Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752783AbbHTKAG (ORCPT ); Thu, 20 Aug 2015 06:00:06 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:3176 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751136AbbHTKAA (ORCPT ); Thu, 20 Aug 2015 06:00:00 -0400 X-IronPort-AV: E=Sophos;i="5.15,714,1432598400"; d="scan'208";a="296246760" Message-ID: <55D5A51D.2060106@citrix.com> Date: Thu, 20 Aug 2015 10:59:57 +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: Julien Grall , CC: Wei Liu , , , , "David Vrabel" , Boris Ostrovsky , Subject: Re: [Xen-devel] [PATCH v3 12/20] xen/balloon: Don't rely on the page granularity is the same for Xen and Linux References: <1438966019-19322-1-git-send-email-julien.grall@citrix.com> <1438966019-19322-13-git-send-email-julien.grall@citrix.com> In-Reply-To: <1438966019-19322-13-git-send-email-julien.grall@citrix.com> 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: 1178 Lines: 34 On 07/08/15 17:46, Julien Grall wrote: > For ARM64 guests, Linux is able to support either 64K or 4K page > granularity. Although, the hypercall interface is always based on 4K > page granularity. > > With 64K page granularity, a single page will be spread over multiple > Xen frame. > > To avoid splitting the page into 4K frame, take advantage of the > extent_order field to directly allocate/free chunk of the Linux page > size. > > Note that PVMMU is only used for PV guest (which is x86) and the page > granularity is always 4KB. Some BUILD_BUG_ON has been added to ensure > that because the code has not been modified. [...] > #ifdef CONFIG_XEN_HAVE_PVMMU > + /* We don't support PV MMU when Linux and Xen is using > + * different page granularity. > + */ > + BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE); You don't need this BUILD_BUG_ON() twice. Otherwise, Reviewed-by: David Vrabel 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/