The patch titled
Subject: sl[au]b: always get the cache from its page in kmem_cache_free()
has been added to the -mm tree. Its filename is
slb-always-get-the-cache-from-its-page-in-kmem_cache_free.patch
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------------------------------------------------------
From: Glauber Costa <glommer@xxxxxxxxxxxxx>
Subject: 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: Glauber Costa <glommer@xxxxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxxx>
Cc: Greg Thelen <gthelen@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: JoonSoo Kim <js1304@xxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Suleiman Souhlal <suleiman@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 5 ++++
mm/slab.c | 6 ++++-
mm/slab.h | 39 +++++++++++++++++++++++++++++++++++
mm/slob.c | 2 -
mm/slub.c | 15 ++-----------
5 files changed, 53 insertions(+), 14 deletions(-)
diff -puN include/linux/memcontrol.h~slb-always-get-the-cache-from-its-page-in-kmem_cache_free include/linux/memcontrol.h
--- a/include/linux/memcontrol.h~slb-always-get-the-cache-from-its-page-in-kmem_cache_free
+++ a/include/linux/memcontrol.h
@@ -547,6 +547,11 @@ memcg_kmem_get_cache(struct kmem_cache *
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)
{
diff -puN mm/slab.c~slb-always-get-the-cache-from-its-page-in-kmem_cache_free mm/slab.c
--- a/mm/slab.c~slb-always-get-the-cache-from-its-page-in-kmem_cache_free
+++ a/mm/slab.c
@@ -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).
@@ -3938,6 +3939,9 @@ 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);
diff -puN mm/slab.h~slb-always-get-the-cache-from-its-page-in-kmem_cache_free mm/slab.h
--- a/mm/slab.h~slb-always-get-the-cache-from-its-page-in-kmem_cache_free
+++ a/mm/slab.h
@@ -108,6 +108,13 @@ static inline bool cache_match_memcg(str
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)
{
@@ -119,5 +126,37 @@ static inline bool cache_match_memcg(str
{
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
diff -puN mm/slob.c~slb-always-get-the-cache-from-its-page-in-kmem_cache_free mm/slob.c
--- a/mm/slob.c~slb-always-get-the-cache-from-its-page-in-kmem_cache_free
+++ a/mm/slob.c
@@ -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).
diff -puN mm/slub.c~slb-always-get-the-cache-from-its-page-in-kmem_cache_free mm/slub.c
--- a/mm/slub.c~slb-always-get-the-cache-from-its-page-in-kmem_cache_free
+++ a/mm/slub.c
@@ -2611,19 +2611,10 @@ redo:
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);
_
Patches currently in -mm which might be from glommer@xxxxxxxxxxxxx are
linux-next.patch
memcg-make-it-possible-to-use-the-stock-for-more-than-one-page.patch
memcg-reclaim-when-more-than-one-page-needed.patch
memcg-change-defines-to-an-enum.patch
memcg-kmem-accounting-basic-infrastructure.patch
mm-add-a-__gfp_kmemcg-flag.patch
memcg-kmem-controller-infrastructure.patch
mm-allocate-kernel-pages-to-the-right-memcg.patch
res_counter-return-amount-of-charges-after-res_counter_uncharge.patch
memcg-kmem-accounting-lifecycle-management.patch
memcg-use-static-branches-when-code-not-in-use.patch
memcg-allow-a-memcg-with-kmem-charges-to-be-destructed.patch
memcg-execute-the-whole-memcg-freeing-in-free_worker.patch
fork-protect-architectures-where-thread_size-=-page_size-against-fork-bombs.patch
memcg-add-documentation-about-the-kmem-controller.patch
slab-slub-struct-memcg_params.patch
slab-annotate-on-slab-caches-nodelist-locks.patch
slab-slub-consider-a-memcg-parameter-in-kmem_create_cache.patch
memcg-allocate-memory-for-memcg-caches-whenever-a-new-memcg-appears.patch
memcg-infrastructure-to-match-an-allocation-to-the-right-cache.patch
memcg-skip-memcg-kmem-allocations-in-specified-code-regions.patch
slb-always-get-the-cache-from-its-page-in-kmem_cache_free.patch
slb-allocate-objects-from-memcg-cache.patch
memcg-destroy-memcg-caches.patch
memcg-slb-track-all-the-memcg-children-of-a-kmem_cache.patch
memcg-slb-shrink-dead-caches.patch
memcg-aggregate-memcg-cache-values-in-slabinfo.patch
slab-propagate-tunable-values.patch
slub-slub-specific-propagation-changes.patch
kmem-add-slab-specific-documentation-about-the-kmem-controller.patch
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