From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030341Ab2LIBB7 (ORCPT ); Sat, 8 Dec 2012 20:01:59 -0500 Received: from mail-pb0-f46.google.com ([209.85.160.46]:45731 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933754Ab2LIBB6 (ORCPT ); Sat, 8 Dec 2012 20:01:58 -0500 Date: Sat, 8 Dec 2012 17:01:42 -0800 (PST) From: Linus Torvalds X-X-Sender: torvalds@air.linux-foundation.org To: Zlatko Calusic cc: Linus Torvalds , Johannes Weiner , Mel Gorman , linux-mm , Linux Kernel Mailing List Subject: Re: kswapd craziness in 3.7 In-Reply-To: <50C3AF80.8040700@iskon.hr> Message-ID: References: <20121128145215.d23aeb1b.akpm@linux-foundation.org> <20121128235412.GW8218@suse.de> <50B77F84.1030907@leemhuis.info> <20121129170512.GI2301@cmpxchg.org> <50B8A8E7.4030108@leemhuis.info> <20121201004520.GK2301@cmpxchg.org> <50BC6314.7060106@leemhuis.info> <20121203194208.GZ24381@cmpxchg.org> <20121204214210.GB20253@cmpxchg.org> <20121205030133.GA17438@wolff.to> <20121206173742.GA27297@wolff.to> <50C32D32.6040800@iskon.hr> <50C3AF80.8040700@iskon.hr> User-Agent: Alpine 2.02 (LFD 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 8 Dec 2012, Zlatko Calusic wrote: > > Or sooner... in short: nothing's changed! > > On a 4GB RAM system, where applications use close to 2GB, kswapd likes to keep > around 1GB free (unused), leaving only 1GB for page/buffer cache. If I force > bigger page cache by reading a big file and thus use the unused 1GB of RAM, > kswapd will soon (in a matter of minutes) evict those (or other) pages out and > once again keep unused memory close to 1GB. Ok, guys, what was the reclaim or kswapd patch during the merge window that actually caused all of these insane problems? It seems it was more fundamentally buggered than the fifteen-million fixes for kswapd we have already picked up. (Ok, I may be exaggerating the number of patches, but it's starting to feel that way - I thought that 3.7 was going to be a calm and easy release, but the kswapd issues seem to just keep happening. We've been fighting the kswapd changes for a while now.) Trying to keep a gigabyte free (presumably because that way we have lots of high-order alloction pages) is ridiculous. Is it one of the compaction changes? Mel? Ideas? Linus