac
    • Jesper Dangaard Brouer's avatar
      slab: use slab_post_alloc_hook in SLAB allocator shared with SLUB · d5e3ed66
      Jesper Dangaard Brouer authored
      
      
      Reviewers notice that the order in slab_post_alloc_hook() of
      kmemcheck_slab_alloc() and kmemleak_alloc_recursive() gets swapped
      compared to slab.c / SLAB allocator.
      
      Also notice memset now occurs before calling kmemcheck_slab_alloc() and
      kmemleak_alloc_recursive().
      
      I assume this reordering of kmemcheck, kmemleak and memset is okay
      because this is the order they are used by the SLUB allocator.
      
      This patch completes the sharing of alloc_hook's between SLUB and SLAB.
      
      Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.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>
      Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d5e3ed66
    • Jesper Dangaard Brouer's avatar
      mm: kmemcheck skip object if slab allocation failed · 0142eae3
      Jesper Dangaard Brouer authored
      
      
      In the SLAB allocator kmemcheck_slab_alloc() is guarded against being
      called in case the object is NULL.  In SLUB allocator this NULL pointer
      invocation can happen, which seems like an oversight.
      
      Move the NULL pointer check into kmemcheck code (kmemcheck_slab_alloc)
      so the check gets moved out of the fastpath, when not compiled with
      CONFIG_KMEMCHECK.
      
      This is a step towards sharing post_alloc_hook between SLUB and SLAB,
      because slab_post_alloc_hook() does not perform this check before
      calling kmemcheck_slab_alloc().
      
      Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.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>
      Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0142eae3
    • Jesper Dangaard Brouer's avatar
      slab: use slab_pre_alloc_hook in SLAB allocator shared with SLUB · 011eceaf
      Jesper Dangaard Brouer authored
      
      
      Deduplicate code in SLAB allocator functions slab_alloc() and
      slab_alloc_node() by using the slab_pre_alloc_hook() call, which is now
      shared between SLUB and SLAB.
      
      Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.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>
      Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      011eceaf
    • Jesper Dangaard Brouer's avatar
      mm: fault-inject take over bootstrap kmem_cache check · fab9963a
      Jesper Dangaard Brouer authored
      
      
      Remove the SLAB specific function slab_should_failslab(), by moving the
      check against fault-injection for the bootstrap slab, into the shared
      function should_failslab() (used by both SLAB and SLUB).
      
      This is a step towards sharing alloc_hook's between SLUB and SLAB.
      
      This bootstrap slab "kmem_cache" is used for allocating struct
      kmem_cache objects to the allocator itself.
      
      Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.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>
      Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      fab9963a
    • Jesper Dangaard Brouer's avatar
      mm/slab: move SLUB alloc hooks to common mm/slab.h · 11c7aec2
      Jesper Dangaard Brouer authored
      
      
      First step towards sharing alloc_hook's between SLUB and SLAB
      allocators.  Move the SLUB allocators *_alloc_hook to the common
      mm/slab.h for internal slab definitions.
      
      Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.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>
      Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      11c7aec2
    • Jesper Dangaard Brouer's avatar
      slub: clean up code for kmem cgroup support to kmem_cache_free_bulk · 376bf125
      Jesper Dangaard Brouer authored
      This change is primarily an attempt to make it easier to realize the
      optimizations the compiler performs in-case CONFIG_MEMCG_KMEM is not
      enabled.
      
      Performance wise, even when CONFIG_MEMCG_KMEM is compiled in, the
      overhead is zero.  This is because, as long as no process have enabled
      kmem cgroups accounting, the assignment is replaced by asm-NOP
      operations.  This is possible because memcg_kmem_enabled() uses a
      static_key_false() construct.
      
      It also helps readability as it avoid accessing the p[] array like:
      p[size - 1] which "expose" that the array is processed backwards inside
      helper function build_detached_freelist().
      
      Lastly this also makes the code more robust, in error case like passing
      NULL pointers in the array.  Which were previously handled before commit
      03374518 ("slub: add missing kmem cgroup support to
      kmem_cache_free_bulk").
      
      Fixes: 03374518
      
       ("slub: add missing kmem cgroup support to kmem_cache_free_bulk")
      Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.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>
      Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      376bf125
    • Arnd Bergmann's avatar
      paride: make 'verbose' parameter an 'int' again · dec63a4d
      Arnd Bergmann authored
      gcc-6.0 found an ancient bug in the paride driver, which had a
      "module_param(verbose, bool, 0);" since before 2.6.12, but actually uses
      it to accept '0', '1' or '2' as arguments:
      
        drivers/block/paride/pd.c: In function 'pd_init_dev_parms':
        drivers/block/paride/pd.c:298:29: warning: comparison of constant '1' with boolean expression is always false [-Wbool-compare]
         #define DBMSG(msg) ((verbose>1)?(msg):NULL)
      
      In 2012, Rusty did a cleanup patch that also changed the type of the
      variable to 'bool', which introduced what is now a gcc warning.
      
      This changes the type back to 'int' and adapts the module_param() line
      instead, so it should work as documented in case anyone ever cares about
      running the ancient driver with debugging.
      
      Fixes: 90ab5ee9
      
       ("module_param: make bool parameters really bool (drivers & misc)")
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      Rusty Russell <rusty@rustcorp.com.au>
      Cc: Tim Waugh <tim@cyberelk.net>
      Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
      Cc: Jens Axboe <axboe@fb.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      dec63a4d
    • San Mehat's avatar
      block: partition: add partition specific uevent callbacks for partition info · 0d9c51a6
      San Mehat authored
      This patch has been carried in the Android tree for quite some time and
      is one of the few patches required to get a mainline kernel up and
      running with an exsiting Android userspace.  So I wanted to submit it
      for review and consideration if it should be merged.
      
      For partitions, add new uevent parameters 'PARTN' which specifies the
      partitions index in the table, and 'PARTNAME', which specifies PARTNAME
      specifices the partition name of a partition device.
      
      Android's userspace uses this for creating device node links from the
      partition name and number, ie:
      
          /dev/block/platform/soc/by-name/system
      or
          /dev/block/platform/soc/by-num/p1
      
      One can see its usage here:
          https://android.googlesource.com/platform/system/core/+/master/init/devices.cpp#355
      and
          https://android.googlesource.com/platform/system/core/+/master/init/devices.cpp#494
      
      
      
      [john.stultz@linaro.org: dropped NPARTS and reworded commit message for context]
      Signed-off-by: default avatarDima Zavin <dima@android.com>
      Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Rom Lemarchand <romlem@google.com>
      Cc: Android Kernel Team <kernel-team@android.com>
      Cc: Jeff Moyer <jmoyer@redhat.com>
      Cc: <harald@redhat.com>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Kay Sievers <kay@vrfy.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0d9c51a6
    • Jun Piao's avatar
      ocfs2/dlm: fix a variable overflow problem in dlmdomain.c · 8d67d3c2
      Jun Piao authored
      
      
      In dlm_send_join_cancels(), node is defined with type unsigned int, but
      initialized with -1, this will lead variable overflow.  Although this
      won't cause any runtime problem, the code looks a little uncoordinated.
      
      Signed-off-by: default avatarJun Piao <piaojun@huawei.com>
      Reviewed-by: default avatarJoseph 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: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8d67d3c2
    • Jiufei Xue's avatar
      ocfs2: fix a tiny race that leads file system read-only · 814ce694
      Jiufei Xue authored
      
      
      when o2hb detect a node down, it first set the dead node to recovery map
      and create ocfs2rec which will replay journal for dead node.  o2hb
      thread then call dlm_do_local_recovery_cleanup() to delete the lock for
      dead node.  After the lock of dead node is gone, locks for other nodes
      can be granted and may modify the meta data without replaying journal of
      the dead node.  The detail is described as follows.
      
           N1                         N2                   N3(master)
      modify the extent tree of
      inode, and commit
      dirty metadata to journal,
      then goes down.
                                                       o2hb thread detects
                                                       N1 goes down, set
                                                       recovery map and
                                                       delete the lock of N1.
      
                                                       dlm_thread flush ast
                                                       for the lock of N2.
                              do not detect the death
                              of N1, so recovery map is
                              empty.
      
                              read inode from disk
                              without replaying
                              the journal of N1 and
                              modify the extent tree
                              of the inode that N1
                              had modified.
                                                       ocfs2rec recover the
                                                       journal of N1.
                                                       The modification of N2
                                                       is lost.
      
      The modification of N1 and N2 are not serial, and it will lead to
      read-only file system.  We can set recovery_waiting flag to the lock
      resource after delete the lock for dead node to prevent other node from
      getting the lock before dlm recovery.  After dlm recovery, the recovery
      map on N2 is not empty, ocfs2_inode_lock_full_nested() will wait for ocfs2
      recovery.
      
      Signed-off-by: default avatarJiufei Xue <xuejiufei@huawei.com>
      Reviewed-by: default avatarJoseph 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: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      814ce694
    • xuejiufei's avatar
      ocfs2/dlm: return EINVAL when the lockres on migration target is in DROPPING_REF state · d277f33e
      xuejiufei authored
      
      
      If master migrate this lock resource to node when it happened to purge
      it, a new lock resource will be created and inserted into hash list.  If
      then master goes down, the lock resource being purged is recovered, so
      there exist two lock resource with different owner.  So return error to
      master if the lock resource is in DROPPING state, master will retry to
      migrate this lock resource.
      
      Signed-off-by: default avatarxuejiufei <xuejiufei@huawei.com>
      Cc: Mark Fasheh <mfasheh@suse.de>
      Cc: Joel Becker <jlbec@evilplan.org>
      Cc: Junxiao Bi <junxiao.bi@oracle.com>
      Reviewed-by: default avatarJoseph Qi <joseph.qi@huawei.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d277f33e
    • xuejiufei's avatar
      ocfs2/dlm: clear DROPPING_REF flag when the master goes down · 8c034396
      xuejiufei authored
      
      
      If the master goes down after return in-progress for deref message.  The
      lock resource on non-master node can not be purged.  Clear the
      DROPPING_REF flag and recovery it.
      
      Signed-off-by: default avatarxuejiufei <xuejiufei@huawei.com>
      Cc: Mark Fasheh <mfasheh@suse.de>
      Cc: Joel Becker <jlbec@evilplan.org>
      Cc: Junxiao Bi <junxiao.bi@oracle.com>
      Reviewed-by: default avatarJoseph Qi <joseph.qi@huawei.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8c034396
    • xuejiufei's avatar
      ocfs2/dlm: return in progress if master can not clear the refmap bit right now · 842b90b6
      xuejiufei authored
      
      
      Master returns in-progress to non-master node when it can not clear the
      refmap bit right now.  And non-master node will not purge the lock
      resource until receiving deref done message.
      
      Signed-off-by: default avatarxuejiufei <xuejiufei@huawei.com>
      Cc: Mark Fasheh <mfasheh@suse.de>
      Cc: Joel Becker <jlbec@evilplan.org>
      Cc: Junxiao Bi <junxiao.bi@oracle.com>
      Reviewed-by: default avatarJoseph Qi <joseph.qi@huawei.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      842b90b6
    • xuejiufei's avatar
      ocfs2/dlm: add DEREF_DONE message · 60d663cb
      xuejiufei authored
      
      
      This series of patches is to fix the dis-order issue of setting/clearing
      refmap bit described below.
      
      Node 1                               Node 2(master)
      dlmlock
      dlm_do_master_request
                                      dlm_master_request_handler
                                      -> dlm_lockres_set_refmap_bit
      dlmlock succeed
      dlmunlock succeed
      
      dlm_purge_lockres
                                      dlm_deref_handler
                                      -> find lock resource is in
                                         DLM_LOCK_RES_SETREF_INPROG state,
                                         so dispatch a deref work
      dlm_purge_lockres succeed.
      
      call dlmlock again
      dlm_do_master_request
                                      dlm_master_request_handler
                                      -> dlm_lockres_set_refmap_bit
      
                                      deref work trigger, call
                                      dlm_lockres_clear_refmap_bit
                                      to clear Node 1 from refmap
      
                                      dlm_purge_lockres succeed
      
      dlm_send_remote_lock_request
                                      return DLM_IVLOCKID because
                                      the lockres is not exist
      BUG if the lockres is $RECOVERY
      
      This series of patches add a new message to keep the order of set and
      clear.  Other nodes can purge the lock resource only after the refmap bit
      on master is cleared.
      
      This patch is to add DEREF_DONE message and corresponding handler.  Node
      can purge the lock resource after receiving this message.  As a new
      message is added, so increase the minor number of dlm protocol version.
      
      Signed-off-by: default avatarxuejiufei <xuejiufei@huawei.com>
      Cc: Mark Fasheh <mfasheh@suse.de>
      Cc: Joel Becker <jlbec@evilplan.org>
      Cc: Junxiao Bi <junxiao.bi@oracle.com>
      Reviewed-by: default avatarJoseph Qi <joseph.qi@huawei.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      60d663cb
    • Joseph Qi's avatar
      ocfs2/dlm: fix a typo in dlmcommon.h · 39b29af0
      Joseph Qi authored
      
      
      Refer to cluster/tcp.h, NET_MAX_PAYLOAD_BYTES is a typo for
      O2NET_MAX_PAYLOAD_BYTES.
      
      Since currently DLM_MIG_LOCKRES_RESERVED is not actually used, it won't
      cause any problem.  But we'd better correct it for further use.
      
      Signed-off-by: default avatarJoseph Qi <joseph.qi@huawei.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: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      39b29af0
    • jiangyiwen's avatar
      ocfs2: use spinlock_irqsave() to downconvert lock in ocfs2_osb_dump() · bfd97a03
      jiangyiwen authored
      Commit a75e9cca
      
       ("ocfs2: use spinlock irqsave for downconvert lock")
      missed an unmodified place in ocfs2_osb_dump(), so it still exists a
      deadlock scenario.
      
          ocfs2_wake_downconvert_thread
          ocfs2_rw_unlock
          ocfs2_dio_end_io
          dio_complete
          .....
          bio_endio
          req_bio_endio
          ....
          scsi_io_completion
          blk_done_softirq
          __do_softirq
          do_softirq
          irq_exit
          do_IRQ
          ocfs2_osb_dump
          cat /sys/kernel/debug/ocfs2/${uuid}/fs_state
      
      This patch still uses spin_lock_irqsave() - replace spin_lock() to solve
      this situation.
      
      Signed-off-by: default avatarYiwen Jiang <jiangyiwen@huawei.com>
      Reviewed-by: default avatarJoseph 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: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      bfd97a03
    • jiangyiwen's avatar
      ocfs2/cluster: replace the interrupt safe spinlocks with common ones · 4d548f61
      jiangyiwen authored
      
      
      There actually no hardware or software interrupts in the context which
      using o2hb_live_lock, so we don't need to worry about race conditions
      caused by irq/softirq with spinlock held.  Turning off irq is not good
      for system performance after all.  Just replace them with a non
      interrupt safe function.
      
      Signed-off-by: default avatarYiwen Jiang <jiangyiwen@huawei.com>
      Reviewed-by: default avatarJoseph 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: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4d548f61
    • Sudip Mukherjee's avatar
      blackfin: define dummy pgprot_writecombine for !MMU · e928f350
      Sudip Mukherjee authored
      blackfin allmodconfig build fails with the error:
      
        ../sound/core/pcm_native.c: In function 'snd_pcm_lib_default_mmap':
        ../sound/core/pcm_native.c:3386:24: error: implicit declaration of function 'pgprot_writecombine' [-Werror=implicit-function-declaration]
           area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
                                ^
        ../sound/core/pcm_native.c:3386:22: error: incompatible types when assigning to type 'pgprot_t {aka struct <anonymous>}' from type 'int'
           area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
                              ^
      
      When !MMU, asm-generic will not define default pgprot_writecombine, so
      blackfin needs to define it by itself.
      
      The patch idea is from commit 65b9ab88
      
       ("arch/c6x/include/asm/pgtable.h:
      define dummy pgprot_writecombine for !MMU")
      
      Signed-off-by: default avatarSudip Mukherjee <sudip@vectorindia.org>
      Cc: Steven Miao <realmz6@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e928f350