Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965109AbWJJJEe (ORCPT ); Tue, 10 Oct 2006 05:04:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965114AbWJJJEe (ORCPT ); Tue, 10 Oct 2006 05:04:34 -0400 Received: from smtp.osdl.org ([65.172.181.4]:41102 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S965109AbWJJJEd (ORCPT ); Tue, 10 Oct 2006 05:04:33 -0400 Date: Tue, 10 Oct 2006 02:04:26 -0700 From: Andrew Morton To: David Gibson Cc: Chen@ozlabs.org, Kenneth W , linux-kernel@vger.kernel.org Subject: Re: Hugepage regression Message-Id: <20061010020426.4d597be2.akpm@osdl.org> In-Reply-To: <20061010084748.GE18681@localhost.localdomain> References: <20061010084748.GE18681@localhost.localdomain> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 944 Lines: 26 On Tue, 10 Oct 2006 18:47:48 +1000 David Gibson wrote: > It seems commit fe1668ae5bf0145014c71797febd9ad5670d5d05 causes a > hugepage regression. A git bisect points the finger at that commit > for causing an oops in the 'alloc-instantiate-race' test from the > libhugetlbfs testsuite. > > Still looking to determine the reason it breaks things. > It's assuming that unmap_hugepage_range() is always freeing these pages. If the page is shared by another mapping, bad things will happen: the threads fight over page->lru. Doing + if (page_count(page) == 1) list_add(&page->lru, &page_list); might help. But then we miss the tlb flush in rare racy conditions. - 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/