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authorVladimir Davydov <vdavydov@virtuozzo.com>2015-11-05 18:49:01 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-05 19:34:48 -0800
commitf3ccb2c42297757d2e9b820ad37960462df7b7c1 (patch)
treec7c7b8d5408338c3d364018cfaf5cb8b060f551a /mm/slab.c
parentd05e83a6f861ad02c2fcba75d4c4cfe49e3bc90f (diff)
memcg: unify slab and other kmem pages charging
We have memcg_kmem_charge and memcg_kmem_uncharge methods for charging and uncharging kmem pages to memcg, but currently they are not used for charging slab pages (i.e. they are only used for charging pages allocated with alloc_kmem_pages). The only reason why the slab subsystem uses special helpers, memcg_charge_slab and memcg_uncharge_slab, is that it needs to charge to the memcg of kmem cache while memcg_charge_kmem charges to the memcg that the current task belongs to. To remove this diversity, this patch adds an extra argument to __memcg_kmem_charge that can be a pointer to a memcg or NULL. If it is not NULL, the function tries to charge to the memcg it points to, otherwise it charge to the current context. Next, it makes the slab subsystem use this function to charge slab pages. Since memcg_charge_kmem and memcg_uncharge_kmem helpers are now used only in __memcg_kmem_charge and __memcg_kmem_uncharge, they are inlined. Since __memcg_kmem_charge stores a pointer to the memcg in the page struct, we don't need memcg_uncharge_slab anymore and can use free_kmem_pages. Besides, one can now detect which memcg a slab page belongs to by reading /proc/kpagecgroup. Note, this patch switches slab to charge-after-alloc design. Since this design is already used for all other memcg charges, it should not make any difference. [hannes@cmpxchg.org: better to have an outer function than a magic parameter for the memcg lookup] Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slab.c')
-rw-r--r--mm/slab.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/mm/slab.c b/mm/slab.c
index 461935bab9ef..272e809404d5 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1593,16 +1593,17 @@ static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
flags |= __GFP_RECLAIMABLE;
- if (memcg_charge_slab(cachep, flags, cachep->gfporder))
- return NULL;
-
page = __alloc_pages_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
if (!page) {
- memcg_uncharge_slab(cachep, cachep->gfporder);
slab_out_of_memory(cachep, flags, nodeid);
return NULL;
}
+ if (memcg_charge_slab(page, flags, cachep->gfporder, cachep)) {
+ __free_pages(page, cachep->gfporder);
+ return NULL;
+ }
+
/* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
if (page_is_pfmemalloc(page))
pfmemalloc_active = true;
@@ -1654,8 +1655,7 @@ static void kmem_freepages(struct kmem_cache *cachep, struct page *page)
if (current->reclaim_state)
current->reclaim_state->reclaimed_slab += nr_freed;
- __free_pages(page, cachep->gfporder);
- memcg_uncharge_slab(cachep, cachep->gfporder);
+ __free_kmem_pages(page, cachep->gfporder);
}
static void kmem_rcu_free(struct rcu_head *head)