From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756090Ab0KXRcO (ORCPT ); Wed, 24 Nov 2010 12:32:14 -0500 Received: from e38.co.us.ibm.com ([32.97.110.159]:58776 "EHLO e38.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753487Ab0KXRcN (ORCPT ); Wed, 24 Nov 2010 12:32:13 -0500 Subject: Re: Sudden and massive page cache eviction From: Dave Hansen To: Peter =?ISO-8859-1?Q?Sch=FCller?= Cc: Andrew Morton , linux-kernel@vger.kernel.org, Mattias de Zalenski , linux-mm@kvack.org In-Reply-To: References: <20101122161158.02699d10.akpm@linux-foundation.org> <1290501502.2390.7029.camel@nimitz> <1290529171.2390.7994.camel@nimitz> Content-Type: text/plain; charset="ISO-8859-1" Date: Wed, 24 Nov 2010 09:32:09 -0800 Message-ID: <1290619929.10586.6.camel@nimitz> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2010-11-24 at 15:14 +0100, Peter Schüller wrote: > >> Do you have any large page (hugetlbfs) or other multi-order (> 1 page) > >> allocations happening in the kernel? > > I forgot to address the second part of this question: How would I best > inspect whether the kernel is doing that? I found out yesterday how to do it with tracing, but it's not a horribly simple thing to do in any case. You can watch the entries in slabinfo and see if any of the ones with sizes over 4096 bytes are getting used often. You can also watch /proc/buddyinfo and see how often columns other than the first couple are moving around. Jumbo ethernet frames would be the most common reason to see these allocations. It's _probably_ not an issue in your case. -- Dave 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 18FE56B0071 for ; Wed, 24 Nov 2010 12:32:20 -0500 (EST) Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e39.co.us.ibm.com (8.14.4/8.13.1) with ESMTP id oAOHKn0t005869 for ; Wed, 24 Nov 2010 10:20:49 -0700 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id oAOHWCNS254040 for ; Wed, 24 Nov 2010 10:32:12 -0700 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id oAOHWBJ0007637 for ; Wed, 24 Nov 2010 10:32:11 -0700 Subject: Re: Sudden and massive page cache eviction From: Dave Hansen In-Reply-To: References: <20101122161158.02699d10.akpm@linux-foundation.org> <1290501502.2390.7029.camel@nimitz> <1290529171.2390.7994.camel@nimitz> Content-Type: text/plain; charset="ISO-8859-1" Date: Wed, 24 Nov 2010 09:32:09 -0800 Message-ID: <1290619929.10586.6.camel@nimitz> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org To: Peter =?ISO-8859-1?Q?Sch=FCller?= Cc: Andrew Morton , linux-kernel@vger.kernel.org, Mattias de Zalenski , linux-mm@kvack.org List-ID: On Wed, 2010-11-24 at 15:14 +0100, Peter Schuller wrote: > >> Do you have any large page (hugetlbfs) or other multi-order (> 1 page) > >> allocations happening in the kernel? > > I forgot to address the second part of this question: How would I best > inspect whether the kernel is doing that? I found out yesterday how to do it with tracing, but it's not a horribly simple thing to do in any case. You can watch the entries in slabinfo and see if any of the ones with sizes over 4096 bytes are getting used often. You can also watch /proc/buddyinfo and see how often columns other than the first couple are moving around. Jumbo ethernet frames would be the most common reason to see these allocations. It's _probably_ not an issue in your case. -- 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