From: Roman Gushchin <guro@xxxxxx> Subject: mm: memcg/slab: remove memcg_kmem_get_cache() The memcg_kmem_get_cache() function became really trivial, so let's just inline it into the single call point: memcg_slab_pre_alloc_hook(). It will make the code less bulky and can also help the compiler to generate a better code. Link: http://lkml.kernel.org/r/20200623174037.3951353-15-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 | 2 -- mm/memcontrol.c | 25 +------------------------ mm/slab.h | 11 +++++++++-- mm/slab_common.c | 2 +- 4 files changed, 11 insertions(+), 29 deletions(-) --- a/include/linux/memcontrol.h~mm-memcg-slab-remove-memcg_kmem_get_cache +++ a/include/linux/memcontrol.h @@ -1403,8 +1403,6 @@ static inline void memcg_set_shrinker_bi } #endif -struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep); - #ifdef CONFIG_MEMCG_KMEM int __memcg_kmem_charge(struct mem_cgroup *memcg, gfp_t gfp, unsigned int nr_pages); --- a/mm/memcontrol.c~mm-memcg-slab-remove-memcg_kmem_get_cache +++ a/mm/memcontrol.c @@ -393,7 +393,7 @@ void memcg_put_cache_ids(void) /* * A lot of the calls to the cache allocation functions are expected to be - * inlined by the compiler. Since the calls to memcg_kmem_get_cache are + * inlined by the compiler. Since the calls to memcg_slab_pre_alloc_hook() are * conditional to this static branch, we'll have to allow modules that does * kmem_cache_alloc and the such to see this symbol as well */ @@ -2901,29 +2901,6 @@ static void memcg_free_cache_id(int id) } /** - * memcg_kmem_get_cache: select memcg or root cache for allocation - * @cachep: the original global kmem cache - * - * Return the kmem_cache we're supposed to use for a slab allocation. - * - * If the cache does not exist yet, if we are the first user of it, we - * create it asynchronously in a workqueue and let the current allocation - * go through with the original cache. - */ -struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep) -{ - struct kmem_cache *memcg_cachep; - - memcg_cachep = READ_ONCE(cachep->memcg_params.memcg_cache); - if (unlikely(!memcg_cachep)) { - queue_work(system_wq, &cachep->memcg_params.work); - return cachep; - } - - return memcg_cachep; -} - -/** * __memcg_kmem_charge: charge a number of kernel pages to a memcg * @memcg: memory cgroup to charge * @gfp: reclaim mode --- a/mm/slab_common.c~mm-memcg-slab-remove-memcg_kmem_get_cache +++ a/mm/slab_common.c @@ -570,7 +570,7 @@ void memcg_create_kmem_cache(struct kmem } /* - * Since readers won't lock (see memcg_kmem_get_cache()), we need a + * Since readers won't lock (see memcg_slab_pre_alloc_hook()), we need a * barrier here to ensure nobody will see the kmem_cache partially * initialized. */ --- a/mm/slab.h~mm-memcg-slab-remove-memcg_kmem_get_cache +++ a/mm/slab.h @@ -365,9 +365,16 @@ static inline struct kmem_cache *memcg_s if (memcg_kmem_bypass()) return s; - cachep = memcg_kmem_get_cache(s); - if (is_root_cache(cachep)) + cachep = READ_ONCE(s->memcg_params.memcg_cache); + if (unlikely(!cachep)) { + /* + * If memcg cache does not exist yet, we schedule it's + * asynchronous creation and let the current allocation + * go through with the root cache. + */ + queue_work(system_wq, &s->memcg_params.work); return s; + } objcg = get_obj_cgroup_from_current(); if (!objcg) _
