Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934874AbZAOWMO (ORCPT ); Thu, 15 Jan 2009 17:12:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933590AbZAOWCM (ORCPT ); Thu, 15 Jan 2009 17:02:12 -0500 Received: from kroah.org ([198.145.64.141]:38225 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933550AbZAOWCG (ORCPT ); Thu, 15 Jan 2009 17:02:06 -0500 Date: Thu, 15 Jan 2009 13:59:30 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , Domenico Andreoli , Willy Tarreau , Rodrigo Rubira Branco , Jake Edge , Eugene Teo , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Ravikiran Thirumalai , Mike Travis , Ingo Molnar Subject: [patch 18/85] x86: fix incorrect __read_mostly on _boot_cpu_pda Message-ID: <20090115215930.GS17227@kroah.com> References: <20090115215237.906089480@mini.kroah.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename="x86-fix-incorrect-__read_mostly-on-_boot_cpu_pda.patch" In-Reply-To: <20090115215812.GA17227@kroah.com> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1346 Lines: 42 2.6.27-stable review patch. If anyone has any objections, please let us know. ------------------ From: Ravikiran G Thirumalai commit 26799a63110dcbe81291ea53178f6b4810d07424 upstream. The pda rework (commit 3461b0af025251bbc6b3d56c821c6ac2de6f7209) to remove static boot cpu pdas introduced a performance bug. _boot_cpu_pda is the actual pda used by the boot cpu and is definitely not "__read_mostly" and ended up polluting the read mostly section with writes. This bug caused regression of about 8-10% on certain syscall intensive workloads. Signed-off-by: Ravikiran Thirumalai Acked-by: Mike Travis Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/head64.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -26,7 +26,7 @@ #include /* boot cpu pda */ -static struct x8664_pda _boot_cpu_pda __read_mostly; +static struct x8664_pda _boot_cpu_pda; #ifdef CONFIG_SMP /* -- 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/