From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx107.postini.com [74.125.245.107]) by kanga.kvack.org (Postfix) with SMTP id 4F3CE6B02D1 for ; Sat, 23 Jun 2012 22:16:55 -0400 (EDT) Received: by dakp5 with SMTP id p5so4738663dak.14 for ; Sat, 23 Jun 2012 19:16:54 -0700 (PDT) From: Wanpeng Li Subject: [PATCH] mm/memcg: add MAX_CHARGE_BATCH to limit unnecessary charge overhead Date: Sun, 24 Jun 2012 10:16:09 +0800 Message-Id: <1340504169-5344-1-git-send-email-liwp.linux@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: Johannes Weiner , Michal Hocko , Balbir Singh , KAMEZAWA Hiroyuki , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Gavin Shan , Wanpeng Li From: Wanpeng Li Since exceeded unused cached charges would add pressure to mem_cgroup_do_charge, more overhead would burn cpu cycles when mem_cgroup_do_charge cause page reclaim or even OOM be triggered just for such exceeded unused cached charges. Add MAX_CHARGE_BATCH to limit max cached charges. Signed-off-by: Wanpeng Li --- mm/memcontrol.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 0e092eb..1ff317a 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1954,6 +1954,14 @@ void mem_cgroup_update_page_stat(struct page *page, * TODO: maybe necessary to use big numbers in big irons. */ #define CHARGE_BATCH 32U + +/* + * Max size of charge stock. Since exceeded unused cached charges would + * add pressure to mem_cgroup_do_charge which will cause page reclaim or + * even oom be triggered. + */ +#define MAX_CHARGE_BATCH 1024U + struct memcg_stock_pcp { struct mem_cgroup *cached; /* this never be root cgroup */ unsigned int nr_pages; @@ -2250,6 +2258,7 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm, unsigned int batch = max(CHARGE_BATCH, nr_pages); int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; struct mem_cgroup *memcg = NULL; + struct memcg_stock_pcp *stock; int ret; /* @@ -2320,6 +2329,13 @@ again: rcu_read_unlock(); } + stock = &get_cpu_var(memcg_stock); + if (memcg == stock->cached && stock->nr_pages) { + if (stock->nr_pages > MAX_CHARGE_BATCH) + batch = nr_pages; + } + put_cpu_var(memcg_stock); + do { bool oom_check; -- 1.7.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org