From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH v2 6/8] kvm tools: Add rwlock wrapper Date: Mon, 30 May 2011 15:32:58 +0300 Message-ID: <4DE38E7A.2050301@redhat.com> References: <1306748796.14564.62.camel@lappy> <20110530095451.GB8461@elte.hu> <20110530201110.f3bf20b5.yoshikawa.takuya@oss.ntt.co.jp> <1306753954.14564.92.camel@lappy> <20110530202646.eff0ea28.yoshikawa.takuya@oss.ntt.co.jp> <4DE381DB.8040804@redhat.com> <20110530114949.GD22324@elte.hu> <1306756681.14564.95.camel@lappy> <20110530122027.GJ22324@elte.hu> <4DE38C50.404@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Ingo Molnar , Sasha Levin , Takuya Yoshikawa , kvm@vger.kernel.org, asias.hejun@gmail.com, gorcunov@gmail.com, prasadjoshi124@gmail.com, "Paul E. McKenney" , takuya.yoshikawa@gmail.com To: Pekka Enberg Return-path: Received: from mx1.redhat.com ([209.132.183.28]:52453 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750835Ab1E3MdP (ORCPT ); Mon, 30 May 2011 08:33:15 -0400 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On 05/30/2011 03:30 PM, Pekka Enberg wrote: > On Mon, May 30, 2011 at 3:23 PM, Avi Kivity wrote: > > IIRC there never was a memset() of all RAM, at least since kvm started > > booting Linux. Windows has a zeroing thread which causes all of RAM to be > > committed shortly after boot, though. > > Yup, I haven't heard of such thing either. AFAIK, it's all done lazily > by the page allocator. Note that in these days of dma engines a zeroing thread makes some sense. During a kernel build I see quite a bit of time spent in clear_page_c() or something. It would be nice to have the dma engine prepare some clear pages so we could skip it. -- error compiling committee.c: too many arguments to function