From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx138.postini.com [74.125.245.138]) by kanga.kvack.org (Postfix) with SMTP id 7AD456B0074 for ; Sat, 8 Dec 2012 20:01:58 -0500 (EST) Received: by mail-pb0-f41.google.com with SMTP id xa7so1172104pbc.14 for ; Sat, 08 Dec 2012 17:01:57 -0800 (PST) Date: Sat, 8 Dec 2012 17:01:42 -0800 (PST) From: Linus Torvalds 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> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Zlatko Calusic Cc: Linus Torvalds , Johannes Weiner , Mel Gorman , linux-mm , Linux Kernel Mailing List 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 -- 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