Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759534Ab3DZKa7 (ORCPT ); Fri, 26 Apr 2013 06:30:59 -0400 Received: from smtp.eu.citrix.com ([46.33.159.39]:48995 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759299Ab3DZKa6 (ORCPT ); Fri, 26 Apr 2013 06:30:58 -0400 X-IronPort-AV: E=Sophos;i="4.87,552,1363132800"; d="scan'208";a="3974815" Message-ID: <1366972256.3142.60.camel@zakaz.uk.xensource.com> Subject: Re: [PATCH v4 2/7] xen/arm: SMP support From: Ian Campbell To: Stefano Stabellini CC: "xen-devel@lists.xensource.com" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "konrad.wilk@oracle.com" Date: Fri, 26 Apr 2013 11:30:56 +0100 In-Reply-To: References: <1366831695-13214-2-git-send-email-stefano.stabellini@eu.citrix.com> <1366897221.20256.544.camel@zakaz.uk.xensource.com> <1366909184.3142.0.camel@zakaz.uk.xensource.com> <1366966304.3142.33.camel@zakaz.uk.xensource.com> Organization: Citrix Systems, Inc. Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2143 Lines: 49 On Fri, 2013-04-26 at 11:27 +0100, Stefano Stabellini wrote: > On Fri, 26 Apr 2013, Ian Campbell wrote: > > On Thu, 2013-04-25 at 19:45 +0100, Stefano Stabellini wrote: > > > On Thu, 25 Apr 2013, Ian Campbell wrote: > > > > > > > @@ -216,6 +245,8 @@ static int __init xen_guest_init(void) > > > > > > > * is required to use VCPUOP_register_vcpu_info to place vcpu info > > > > > > > * for secondary CPUs as they are brought up. */ > > > > > > > per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; > > > > > > > + for_each_online_cpu(i) > > > > > > > + xen_secondary_init(i); > > > > > > > > > > > > > > gnttab_init(); > > > > > > > if (!xen_initial_domain()) > > > > > > [...] > > > > > > > @@ -244,7 +280,7 @@ static int __init xen_init_events(void) > > > > > > > return -EINVAL; > > > > > > > } > > > > > > > > > > > > > > - enable_percpu_irq(xen_events_irq, 0); > > > > > > > + on_each_cpu(xen_percpu_enable_events, NULL, 0); > > > > > > > > > > > > It feels like there ought to be some sort of per-cpu bringup callback > > > > > > which takes care of these dynamically. Maybe that doesn't matter until > > > > > > we get vcpu hotplug going? > > > > > > > > > > I suspect there isn't one, considering that on_each_cpu is also used by > > > > > kvm_vgic_hyp_init, kvm_timer_hyp_init and others. > > > > > > > > Could we use cpu_notifiers for this? > > > > > > cpu_notifiers are for cpu hotplug, not for secondary cpu bringup > > > > Are you sure they don't also trigger during bringup, because the > > distinction is a little bit academic... > > My mistake, they do run on secondary cpus, but not in our case because > xen_guest_init is called *after* cpu_notifiers are called. > So, they are too early for Xen. Another reason to consider calling xen_guest_init much earlier then IMHO. although we can live with the solution you have now I suppose. Ian. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/