From: Roman Gushchin <guro@xxxxxx> 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. Link: http://lkml.kernel.org/r/20200623174037.3951353-9-guro@xxxxxx Signed-off-by: Roman Gushchin <guro@xxxxxx> Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx> Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/memcontrol.h | 3 + mm/memcontrol.c | 14 +++++++- mm/slab.c | 18 ++++++---- mm/slab.h | 60 +++++++++++++++++++++++++++++++---- mm/slub.c | 14 +++++--- 5 files changed, 88 insertions(+), 21 deletions(-) --- a/include/linux/memcontrol.h~mm-memcg-slab-save-obj_cgroup-for-non-root-slab-objects +++ a/include/linux/memcontrol.h @@ -1404,7 +1404,8 @@ static inline void memcg_set_shrinker_bi } #endif -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); void memcg_kmem_put_cache(struct kmem_cache *cachep); #ifdef CONFIG_MEMCG_KMEM --- a/mm/memcontrol.c~mm-memcg-slab-save-obj_cgroup-for-non-root-slab-objects +++ a/mm/memcontrol.c @@ -2973,7 +2973,8 @@ static inline bool memcg_kmem_bypass(voi * 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( */ 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; --- a/mm/slab.c~mm-memcg-slab-save-obj_cgroup-for-non-root-slab-objects +++ a/mm/slab.c @@ -3228,9 +3228,10 @@ slab_alloc_node(struct kmem_cache *cache unsigned long save_flags; void *ptr; int slab_node = numa_mem_id(); + struct obj_cgroup *objcg = NULL; flags &= gfp_allowed_mask; - cachep = slab_pre_alloc_hook(cachep, flags); + cachep = slab_pre_alloc_hook(cachep, &objcg, 1, flags); if (unlikely(!cachep)) return NULL; @@ -3266,7 +3267,7 @@ slab_alloc_node(struct kmem_cache *cache if (unlikely(slab_want_init_on_alloc(flags, cachep)) && ptr) memset(ptr, 0, cachep->object_size); - slab_post_alloc_hook(cachep, flags, 1, &ptr); + slab_post_alloc_hook(cachep, objcg, flags, 1, &ptr); return ptr; } @@ -3307,9 +3308,10 @@ slab_alloc(struct kmem_cache *cachep, gf { unsigned long save_flags; void *objp; + struct obj_cgroup *objcg = NULL; flags &= gfp_allowed_mask; - cachep = slab_pre_alloc_hook(cachep, flags); + cachep = slab_pre_alloc_hook(cachep, &objcg, 1, flags); if (unlikely(!cachep)) return NULL; @@ -3323,7 +3325,7 @@ slab_alloc(struct kmem_cache *cachep, gf if (unlikely(slab_want_init_on_alloc(flags, cachep)) && objp) memset(objp, 0, cachep->object_size); - slab_post_alloc_hook(cachep, flags, 1, &objp); + slab_post_alloc_hook(cachep, objcg, flags, 1, &objp); return objp; } @@ -3450,6 +3452,7 @@ 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); /* * Skip calling cache_free_alien() when the platform is not numa. @@ -3515,8 +3518,9 @@ int kmem_cache_alloc_bulk(struct kmem_ca void **p) { size_t i; + struct obj_cgroup *objcg = NULL; - s = slab_pre_alloc_hook(s, flags); + s = slab_pre_alloc_hook(s, &objcg, size, flags); if (!s) return 0; @@ -3539,13 +3543,13 @@ int kmem_cache_alloc_bulk(struct kmem_ca for (i = 0; i < size; i++) memset(p[i], 0, s->object_size); - slab_post_alloc_hook(s, flags, size, p); + slab_post_alloc_hook(s, objcg, flags, size, p); /* FIXME: Trace call missing. Christoph would like a bulk variant */ return size; error: local_irq_enable(); cache_alloc_debugcheck_after_bulk(s, flags, i, p, _RET_IP_); - slab_post_alloc_hook(s, flags, i, p); + slab_post_alloc_hook(s, objcg, flags, i, p); __kmem_cache_free_bulk(s, i, p); return 0; } --- a/mm/slab.h~mm-memcg-slab-save-obj_cgroup-for-non-root-slab-objects +++ a/mm/slab.h @@ -470,6 +470,41 @@ static inline void memcg_free_page_obj_c page->obj_cgroups = NULL; } +static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s, + struct obj_cgroup *objcg, + size_t size, void **p) +{ + struct page *page; + unsigned long off; + size_t i; + + for (i = 0; i < size; i++) { + if (likely(p[i])) { + page = virt_to_head_page(p[i]); + off = obj_to_index(s, page, p[i]); + obj_cgroup_get(objcg); + page_obj_cgroups(page)[off] = objcg; + } + } + obj_cgroup_put(objcg); + memcg_kmem_put_cache(s); +} + +static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page, + void *p) +{ + struct obj_cgroup *objcg; + unsigned int off; + + if (!memcg_kmem_enabled() || is_root_cache(s)) + return; + + off = obj_to_index(s, page, p); + objcg = page_obj_cgroups(page)[off]; + page_obj_cgroups(page)[off] = NULL; + obj_cgroup_put(objcg); +} + extern void slab_init_memcg_params(struct kmem_cache *); extern void memcg_link_cache(struct kmem_cache *s, struct mem_cgroup *memcg); @@ -529,6 +564,17 @@ static inline void memcg_free_page_obj_c { } +static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s, + struct obj_cgroup *objcg, + size_t size, void **p) +{ +} + +static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page, + void *p) +{ +} + static inline void slab_init_memcg_params(struct kmem_cache *s) { } @@ -631,7 +677,8 @@ static inline size_t slab_ksize(const st } static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s, - gfp_t flags) + struct obj_cgroup **objcgp, + size_t size, gfp_t flags) { flags &= gfp_allowed_mask; @@ -645,13 +692,14 @@ static inline struct kmem_cache *slab_pr if (memcg_kmem_enabled() && ((flags & __GFP_ACCOUNT) || (s->flags & SLAB_ACCOUNT))) - return memcg_kmem_get_cache(s); + return memcg_kmem_get_cache(s, objcgp); return s; } -static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, - size_t size, void **p) +static inline void slab_post_alloc_hook(struct kmem_cache *s, + struct obj_cgroup *objcg, + gfp_t flags, size_t size, void **p) { size_t i; @@ -663,8 +711,8 @@ static inline void slab_post_alloc_hook( s->flags, flags); } - if (memcg_kmem_enabled()) - memcg_kmem_put_cache(s); + if (memcg_kmem_enabled() && !is_root_cache(s)) + memcg_slab_post_alloc_hook(s, objcg, size, p); } #ifndef CONFIG_SLOB --- a/mm/slub.c~mm-memcg-slab-save-obj_cgroup-for-non-root-slab-objects +++ a/mm/slub.c @@ -2817,8 +2817,9 @@ static __always_inline void *slab_alloc_ struct kmem_cache_cpu *c; struct page *page; unsigned long tid; + struct obj_cgroup *objcg = NULL; - s = slab_pre_alloc_hook(s, gfpflags); + s = slab_pre_alloc_hook(s, &objcg, 1, gfpflags); if (!s) return NULL; redo: @@ -2894,7 +2895,7 @@ redo: if (unlikely(slab_want_init_on_alloc(gfpflags, s)) && object) memset(object, 0, s->object_size); - slab_post_alloc_hook(s, gfpflags, 1, &object); + slab_post_alloc_hook(s, objcg, gfpflags, 1, &object); return object; } @@ -3099,6 +3100,8 @@ static __always_inline void do_slab_free void *tail_obj = tail ? : head; struct kmem_cache_cpu *c; unsigned long tid; + + memcg_slab_free_hook(s, page, head); redo: /* * Determine the currently cpus per cpu slab. @@ -3278,9 +3281,10 @@ int kmem_cache_alloc_bulk(struct kmem_ca { struct kmem_cache_cpu *c; int i; + struct obj_cgroup *objcg = NULL; /* memcg and kmem_cache debug support */ - s = slab_pre_alloc_hook(s, flags); + s = slab_pre_alloc_hook(s, &objcg, size, flags); if (unlikely(!s)) return false; /* @@ -3334,11 +3338,11 @@ int kmem_cache_alloc_bulk(struct kmem_ca } /* memcg and kmem_cache debug support */ - slab_post_alloc_hook(s, flags, size, p); + slab_post_alloc_hook(s, objcg, flags, size, p); return i; error: local_irq_enable(); - slab_post_alloc_hook(s, flags, i, p); + slab_post_alloc_hook(s, objcg, flags, i, p); __kmem_cache_free_bulk(s, i, p); return 0; } _
