From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from burns.conectiva (burns.conectiva [10.0.0.4]) by perninha.conectiva.com.br (Postfix) with SMTP id 516E216B6D for ; Wed, 23 May 2001 12:39:32 -0300 (EST) Date: Wed, 23 May 2001 12:39:31 -0300 (BRST) From: Rik van Riel Subject: Re: write drop behind effect on active scanning In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Marcelo Tosatti Cc: "Stephen C. Tweedie" , lkml , linux-mm@kvack.org List-ID: On Wed, 23 May 2001, Marcelo Tosatti wrote: > I just noticed a "bad" effect of write drop behind yesterday during some > tests. > > The problem is that we deactivate written pages, thus making the inactive > list become pretty big (full of unfreeable pages) under write intensive IO > workloads. > > So what happens is that we don't do _any_ aging on the active list, and in > the meantime the inactive list (which should have "easily" freeable > pages) is full of locked pages. > > I'm going to fix this one by replacing "deactivate_page(page)" to > "ClearPageReferenced(page)" in generic_file_write(). This way the written > pages are aged faster but we avoid the bad effect just described. > > Any comments on the fix ? 1) I agree with it, drop-behind should make the pages we write very likely for eviction, but we don't want that to stop the eviction of other not-used pages ... 2) OTOH, if writeout of dirty pages is a problem for the system, I guess we will want to fix that problem somehow ;) (but that's another issue) regards, Rik -- Linux MM bugzilla: http://linux-mm.org/bugzilla.shtml Virtual memory is like a game you can't win; However, without VM there's truly nothing to lose... http://www.surriel.com/ http://www.conectiva.com/ http://distro.conectiva.com/ -- 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.eu.org/Linux-MM/