From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756409AbZLUBUp (ORCPT ); Sun, 20 Dec 2009 20:20:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756367AbZLUBUg (ORCPT ); Sun, 20 Dec 2009 20:20:36 -0500 Received: from one.firstfloor.org ([213.235.205.2]:37717 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756360AbZLUBUb (ORCPT ); Sun, 20 Dec 2009 20:20:31 -0500 From: Andi Kleen References: <20091221220.243954235@firstfloor.org> In-Reply-To: <20091221220.243954235@firstfloor.org> To: linux-kernel@vger.kernel.org, paulmck@linux.vnet.ibm.com, ebiederm@xmission.com Subject: [PATCH] [9/11] SYSCTL: Add a mutex to the page_alloc zone order sysctl Message-Id: <20091221012030.B1940B158A@basil.firstfloor.org> Date: Mon, 21 Dec 2009 02:20:30 +0100 (CET) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The zone list code clearly cannot tolerate concurrent writers (I couldn't find any locks for that), so simply add a global mutex. No need for RCU in this case. Signed-off-by: Andi Kleen --- mm/page_alloc.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) Index: linux-2.6.33-rc1-ak/mm/page_alloc.c =================================================================== --- linux-2.6.33-rc1-ak.orig/mm/page_alloc.c +++ linux-2.6.33-rc1-ak/mm/page_alloc.c @@ -2401,13 +2401,14 @@ int numa_zonelist_order_handler(ctl_tabl { char saved_string[NUMA_ZONELIST_ORDER_LEN]; int ret; + static DEFINE_MUTEX(zl_order_mutex); + mutex_lock(&zl_order_mutex); if (write) - strncpy(saved_string, (char*)table->data, - NUMA_ZONELIST_ORDER_LEN); + strcpy(saved_string, (char*)table->data); ret = proc_dostring(table, write, buffer, length, ppos); if (ret) - return ret; + goto out; if (write) { int oldval = user_zonelist_order; if (__parse_numa_zonelist_order((char*)table->data)) { @@ -2420,7 +2421,9 @@ int numa_zonelist_order_handler(ctl_tabl } else if (oldval != user_zonelist_order) build_all_zonelists(); } - return 0; +out: + mutex_unlock(&zl_order_mutex); + return ret; }