From 9c315e4d7d8c3bddad3893777bbab4164b298818 Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Wed, 1 Apr 2020 21:06:53 -0700 Subject: [PATCH] mm: memcg/slab: cache page number in memcg_(un)charge_slab() There are many places in memcg_charge_slab() and memcg_uncharge_slab() which are calculating the number of pages to charge, css references to grab etc depending on the order of the slab page. Let's simplify the code by calculating it once and caching in the local variable. Signed-off-by: Roman Gushchin Signed-off-by: Andrew Morton Reviewed-by: Shakeel Butt Acked-by: Johannes Weiner Cc: Michal Hocko Cc: Vladimir Davydov Link: http://lkml.kernel.org/r/20200109202659.752357-6-guro@fb.com Signed-off-by: Linus Torvalds --- mm/slab.h | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/mm/slab.h b/mm/slab.h index d96c87a30a9b..43f8ce4aa325 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -348,6 +348,7 @@ static __always_inline int memcg_charge_slab(struct page *page, gfp_t gfp, int order, struct kmem_cache *s) { + unsigned int nr_pages = 1 << order; struct mem_cgroup *memcg; struct lruvec *lruvec; int ret; @@ -360,21 +361,21 @@ static __always_inline int memcg_charge_slab(struct page *page, if (unlikely(!memcg || mem_cgroup_is_root(memcg))) { mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s), - (1 << order)); - percpu_ref_get_many(&s->memcg_params.refcnt, 1 << order); + nr_pages); + percpu_ref_get_many(&s->memcg_params.refcnt, nr_pages); return 0; } - ret = memcg_kmem_charge_memcg(memcg, gfp, 1 << order); + ret = memcg_kmem_charge_memcg(memcg, gfp, nr_pages); if (ret) goto out; lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page)); - mod_lruvec_state(lruvec, cache_vmstat_idx(s), 1 << order); + mod_lruvec_state(lruvec, cache_vmstat_idx(s), nr_pages); /* transer try_charge() page references to kmem_cache */ - percpu_ref_get_many(&s->memcg_params.refcnt, 1 << order); - css_put_many(&memcg->css, 1 << order); + percpu_ref_get_many(&s->memcg_params.refcnt, nr_pages); + css_put_many(&memcg->css, nr_pages); out: css_put(&memcg->css); return ret; @@ -387,6 +388,7 @@ out: static __always_inline void memcg_uncharge_slab(struct page *page, int order, struct kmem_cache *s) { + unsigned int nr_pages = 1 << order; struct mem_cgroup *memcg; struct lruvec *lruvec; @@ -394,15 +396,15 @@ static __always_inline void memcg_uncharge_slab(struct page *page, int order, memcg = READ_ONCE(s->memcg_params.memcg); if (likely(!mem_cgroup_is_root(memcg))) { lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page)); - mod_lruvec_state(lruvec, cache_vmstat_idx(s), -(1 << order)); - memcg_kmem_uncharge_memcg(memcg, order); + mod_lruvec_state(lruvec, cache_vmstat_idx(s), -nr_pages); + memcg_kmem_uncharge_memcg(memcg, nr_pages); } else { mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s), - -(1 << order)); + -nr_pages); } rcu_read_unlock(); - percpu_ref_put_many(&s->memcg_params.refcnt, 1 << order); + percpu_ref_put_many(&s->memcg_params.refcnt, nr_pages); } extern void slab_init_memcg_params(struct kmem_cache *); -- 2.20.1