From patchwork Thu Jun 27 19:57:33 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Srivatsa S. Bhat" X-Patchwork-Id: 255166 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3E0AE2C0D45 for ; Fri, 28 Jun 2013 06:06:55 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754994Ab3F0UBJ (ORCPT ); Thu, 27 Jun 2013 16:01:09 -0400 Received: from e23smtp05.au.ibm.com ([202.81.31.147]:46393 "EHLO e23smtp05.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754990Ab3F0UBG (ORCPT ); Thu, 27 Jun 2013 16:01:06 -0400 Received: from /spool/local by e23smtp05.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 28 Jun 2013 05:54:54 +1000 Received: from d23dlp02.au.ibm.com (202.81.31.213) by e23smtp05.au.ibm.com (202.81.31.211) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Fri, 28 Jun 2013 05:54:51 +1000 Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [9.190.235.21]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 8E0C02BB0057; Fri, 28 Jun 2013 06:00:59 +1000 (EST) Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r5RK0oFo262592; Fri, 28 Jun 2013 06:00:50 +1000 Received: from d23av04.au.ibm.com (loopback [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r5RK0tCH013715; Fri, 28 Jun 2013 06:00:59 +1000 Received: from srivatsabhat.in.ibm.com ([9.79.209.72]) by d23av04.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id r5RK0l81013521; Fri, 28 Jun 2013 06:00:48 +1000 From: "Srivatsa S. Bhat" Subject: [PATCH v3 30/45] x86/xen: Use get/put_online_cpus_atomic() to prevent CPU offline To: tglx@linutronix.de, peterz@infradead.org, tj@kernel.org, oleg@redhat.com, paulmck@linux.vnet.ibm.com, rusty@rustcorp.com.au, mingo@kernel.org, akpm@linux-foundation.org, namhyung@kernel.org, walken@google.com, vincent.guittot@linaro.org, laijs@cn.fujitsu.com, David.Laight@aculab.com Cc: rostedt@goodmis.org, wangyun@linux.vnet.ibm.com, xiaoguangrong@linux.vnet.ibm.com, sbw@mit.edu, fweisbec@gmail.com, zhong@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, srivatsa.bhat@linux.vnet.ibm.com, linux-pm@vger.kernel.org, linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Konrad Rzeszutek Wilk , Jeremy Fitzhardinge , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, xen-devel@lists.xensource.com, virtualization@lists.linux-foundation.org, "Srivatsa S. Bhat" Date: Fri, 28 Jun 2013 01:27:33 +0530 Message-ID: <20130627195733.29830.8002.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130627195136.29830.10445.stgit@srivatsabhat.in.ibm.com> References: <20130627195136.29830.10445.stgit@srivatsabhat.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13062719-1396-0000-0000-0000032F2AFD Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Once stop_machine() is gone from the CPU offline path, we won't be able to depend on disabling preemption to prevent CPUs from going offline from under us. Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going offline, while invoking from atomic context. Cc: Konrad Rzeszutek Wilk Cc: Jeremy Fitzhardinge Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: x86@kernel.org Cc: xen-devel@lists.xensource.com Cc: virtualization@lists.linux-foundation.org Signed-off-by: Srivatsa S. Bhat --- arch/x86/xen/mmu.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index fdc3ba2..3229c4f 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -39,6 +39,7 @@ * Jeremy Fitzhardinge , XenSource Inc, 2007 */ #include +#include #include #include #include @@ -1163,9 +1164,13 @@ static void xen_drop_mm_ref(struct mm_struct *mm) */ static void xen_exit_mmap(struct mm_struct *mm) { - get_cpu(); /* make sure we don't move around */ + /* + * Make sure we don't move around, and also prevent CPUs from + * going offline. + */ + get_online_cpus_atomic(); xen_drop_mm_ref(mm); - put_cpu(); + put_online_cpus_atomic(); spin_lock(&mm->page_table_lock);