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From: Muchun Song <songmuchun@bytedance.com>
To: guro@fb.com, hannes@cmpxchg.org, mhocko@kernel.org,
	akpm@linux-foundation.org, shakeelb@google.com,
	vdavydov.dev@gmail.com
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	duanxiongchun@bytedance.com,
	Muchun Song <songmuchun@bytedance.com>
Subject: [PATCH v5 4/7] mm: memcontrol: change ug->dummy_page only if memcg changed
Date: Sat, 20 Mar 2021 00:38:17 +0800	[thread overview]
Message-ID: <20210319163821.20704-5-songmuchun@bytedance.com> (raw)
In-Reply-To: <20210319163821.20704-1-songmuchun@bytedance.com>

Just like assignment to ug->memcg, we only need to update ug->dummy_page
if memcg changed. So move it to there. This is a very small optimization.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 mm/memcontrol.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9489c7fc1e04..8d28a5a2ee58 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6854,6 +6854,7 @@ static void uncharge_page(struct page *page, struct uncharge_gather *ug)
 			uncharge_gather_clear(ug);
 		}
 		ug->memcg = page_memcg(page);
+		ug->dummy_page = page;
 
 		/* pairs with css_put in uncharge_batch */
 		css_get(&ug->memcg->css);
@@ -6867,7 +6868,6 @@ static void uncharge_page(struct page *page, struct uncharge_gather *ug)
 	else
 		ug->pgpgout++;
 
-	ug->dummy_page = page;
 	page->memcg_data = 0;
 	css_put(&ug->memcg->css);
 }
-- 
2.11.0


  parent reply	other threads:[~2021-03-19 16:39 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-19 16:38 [PATCH v5 0/7] Use obj_cgroup APIs to charge kmem pages Muchun Song
2021-03-19 16:38 ` [PATCH v5 1/7] mm: memcontrol: slab: fix obtain a reference to a freeing memcg Muchun Song
2021-03-19 18:26   ` Shakeel Butt
2021-03-19 18:26     ` Shakeel Butt
2021-03-22 14:46   ` Johannes Weiner
2021-03-23  9:18     ` [External] " Muchun Song
2021-03-23  9:18       ` Muchun Song
2021-03-22 18:17   ` Roman Gushchin
2021-03-19 16:38 ` [PATCH v5 2/7] mm: memcontrol: introduce obj_cgroup_{un}charge_pages Muchun Song
2021-03-19 16:38 ` [PATCH v5 3/7] mm: memcontrol: directly access page->memcg_data in mm/page_alloc.c Muchun Song
2021-03-19 16:38 ` Muchun Song [this message]
2021-03-19 16:38 ` [PATCH v5 5/7] mm: memcontrol: use obj_cgroup APIs to charge kmem pages Muchun Song
2021-03-19 18:27   ` Shakeel Butt
2021-03-19 18:27     ` Shakeel Butt
2021-03-22 18:13   ` Roman Gushchin
2021-03-19 16:38 ` [PATCH v5 6/7] mm: memcontrol: inline __memcg_kmem_{un}charge() into obj_cgroup_{un}charge_pages() Muchun Song
2021-03-19 18:41   ` Shakeel Butt
2021-03-19 18:41     ` Shakeel Butt
2021-03-22 14:34   ` Johannes Weiner
2021-03-22 18:14   ` Roman Gushchin
2021-03-19 16:38 ` [PATCH v5 7/7] mm: memcontrol: move PageMemcgKmem to the scope of CONFIG_MEMCG_KMEM Muchun Song

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