From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 3 Mar 2007 17:51:58 -0800 From: Andrew Morton Subject: Re: The performance and behaviour of the anti-fragmentation related patches Message-Id: <20070303175158.00d867cb.akpm@linux-foundation.org> In-Reply-To: <45EA2037.9060303@redhat.com> References: <20070302050625.GD15867@wotan.suse.de> <20070302054944.GE15867@wotan.suse.de> <20070302060831.GF15867@wotan.suse.de> <20070302062950.GG15867@wotan.suse.de> <20070302071955.GA5557@wotan.suse.de> <20070302081210.GD5557@wotan.suse.de> <45EA2037.9060303@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: Nick Piggin , Christoph Lameter , Mel Gorman , mingo@elte.hu, jschopp@austin.ibm.com, arjan@infradead.org, torvalds@linux-foundation.org, mbligh@mbligh.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Sat, 03 Mar 2007 20:26:15 -0500 Rik van Riel wrote: > Nick Piggin wrote: > > > Different issue, isn't it? Rik wants to be smarter in figuring out which > > pages to throw away. More work per page == worse for you. > > Being smarter about figuring out which pages to evict does > not equate to spending more work. One big component is > sorting the pages beforehand, so we do not end up scanning > through (and randomizing the LRU order of) anonymous pages > when we do not want to, or cannot, evict them anyway. > My gut feel is that we could afford to expend a lot more cycles-per-page doing stuff to avoid IO than we presently do. At least, reclaim normally just doesn't figure in system CPU time, except for when it's gone completely stupid. It could well be that we sleep too much in there though. -- 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