Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753042Ab0DUJD6 (ORCPT ); Wed, 21 Apr 2010 05:03:58 -0400 Received: from f0.cmpxchg.org ([85.214.51.133]:49157 "EHLO cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752467Ab0DUJD5 (ORCPT ); Wed, 21 Apr 2010 05:03:57 -0400 Date: Wed, 21 Apr 2010 11:03:27 +0200 From: Johannes Weiner To: Christian Ehrhardt Cc: Rik van Riel , Mel Gorman , Andrew Morton , linux-mm@kvack.org, Nick Piggin , Chris Mason , Jens Axboe , linux-kernel@vger.kernel.org, gregkh@novell.com, Corrado Zoccolo Subject: Re: [RFC PATCH 0/3] Avoid the use of congestion_wait under zone pressure Message-ID: <20100421090327.GD5336@cmpxchg.org> References: <20100322235053.GD9590@csn.ul.ie> <4BA940E7.2030308@redhat.com> <20100324145028.GD2024@csn.ul.ie> <4BCC4B0C.8000602@linux.vnet.ibm.com> <20100419214412.GB5336@cmpxchg.org> <4BCD55DA.2020000@linux.vnet.ibm.com> <20100420153202.GC5336@cmpxchg.org> <4BCDE2F0.3010009@redhat.com> <4BCE7DD1.70900@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4BCE7DD1.70900@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1385 Lines: 29 On Wed, Apr 21, 2010 at 06:23:45AM +0200, Christian Ehrhardt wrote: > Rik van Riel wrote: > >You do not want the backup to kick the working set > >out of memory, because when the user returns in the > >morning the desktop should come back quickly after > >the screensaver is unlocked. > > IMHO it is fine to prevent that nightly backup job from not being > finished when the user arrives at morning because we didn't give him > some more cache - and e.g. a 30 sec transition from/to both optimized > states is fine. For batched work maybe :-) > What we could do is combine all our thoughts we had so far: > a) Rik could create an experimental patch that excludes the in flight pages > b) Johannes could create one for his suggestion to "always scan active > file pages but only deactivate them when the ratio is off and otherwise > strip buffers of clean pages" Please drop that idea, that 'Buffers:' is a red herring. It's just pages that do not back files but block devices. Stripping buffer_heads won't achieve anything, we need to get rid of the pages. Sorry, I should have slept and thought before writing that suggestion. -- 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/