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 SMTP id B7CD06B0078 for ; Tue, 2 Mar 2010 18:31:02 -0500 (EST) Received: from m6.gw.fujitsu.co.jp ([10.0.50.76]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o22NV2kZ001026 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Wed, 3 Mar 2010 08:31:02 +0900 Received: from smail (m6 [127.0.0.1]) by outgoing.m6.gw.fujitsu.co.jp (Postfix) with ESMTP id 4DFD745DE55 for ; Wed, 3 Mar 2010 08:31:02 +0900 (JST) Received: from s6.gw.fujitsu.co.jp (s6.gw.fujitsu.co.jp [10.0.50.96]) by m6.gw.fujitsu.co.jp (Postfix) with ESMTP id 2CD3E45DE4C for ; Wed, 3 Mar 2010 08:31:02 +0900 (JST) Received: from s6.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s6.gw.fujitsu.co.jp (Postfix) with ESMTP id 169791DB8019 for ; Wed, 3 Mar 2010 08:31:02 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s6.gw.fujitsu.co.jp (Postfix) with ESMTP id BFC101DB8014 for ; Wed, 3 Mar 2010 08:31:01 +0900 (JST) From: KOSAKI Motohiro Subject: Re: Memory management woes - order 1 allocation failures In-Reply-To: <20100302183451.75d44f03@lxorguk.ukuu.org.uk> References: <20100302172606.GA11355@csn.ul.ie> <20100302183451.75d44f03@lxorguk.ukuu.org.uk> Message-Id: <20100303082239.D614.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Wed, 3 Mar 2010 08:31:01 +0900 (JST) Sender: owner-linux-mm@kvack.org To: Alan Cox Cc: kosaki.motohiro@jp.fujitsu.com, Mel Gorman , Pekka Enberg , Greg Kroah-Hartman , Christoph Lameter , Frans Pop , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mel Gorman List-ID: > > For reasons that are not particularly clear to me, tty_buffer_alloc() is > > called far more frequently in 2.6.33 than in 2.6.24. I instrumented the > > function to print out the size of the buffers allocated, booted under > > qemu and would just "cat /bin/ls" to see what buffers were allocated. > > 2.6.33 allocates loads, including high-order allocations. 2.6.24 > > appeared to allocate once and keep silent. > > The pty layer is using them now and didn't before. That will massively > distort your numhers. > > > While there have been snags recently with respect to high-order > > allocation failures in recent kernels, this might be one of the cases > > where it's due to subsystems requesting high-order allocations more. > > The pty code certainly triggered more such allocations. I've sent Greg > patches to make the tty buffering layer allocate sensible sizes as it > doesn't need multiple page allocations in the first place. Wow, great! :) -- 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