From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751987AbaKKRst (ORCPT ); Tue, 11 Nov 2014 12:48:49 -0500 Received: from smtp.citrix.com ([66.165.176.89]:64999 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751274AbaKKRss (ORCPT ); Tue, 11 Nov 2014 12:48:48 -0500 X-IronPort-AV: E=Sophos;i="5.07,362,1413244800"; d="scan'208";a="190235669" Message-ID: <54624BFC.6000205@citrix.com> Date: Tue, 11 Nov 2014 17:48:44 +0000 From: David Vrabel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Icedove/24.5.0 MIME-Version: 1.0 To: Juergen Gross , , , , , , , , , Subject: Re: [Xen-devel] [PATCH V3 8/8] xen: Speed up set_phys_to_machine() by using read-only mappings References: <1415684626-18590-1-git-send-email-jgross@suse.com> <1415684626-18590-9-git-send-email-jgross@suse.com> In-Reply-To: <1415684626-18590-9-git-send-email-jgross@suse.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/11/14 05:43, Juergen Gross wrote: > Instead of checking at each call of set_phys_to_machine() whether a > new p2m page has to be allocated due to writing an entry in a large > invalid or identity area, just map those areas read only and react > to a page fault on write by allocating the new page. > > This change will make the common path with no allocation much > faster as it only requires a single write of the new mfn instead > of walking the address translation tables and checking for the > special cases. Reviewed-by: David Vrabel David