From 10befea91b61c4e2c2d1df06a2e978d182fcf792 Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Thu, 6 Aug 2020 23:21:27 -0700 Subject: mm: memcg/slab: use a single set of kmem_caches for all allocations Instead of having two sets of kmem_caches: one for system-wide and non-accounted allocations and the second one shared by all accounted allocations, we can use just one. The idea is simple: space for obj_cgroup metadata can be allocated on demand and filled only for accounted allocations. It allows to remove a bunch of code which is required to handle kmem_cache clones for accounted allocations. There is no more need to create them, accumulate statistics, propagate attributes, etc. It's a quite significant simplification. Also, because the total number of slab_caches is reduced almost twice (not all kmem_caches have a memcg clone), some additional memory savings are expected. On my devvm it additionally saves about 3.5% of slab memory. [guro@fb.com: fix build on MIPS] Link: http://lkml.kernel.org/r/20200717214810.3733082-1-guro@fb.com Suggested-by: Johannes Weiner Signed-off-by: Roman Gushchin Signed-off-by: Andrew Morton Reviewed-by: Vlastimil Babka Reviewed-by: Shakeel Butt Cc: Christoph Lameter Cc: Michal Hocko Cc: Tejun Heo Cc: Naresh Kamboju Link: http://lkml.kernel.org/r/20200623174037.3951353-18-guro@fb.com Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) (limited to 'mm/memcontrol.c') diff --git a/mm/memcontrol.c b/mm/memcontrol.c index a8113b77b23a..473f9b91d51f 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2800,6 +2800,26 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg) } #ifdef CONFIG_MEMCG_KMEM +int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s, + gfp_t gfp) +{ + unsigned int objects = objs_per_slab_page(s, page); + void *vec; + + vec = kcalloc_node(objects, sizeof(struct obj_cgroup *), gfp, + page_to_nid(page)); + if (!vec) + return -ENOMEM; + + if (cmpxchg(&page->obj_cgroups, NULL, + (struct obj_cgroup **) ((unsigned long)vec | 0x1UL))) + kfree(vec); + else + kmemleak_not_leak(vec); + + return 0; +} + /* * Returns a pointer to the memory cgroup to which the kernel object is charged. * @@ -2826,7 +2846,10 @@ struct mem_cgroup *mem_cgroup_from_obj(void *p) off = obj_to_index(page->slab_cache, page, p); objcg = page_obj_cgroups(page)[off]; - return obj_cgroup_memcg(objcg); + if (objcg) + return obj_cgroup_memcg(objcg); + + return NULL; } /* All other pages use page->mem_cgroup */ -- cgit v1.2.3