From: Bharata B Rao bharata@linux.ibm.com Subject: mm: memcg/slab: uncharge during kmem_cache_free_bulk()
Object cgroup charging is done for all the objects during allocation, but during freeing, uncharging ends up happening for only one object in the case of bulk allocation/freeing.
Fix this by having a separate call to uncharge all the objects from kmem_cache_free_bulk() and by modifying memcg_slab_free_hook() to take care of bulk uncharging.
Link: https://lkml.kernel.org/r/20201009060423.390479-1-bharata@linux.ibm.com Fixes: 964d4bd370d5 ("mm: memcg/slab: save obj_cgroup for non-root slab objects" Signed-off-by: Bharata B Rao bharata@linux.ibm.com Acked-by: Roman Gushchin guro@fb.com Cc: Christoph Lameter cl@linux.com Cc: David Rientjes rientjes@google.com Cc: Joonsoo Kim iamjoonsoo.kim@lge.com Cc: Vlastimil Babka vbabka@suse.cz Cc: Shakeel Butt shakeelb@google.com Cc: Johannes Weiner hannes@cmpxchg.org Cc: Michal Hocko mhocko@kernel.org Cc: Tejun Heo tj@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
mm/slab.c | 2 +- mm/slab.h | 50 +++++++++++++++++++++++++++++++------------------- mm/slub.c | 3 ++- 3 files changed, 34 insertions(+), 21 deletions(-)
--- a/mm/slab.c~mm-memcg-slab-uncharge-during-kmem_cache_free_bulk +++ a/mm/slab.c @@ -3438,7 +3438,7 @@ void ___cache_free(struct kmem_cache *ca memset(objp, 0, cachep->object_size); kmemleak_free_recursive(objp, cachep->flags); objp = cache_free_debugcheck(cachep, objp, caller); - memcg_slab_free_hook(cachep, virt_to_head_page(objp), objp); + memcg_slab_free_hook(cachep, &objp, 1);
/* * Skip calling cache_free_alien() when the platform is not numa. --- a/mm/slab.h~mm-memcg-slab-uncharge-during-kmem_cache_free_bulk +++ a/mm/slab.h @@ -345,30 +345,42 @@ static inline void memcg_slab_post_alloc obj_cgroup_put(objcg); }
-static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page, - void *p) +static inline void memcg_slab_free_hook(struct kmem_cache *s_orig, + void **p, int objects) { + struct kmem_cache *s; struct obj_cgroup *objcg; + struct page *page; unsigned int off; + int i;
if (!memcg_kmem_enabled()) return;
- if (!page_has_obj_cgroups(page)) - return; - - off = obj_to_index(s, page, p); - objcg = page_obj_cgroups(page)[off]; - page_obj_cgroups(page)[off] = NULL; - - if (!objcg) - return; - - obj_cgroup_uncharge(objcg, obj_full_size(s)); - mod_objcg_state(objcg, page_pgdat(page), cache_vmstat_idx(s), - -obj_full_size(s)); - - obj_cgroup_put(objcg); + for (i = 0; i < objects; i++) { + if (unlikely(!p[i])) + continue; + + page = virt_to_head_page(p[i]); + if (!page_has_obj_cgroups(page)) + continue; + + if (!s_orig) + s = page->slab_cache; + else + s = s_orig; + + off = obj_to_index(s, page, p[i]); + objcg = page_obj_cgroups(page)[off]; + if (!objcg) + continue; + + page_obj_cgroups(page)[off] = NULL; + obj_cgroup_uncharge(objcg, obj_full_size(s)); + mod_objcg_state(objcg, page_pgdat(page), cache_vmstat_idx(s), + -obj_full_size(s)); + obj_cgroup_put(objcg); + } }
#else /* CONFIG_MEMCG_KMEM */ @@ -406,8 +418,8 @@ static inline void memcg_slab_post_alloc { }
-static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page, - void *p) +static inline void memcg_slab_free_hook(struct kmem_cache *s, + void **p, int objects) { } #endif /* CONFIG_MEMCG_KMEM */ --- a/mm/slub.c~mm-memcg-slab-uncharge-during-kmem_cache_free_bulk +++ a/mm/slub.c @@ -3095,7 +3095,7 @@ static __always_inline void do_slab_free struct kmem_cache_cpu *c; unsigned long tid;
- memcg_slab_free_hook(s, page, head); + memcg_slab_free_hook(s, &head, 1); redo: /* * Determine the currently cpus per cpu slab. @@ -3257,6 +3257,7 @@ void kmem_cache_free_bulk(struct kmem_ca if (WARN_ON(!size)) return;
+ memcg_slab_free_hook(s, p, size); do { struct detached_freelist df;
_