Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262165AbUCLPDs (ORCPT ); Fri, 12 Mar 2004 10:03:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262169AbUCLPDs (ORCPT ); Fri, 12 Mar 2004 10:03:48 -0500 Received: from lax-gate3.raytheon.com ([199.46.200.232]:35447 "EHLO lax-gate3.raytheon.com") by vger.kernel.org with ESMTP id S262165AbUCLPDp (ORCPT ); Fri, 12 Mar 2004 10:03:45 -0500 Subject: Re: [PATCH] 2.6.4-rc2-mm1: vm-split-active-lists To: Nick Piggin Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, mfedyk@matchmail.com, m.c.p@wolk-project.de, owner-linux-mm@kvack.org, plate@gmx.tm X-Mailer: Lotus Notes Release 5.0.9 November 16, 2001 Message-ID: From: Mark_H_Johnson@raytheon.com Date: Fri, 12 Mar 2004 09:00:43 -0600 X-MIMETrack: Serialize by Router on RTSHOU-DS01/RTS/Raytheon/US(Release 6.0.2CF2|July 23, 2003) at 03/12/2004 09:00:45 AM MIME-Version: 1.0 Content-type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2094 Lines: 50 Nick Piggin wrote: >Mark_H_Johnson@Raytheon.com wrote: >>Nick Piggin wrote: >> >>>Andrew Morton wrote: >>> >> >>>>That effect is to cause the whole world to be swapped out when people >>>>return to their machines in the morning. Once they're swapped back in >>>> [this is the symptom being reported] >>Just a question, but I remember from VMS a long time ago that >>as part of the working set limits, the "free list" was used to keep >>pages that could be freely used but could be put back into the working >>set quite easily (a "fast" page fault). Could you keep track of the >>swapped pages in a similar manner so you don't have to go to disk to >>get these pages [or is this already being done]? You would pull them >>back from the free list and avoid the disk I/O in the morning. > >Not too sure what you mean. If we've swapped out the pages, it is >because we need the memory for something else. So no. Actually - no, from what Andrew said, the system was not under memory pressure and did not need the memory for something else. The swapping occurred "just because". In that case, it would be better to keep track of where the pages came from (i.e., swap them in from the free list). Don't get me wrong - that behavior may be the "right thing" from an overall performance standpoint. A little extra disk I/O when the system is relatively idle may provide needed reserve (free pages) for when the system gets busy again. >One thing you could do is re read swapped pages when you have >plenty of free memory and the disks are idle. That may also be a good idea. However, if you keep a mapping between pages on the "free list" and those in the swap file / partition, you do not actually have to do the disk I/O to accomplish that. --Mark H Johnson - 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/