1. 06 Nov, 2015 5 commits
  2. 08 Sep, 2015 2 commits
  3. 04 Sep, 2015 1 commit
    • Christoph Lameter's avatar
      slab: infrastructure for bulk object allocation and freeing · 484748f0
      Christoph Lameter authored
      
      
      Add the basic infrastructure for alloc/free operations on pointer arrays.
      It includes a generic function in the common slab code that is used in
      this infrastructure patch to create the unoptimized functionality for slab
      bulk operations.
      
      Allocators can then provide optimized allocation functions for situations
      in which large numbers of objects are needed.  These optimization may
      avoid taking locks repeatedly and bypass metadata creation if all objects
      in slab pages can be used to provide the objects required.
      
      Allocators can extend the skeletons provided and add their own code to the
      bulk alloc and free functions.  They can keep the generic allocation and
      freeing and just fall back to those if optimizations would not work (like
      for example when debugging is on).
      
      Signed-off-by: default avatarChristoph Lameter <cl@linux.com>
      Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      484748f0
  4. 07 Aug, 2015 1 commit
  5. 01 Jul, 2015 1 commit
  6. 29 Jun, 2015 1 commit
  7. 25 Jun, 2015 2 commits
    • Daniel Sanders's avatar
      slab: correct size_index table before replacing the bootstrap kmem_cache_node · 34cc6990
      Daniel Sanders authored
      
      
      This patch moves the initialization of the size_index table slightly
      earlier so that the first few kmem_cache_node's can be safely allocated
      when KMALLOC_MIN_SIZE is large.
      
      There are currently two ways to generate indices into kmalloc_caches (via
      kmalloc_index() and via the size_index table in slab_common.c) and on some
      arches (possibly only MIPS) they potentially disagree with each other
      until create_kmalloc_caches() has been called.  It seems that the
      intention is that the size_index table is a fast equivalent to
      kmalloc_index() and that create_kmalloc_caches() patches the table to
      return the correct value for the cases where kmalloc_index()'s
      if-statements apply.
      
      The failing sequence was:
      * kmalloc_caches contains NULL elements
      * kmem_cache_init initialises the element that 'struct
        kmem_cache_node' will be allocated to. For 32-bit Mips, this is a
        56-byte struct and kmalloc_index returns KMALLOC_SHIFT_LOW (7).
      * init_list is called which calls kmalloc_node to allocate a 'struct
        kmem_cache_node'.
      * kmalloc_slab selects the kmem_caches element using
        size_index[size_index_elem(size)]. For MIPS, size is 56, and the
        expression returns 6.
      * This element of kmalloc_caches is NULL and allocation fails.
      * If it had not already failed, it would have called
        create_kmalloc_caches() at this point which would have changed
        size_index[size_index_elem(size)] to 7.
      
      I don't believe the bug to be LLVM specific but GCC doesn't normally
      encounter the problem.  I haven't been able to identify exactly what GCC
      is doing better (probably inlining) but it seems that GCC is managing to
      optimize to the point that it eliminates the problematic allocations.
      This theory is supported by the fact that GCC can be made to fail in the
      same way by changing inline, __inline, __inline__, and __always_inline in
      include/linux/compiler-gcc.h such that they don't actually inline things.
      
      Signed-off-by: default avatarDaniel Sanders <daniel.sanders@imgtec.com>
      Acked-by: default avatarPekka Enberg <penberg@kernel.org>
      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>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      34cc6990
    • Gavin Guo's avatar
      mm/slab_common: support the slub_debug boot option on specific object size · 4066c33d
      Gavin Guo authored
      
      
      The slub_debug=PU,kmalloc-xx cannot work because in the
      create_kmalloc_caches() the s->name is created after the
      create_kmalloc_cache() is called.  The name is NULL in the
      create_kmalloc_cache() so the kmem_cache_flags() would not set the
      slub_debug flags to the s->flags.  The fix here set up a kmalloc_names
      string array for the initialization purpose and delete the dynamic name
      creation of kmalloc_caches.
      
      [akpm@linux-foundation.org: s/kmalloc_names/kmalloc_info/, tweak comment text]
      Signed-off-by: default avatarGavin Guo <gavin.guo@canonical.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>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4066c33d
  8. 14 Feb, 2015 2 commits
    • Andrey Ryabinin's avatar
      mm: slub: add kernel address sanitizer support for slub allocator · 0316bec2
      Andrey Ryabinin authored
      
      
      With this patch kasan will be able to catch bugs in memory allocated by
      slub.  Initially all objects in newly allocated slab page, marked as
      redzone.  Later, when allocation of slub object happens, requested by
      caller number of bytes marked as accessible, and the rest of the object
      (including slub's metadata) marked as redzone (inaccessible).
      
      We also mark object as accessible if ksize was called for this object.
      There is some places in kernel where ksize function is called to inquire
      size of really allocated area.  Such callers could validly access whole
      allocated memory, so it should be marked as accessible.
      
      Code in slub.c and slab_common.c files could validly access to object's
      metadata, so instrumentation for this files are disabled.
      
      Signed-off-by: default avatarAndrey Ryabinin <a.ryabinin@samsung.com>
      Signed-off-by: default avatarDmitry Chernenkov <dmitryc@google.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: Konstantin Serebryany <kcc@google.com>
      Signed-off-by: default avatarAndrey Konovalov <adech.fo@gmail.com>
      Cc: Yuri Gribov <tetra2005@gmail.com>
      Cc: Konstantin Khlebnikov <koct9i@gmail.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0316bec2
    • Andrzej Hajda's avatar
      mm/slab: convert cache name allocations to kstrdup_const · 3dec16ea
      Andrzej Hajda authored
      
      
      slab frequently performs duplication of strings located in read-only
      memory section.  Replacing kstrdup by kstrdup_const allows to avoid such
      operations.
      
      [akpm@linux-foundation.org: make the handling of kmem_cache.name const-correct]
      Signed-off-by: default avatarAndrzej Hajda <a.hajda@samsung.com>
      Cc: Marek Szyprowski <m.szyprowski@samsung.com>
      Cc: Kyungmin Park <kyungmin.park@samsung.com>
      Cc: Mike Turquette <mturquette@linaro.org>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      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: Tejun Heo <tj@kernel.org>
      Cc: Greg KH <greg@kroah.com>
      Cc: Geert Uytterhoeven <geert@linux-m68k.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3dec16ea
  9. 13 Feb, 2015 7 commits
    • Vladimir Davydov's avatar
      slub: make dead caches discard free slabs immediately · d6e0b7fa
      Vladimir Davydov authored
      To speed up further allocations SLUB may store empty slabs in per cpu/node
      partial lists instead of freeing them immediately.  This prevents per
      memcg caches destruction, because kmem caches created for a memory cgroup
      are only destroyed after the last page charged to the cgroup is freed.
      
      To fix this issue, this patch resurrects approach first proposed in [1].
      It forbids SLUB to cache empty slabs after the memory cgroup that the
      cache belongs to was destroyed.  It is achieved by setting kmem_cache's
      cpu_partial and min_partial constants to 0 and tuning put_cpu_partial() so
      that it would drop frozen empty slabs immediately if cpu_partial = 0.
      
      The runtime overhead is minimal.  From all the hot functions, we only
      touch relatively cold put_cpu_partial(): we make it call
      unfreeze_partials() after freezing a slab that belongs to an offline
      memory cgroup.  Since slab freezing exists to avoid moving slabs from/to a
      partial list on free/alloc, and there can't be allocations from dead
      caches, it shouldn't cause any overhead.  We do have to disable preemption
      for put_cpu_partial() to achieve that though.
      
      The original patch was accepted well and even merged to the mm tree.
      However, I decided to withdraw it due to changes happening to the memcg
      core at that time.  I had an idea of introducing per-memcg shrinkers for
      kmem caches, but now, as memcg has finally settled down, I do not see it
      as an option, because SLUB shrinker would be too costly to call since SLUB
      does not keep free slabs on a separate list.  Besides, we currently do not
      even call per-memcg shrinkers for offline memcgs.  Overall, it would
      introduce much more complexity to both SLUB and memcg than this small
      patch.
      
      Regarding to SLAB, there's no problem with it, because it shrinks
      per-cpu/node caches periodically.  Thanks to list_lru reparenting, we no
      longer keep entries for offline cgroups in per-memcg arrays (such as
      memcg_cache_params->memcg_caches), so we do not have to bother if a
      per-memcg cache will be shrunk a bit later than it could be.
      
      [1] http://thread.gmane.org/gmane.linux.kernel.mm/118649/focus=118650
      
      
      
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d6e0b7fa
    • Vladimir Davydov's avatar
      memcg: free memcg_caches slot on css offline · 2a4db7eb
      Vladimir Davydov authored
      
      
      We need to look up a kmem_cache in ->memcg_params.memcg_caches arrays only
      on allocations, so there is no need to have the array entries set until
      css free - we can clear them on css offline.  This will allow us to reuse
      array entries more efficiently and avoid costly array relocations.
      
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2a4db7eb
    • Vladimir Davydov's avatar
      slab: use css id for naming per memcg caches · f1008365
      Vladimir Davydov authored
      
      
      Currently, we use mem_cgroup->kmemcg_id to guarantee kmem_cache->name
      uniqueness.  This is correct, because kmemcg_id is only released on css
      free after destroying all per memcg caches.
      
      However, I am going to change that and release kmemcg_id on css offline,
      because it is not wise to keep it for so long, wasting valuable entries of
      memcg_cache_params->memcg_caches arrays.  Therefore, to preserve cache
      name uniqueness, let us switch to css->id.
      
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f1008365
    • Vladimir Davydov's avatar
      slab: link memcg caches of the same kind into a list · 426589f5
      Vladimir Davydov authored
      
      
      Sometimes, we need to iterate over all memcg copies of a particular root
      kmem cache.  Currently, we use memcg_cache_params->memcg_caches array for
      that, because it contains all existing memcg caches.
      
      However, it's a bad practice to keep all caches, including those that
      belong to offline cgroups, in this array, because it will be growing
      beyond any bounds then.  I'm going to wipe away dead caches from it to
      save space.  To still be able to perform iterations over all memcg caches
      of the same kind, let us link them into a list.
      
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      426589f5
    • Vladimir Davydov's avatar
      slab: embed memcg_cache_params to kmem_cache · f7ce3190
      Vladimir Davydov authored
      
      
      Currently, kmem_cache stores a pointer to struct memcg_cache_params
      instead of embedding it.  The rationale is to save memory when kmem
      accounting is disabled.  However, the memcg_cache_params has shrivelled
      drastically since it was first introduced:
      
      * Initially:
      
      struct memcg_cache_params {
      	bool is_root_cache;
      	union {
      		struct kmem_cache *memcg_caches[0];
      		struct {
      			struct mem_cgroup *memcg;
      			struct list_head list;
      			struct kmem_cache *root_cache;
      			bool dead;
      			atomic_t nr_pages;
      			struct work_struct destroy;
      		};
      	};
      };
      
      * Now:
      
      struct memcg_cache_params {
      	bool is_root_cache;
      	union {
      		struct {
      			struct rcu_head rcu_head;
      			struct kmem_cache *memcg_caches[0];
      		};
      		struct {
      			struct mem_cgroup *memcg;
      			struct kmem_cache *root_cache;
      		};
      	};
      };
      
      So the memory saving does not seem to be a clear win anymore.
      
      OTOH, keeping a pointer to memcg_cache_params struct instead of embedding
      it results in touching one more cache line on kmem alloc/free hot paths.
      Besides, it makes linking kmem caches in a list chained by a field of
      struct memcg_cache_params really painful due to a level of indirection,
      while I want to make them linked in the following patch.  That said, let
      us embed it.
      
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Dan Carpenter <dan.carpenter@oracle.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f7ce3190
    • Vladimir Davydov's avatar
      memcg: add rwsem to synchronize against memcg_caches arrays relocation · 05257a1a
      Vladimir Davydov authored
      
      
      We need a stable value of memcg_nr_cache_ids in kmem_cache_create()
      (memcg_alloc_cache_params() wants it for root caches), where we only
      hold the slab_mutex and no memcg-related locks.  As a result, we have to
      update memcg_nr_cache_ids under the slab_mutex, which we can only take
      on the slab's side (see memcg_update_array_size).  This looks awkward
      and will become even worse when per-memcg list_lru is introduced, which
      also wants stable access to memcg_nr_cache_ids.
      
      To get rid of this dependency between the memcg_nr_cache_ids and the
      slab_mutex, this patch introduces a special rwsem.  The rwsem is held
      for writing during memcg_caches arrays relocation and memcg_nr_cache_ids
      updates.  Therefore one can take it for reading to get a stable access
      to memcg_caches arrays and/or memcg_nr_cache_ids.
      
      Currently the semaphore is taken for reading only from
      kmem_cache_create, right before taking the slab_mutex, so right now
      there's no much point in using rwsem instead of mutex.  However, once
      list_lru is made per-memcg it will allow list_lru initializations to
      proceed concurrently.
      
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: Glauber Costa <glommer@gmail.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      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: Tejun Heo <tj@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      05257a1a
    • Vladimir Davydov's avatar
      memcg: rename some cache id related variables · dbcf73e2
      Vladimir Davydov authored
      
      
      memcg_limited_groups_array_size, which defines the size of memcg_caches
      arrays, sounds rather cumbersome.  Also it doesn't point anyhow that
      it's related to kmem/caches stuff.  So let's rename it to
      memcg_nr_cache_ids.  It's concise and points us directly to
      memcg_cache_id.
      
      Also, rename kmem_limited_groups to memcg_cache_ida.
      
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: Glauber Costa <glommer@gmail.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      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: Tejun Heo <tj@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      dbcf73e2
  10. 10 Feb, 2015 3 commits
  11. 11 Dec, 2014 3 commits
    • Vladimir Davydov's avatar
      memcg: use generic slab iterators for showing slabinfo · b047501c
      Vladimir Davydov authored
      
      
      Let's use generic slab_start/next/stop for showing memcg caches info.  In
      contrast to the current implementation, this will work even if all memcg
      caches' info doesn't fit into a seq buffer (a page), plus it simply looks
      neater.
      
      Actually, the main reason I do this isn't mere cleanup.  I'm going to zap
      the memcg_slab_caches list, because I find it useless provided we have the
      slab_caches list, and this patch is a step in this direction.
      
      It should be noted that before this patch an attempt to read
      memory.kmem.slabinfo of a cgroup that doesn't have kmem limit set resulted
      in -EIO, while after this patch it will silently show nothing except the
      header, but I don't think it will frustrate anyone.
      
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.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: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b047501c
    • Joonsoo Kim's avatar
      mm/slab: reverse iteration on find_mergeable() · 54362057
      Joonsoo Kim authored
      Unlike SLUB, sometimes, object isn't started at the beginning of the slab
      in the SLAB.  This causes the unalignment problem when after slab merging
      is supported by commit 12220dea
      
       ("mm/slab: support slab merge").
      Alignment mismatch check is introduced ("mm/slab: fix unalignment problem
      on Malta with EVA due to slab merge") to prevent merge in this case.
      
      This causes undesirable result that merging happens between infrequently
      used kmem_caches if there are kmem_caches with same size and is 256 bytes,
      are merged into pool_workqueue rather than kmalloc-256, because
      kmem_caches for kmalloc are at the tail of the list.
      
      To prevent this situation, this patch reverses iteration order in
      find_mergeable() to find frequently used kmem_caches.  This change helps
      to merge kmem_cache to frequently used kmem_caches, such as kmalloc
      kmem_caches.
      
      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>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      54362057
    • Vladimir Davydov's avatar
      slab: print slabinfo header in seq show · 1df3b26f
      Vladimir Davydov authored
      
      
      Currently we print the slabinfo header in the seq start method, which
      makes it unusable for showing leaks, so we have leaks_show, which does
      practically the same as s_show except it doesn't show the header.
      
      However, we can print the header in the seq show method - we only need
      to check if the current element is the first on the list.  This will
      allow us to use the same set of seq iterators for both leaks and
      slabinfo reporting, which is nice.
      
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.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: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      1df3b26f
  12. 14 Nov, 2014 1 commit
    • Joonsoo Kim's avatar
      mm/slab: fix unalignment problem on Malta with EVA due to slab merge · 95069ac8
      Joonsoo Kim authored
      Unlike SLUB, sometimes, object isn't started at the beginning of the
      slab in SLAB.  This causes the unalignment problem after slab merging is
      supported by commit 12220dea ("mm/slab: support slab merge").
      
      Following is the report from Markos that fail to boot on Malta with EVA.
      
          Calibrating delay loop... 19.86 BogoMIPS (lpj=99328)
          pid_max: default: 32768 minimum: 301
          Mount-cache hash table entries: 4096 (order: 0, 16384 bytes)
          Mountpoint-cache hash table entries: 4096 (order: 0, 16384 bytes)
          Kernel bug detected[#1]:
          CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.17.0-05639-g12220dea
      
       #1631
          task: 1f04f5d8 ti: 1f050000 task.ti: 1f050000
          epc   : 80141190 alloc_unbound_pwq+0x234/0x304
              Not tainted
          ra    : 80141184 alloc_unbound_pwq+0x228/0x304
          Process swapper/0 (pid: 1, threadinfo=1f050000, task=1f04f5d8, tls=00000000)
          Call Trace:
            alloc_unbound_pwq+0x234/0x304
            apply_workqueue_attrs+0x11c/0x294
            __alloc_workqueue_key+0x23c/0x470
            init_workqueues+0x320/0x400
            do_one_initcall+0xe8/0x23c
            kernel_init_freeable+0x9c/0x224
            kernel_init+0x10/0x100
            ret_from_kernel_thread+0x14/0x1c
          [ end trace cb88537fdc8fa200 ]
          Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
      
      alloc_unbound_pwq() allocates slab object from pool_workqueue.  This
      kmem_cache requires 256 bytes alignment, but, current merging code
      doesn't honor that, and merge it with kmalloc-256.  kmalloc-256 requires
      only cacheline size alignment so that above failure occurs.  However, in
      x86, kmalloc-256 is luckily aligned in 256 bytes, so the problem didn't
      happen on it.
      
      To fix this problem, this patch introduces alignment mismatch check in
      find_mergeable().  This will fix the problem.
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
      Reported-by: default avatarMarkos Chandras <Markos.Chandras@imgtec.com>
      Tested-by: default avatarMarkos Chandras <Markos.Chandras@imgtec.com>
      Acked-by: default avatarChristoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      95069ac8
  13. 29 Oct, 2014 1 commit
    • Mikulas Patocka's avatar
      mm/slab_common: don't check for duplicate cache names · 8aba7e0a
      Mikulas Patocka authored
      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 69461747 ("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
      12220dea
      
       ("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: default avatarMikulas Patocka <mpatocka@redhat.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>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8aba7e0a
  14. 10 Oct, 2014 5 commits
    • Vladimir Davydov's avatar
      memcg: move memcg_update_cache_size() to slab_common.c · 6f817f4c
      Vladimir Davydov authored
      
      
      `While growing per memcg caches arrays, we jump between memcontrol.c and
      slab_common.c in a weird way:
      
        memcg_alloc_cache_id - memcontrol.c
          memcg_update_all_caches - slab_common.c
            memcg_update_cache_size - memcontrol.c
      
      There's absolutely no reason why memcg_update_cache_size can't live on the
      slab's side though.  So let's move it there and settle it comfortably amid
      per-memcg cache allocation functions.
      
      Besides, this patch cleans this function up a bit, removing all the
      useless comments from it, and renames it to memcg_update_cache_params to
      conform to memcg_alloc/free_cache_params, which we already have in
      slab_common.c.
      
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Glauber Costa <glommer@gmail.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6f817f4c
    • Vladimir Davydov's avatar
      memcg: move memcg_{alloc,free}_cache_params to slab_common.c · 33a690c4
      Vladimir Davydov authored
      
      
      The only reason why they live in memcontrol.c is that we get/put css
      reference to the owner memory cgroup in them.  However, we can do that in
      memcg_{un,}register_cache.  OTOH, there are several reasons to move them
      to slab_common.c.
      
      First, I think that the less public interface functions we have in
      memcontrol.h the better.  Since the functions I move don't depend on
      memcontrol, I think it's worth making them private to slab, especially
      taking into account that the arrays are defined on the slab's side too.
      
      Second, the way how per-memcg arrays are updated looks rather awkward: it
      proceeds from memcontrol.c (__memcg_activate_kmem) to slab_common.c
      (memcg_update_all_caches) and back to memcontrol.c again
      (memcg_update_array_size).  In the following patches I move the function
      relocating the arrays (memcg_update_array_size) to slab_common.c and
      therefore get rid this circular call path.  I think we should have the
      cache allocation stuff in the same place where we have relocation, because
      it's easier to follow the code then.  So I move arrays alloc/free
      functions to slab_common.c too.
      
      The third point isn't obvious.  I'm going to make the list_lru structure
      per-memcg to allow targeted kmem reclaim.  That means we will have
      per-memcg arrays in list_lrus too.  It turns out that it's much easier to
      update these arrays in list_lru.c rather than in memcontrol.c, because all
      the stuff we need is defined there.  This patch makes memcg caches arrays
      allocation path conform that of the upcoming list_lru.
      
      So let's move these functions to slab_common.c and make them static.
      
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Glauber Costa <glommer@gmail.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      33a690c4
    • Joonsoo Kim's avatar
      mm/slab_common: commonize slab merge logic · 423c929c
      Joonsoo Kim authored
      
      
      Slab merge is good feature to reduce fragmentation.  Now, it is only
      applied to SLUB, but, it would be good to apply it to SLAB.  This patch is
      preparation step to apply slab merge to SLAB by commonizing slab merge
      logic.
      
      Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Randy Dunlap <rdunlap@infradead.org>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      423c929c
    • Joonsoo Kim's avatar
      mm/slab_common: move kmem_cache definition to internal header · 07f361b2
      Joonsoo Kim authored
      
      
      We don't need to keep kmem_cache definition in include/linux/slab.h if we
      don't need to inline kmem_cache_size().  According to my code inspection,
      this function is only called at lc_create() in lib/lru_cache.c which may
      be called at initialization phase of something, so we don't need to inline
      it.  Therfore, move it to slab_common.c and move kmem_cache definition to
      internal header.
      
      After this change, we can change kmem_cache definition easily without full
      kernel build.  For instance, we can turn on/off CONFIG_SLUB_STATS without
      full kernel build.
      
      [akpm@linux-foundation.org: export kmem_cache_size() to modules]
      [rdunlap@infradead.org: add header files to fix kmemcheck.c build errors]
      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: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
      Signed-off-by: default avatarRandy Dunlap <rdunlap@infradead.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      07f361b2
    • Andrew Morton's avatar
      mm/slab_common.c: suppress warning · 3aa24f51
      Andrew Morton authored
      
      
      False positive:
      
      mm/slab_common.c: In function 'kmem_cache_create':
      mm/slab_common.c:204: warning: 's' may be used uninitialized in this function
      
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3aa24f51
  15. 07 Aug, 2014 1 commit
  16. 04 Jun, 2014 4 commits
    • Vladimir Davydov's avatar
      slab: delete cache from list after __kmem_cache_shutdown succeeds · 0bd62b11
      Vladimir Davydov authored
      Currently, on kmem_cache_destroy we delete the cache from the slab_list
      before __kmem_cache_shutdown, inserting it back to the list on failure.
      Initially, this was done, because we could release the slab_mutex in
      __kmem_cache_shutdown to delete sysfs slub entry, but since commit
      41a21285
      
       ("slub: use sysfs'es release mechanism for kmem_cache") we
      remove sysfs entry later in kmem_cache_destroy after dropping the
      slab_mutex, so that no implementation of __kmem_cache_shutdown can ever
      release the lock.  Therefore we can simplify the code a bit by moving
      list_del after __kmem_cache_shutdown.
      
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Cc: Christoph Lameter <cl@linux-foundation.org>
      Cc: Pekka Enberg <penberg@kernel.org>
      Acked-by: default avatarDavid Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0bd62b11
    • Vladimir Davydov's avatar
      memcg: cleanup kmem cache creation/destruction functions naming · 776ed0f0
      Vladimir Davydov authored
      
      
      Current names are rather inconsistent. Let's try to improve them.
      
      Brief change log:
      
      ** old name **                          ** new name **
      
      kmem_cache_create_memcg                 memcg_create_kmem_cache
      memcg_kmem_create_cache                 memcg_regsiter_cache
      memcg_kmem_destroy_cache                memcg_unregister_cache
      
      kmem_cache_destroy_memcg_children       memcg_cleanup_cache_params
      mem_cgroup_destroy_all_caches           memcg_unregister_all_caches
      
      create_work                             memcg_register_cache_work
      memcg_create_cache_work_func            memcg_register_cache_func
      memcg_create_cache_enqueue              memcg_schedule_register_cache
      
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      776ed0f0
    • Vladimir Davydov's avatar
      memcg: get rid of memcg_create_cache_name · 073ee1c6
      Vladimir Davydov authored
      
      
      Instead of calling back to memcontrol.c from kmem_cache_create_memcg in
      order to just create the name of a per memcg cache, let's allocate it in
      place.  We only need to pass the memcg name to kmem_cache_create_memcg for
      that - everything else can be done in slab_common.c.
      
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      073ee1c6
    • Vladimir Davydov's avatar
      memcg, slab: simplify synchronization scheme · bd673145
      Vladimir Davydov authored
      
      
      At present, we have the following mutexes protecting data related to per
      memcg kmem caches:
      
       - slab_mutex.  This one is held during the whole kmem cache creation
         and destruction paths.  We also take it when updating per root cache
         memcg_caches arrays (see memcg_update_all_caches).  As a result, taking
         it guarantees there will be no changes to any kmem cache (including per
         memcg).  Why do we need something else then?  The point is it is
         private to slab implementation and has some internal dependencies with
         other mutexes (get_online_cpus).  So we just don't want to rely upon it
         and prefer to introduce additional mutexes instead.
      
       - activate_kmem_mutex.  Initially it was added to synchronize
         initializing kmem limit (memcg_activate_kmem).  However, since we can
         grow per root cache memcg_caches arrays only on kmem limit
         initialization (see memcg_update_all_caches), we also employ it to
         protect against memcg_caches arrays relocation (e.g.  see
         __kmem_cache_destroy_memcg_children).
      
       - We have a convention not to take slab_mutex in memcontrol.c, but we
         want to walk over per memcg memcg_slab_caches lists there (e.g.  for
         destroying all memcg caches on offline).  So we have per memcg
         slab_caches_mutex's protecting those lists.
      
      The mutexes are taken in the following order:
      
         activate_kmem_mutex -> slab_mutex -> memcg::slab_caches_mutex
      
      Such a syncrhonization scheme has a number of flaws, for instance:
      
       - We can't call kmem_cache_{destroy,shrink} while walking over a
         memcg::memcg_slab_caches list due to locking order.  As a result, in
         mem_cgroup_destroy_all_caches we schedule the
         memcg_cache_params::destroy work shrinking and destroying the cache.
      
       - We don't have a mutex to synchronize per memcg caches destruction
         between memcg offline (mem_cgroup_destroy_all_caches) and root cache
         destruction (__kmem_cache_destroy_memcg_children).  Currently we just
         don't bother about it.
      
      This patch simplifies it by substituting per memcg slab_caches_mutex's
      with the global memcg_slab_mutex.  It will be held whenever a new per
      memcg cache is created or destroyed, so it protects per root cache
      memcg_caches arrays and per memcg memcg_slab_caches lists.  The locking
      order is following:
      
         activate_kmem_mutex -> memcg_slab_mutex -> slab_mutex
      
      This allows us to call kmem_cache_{create,shrink,destroy} under the
      memcg_slab_mutex.  As a result, we don't need memcg_cache_params::destroy
      work any more - we can simply destroy caches while iterating over a per
      memcg slab caches list.
      
      Also using the global mutex simplifies synchronization between concurrent
      per memcg caches creation/destruction, e.g.  mem_cgroup_destroy_all_caches
      vs __kmem_cache_destroy_memcg_children.
      
      The downside of this is that we substitute per-memcg slab_caches_mutex's
      with a hummer-like global mutex, but since we already take either the
      slab_mutex or the cgroup_mutex along with a memcg::slab_caches_mutex, it
      shouldn't hurt concurrency a lot.
      
      Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Glauber Costa <glommer@gmail.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      bd673145