Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752925Ab0ACX7w (ORCPT ); Sun, 3 Jan 2010 18:59:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752837Ab0ACX7u (ORCPT ); Sun, 3 Jan 2010 18:59:50 -0500 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:54747 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752646Ab0ACX7u (ORCPT ); Sun, 3 Jan 2010 18:59:50 -0500 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Mon, 4 Jan 2010 08:56:32 +0900 From: KAMEZAWA Hiroyuki To: "Kirill A. Shutemov" Cc: containers@lists.linux-foundation.org, linux-mm@kvack.org, Paul Menage , Li Zefan , Andrew Morton , Balbir Singh , Pavel Emelyanov , Dan Malek , Vladislav Buzov , Daisuke Nishimura , Alexander Shishkin , linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 3/4] memcg: rework usage of stats by soft limit Message-Id: <20100104085632.1ac97a5a.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <03152dd4f660cff87b16bb581718b1c53d4775aa.1262186098.git.kirill@shutemov.name> References: <9411cbdd545e1232c916bfef03a60cf95510016d.1262186098.git.kirill@shutemov.name> <34fedc324199dd64149889ed6eac5d8f9441a9db.1262186098.git.kirill@shutemov.name> <03152dd4f660cff87b16bb581718b1c53d4775aa.1262186098.git.kirill@shutemov.name> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 2.7.1 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3189 Lines: 87 On Wed, 30 Dec 2009 17:57:58 +0200 "Kirill A. Shutemov" wrote: > 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 > Acked-by: KAMEZAWA Hiroyuki > --- > > 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/