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Commit b9ce5ef4 authored by Glauber Costa's avatar Glauber Costa Committed by Linus Torvalds
Browse files

sl[au]b: always get the cache from its page in kmem_cache_free() 



struct page already has this information.  If we start chaining caches,
this information will always be more trustworthy than whatever is passed
into the function.

Signed-off-by: default avatarGlauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.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>
parent 0e9d92f2

include/linux/memcontrol.h

+5 −0
Original line number Diff line number Diff line
@@ -554,6 +554,11 @@ memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp) 
	return __memcg_kmem_get_cache(cachep, gfp);

}

#else

static inline bool memcg_kmem_enabled(void)

{

	return false;

}



static inline bool

memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg, int order)

{

mm/slab.c

+5 −1
Original line number Diff line number Diff line
@@ -87,7 +87,6 @@ 
 */



#include	<linux/slab.h>

#include	"slab.h"

#include	<linux/mm.h>

#include	<linux/poison.h>

#include	<linux/swap.h>
@@ -128,6 +127,8 @@ 


#include	"internal.h"



#include	"slab.h"



/*

 * DEBUG	- 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON.

 *		  0 for faster, smaller code (especially in the critical paths).
@@ -3883,6 +3884,9 @@ EXPORT_SYMBOL(__kmalloc); 
void kmem_cache_free(struct kmem_cache *cachep, void *objp)

{

	unsigned long flags;

	cachep = cache_from_obj(cachep, objp);

	if (!cachep)

		return;



	local_irq_save(flags);

	debug_check_no_locks_freed(objp, cachep->object_size);

mm/slab.h

+39 −0
Original line number Diff line number Diff line
@@ -116,6 +116,13 @@ static inline bool cache_match_memcg(struct kmem_cache *cachep, 
	return (is_root_cache(cachep) && !memcg) ||

				(cachep->memcg_params->memcg == memcg);

}



static inline bool slab_equal_or_root(struct kmem_cache *s,

					struct kmem_cache *p)

{

	return (p == s) ||

		(s->memcg_params && (p == s->memcg_params->root_cache));

}

#else

static inline bool is_root_cache(struct kmem_cache *s)

{
@@ -127,5 +134,37 @@ static inline bool cache_match_memcg(struct kmem_cache *cachep, 
{

	return true;

}



static inline bool slab_equal_or_root(struct kmem_cache *s,

				      struct kmem_cache *p)

{

	return true;

}

#endif



static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)

{

	struct kmem_cache *cachep;

	struct page *page;



	/*

	 * When kmemcg is not being used, both assignments should return the

	 * same value. but we don't want to pay the assignment price in that

	 * case. If it is not compiled in, the compiler should be smart enough

	 * to not do even the assignment. In that case, slab_equal_or_root

	 * will also be a constant.

	 */

	if (!memcg_kmem_enabled() && !unlikely(s->flags & SLAB_DEBUG_FREE))

		return s;



	page = virt_to_head_page(x);

	cachep = page->slab_cache;

	if (slab_equal_or_root(cachep, s))

		return cachep;



	pr_err("%s: Wrong slab cache. %s but object is from %s\n",

		__FUNCTION__, cachep->name, s->name);

	WARN_ON_ONCE(1);

	return s;

}

#endif

mm/slob.c

+1 −1
Original line number Diff line number Diff line
@@ -58,7 +58,6 @@ 


#include <linux/kernel.h>

#include <linux/slab.h>

#include "slab.h"



#include <linux/mm.h>

#include <linux/swap.h> /* struct reclaim_state */
@@ -73,6 +72,7 @@ 


#include <linux/atomic.h>



#include "slab.h"

/*

 * slob_block has a field 'units', which indicates size of block if +ve,

 * or offset of next block if -ve (in SLOB_UNITs).

mm/slub.c

+3 −12
Original line number Diff line number Diff line
@@ -2611,19 +2611,10 @@ static __always_inline void slab_free(struct kmem_cache *s, 


void kmem_cache_free(struct kmem_cache *s, void *x)

{

	struct page *page;



	page = virt_to_head_page(x);



	if (kmem_cache_debug(s) && page->slab_cache != s) {

		pr_err("kmem_cache_free: Wrong slab cache. %s but object"

			" is from  %s\n", page->slab_cache->name, s->name);

		WARN_ON_ONCE(1);

	s = cache_from_obj(s, x);

	if (!s)

		return;

	}



	slab_free(s, page, x, _RET_IP_);



	slab_free(s, virt_to_head_page(x), x, _RET_IP_);

	trace_kmem_cache_free(_RET_IP_, x);

}

EXPORT_SYMBOL(kmem_cache_free);