Re: [PATCH v2 14/21] mm/slab: move memcg related functions from slab.h to slub.c

Hyeonggon Yoo
2023-12-07T01:00:04Z

On Mon, Nov 20, 2023 at 07:34:25PM +0100, Vlastimil Babka wrote:
> We don't share those between SLAB and SLUB anymore, so most memcg
> related functions can be moved to slub.c proper.
>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Acked-by: Michal Hocko <mhocko@suse.com>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> ---
> mm/slab.h | 206 --------------------------------------------------------------
> mm/slub.c | 205 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 205 insertions(+), 206 deletions(-)
>
> diff --git a/mm/slab.h b/mm/slab.h
> index 65ebf86b3fe9..a81ef7c9282d 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -486,12 +486,6 @@ void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
> ssize_t slabinfo_write(struct file *file, const char __user *buffer,
> size_t count, loff_t *ppos);
>
> -static inline enum node_stat_item cache_vmstat_idx(struct kmem_cache *s)
> -{
> - return (s->flags & SLAB_RECLAIM_ACCOUNT) ?
> - NR_SLAB_RECLAIMABLE_B : NR_SLAB_UNRECLAIMABLE_B;
> -}
> -
> #ifdef CONFIG_SLUB_DEBUG
> #ifdef CONFIG_SLUB_DEBUG_ON
> DECLARE_STATIC_KEY_TRUE(slub_debug_enabled);
> @@ -551,220 +545,20 @@ int memcg_alloc_slab_cgroups(struct slab *slab, struct kmem_cache *s,
> gfp_t gfp, bool new_slab);
> void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
> enum node_stat_item idx, int nr);
> -
> -static inline void memcg_free_slab_cgroups(struct slab *slab)
> -{
> - kfree(slab_objcgs(slab));
> - slab->memcg_data = 0;
> -}
> -
> -static inline size_t obj_full_size(struct kmem_cache *s)
> -{
> - /*
> - * For each accounted object there is an extra space which is used
> - * to store obj_cgroup membership. Charge it too.
> - */
> - return s->size + sizeof(struct obj_cgroup *);
> -}
> -
> -/*
> - * Returns false if the allocation should fail.
> - */
> -static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
> - struct list_lru *lru,
> - struct obj_cgroup **objcgp,
> - size_t objects, gfp_t flags)
> -{
> - struct obj_cgroup *objcg;
> -
> - if (!memcg_kmem_online())
> - return true;
> -
> - if (!(flags & __GFP_ACCOUNT) && !(s->flags & SLAB_ACCOUNT))
> - return true;
> -
> - /*
> - * The obtained objcg pointer is safe to use within the current scope,
> - * defined by current task or set_active_memcg() pair.
> - * obj_cgroup_get() is used to get a permanent reference.
> - */
> - objcg = current_obj_cgroup();
> - if (!objcg)
> - return true;
> -
> - if (lru) {
> - int ret;
> - struct mem_cgroup *memcg;
> -
> - memcg = get_mem_cgroup_from_objcg(objcg);
> - ret = memcg_list_lru_alloc(memcg, lru, flags);
> - css_put(&memcg->css);
> -
> - if (ret)
> - return false;
> - }
> -
> - if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s)))
> - return false;
> -
> - *objcgp = objcg;
> - return true;
> -}
> -
> -static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
> - struct obj_cgroup *objcg,
> - gfp_t flags, size_t size,
> - void **p)
> -{
> - struct slab *slab;
> - unsigned long off;
> - size_t i;
> -
> - if (!memcg_kmem_online() || !objcg)
> - return;
> -
> - for (i = 0; i < size; i++) {
> - if (likely(p[i])) {
> - slab = virt_to_slab(p[i]);
> -
> - if (!slab_objcgs(slab) &&
> - memcg_alloc_slab_cgroups(slab, s, flags,
> - false)) {
> - obj_cgroup_uncharge(objcg, obj_full_size(s));
> - continue;
> - }
> -
> - off = obj_to_index(s, slab, p[i]);
> - obj_cgroup_get(objcg);
> - slab_objcgs(slab)[off] = objcg;
> - mod_objcg_state(objcg, slab_pgdat(slab),
> - cache_vmstat_idx(s), obj_full_size(s));
> - } else {
> - obj_cgroup_uncharge(objcg, obj_full_size(s));
> - }
> - }
> -}
> -
> -static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
> - void **p, int objects)
> -{
> - struct obj_cgroup **objcgs;
> - int i;
> -
> - if (!memcg_kmem_online())
> - return;
> -
> - objcgs = slab_objcgs(slab);
> - if (!objcgs)
> - return;
> -
> - for (i = 0; i < objects; i++) {
> - struct obj_cgroup *objcg;
> - unsigned int off;
> -
> - off = obj_to_index(s, slab, p[i]);
> - objcg = objcgs[off];
> - if (!objcg)
> - continue;
> -
> - objcgs[off] = NULL;
> - obj_cgroup_uncharge(objcg, obj_full_size(s));
> - mod_objcg_state(objcg, slab_pgdat(slab), cache_vmstat_idx(s),
> - -obj_full_size(s));
> - obj_cgroup_put(objcg);
> - }
> -}
> -
> #else /* CONFIG_MEMCG_KMEM */
> static inline struct obj_cgroup **slab_objcgs(struct slab *slab)
> {
> return NULL;
> }
>
> -static inline struct mem_cgroup *memcg_from_slab_obj(void *ptr)
> -{
> - return NULL;
> -}
> -
> static inline int memcg_alloc_slab_cgroups(struct slab *slab,
> struct kmem_cache *s, gfp_t gfp,
> bool new_slab)
> {
> return 0;
> }
> -
> -static inline void memcg_free_slab_cgroups(struct slab *slab)
> -{
> -}
> -
> -static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
> - struct list_lru *lru,
> - struct obj_cgroup **objcgp,
> - size_t objects, gfp_t flags)
> -{
> - return true;
> -}
> -
> -static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
> - struct obj_cgroup *objcg,
> - gfp_t flags, size_t size,
> - void **p)
> -{
> -}
> -
> -static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
> - void **p, int objects)
> -{
> -}
> #endif /* CONFIG_MEMCG_KMEM */
>
> -static inline struct kmem_cache *virt_to_cache(const void *obj)
> -{
> - struct slab *slab;
> -
> - slab = virt_to_slab(obj);
> - if (WARN_ONCE(!slab, "%s: Object is not a Slab page!\n",
> - __func__))
> - return NULL;
> - return slab->slab_cache;
> -}
> -
> -static __always_inline void account_slab(struct slab *slab, int order,
> - struct kmem_cache *s, gfp_t gfp)
> -{
> - if (memcg_kmem_online() && (s->flags & SLAB_ACCOUNT))
> - memcg_alloc_slab_cgroups(slab, s, gfp, true);
> -
> - mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
> - PAGE_SIZE << order);
> -}
> -
> -static __always_inline void unaccount_slab(struct slab *slab, int order,
> - struct kmem_cache *s)
> -{
> - if (memcg_kmem_online())
> - memcg_free_slab_cgroups(slab);
> -
> - mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
> - -(PAGE_SIZE << order));
> -}
> -
> -static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
> -{
> - struct kmem_cache *cachep;
> -
> - if (!IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) &&
> - !kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS))
> - return s;
> -
> - cachep = virt_to_cache(x);
> - if (WARN(cachep && cachep != s,
> - "%s: Wrong slab cache. %s but object is from %s\n",
> - __func__, s->name, cachep->name))
> - print_tracking(cachep, x);
> - return cachep;
> -}
> -
> void free_large_kmalloc(struct folio *folio, void *object);
>
> size_t __ksize(const void *objp);
> diff --git a/mm/slub.c b/mm/slub.c
> index 9eb6508152c2..844e0beb84ee 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -1814,6 +1814,165 @@ static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
> #endif
> #endif /* CONFIG_SLUB_DEBUG */
>
> +static inline enum node_stat_item cache_vmstat_idx(struct kmem_cache *s)
> +{
> + return (s->flags & SLAB_RECLAIM_ACCOUNT) ?
> + NR_SLAB_RECLAIMABLE_B : NR_SLAB_UNRECLAIMABLE_B;
> +}
> +
> +#ifdef CONFIG_MEMCG_KMEM
> +static inline void memcg_free_slab_cgroups(struct slab *slab)
> +{
> + kfree(slab_objcgs(slab));
> + slab->memcg_data = 0;
> +}
> +
> +static inline size_t obj_full_size(struct kmem_cache *s)
> +{
> + /*
> + * For each accounted object there is an extra space which is used
> + * to store obj_cgroup membership. Charge it too.
> + */
> + return s->size + sizeof(struct obj_cgroup *);
> +}
> +
> +/*
> + * Returns false if the allocation should fail.
> + */
> +static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
> + struct list_lru *lru,
> + struct obj_cgroup **objcgp,
> + size_t objects, gfp_t flags)
> +{
> + struct obj_cgroup *objcg;
> +
> + if (!memcg_kmem_online())
> + return true;
> +
> + if (!(flags & __GFP_ACCOUNT) && !(s->flags & SLAB_ACCOUNT))
> + return true;
> +
> + /*
> + * The obtained objcg pointer is safe to use within the current scope,
> + * defined by current task or set_active_memcg() pair.
> + * obj_cgroup_get() is used to get a permanent reference.
> + */
> + objcg = current_obj_cgroup();
> + if (!objcg)
> + return true;
> +
> + if (lru) {
> + int ret;
> + struct mem_cgroup *memcg;
> +
> + memcg = get_mem_cgroup_from_objcg(objcg);
> + ret = memcg_list_lru_alloc(memcg, lru, flags);
> + css_put(&memcg->css);
> +
> + if (ret)
> + return false;
> + }
> +
> + if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s)))
> + return false;
> +
> + *objcgp = objcg;
> + return true;
> +}
> +
> +static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
> + struct obj_cgroup *objcg,
> + gfp_t flags, size_t size,
> + void **p)
> +{
> + struct slab *slab;
> + unsigned long off;
> + size_t i;
> +
> + if (!memcg_kmem_online() || !objcg)
> + return;
> +
> + for (i = 0; i < size; i++) {
> + if (likely(p[i])) {
> + slab = virt_to_slab(p[i]);
> +
> + if (!slab_objcgs(slab) &&
> + memcg_alloc_slab_cgroups(slab, s, flags, false)) {
> + obj_cgroup_uncharge(objcg, obj_full_size(s));
> + continue;
> + }
> +
> + off = obj_to_index(s, slab, p[i]);
> + obj_cgroup_get(objcg);
> + slab_objcgs(slab)[off] = objcg;
> + mod_objcg_state(objcg, slab_pgdat(slab),
> + cache_vmstat_idx(s), obj_full_size(s));
> + } else {
> + obj_cgroup_uncharge(objcg, obj_full_size(s));
> + }
> + }
> +}
> +
> +static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
> + void **p, int objects)
> +{
> + struct obj_cgroup **objcgs;
> + int i;
> +
> + if (!memcg_kmem_online())
> + return;
> +
> + objcgs = slab_objcgs(slab);
> + if (!objcgs)
> + return;
> +
> + for (i = 0; i < objects; i++) {
> + struct obj_cgroup *objcg;
> + unsigned int off;
> +
> + off = obj_to_index(s, slab, p[i]);
> + objcg = objcgs[off];
> + if (!objcg)
> + continue;
> +
> + objcgs[off] = NULL;
> + obj_cgroup_uncharge(objcg, obj_full_size(s));
> + mod_objcg_state(objcg, slab_pgdat(slab), cache_vmstat_idx(s),
> + -obj_full_size(s));
> + obj_cgroup_put(objcg);
> + }
> +}
> +#else /* CONFIG_MEMCG_KMEM */
> +static inline struct mem_cgroup *memcg_from_slab_obj(void *ptr)
> +{
> + return NULL;
> +}
> +
> +static inline void memcg_free_slab_cgroups(struct slab *slab)
> +{
> +}
> +
> +static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
> + struct list_lru *lru,
> + struct obj_cgroup **objcgp,
> + size_t objects, gfp_t flags)
> +{
> + return true;
> +}
> +
> +static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
> + struct obj_cgroup *objcg,
> + gfp_t flags, size_t size,
> + void **p)
> +{
> +}
> +
> +static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
> + void **p, int objects)
> +{
> +}
> +#endif /* CONFIG_MEMCG_KMEM */
> +
> /*
> * Hooks for other subsystems that check memory allocations. In a typical
> * production configuration these hooks all should produce no code at all.
> @@ -2048,6 +2207,26 @@ static inline bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
> }
> #endif /* CONFIG_SLAB_FREELIST_RANDOM */
>
> +static __always_inline void account_slab(struct slab *slab, int order,
> + struct kmem_cache *s, gfp_t gfp)
> +{
> + if (memcg_kmem_online() && (s->flags & SLAB_ACCOUNT))
> + memcg_alloc_slab_cgroups(slab, s, gfp, true);
> +
> + mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
> + PAGE_SIZE << order);
> +}
> +
> +static __always_inline void unaccount_slab(struct slab *slab, int order,
> + struct kmem_cache *s)
> +{
> + if (memcg_kmem_online())
> + memcg_free_slab_cgroups(slab);
> +
> + mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
> + -(PAGE_SIZE << order));
> +}
> +
> static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
> {
> struct slab *slab;
> @@ -3965,6 +4144,32 @@ void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
> }
> #endif
>
> +static inline struct kmem_cache *virt_to_cache(const void *obj)
> +{
> + struct slab *slab;
> +
> + slab = virt_to_slab(obj);
> + if (WARN_ONCE(!slab, "%s: Object is not a Slab page!\n", __func__))
> + return NULL;
> + return slab->slab_cache;
> +}
> +
> +static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
> +{
> + struct kmem_cache *cachep;
> +
> + if (!IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) &&
> + !kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS))
> + return s;
> +
> + cachep = virt_to_cache(x);
> + if (WARN(cachep && cachep != s,
> + "%s: Wrong slab cache. %s but object is from %s\n",
> + __func__, s->name, cachep->name))
> + print_tracking(cachep, x);
> + return cachep;
> +}
> +
> void __kmem_cache_free(struct kmem_cache *s, void *x, unsigned long caller)
> {
> slab_free(s, virt_to_slab(x), x, NULL, &x, 1, caller);
>
> --

Looks good to me,
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

> 2.42.1
>
>