From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266899AbUHITD5 (ORCPT ); Mon, 9 Aug 2004 15:03:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266902AbUHITAl (ORCPT ); Mon, 9 Aug 2004 15:00:41 -0400 Received: from holomorphy.com ([207.189.100.168]:7906 "EHLO holomorphy.com") by vger.kernel.org with ESMTP id S266885AbUHIS7h (ORCPT ); Mon, 9 Aug 2004 14:59:37 -0400 Date: Mon, 9 Aug 2004 11:59:28 -0700 From: William Lee Irwin III To: "Seth, Rohit" Cc: "Chen, Kenneth W" , Hirokazu Takahashi , linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org Subject: Re: Hugetlb demanding paging for -mm tree Message-ID: <20040809185928.GR11200@holomorphy.com> Mail-Followup-To: William Lee Irwin III , "Seth, Rohit" , "Chen, Kenneth W" , Hirokazu Takahashi , linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org References: <01EF044AAEE12F4BAAD955CB7506494302005232@scsmsx401.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <01EF044AAEE12F4BAAD955CB7506494302005232@scsmsx401.amr.corp.intel.com> User-Agent: Mutt/1.5.6+20040722i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Chen, Kenneth W wrote on Monday, >> I suppose this is fixable in update_mmu_cache() where it can check the >> type of pte and do appropriate sizing and other things. ia64 would >> have >> to check the address instead of looking at the pte. On Mon, Aug 09, 2004 at 11:43:32AM -0700, Seth, Rohit wrote: > Why do we need update_mmu_cache for hugepages? As things stand in mainline, it's not an obvious issue. Ken appears to be calling it for hugetlb in the ZFOD fault handling patches, which have the issue that it may behave badly in several respects when acting on large pages. The cache coherency bits in update_mmu_fault() are necessary in general, but mainline omits them. It should only result in intermittent failures on machines with sufficiently incoherent caches. -- wli From mboxrd@z Thu Jan 1 00:00:00 1970 From: William Lee Irwin III Date: Mon, 09 Aug 2004 18:59:28 +0000 Subject: Re: Hugetlb demanding paging for -mm tree Message-Id: <20040809185928.GR11200@holomorphy.com> List-Id: References: <01EF044AAEE12F4BAAD955CB7506494302005232@scsmsx401.amr.corp.intel.com> In-Reply-To: <01EF044AAEE12F4BAAD955CB7506494302005232@scsmsx401.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "Seth, Rohit" Cc: "Chen, Kenneth W" , Hirokazu Takahashi , linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org Chen, Kenneth W wrote on Monday, >> I suppose this is fixable in update_mmu_cache() where it can check the >> type of pte and do appropriate sizing and other things. ia64 would >> have >> to check the address instead of looking at the pte. On Mon, Aug 09, 2004 at 11:43:32AM -0700, Seth, Rohit wrote: > Why do we need update_mmu_cache for hugepages? As things stand in mainline, it's not an obvious issue. Ken appears to be calling it for hugetlb in the ZFOD fault handling patches, which have the issue that it may behave badly in several respects when acting on large pages. The cache coherency bits in update_mmu_fault() are necessary in general, but mainline omits them. It should only result in intermittent failures on machines with sufficiently incoherent caches. -- wli