From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: Re: + mm-retry-page-fault-when-blocking-on-disk-transfer.patch added to -mm tree Date: Wed, 6 Oct 2010 10:46:05 +0800 Message-ID: <20101006024605.GC8454@localhost> References: <201010052015.o95KFP1G017428@imap1.linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mga03.intel.com ([143.182.124.21]:11594 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756680Ab0JFCqM (ORCPT ); Tue, 5 Oct 2010 22:46:12 -0400 Content-Disposition: inline In-Reply-To: <201010052015.o95KFP1G017428@imap1.linux-foundation.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: "akpm@linux-foundation.org" Cc: "mm-commits@vger.kernel.org" , "walken@google.com" , "a.p.zijlstra@chello.nl" , "hpa@zytor.com" , "linux-arch@vger.kernel.org" , "mingo@elte.hu" , "nickpiggin@yahoo.com.au" , "riel@redhat.com" , "tglx@linutronix.de" , "torvalds@linux-foundation.org" , "yinghan@google.com" On Wed, Oct 06, 2010 at 04:15:25AM +0800, Andrew Morton wrote: > > The patch titled > mm: retry page fault when blocking on disk transfer > has been added to the -mm tree. Its filename is > mm-retry-page-fault-when-blocking-on-disk-transfer.patch > > Before you just go and hit "reply", please: > a) Consider who else should be cc'ed > b) Prefer to cc a suitable mailing list as well > c) Ideally: find the original patch on the mailing list and do a > reply-to-all to that, adding suitable additional cc's > > *** Remember to use Documentation/SubmitChecklist when testing your code *** > > See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find > out what to do about this > > The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ > > ------------------------------------------------------ > Subject: mm: retry page fault when blocking on disk transfer > From: Michel Lespinasse > > 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 Reviewed-by: Wu Fengguang Also would like to see Ying Han's Signed-off-by :) Thanks, Fengguang