Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752198Ab1CQQ1O (ORCPT ); Thu, 17 Mar 2011 12:27:14 -0400 Received: from one.firstfloor.org ([213.235.205.2]:57041 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751817Ab1CQQ1M (ORCPT ); Thu, 17 Mar 2011 12:27:12 -0400 Date: Thu, 17 Mar 2011 17:27:10 +0100 From: Andi Kleen To: Andrea Arcangeli Cc: Andi Kleen , Hidetoshi Seto , Andrew Morton , Huang Ying , Jin Dongming , linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/4] Check whether pages are poisoned before copying Message-ID: <20110317162710.GH11094@one.firstfloor.org> References: <4D817234.9070106@jp.fujitsu.com> <4D8172D7.3040201@jp.fujitsu.com> <20110317041424.GD11094@one.firstfloor.org> <4D819A2A.8050606@jp.fujitsu.com> <20110317062612.GE11094@one.firstfloor.org> <4D81BB87.10803@jp.fujitsu.com> <20110317140401.GX10696@random.random> <20110317152559.GG11094@one.firstfloor.org> <20110317161219.GZ10696@random.random> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110317161219.GZ10696@random.random> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1275 Lines: 29 > What I can tell is with the default khugepaged scan rate, the > collapse_huge_page will have an impact much smaller than KSM. It could > have more impact than KSM if you increase khugepaged load to 100% with > sysfs (because of the more memory that is covered by khugepaged > compared to only the shared portion of KSM). Then the window gets much > bigger, but still minor, if you can't trigger it with the testsuite > it's even less likely to ever happen in practice. You mean randomly injecting errors? That tends to be hard and unreliable -- usually we try to have a specific tester that is not random. > Did you try the testsuite with khugepaged at 100% load? I think that's > good indication if this window has any practical significance. The measurement is simple: run the workloads and do some dumps with pagetypes and check if the memory with lots of pages has a state that can be handled by memory_failure() AFAIK this hasn't been done so far with THP. -Andi -- ak@linux.intel.com -- Speaking for myself only. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/