From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753237Ab0JERjQ (ORCPT ); Tue, 5 Oct 2010 13:39:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:20145 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752252Ab0JERjP (ORCPT ); Tue, 5 Oct 2010 13:39:15 -0400 Message-ID: <4CAB628D.3030205@redhat.com> Date: Tue, 05 Oct 2010 13:38:21 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.7) Gecko/20100720 Fedora/3.1.1-1.fc13 Lightning/1.0b2pre Thunderbird/3.1.1 MIME-Version: 1.0 To: Michel Lespinasse CC: linux-mm@kvack.org, Linus Torvalds , Ying Han , linux-kernel@vger.kernel.org, Andrew Morton , Nick Piggin , Peter Zijlstra Subject: Re: [PATCH 2/3] Retry page fault when blocking on disk transfer. References: <1286265215-9025-1-git-send-email-walken@google.com> <1286265215-9025-3-git-send-email-walken@google.com> In-Reply-To: <1286265215-9025-3-git-send-email-walken@google.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/05/2010 03:53 AM, Michel Lespinasse wrote: > This change reduces mmap_sem hold times that are caused by waiting for > disk transfers when accessing file mapped VMAs. It introduces the > VM_FAULT_ALLOW_RETRY flag, which indicates that the call site wants > mmap_sem to be released if blocking on a pending disk transfer. > In that case, filemap_fault() returns the VM_FAULT_RETRY status bit > and do_page_fault() will then re-acquire mmap_sem and retry the page fault. > It is expected that the retry will hit the same page which will now be > cached, and thus it will complete with a low mmap_sem hold time. > > Signed-off-by: Michel Lespinasse Acked-by: Rik van Riel Looks like it should be relatively easy to do something similar in do_swap_page also.