From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id 93C086B0087 for ; Tue, 23 Nov 2010 03:35:36 -0500 (EST) Received: from d01relay01.pok.ibm.com (d01relay01.pok.ibm.com [9.56.227.233]) by e6.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id oAN8afgs011312 for ; Tue, 23 Nov 2010 03:36:41 -0500 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay01.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id oAN8ZYPw403454 for ; Tue, 23 Nov 2010 03:35:34 -0500 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id oAN8ZYKm028757 for ; Tue, 23 Nov 2010 03:35:34 -0500 Subject: Re: Free memory never fully used, swapping From: Dave Hansen In-Reply-To: <20101122154419.ee0e09d2.akpm@linux-foundation.org> References: <20101115195246.GB17387@hostway.ca> <20101122154419.ee0e09d2.akpm@linux-foundation.org> Content-Type: text/plain; charset="ANSI_X3.4-1968" Date: Tue, 23 Nov 2010 00:35:31 -0800 Message-ID: <1290501331.2390.7023.camel@nimitz> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Andrew Morton Cc: Simon Kirby , linux-kernel , linux-mm@kvack.org List-ID: On Mon, 2010-11-22 at 15:44 -0800, Andrew Morton wrote: > > These are all x86_64, and so there is no highmem garbage going on. > > The only zones would be for DMA, right? There shouldn't be any highmem-related action going on. > Is the combination of memory fragmentation and large-order allocations > the only thing that would be causing this reclaim here? It does sound somewhat suspicious. Are you using hugetlbfs or allocating large pages? What are your high-order allocations going to? > Is there some easy bake knob for finding what > is causing the free memory jumps each time this happens? I wish. :) The best thing to do is to watch stuff like /proc/vmstat along with its friends like /proc/{buddy,meminfo,slabinfo}. Could you post some samples of those with some indication of where the bad behavior was seen? I've definitely seen swapping in the face of lots of free memory, but only in cases where I was being a bit unfair about the numbers of hugetlbfs pages I was trying to reserve. -- Dave -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org