From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 9FD366B01EE for ; Wed, 21 Apr 2010 05:03:55 -0400 (EDT) Date: Wed, 21 Apr 2010 11:03:27 +0200 From: Johannes Weiner 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: owner-linux-mm@kvack.org 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 List-ID: 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, 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