From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m4.gw.fujitsu.co.jp ([10.0.50.74]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id m990gX2w001768 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Thu, 9 Oct 2008 09:42:34 +0900 Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id C89102AC026 for ; Thu, 9 Oct 2008 09:42:33 +0900 (JST) Received: from s5.gw.fujitsu.co.jp (s5.gw.fujitsu.co.jp [10.0.50.95]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 9C6E112C046 for ; Thu, 9 Oct 2008 09:42:33 +0900 (JST) Received: from s5.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s5.gw.fujitsu.co.jp (Postfix) with ESMTP id E57431DB803A for ; Thu, 9 Oct 2008 09:42:32 +0900 (JST) Received: from m105.s.css.fujitsu.com (m105.s.css.fujitsu.com [10.249.87.105]) by s5.gw.fujitsu.co.jp (Postfix) with ESMTP id 921A81DB8041 for ; Thu, 9 Oct 2008 09:42:29 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH] documentation: clarify dirty_ratio and dirty_background_ratio description In-Reply-To: <48EC90EC.8060306@gmail.com> References: <48EC90EC.8060306@gmail.com> Message-Id: <20081009094134.DEB8.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Thu, 9 Oct 2008 09:42:28 +0900 (JST) Sender: owner-linux-mm@kvack.org Return-Path: To: righi.andrea@gmail.com Cc: kosaki.motohiro@jp.fujitsu.com, Randy Dunlap , Michael Kerrisk , Peter Zijlstra , KAMEZAWA Hiroyuki , Andrew Morton , Michael Rubin , linux-mm@kvack.org, LKML List-ID: > The current documentation of dirty_ratio and dirty_background_ratio is a > bit misleading. > > In the documentation we say that they are "a percentage of total system > memory", but the current page writeback policy, intead, is to apply the > percentages to the dirtyable memory, that means free pages + reclaimable > pages. > > Better to be more explicit to clarify this concept. > > Signed-off-by: Andrea Righi looks good to me. > --- > Documentation/filesystems/proc.txt | 11 ++++++----- > 1 files changed, 6 insertions(+), 5 deletions(-) > > diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt > index f566ad9..be69c8b 100644 > --- a/Documentation/filesystems/proc.txt > +++ b/Documentation/filesystems/proc.txt > @@ -1380,15 +1380,16 @@ causes the kernel to prefer to reclaim dentries and inodes. > dirty_background_ratio > ---------------------- > > -Contains, as a percentage of total system memory, the number of pages at which > -the pdflush background writeback daemon will start writing out dirty data. > +Contains, as a percentage of the dirtyable system memory (free pages + > +reclaimable pages), the number of pages at which the pdflush background > +writeback daemon will start writing out dirty data. > > dirty_ratio > ----------------- > > -Contains, as a percentage of total system memory, the number of pages at which > -a process which is generating disk writes will itself start writing out dirty > -data. > +Contains, as a percentage of the dirtyable system memory (free pages + > +reclaimable pages), the number of pages at which a process which is generating > +disk writes will itself start writing out dirty data. > > dirty_writeback_centisecs > ------------------------- -- 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