From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756054Ab2BAJSR (ORCPT ); Wed, 1 Feb 2012 04:18:17 -0500 Received: from 173-166-109-252-newengland.hfc.comcastbusiness.net ([173.166.109.252]:58285 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753949Ab2BAJSO (ORCPT ); Wed, 1 Feb 2012 04:18:14 -0500 Date: Wed, 1 Feb 2012 04:18:07 -0500 From: Christoph Hellwig To: Vivek Goyal Cc: Andrew Morton , Shaohua Li , lkml , linux-mm , Jens Axboe , Herbert Poetzl , Eric Dumazet , Wu Fengguang Subject: Re: [PATCH] fix readahead pipeline break caused by block plug Message-ID: <20120201091807.GA7451@infradead.org> References: <1327996780.21268.42.camel@sli10-conroe> <20120131220333.GD4378@redhat.com> <20120131141301.ba35ffe0.akpm@linux-foundation.org> <20120131222217.GE4378@redhat.com> <20120201033653.GA12092@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120201033653.GA12092@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 31, 2012 at 10:36:53PM -0500, Vivek Goyal wrote: > I still see that IO is being submitted one page at a time. The only > real difference seems to be that queue unplug happening at random times > and many a times we are submitting much smaller requests (40 sectors, 48 > sectors etc). This is expected given that the block device node uses block_read_full_page, and not mpage_readpage(s).