From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756445Ab3EANZ3 (ORCPT ); Wed, 1 May 2013 09:25:29 -0400 Received: from smtp.citrix.com ([66.165.176.89]:55980 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755142Ab3EANZV (ORCPT ); Wed, 1 May 2013 09:25:21 -0400 X-IronPort-AV: E=Sophos;i="4.87,589,1363132800"; d="scan'208";a="22608142" Date: Wed, 1 May 2013 14:25:16 +0100 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Konrad Rzeszutek Wilk CC: Stefano Stabellini , "linux-kernel@vger.kernel.org" , "xen-devel@lists.xensource.com" Subject: Re: [PATCH 8/9] xen/smp/pvhvm: Don't initialize IRQ_WORKER as we are using the native one. In-Reply-To: <20130429183404.GA9431@phenom.dumpdata.com> Message-ID: References: <1366142947-18655-1-git-send-email-konrad.wilk@oracle.com> <1366142947-18655-9-git-send-email-konrad.wilk@oracle.com> <20130429183404.GA9431@phenom.dumpdata.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 29 Apr 2013, Konrad Rzeszutek Wilk wrote: > On Fri, Apr 26, 2013 at 05:27:20PM +0100, Stefano Stabellini wrote: > > On Tue, 16 Apr 2013, Konrad Rzeszutek Wilk wrote: > > > There is no need to use the PV version of the IRQ_WORKER mechanism > > > as under PVHVM we are using the native version. The native > > > version is using the SMP API. > > > > > > They just sit around unused: > > > > > > 69: 0 0 xen-percpu-ipi irqwork0 > > > 83: 0 0 xen-percpu-ipi irqwork1 > > > > > > Signed-off-by: Konrad Rzeszutek Wilk > > > > Might be worth trying to make it work instead? > > Is it just because we don't set the apic->send_IPI_* functions to the > > xen specific version on PVHVM? > > > > Right. We use the baremetal mechanism to do it. And it works fine. OK, it works fine, but won't it generate many mores trap and emulate cycles? > > > arch/x86/xen/smp.c | 13 ++++++++++++- > > > 1 file changed, 12 insertions(+), 1 deletion(-) > > > > > > diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c > > > index 22c800a..415694c 100644 > > > --- a/arch/x86/xen/smp.c > > > +++ b/arch/x86/xen/smp.c > > > @@ -144,6 +144,13 @@ static int xen_smp_intr_init(unsigned int cpu) > > > goto fail; > > > per_cpu(xen_callfuncsingle_irq, cpu) = rc; > > > > > > + /* > > > + * The IRQ worker on PVHVM goes through the native path and uses the > > > + * IPI mechanism. > > > + */ > > > + if (xen_hvm_domain()) > > > + return 0; > > > + > > > callfunc_name = kasprintf(GFP_KERNEL, "irqwork%d", cpu); > > > rc = bind_ipi_to_irqhandler(XEN_IRQ_WORK_VECTOR, > > > cpu, > > > @@ -167,6 +174,9 @@ static int xen_smp_intr_init(unsigned int cpu) > > > if (per_cpu(xen_callfuncsingle_irq, cpu) >= 0) > > > unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu), > > > NULL); > > > + if (xen_hvm_domain()) > > > + return rc; > > > + > > > if (per_cpu(xen_irq_work, cpu) >= 0) > > > unbind_from_irqhandler(per_cpu(xen_irq_work, cpu), NULL); > > > > > > @@ -661,7 +671,8 @@ static void xen_hvm_cpu_die(unsigned int cpu) > > > unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu), NULL); > > > unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu), NULL); > > > unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu), NULL); > > > - unbind_from_irqhandler(per_cpu(xen_irq_work, cpu), NULL); > > > + if (!xen_hvm_domain()) > > > + unbind_from_irqhandler(per_cpu(xen_irq_work, cpu), NULL); > > > xen_uninit_lock_cpu(cpu); > > > xen_teardown_timer(cpu); > > > native_cpu_die(cpu); > > > -- > > > 1.8.1.4 > > > >