[obsolete] slub-track-number-of-slabs-irrespective-of-config_slub_debug.patch removed from -mm tree
From: akpm@linux-foundation.org
Date: 2018-07-27 00:46:30
The patch titled
Subject: slub: track number of slabs irrespective of CONFIG_SLUB_DEBUG
has been removed from the -mm tree. Its filename was
slub-track-number-of-slabs-irrespective-of-config_slub_debug.patch
This patch was dropped because it is obsolete
------------------------------------------------------
From: Shakeel Butt <redacted>
Subject: slub: track number of slabs irrespective of CONFIG_SLUB_DEBUG
For !CONFIG_SLUB_DEBUG, SLUB does not maintain the number of slabs
allocated per node for a kmem_cache. Thus, slabs_node() in
__kmem_cache_empty(), __kmem_cache_shrink() and __kmem_cache_destroy()
will always return 0 for such config. This is wrong and can cause issues
for all users of these functions.
In fact in [1] Jason has reported a system crash while using SLUB without
CONFIG_SLUB_DEBUG. The reason was the usage of slabs_node() by
__kmem_cache_empty().
The right solution is to make slabs_node() work even for
!CONFIG_SLUB_DEBUG. The commit 0f389ec63077 ("slub: No need for per node
slab counters if !SLUB_DEBUG") had put the per node slab counter under
CONFIG_SLUB_DEBUG because it was only read through sysfs API and the sysfs
API was disabled on !CONFIG_SLUB_DEBUG. However the users of the per node
slab counter assumed that it will work in the absence of
CONFIG_SLUB_DEBUG. So, make the counter work for !CONFIG_SLUB_DEBUG.
Please note that f9e13c0a5a33 ("slab, slub: skip unnecessary
kasan_cache_shutdown()") exposed this issue but it is present even before.
[1] http://lkml.kernel.org/r/CAHmME9rtoPwxUSnktxzKso14iuVCWT7BE_-_8PAC=pGw1iJnQg@mail.gmail.com
Link: http://lkml.kernel.org/r/20180620224147.23777-1-shakeelb@google.com
Fixes: f9e13c0a5a33 ("slab, slub: skip unnecessary kasan_cache_shutdown()")
Signed-off-by: Shakeel Butt <redacted>
Suggested-by: David Rientjes <rientjes@google.com>
Reported-by: Jason A . Donenfeld <Jason@zx2c4.com>
Cc: Christoph Lameter <redacted>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <redacted>
Cc: Andrey Ryabinin <redacted>
Cc: <redacted>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/slab.h | 2 -
mm/slub.c | 80 ++++++++++++++++++++++++----------------------------
2 files changed, 38 insertions(+), 44 deletions(-)
diff -puN mm/slab.h~slub-track-number-of-slabs-irrespective-of-config_slub_debug mm/slab.h--- a/mm/slab.h~slub-track-number-of-slabs-irrespective-of-config_slub_debug
+++ a/mm/slab.h@@ -473,8 +473,8 @@ struct kmem_cache_node { #ifdef CONFIG_SLUB unsigned long nr_partial; struct list_head partial; -#ifdef CONFIG_SLUB_DEBUG atomic_long_t nr_slabs; +#ifdef CONFIG_SLUB_DEBUG atomic_long_t total_objects; struct list_head full; #endif
diff -puN mm/slub.c~slub-track-number-of-slabs-irrespective-of-config_slub_debug mm/slub.c
--- a/mm/slub.c~slub-track-number-of-slabs-irrespective-of-config_slub_debug
+++ a/mm/slub.c@@ -1030,42 +1030,6 @@ static void remove_full(struct kmem_cach list_del(&page->lru); } -/* Tracking of the number of slabs for debugging purposes */ -static inline unsigned long slabs_node(struct kmem_cache *s, int node) -{ - struct kmem_cache_node *n = get_node(s, node); - - return atomic_long_read(&n->nr_slabs); -} - -static inline unsigned long node_nr_slabs(struct kmem_cache_node *n) -{ - return atomic_long_read(&n->nr_slabs); -} - -static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects) -{ - struct kmem_cache_node *n = get_node(s, node); - - /* - * May be called early in order to allocate a slab for the - * kmem_cache_node structure. Solve the chicken-egg - * dilemma by deferring the increment of the count during - * bootstrap (see early_kmem_cache_node_alloc). - */ - if (likely(n)) { - atomic_long_inc(&n->nr_slabs); - atomic_long_add(objects, &n->total_objects); - } -} -static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects) -{ - struct kmem_cache_node *n = get_node(s, node); - - atomic_long_dec(&n->nr_slabs); - atomic_long_sub(objects, &n->total_objects); -} - /* Object debug checks for alloc/free paths */ static void setup_object_debug(struct kmem_cache *s, struct page *page, void *object)
@@ -1321,16 +1285,46 @@ slab_flags_t kmem_cache_flags(unsigned i #define disable_higher_order_debug 0 +#endif /* CONFIG_SLUB_DEBUG */ + static inline unsigned long slabs_node(struct kmem_cache *s, int node) - { return 0; } +{ + struct kmem_cache_node *n = get_node(s, node); + + return atomic_long_read(&n->nr_slabs); +} + static inline unsigned long node_nr_slabs(struct kmem_cache_node *n) - { return 0; } -static inline void inc_slabs_node(struct kmem_cache *s, int node, - int objects) {} -static inline void dec_slabs_node(struct kmem_cache *s, int node, - int objects) {} +{ + return atomic_long_read(&n->nr_slabs); +} -#endif /* CONFIG_SLUB_DEBUG */ +static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects) +{ + struct kmem_cache_node *n = get_node(s, node); + + /* + * May be called early in order to allocate a slab for the + * kmem_cache_node structure. Solve the chicken-egg + * dilemma by deferring the increment of the count during + * bootstrap (see early_kmem_cache_node_alloc). + */ + if (likely(n)) { + atomic_long_inc(&n->nr_slabs); +#ifdef CONFIG_SLUB_DEBUG + atomic_long_add(objects, &n->total_objects); +#endif + } +} +static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects) +{ + struct kmem_cache_node *n = get_node(s, node); + + atomic_long_dec(&n->nr_slabs); +#ifdef CONFIG_SLUB_DEBUG + atomic_long_sub(objects, &n->total_objects); +#endif +} /* * Hooks for other subsystems that check memory allocations. In a typical
_ Patches currently in -mm which might be from shakeelb@google.com are kvm-mm-account-shadow-page-tables-to-kmemcg.patch fs-fsnotify-account-fsnotify-metadata-to-kmemcg.patch fs-fsnotify-account-fsnotify-metadata-to-kmemcg-fix.patch fs-mm-account-buffer_head-to-kmemcg.patch fs-mm-account-buffer_head-to-kmemcgpatchfix.patch memcg-reduce-memcg-tree-traversals-for-stats-collection.patch