From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id 63E0D6B009E for ; Tue, 12 May 2009 13:39:48 -0400 (EDT) Message-ID: <4A09B46D.9010705@redhat.com> Date: Tue, 12 May 2009 13:39:57 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH -mm] vmscan: protect a fraction of file backed mapped pages from reclaim References: <20090508125859.210a2a25.akpm@linux-foundation.org> <20090512025246.GC7518@localhost> <20090512120002.D616.A69D9226@jp.fujitsu.com> <4A09AC91.4060506@redhat.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Christoph Lameter Cc: KOSAKI Motohiro , Wu Fengguang , Andrew Morton , "hannes@cmpxchg.org" , "peterz@infradead.org" , "linux-kernel@vger.kernel.org" , "tytso@mit.edu" , "linux-mm@kvack.org" , "elladan@eskimo.com" , "npiggin@suse.de" , "minchan.kim@gmail.com" List-ID: Christoph Lameter wrote: > On Tue, 12 May 2009, Rik van Riel wrote: > >> The patch that only allows active file pages to be deactivated >> if the active file LRU is larger than the inactive file LRU should >> protect the working set from being evicted due to streaming IO. > > Streaming I/O means access once? Yeah, "used-once pages" would be a better criteria, since you could go through a gigantic set of used-once pages without doing linear IO. I expect that some databases might do that. > What exactly are the criteria for a page > to be part of streaming I/O? AFAICT the definition is more dependent on > the software running than on a certain usage pattern discernible to the > VM. Software may after all perform multiple scans over a stream of data or > go back to prior locations in the file. -- All rights reversed. -- 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