From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id C72B86B006A for ; Wed, 6 Oct 2010 00:03:35 -0400 (EDT) Message-ID: <4CABF4C0.8060405@zytor.com> Date: Tue, 05 Oct 2010 21:02:08 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 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=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Michel Lespinasse Cc: linux-mm@kvack.org, Linus Torvalds , Ying Han , linux-kernel@vger.kernel.org, Andrew Morton , Rik van Riel , Nick Piggin , Peter Zijlstra Andrew Morton List-ID: On 10/05/2010 12:53 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 > --- > arch/x86/mm/fault.c | 38 ++++++++++++++++++++++++++------------ > include/linux/mm.h | 2 ++ > mm/filemap.c | 23 ++++++++++++++++++++++- > mm/memory.c | 3 ++- > 4 files changed, 52 insertions(+), 14 deletions(-) > Acked-by: H. Peter Anvin -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org