Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752552AbZL3P6w (ORCPT ); Wed, 30 Dec 2009 10:58:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752392AbZL3P6v (ORCPT ); Wed, 30 Dec 2009 10:58:51 -0500 Received: from mail-fx0-f225.google.com ([209.85.220.225]:41932 "EHLO mail-fx0-f225.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752351AbZL3P6R (ORCPT ); Wed, 30 Dec 2009 10:58:17 -0500 From: "Kirill A. Shutemov" To: containers@lists.linux-foundation.org, linux-mm@kvack.org Cc: Paul Menage , Li Zefan , Andrew Morton , KAMEZAWA Hiroyuki , Balbir Singh , Pavel Emelyanov , Dan Malek , Vladislav Buzov , Daisuke Nishimura , Alexander Shishkin , linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCH v5 3/4] memcg: rework usage of stats by soft limit Date: Wed, 30 Dec 2009 17:57:58 +0200 Message-Id: <03152dd4f660cff87b16bb581718b1c53d4775aa.1262186098.git.kirill@shutemov.name> X-Mailer: git-send-email 1.6.5.7 In-Reply-To: <34fedc324199dd64149889ed6eac5d8f9441a9db.1262186098.git.kirill@shutemov.name> References: <9411cbdd545e1232c916bfef03a60cf95510016d.1262186098.git.kirill@shutemov.name> <34fedc324199dd64149889ed6eac5d8f9441a9db.1262186098.git.kirill@shutemov.name> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2886 Lines: 80 Instead of incrementing counter on each page in/out and comparing it with constant, we set counter to constant, decrement counter on each page in/out and compare it with zero. We want to make comparing as fast as possible. On many RISC systems (probably not only RISC) comparing with zero is more effective than comparing with a constant, since not every constant can be immediate operand for compare instruction. Also, I've renamed MEM_CGROUP_STAT_EVENTS to MEM_CGROUP_STAT_SOFTLIMIT, since really it's not a generic counter. Signed-off-by: Kirill A. Shutemov --- KAMEZAWA-san, I've changed the patch a bit. Can I reuse your Acked-by? --- mm/memcontrol.c | 18 ++++++++++-------- 1 files changed, 10 insertions(+), 8 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 1d71cb4..c36d4f3 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -69,8 +69,9 @@ enum mem_cgroup_stat_index { MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */ MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */ MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */ - MEM_CGROUP_STAT_EVENTS, /* sum of pagein + pageout for internal use */ MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */ + MEM_CGROUP_STAT_SOFTLIMIT, /* decrements on each page in/out. + used by soft limit implementation */ MEM_CGROUP_STAT_NSTATS, }; @@ -84,10 +85,10 @@ struct mem_cgroup_stat { }; static inline void -__mem_cgroup_stat_reset_safe(struct mem_cgroup_stat_cpu *stat, - enum mem_cgroup_stat_index idx) +__mem_cgroup_stat_set_safe(struct mem_cgroup_stat_cpu *stat, + enum mem_cgroup_stat_index idx, s64 val) { - stat->count[idx] = 0; + stat->count[idx] = val; } static inline s64 @@ -380,9 +381,10 @@ static bool mem_cgroup_soft_limit_check(struct mem_cgroup *mem) cpu = get_cpu(); cpustat = &mem->stat.cpustat[cpu]; - val = __mem_cgroup_stat_read_local(cpustat, MEM_CGROUP_STAT_EVENTS); - if (unlikely(val > SOFTLIMIT_EVENTS_THRESH)) { - __mem_cgroup_stat_reset_safe(cpustat, MEM_CGROUP_STAT_EVENTS); + val = __mem_cgroup_stat_read_local(cpustat, MEM_CGROUP_STAT_SOFTLIMIT); + if (unlikely(val < 0)) { + __mem_cgroup_stat_set_safe(cpustat, MEM_CGROUP_STAT_SOFTLIMIT, + SOFTLIMIT_EVENTS_THRESH); ret = true; } put_cpu(); @@ -515,7 +517,7 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, else __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_PGPGOUT_COUNT, 1); - __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_EVENTS, 1); + __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_SOFTLIMIT, -1); put_cpu(); } -- 1.6.5.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/