From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dor Laor Subject: Re: KSM and HugePages Date: Sun, 25 Oct 2009 00:13:25 +0200 Message-ID: <4AE37C05.2060907@redhat.com> References: <42da86010910231121i6c0e3835qca8e98cf96a181b4@mail.gmail.com> Reply-To: dlaor@redhat.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: David Martin Return-path: Received: from mx1.redhat.com ([209.132.183.28]:53339 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751331AbZJXWNW (ORCPT ); Sat, 24 Oct 2009 18:13:22 -0400 In-Reply-To: <42da86010910231121i6c0e3835qca8e98cf96a181b4@mail.gmail.com> Sender: kvm-owner@vger.kernel.org List-ID: On 10/23/2009 08:21 PM, David Martin wrote: > Does KSM support HugePages? Reading the Fedora 12 feature list I notice this: > "Using huge pages for guest memory does have a downside, however - you > can no longer swap nor balloon guest memory." > However it is unclear to me if that includes KSM. ksm pages are only standard 4k pages. > > If I use 1GB HugePages and KSM (assuming this is possible), does that > mean the entire 1GB page has to match another for them to merge? Are > there any other downsides to using them other than swapping and > ballooning? It needs to be available at VM creation time. Also the tlb size for use pages is smaller although it does bring better results than 4k pages. > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html