From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752667AbbDTQ7N (ORCPT ); Mon, 20 Apr 2015 12:59:13 -0400 Received: from mail-wi0-f173.google.com ([209.85.212.173]:35311 "EHLO mail-wi0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750771AbbDTQ7K (ORCPT ); Mon, 20 Apr 2015 12:59:10 -0400 Message-ID: <55353058.2000008@redhat.com> Date: Mon, 20 Apr 2015 18:59:04 +0200 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Marcelo Tosatti CC: Peter Zijlstra , torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, gleb@kernel.org, kvm@vger.kernel.org, Ralf Baechle , luto@kernel.org Subject: Re: [GIT PULL] First batch of KVM changes for 4.1 References: <20150417091745.GA24151@twins.programming.kicks-ass.net> <5530DBED.5080508@redhat.com> <20150417103654.GE5029@twins.programming.kicks-ass.net> <5530E28F.2030401@redhat.com> <20150417105506.GF5029@twins.programming.kicks-ass.net> <553100C1.5000408@redhat.com> <20150417131037.GG23123@twins.programming.kicks-ass.net> <55310CF2.6070107@redhat.com> <20150417190146.GA24395@amt.cnet> <55316598.908@redhat.com> <20150417201841.GA31302@amt.cnet> In-Reply-To: <20150417201841.GA31302@amt.cnet> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17/04/2015 22:18, Marcelo Tosatti wrote: > The bug which this is fixing is very rare, have no memory of a report. > > In fact, its even difficult to create a synthetic reproducer. But then why was the task migration notifier even in Jeremy's original code for Xen? Was it supposed to work even on non-synchronized TSC? If that's the case, then it could be reverted indeed; but then why did you commit this patch to 4.1? Did you think of something that would cause the seqcount-like protocol to fail, and that turned out not to be the case later? I was only following the mailing list sparsely in March. Paolo