From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752464Ab3B1LH3 (ORCPT ); Thu, 28 Feb 2013 06:07:29 -0500 Received: from nat28.tlf.novell.com ([130.57.49.28]:58838 "EHLO nat28.tlf.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751163Ab3B1LH2 convert rfc822-to-8bit (ORCPT ); Thu, 28 Feb 2013 06:07:28 -0500 Message-Id: <512F487D02000078000C1E30@nat28.tlf.novell.com> X-Mailer: Novell GroupWise Internet Agent 12.0.1 Date: Thu, 28 Feb 2013 11:07:25 +0000 From: "Jan Beulich" To: "Roger Pau Monne" Cc: , "Konrad Rzeszutek Wilk" , Subject: Re: [Xen-devel] [PATCH RFC 09/12] xen-blkback: move pending handles list from blkbk to pending_req References: <1362047335-26402-1-git-send-email-roger.pau@citrix.com> <1362047335-26402-10-git-send-email-roger.pau@citrix.com> In-Reply-To: <1362047335-26402-10-git-send-email-roger.pau@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> On 28.02.13 at 11:28, Roger Pau Monne wrote: > Moving grant ref handles from blkbk to pending_req will allow us to > get rid of the shared blkbk structure. At the expense of (slightly?) higher memory requirements? > --- a/drivers/block/xen-blkback/blkback.c > +++ b/drivers/block/xen-blkback/blkback.c > @@ -136,6 +136,7 @@ struct pending_req { > struct list_head free_list; > struct persistent_gnt *persistent_gnts[BLKIF_MAX_SEGMENTS_PER_REQUEST]; > struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST]; > + grant_handle_t grant_handles[BLKIF_MAX_SEGMENTS_PER_REQUEST]; Adding yet another array here makes it even more desirable to switch from multiple arrays to a singly array of a structure, thus improving locality of the memory accesses involved in processing an individual segment. Jan