From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takuya Yoshikawa Subject: Re: [PATCH 00/13] KVM: MMU: fast page fault Date: Wed, 11 Apr 2012 21:15:14 +0900 Message-ID: <20120411211514.35db29c11460516e604059b6@gmail.com> References: <4F742951.7080003@linux.vnet.ibm.com> <4F82E04E.6000900@redhat.com> <20120409175829.GB21894@amt.cnet> <4F8329D3.7000605@gmail.com> <20120409194614.GB23053@amt.cnet> <4F840DD2.3090101@redhat.com> <20120410204031.ffb5b976225ac9fe6dae474e@gmail.com> <4F842074.1050108@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Avi Kivity , Marcelo Tosatti , Xiao Guangrong , LKML , KVM To: Xiao Guangrong Return-path: Received: from mail-pz0-f52.google.com ([209.85.210.52]:65005 "EHLO mail-pz0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757268Ab2DKMPT (ORCPT ); Wed, 11 Apr 2012 08:15:19 -0400 In-Reply-To: <4F842074.1050108@linux.vnet.ibm.com> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, 10 Apr 2012 19:58:44 +0800 Xiao Guangrong wrote: > No, i do not really agree with that. > > We really can get great benefit from O(1) especially if lockless write-protect > is introduced for O(1), live migration is very useful for cloud computing > architecture to balance the overload on all nodes. Recently, you said to me that you were not familiar with live migration. Actually you did not know the basics of pre-copy live migration. I know live migration better than you because NTT has Kemari and it uses live migration infrastructure. My work is originated from the data I got during profiling Kemari. SRCU-less dirty logging was also motivated by the pressures from scheduler developers. Everything was really needed. Have you ever used live migration for real service? I cannot say whether O(1) is OK with me without any real background. Takuya