From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [PATCH 06/17] Use statfs to determine size of huge pages Date: Mon, 18 May 2009 08:10:28 -0500 Message-ID: <4A115E44.4050505@us.ibm.com> References: <1242574999-20887-1-git-send-email-aliguori@us.ibm.com> <1242574999-20887-7-git-send-email-aliguori@us.ibm.com> <4A1042B8.2010407@redhat.com> <20090518090230.GZ9835@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Avi Kivity , kvm@vger.kernel.org, Glauber Costa To: Joerg Roedel Return-path: Received: from e1.ny.us.ibm.com ([32.97.182.141]:34131 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750950AbZERNKc (ORCPT ); Mon, 18 May 2009 09:10:32 -0400 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e1.ny.us.ibm.com (8.13.1/8.13.1) with ESMTP id n4ID6cNh024249 for ; Mon, 18 May 2009 09:06:38 -0400 Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n4IDAVB5256104 for ; Mon, 18 May 2009 09:10:31 -0400 Received: from d01av03.pok.ibm.com (loopback [127.0.0.1]) by d01av03.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n4IDAU2Z030452 for ; Mon, 18 May 2009 09:10:31 -0400 In-Reply-To: <20090518090230.GZ9835@amd.com> Sender: kvm-owner@vger.kernel.org List-ID: Joerg Roedel wrote: > On Sun, May 17, 2009 at 08:00:40PM +0300, Avi Kivity wrote: > >> Anthony Liguori wrote: >> >>> From: Joerg Roedel >>> >>> The current method of finding out the size of huge pages does not work >>> reliably anymore. Current Linux supports more than one huge page size >>> but /proc/meminfo only show one of the supported sizes. >>> To find out the real page size used can be found by calling statfs. This >>> patch changes qemu to use statfs instead of parsing /proc/meminfo. >>> >>> >> Since we don't support 1GBpages in stable-0.10, this is unneeded. >> > > This patch is needed to run current KVM on a hugetlbfs backed with > 1GB pages. Therefore I think this patch is needed. It is an improvement > over the /proc/meminfo parsing anyway and is not strictly related to > kvm kernel support for 1GB pages. > Is there any userspace support requirements for 1GB pages? That is, if you had a 2.6.31 kernel and stable-0.10, would 1GB pages work (assuming this patch is backported)? This patch could still be considered a feature vs. bug fix but I'm mostly curious. Regards, Anthony Liguori > Joerg > > -- Regards, Anthony Liguori