Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756592Ab2BCOLJ (ORCPT ); Fri, 3 Feb 2012 09:11:09 -0500 Received: from mail-wi0-f174.google.com ([209.85.212.174]:51564 "EHLO mail-wi0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755929Ab2BCOLI convert rfc822-to-8bit (ORCPT ); Fri, 3 Feb 2012 09:11:08 -0500 MIME-Version: 1.0 In-Reply-To: References: <1328275626-5322-1-git-send-email-amit.sahrawat83@gmail.com> <1328275948.2662.15.camel@laptop> Date: Fri, 3 Feb 2012 19:41:07 +0530 Message-ID: Subject: Re: [PATCH 2/2] mm: make do_writepages() use plugging From: Amit Sahrawat To: Peter Zijlstra Cc: Wu Fengguang , Jan Kara , Andrew Morton , Johannes Weiner , Amit Sahrawat , linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2286 Lines: 70 Is there a case for introducing blk_plug in write_one_page() can't seem to find that support in the code flow write_one_page()->mpage_writepage() Regards, Amit Sahrawat On Fri, Feb 3, 2012 at 7:31 PM, Amit Sahrawat wrote: > Hi Peter, > Thanks for pointing out. > > While checking the plug support in Write code flow, I came across this > main point from which - we invoke > writepages(mapping->a_ops->writepages(mapping, wbc)) from almost all > the the filesystems. > > By mistake I checked 2 different kernel versions for this code(and > missed that the current version already has put plug in > mpage_writepages) ... so may be this patch is not worth considering. > > Regards, > Amit Sahrawat > > > On Fri, Feb 3, 2012 at 7:02 PM, Peter Zijlstra wrote: >> On Fri, 2012-02-03 at 18:57 +0530, Amit Sahrawat wrote: >>> This will cover all the invocations for writepages to be called with >>> plugging support. >> >> This changelog fails to explain why this is a good thing... I thought >> the idea of the new plugging stuff was that we now don't need to >> sprinkle plugs all over the kernel.. >> >>> Signed-off-by: Amit Sahrawat >>> --- >>> ?mm/page-writeback.c | ? ?4 ++++ >>> ?1 files changed, 4 insertions(+), 0 deletions(-) >>> >>> diff --git a/mm/page-writeback.c b/mm/page-writeback.c >>> index 363ba70..2bea32c 100644 >>> --- a/mm/page-writeback.c >>> +++ b/mm/page-writeback.c >>> @@ -1866,14 +1866,18 @@ EXPORT_SYMBOL(generic_writepages); >>> >>> ?int do_writepages(struct address_space *mapping, struct writeback_control *wbc) >>> ?{ >>> + ? ? struct blk_plug plug; >>> ? ? ? int ret; >>> >>> ? ? ? if (wbc->nr_to_write <= 0) >>> ? ? ? ? ? ? ? return 0; >>> + >>> + ? ? blk_start_plug(&plug); >>> ? ? ? if (mapping->a_ops->writepages) >>> ? ? ? ? ? ? ? ret = mapping->a_ops->writepages(mapping, wbc); >>> ? ? ? else >>> ? ? ? ? ? ? ? ret = generic_writepages(mapping, wbc); >>> + ? ? blk_finish_plug(&plug); >>> ? ? ? return ret; >>> ?} >>> >> >> >> -- 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/