Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752221AbbHJMOi (ORCPT ); Mon, 10 Aug 2015 08:14:38 -0400 Received: from smtp.citrix.com ([66.165.176.89]:25293 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750965AbbHJMOh (ORCPT ); Mon, 10 Aug 2015 08:14:37 -0400 X-IronPort-AV: E=Sophos;i="5.15,645,1432598400"; d="scan'208";a="289620009" Message-ID: <55C895A8.9020004@citrix.com> Date: Mon, 10 Aug 2015 13:14:32 +0100 From: David Vrabel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.8.0 MIME-Version: 1.0 To: Stefano Stabellini , Julien Grall CC: , , David Vrabel , , Boris Ostrovsky , Subject: Re: [Xen-devel] [PATCH v3 19/20] xen/privcmd: Add support for Linux 64KB page granularity References: <1438966019-19322-1-git-send-email-julien.grall@citrix.com> <1438966019-19322-20-git-send-email-julien.grall@citrix.com> In-Reply-To: Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 827 Lines: 24 On 10/08/15 13:03, Stefano Stabellini wrote: > On Fri, 7 Aug 2015, Julien Grall wrote: >> - rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp); >> - return rc < 0 ? rc : err; >> + for (i = 0; i < nr_gfn; i++) { >> + if ((i % XEN_PFN_PER_PAGE) == 0) { >> + page = pages[i / XEN_PFN_PER_PAGE]; > > If this function is going to be called very frequently you might want to > consider using a shift instead. > > page = pages[i >> 4]; > > With an appropriate macro of course. This change isn't necessary. Compilers already turn divides into suitable shifts. David -- 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/