From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756326AbdKNSCj (ORCPT ); Tue, 14 Nov 2017 13:02:39 -0500 Received: from mail-wm0-f47.google.com ([74.125.82.47]:36954 "EHLO mail-wm0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756263AbdKNSCA (ORCPT ); Tue, 14 Nov 2017 13:02:00 -0500 X-Google-Smtp-Source: AGs4zMadlY3b8E+BMIX60QgLQRY4+SLxxWtcwuG3y8Vi02al2J1c8noZMAaaViCNu5jl08e8PBb2fA== Subject: Re: [RFC PATCH 0/2] x86: Fix missing core serialization on migration To: Peter Zijlstra Cc: Andy Lutomirski , Thomas Gleixner , Mathieu Desnoyers , Avi Kivity , Linus Torvalds , linux-kernel , linux-api , "Paul E. McKenney" , Boqun Feng , Andrew Hunter , maged michael , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Dave Watson , Ingo Molnar , "H. Peter Anvin" , Andrea Parri , "Russell King, ARM Linux" , Greg Hackmann , Will Deacon , David Sehr , x86 References: <885227610.13045.1510351034488.JavaMail.zimbra@efficios.com> <617343212.13932.1510592207202.JavaMail.zimbra@efficios.com> <4d47fbb8-8f99-19d3-a9cf-66841aeffac3@scylladb.com> <4431530.14831.1510672632887.JavaMail.zimbra@efficios.com> <20171114160541.GC3165@worktop.lehotels.local> <20171114163159.GD3165@worktop.lehotels.local> <6f9f57fa-8057-cdbe-231b-20920b3b3670@redhat.com> <20171114174049.GF3165@worktop.lehotels.local> From: Daniel Bristot de Oliveira Message-ID: Date: Tue, 14 Nov 2017 19:01:55 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <20171114174049.GF3165@worktop.lehotels.local> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/14/2017 06:40 PM, Peter Zijlstra wrote: > On Tue, Nov 14, 2017 at 06:17:13PM +0100, Daniel Bristot de Oliveira wrote: > >> IIRC, if the dest cpu is idle and the system is with idle=poll, no IPI >> is fired as well, but that is not a very common case. > > You're thinking about wake from idle? That is almost always without IPI, > even without idle=poll. > I meant the resched_curr(rq) of an rq on another CPU. If the dest is idle && idle=poll, the IPI will not be send. -- Daniel From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Bristot de Oliveira Subject: Re: [RFC PATCH 0/2] x86: Fix missing core serialization on migration Date: Tue, 14 Nov 2017 19:01:55 +0100 Message-ID: References: <885227610.13045.1510351034488.JavaMail.zimbra@efficios.com> <617343212.13932.1510592207202.JavaMail.zimbra@efficios.com> <4d47fbb8-8f99-19d3-a9cf-66841aeffac3@scylladb.com> <4431530.14831.1510672632887.JavaMail.zimbra@efficios.com> <20171114160541.GC3165@worktop.lehotels.local> <20171114163159.GD3165@worktop.lehotels.local> <6f9f57fa-8057-cdbe-231b-20920b3b3670@redhat.com> <20171114174049.GF3165@worktop.lehotels.local> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20171114174049.GF3165-IIpfhp3q70x9+YH6RuovlLjjLBE8jN/0@public.gmane.org> Content-Language: en-US Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Peter Zijlstra Cc: Andy Lutomirski , Thomas Gleixner , Mathieu Desnoyers , Avi Kivity , Linus Torvalds , linux-kernel , linux-api , "Paul E. McKenney" , Boqun Feng , Andrew Hunter , maged michael , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Dave Watson , Ingo Molnar , "H. Peter Anvin" , Andrea Parri , "Russell King, ARM Linux" List-Id: linux-api@vger.kernel.org On 11/14/2017 06:40 PM, Peter Zijlstra wrote: > On Tue, Nov 14, 2017 at 06:17:13PM +0100, Daniel Bristot de Oliveira wrote: > >> IIRC, if the dest cpu is idle and the system is with idle=poll, no IPI >> is fired as well, but that is not a very common case. > > You're thinking about wake from idle? That is almost always without IPI, > even without idle=poll. > I meant the resched_curr(rq) of an rq on another CPU. If the dest is idle && idle=poll, the IPI will not be send. -- Daniel