From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753080AbbF3BEr (ORCPT ); Mon, 29 Jun 2015 21:04:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39331 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752640AbbF3BEk (ORCPT ); Mon, 29 Jun 2015 21:04:40 -0400 Date: Tue, 30 Jun 2015 03:03:15 +0200 From: Oleg Nesterov To: Peter Zijlstra Cc: paulmck@linux.vnet.ibm.com, tj@kernel.org, mingo@redhat.com, der.herr@hofr.at, dave@stgolabs.net, riel@redhat.com, viro@ZenIV.linux.org.uk, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 0/6] stop_machine: kill stop_cpus_mutex and stop_cpus_lock Message-ID: <20150630010315.GA22559@redhat.com> References: <20150626021455.GA5675@redhat.com> <20150626122330.GY19282@twins.programming.kicks-ass.net> <20150626204612.GA14573@redhat.com> <20150629084929.GE19282@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150629084929.GE19282@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/29, Peter Zijlstra wrote: > > On Fri, Jun 26, 2015 at 10:46:12PM +0200, Oleg Nesterov wrote: > > > So I am still not convinced... But probably I am too biased ;) > > I'm just a tad worried, I don't want to make the relatively cheap > operation of stop_two_cpus() more expensive to the benefit of > stop_cpus(). OK. And I have another (simple) idea... Never say tomorrow, but I will try to re-check and make the patch tomorrow ;) But let me send some cleanups first. Plus I believe I found another stop_machine bug, see the last patch. So I hope these changes make sense in any case. Oleg.