From 964d4bd370d559d9bd8e4abc139e85d2753956fb Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Thu, 6 Aug 2020 23:20:56 -0700 Subject: mm: memcg/slab: save obj_cgroup for non-root slab objects Store the obj_cgroup pointer in the corresponding place of page->obj_cgroups for each allocated non-root slab object. Make sure that each allocated object holds a reference to obj_cgroup. Objcg pointer is obtained from the memcg->objcg dereferencing in memcg_kmem_get_cache() and passed from pre_alloc_hook to post_alloc_hook. Then in case of successful allocation(s) it's getting stored in the page->obj_cgroups vector. The objcg obtaining part look a bit bulky now, but it will be simplified by next commits in the series. Signed-off-by: Roman Gushchin Signed-off-by: Andrew Morton Reviewed-by: Vlastimil Babka Reviewed-by: Shakeel Butt Cc: Christoph Lameter Cc: Johannes Weiner Cc: Michal Hocko Cc: Tejun Heo Link: http://lkml.kernel.org/r/20200623174037.3951353-9-guro@fb.com Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'mm/memcontrol.c') diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e6cd4c0d44d1..ab96a120e630 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2973,7 +2973,8 @@ static inline bool memcg_kmem_bypass(void) * done with it, memcg_kmem_put_cache() must be called to release the * reference. */ -struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep) +struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep, + struct obj_cgroup **objcgp) { struct mem_cgroup *memcg; struct kmem_cache *memcg_cachep; @@ -3029,8 +3030,17 @@ struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep) */ if (unlikely(!memcg_cachep)) memcg_schedule_kmem_cache_create(memcg, cachep); - else if (percpu_ref_tryget(&memcg_cachep->memcg_params.refcnt)) + else if (percpu_ref_tryget(&memcg_cachep->memcg_params.refcnt)) { + struct obj_cgroup *objcg = rcu_dereference(memcg->objcg); + + if (!objcg || !obj_cgroup_tryget(objcg)) { + percpu_ref_put(&memcg_cachep->memcg_params.refcnt); + goto out_unlock; + } + + *objcgp = objcg; cachep = memcg_cachep; + } out_unlock: rcu_read_unlock(); return cachep; -- cgit v1.2.3