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From: Roman Gushchin <guro@fb.com>
To: <linux-mm@kvack.org>, Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Shakeel Butt <shakeelb@google.com>,
	Vladimir Davydov <vdavydov.dev@gmail.com>,
	<linux-kernel@vger.kernel.org>, <kernel-team@fb.com>,
	Roman Gushchin <guro@fb.com>
Subject: [PATCH v2 5/6] mm: memcg/slab: cache page number in memcg_(un)charge_slab()
Date: Thu, 9 Jan 2020 12:26:58 -0800
Message-ID: <20200109202659.752357-6-guro@fb.com> (raw)
In-Reply-To: <20200109202659.752357-1-guro@fb.com>

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 <guro@fb.com>
---
 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 @@ static __always_inline int memcg_charge_slab(struct page *page,
 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 *);
-- 
2.21.1



  parent reply index

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-09 20:26 [PATCH v2 0/6] mm: memcg: kmem API cleanup Roman Gushchin
2020-01-09 20:26 ` [PATCH v2 1/6] mm: kmem: cleanup (__)memcg_kmem_charge_memcg() arguments Roman Gushchin
2020-01-11  0:23   ` Shakeel Butt
2020-01-16 16:42   ` Johannes Weiner
2020-01-09 20:26 ` [PATCH v2 2/6] mm: kmem: cleanup memcg_kmem_uncharge_memcg() arguments Roman Gushchin
2020-01-11  0:23   ` Shakeel Butt
2020-01-13 15:11     ` Roman Gushchin
2020-01-16 16:44   ` Johannes Weiner
2020-01-09 20:26 ` [PATCH v2 3/6] mm: kmem: rename memcg_kmem_(un)charge() into memcg_kmem_(un)charge_page() Roman Gushchin
2020-01-11  0:25   ` Shakeel Butt
2020-01-16 16:47   ` Johannes Weiner
2020-01-09 20:26 ` [PATCH v2 4/6] mm: kmem: switch to nr_pages in (__)memcg_kmem_charge_memcg() Roman Gushchin
2020-01-11  0:27   ` Shakeel Butt
2020-01-16 17:24   ` Johannes Weiner
2020-01-09 20:26 ` Roman Gushchin [this message]
2020-01-11  0:28   ` [PATCH v2 5/6] mm: memcg/slab: cache page number in memcg_(un)charge_slab() Shakeel Butt
2020-01-16 17:26   ` Johannes Weiner
2020-01-09 20:26 ` [PATCH v2 6/6] mm: kmem: rename (__)memcg_kmem_(un)charge_memcg() to __memcg_kmem_(un)charge() Roman Gushchin
2020-01-11  0:32   ` Shakeel Butt
2020-01-16 17:30   ` Johannes Weiner
2020-01-16 17:40     ` Roman Gushchin

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