From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id AB8A8900194 for ; Wed, 22 Jun 2011 19:04:51 -0400 (EDT) Message-ID: <4E0274FC.5070505@redhat.com> Date: Wed, 22 Jun 2011 19:04:28 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH RFC] fadvise: move active pages to inactive list with POSIX_FADV_DONTNEED References: <1308779480-4950-1-git-send-email-andrea@betterlinux.com> In-Reply-To: <1308779480-4950-1-git-send-email-andrea@betterlinux.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrea Righi Cc: Andrew Morton , Minchan Kim , Peter Zijlstra , Johannes Weiner , KAMEZAWA Hiroyuki , Andrea Arcangeli , Hugh Dickins , Jerry James , Marcus Sorensen , Matt Heaton , linux-mm , LKML On 06/22/2011 05:51 PM, Andrea Righi wrote: > There were some reported problems in the past about trashing page cache > when a backup software (i.e., rsync) touches a huge amount of pages (see > for example [1]). > > This problem has been almost fixed by the Minchan Kim's patch [2] and a > proper use of fadvise() in the backup software. For example this patch > set [3] has been proposed for inclusion in rsync. > > However, there can be still other similar trashing problems: when the > backup software reads all the source files, some of them may be part of > the actual working set of the system. When a > posix_fadvise(POSIX_FADV_DONTNEED) is performed _all_ pages are evicted > from pagecache, both the working set and the use-once pages touched only > by the backup software. > > With the following solution when posix_fadvise(POSIX_FADV_DONTNEED) is > called for an active page instead of removing it from the page cache it > is added to the tail of the inactive list. Otherwise, if it's already in > the inactive list the page is removed from the page cache. > Signed-off-by: Andrea Righi Acked-by: Rik van Riel -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org