From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933956AbcI2Kc2 (ORCPT ); Thu, 29 Sep 2016 06:32:28 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:50703 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933834AbcI2Kbr (ORCPT ); Thu, 29 Sep 2016 06:31:47 -0400 Date: Thu, 29 Sep 2016 12:31:33 +0200 From: Peter Zijlstra To: Christian Borntraeger Cc: Pan Xinhui , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, virtualization@lists.linux-foundation.org, linux-s390@vger.kernel.org, xen-devel-request@lists.xenproject.org, kvm@vger.kernel.org, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, mingo@redhat.com, paulmck@linux.vnet.ibm.com, will.deacon@arm.com, kernellwp@gmail.com, jgross@suse.com, pbonzini@redhat.com, bsingharora@gmail.com, Heiko Carstens Subject: Re: [PATCH v3 0/4] implement vcpu preempted check Message-ID: <20160929103133.GW5016@twins.programming.kicks-ass.net> References: <1469101514-49475-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> <20160929101040.GV5016@twins.programming.kicks-ass.net> <166f3bad-f700-4624-6c1c-996f90ad609c@de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <166f3bad-f700-4624-6c1c-996f90ad609c@de.ibm.com> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 29, 2016 at 12:23:19PM +0200, Christian Borntraeger wrote: > On 09/29/2016 12:10 PM, Peter Zijlstra wrote: > > On Thu, Jul 21, 2016 at 07:45:10AM -0400, Pan Xinhui wrote: > >> change from v2: > >> no code change, fix typos, update some comments > >> > >> change from v1: > >> a simplier definition of default vcpu_is_preempted > >> skip mahcine type check on ppc, and add config. remove dedicated macro. > >> add one patch to drop overload of rwsem_spin_on_owner and mutex_spin_on_owner. > >> add more comments > >> thanks boqun and Peter's suggestion. > >> > >> This patch set aims to fix lock holder preemption issues. > > > > So I really like the concept, but I would also really like to see > > support for more hypervisors included before we can move forward with > > this. > > > > Please consider s390 and (x86/arm) KVM. Once we have a few, more can > > follow later, but I think its important to not only have PPC support for > > this. > > Actually the s390 preemted check via sigp sense running is available for > all hypervisors (z/VM, LPAR and KVM) which implies everywhere as you can no > longer buy s390 systems without LPAR. > > As Heiko already pointed out we could simply use a small inline function > that calls cpu_is_preempted from arch/s390/lib/spinlock (or smp_vcpu_scheduled from smp.c) Sure, and I had vague memories of Heiko's email. This patch set however completely fails to do that trivial hooking up.