From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755581Ab0JUBii (ORCPT ); Wed, 20 Oct 2010 21:38:38 -0400 Received: from mga14.intel.com ([143.182.124.37]:64041 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751054Ab0JUBih (ORCPT ); Wed, 20 Oct 2010 21:38:37 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.58,214,1286175600"; d="scan'208";a="338592101" Date: Thu, 21 Oct 2010 09:38:33 +0800 From: Shaohua Li To: "hpa@zytor.com" Cc: "linux-kernel@vger.kernel.org" , "hpa@zytor.com" , "mingo@redhat.com" , "eric.dumazet@gmail.com" , "tglx@linutronix.de" , "hpa@linux.intel.com" Subject: Re: [tip:x86/mm] percpu: Introduce a read-mostly percpu API Message-ID: <20101021013833.GA21863@sli10-conroe.sh.intel.com> References: <1287544022.4571.7.camel@sli10-conroe.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi hpa, On Thu, Oct 21, 2010 at 07:06:59AM +0800, tip-bot for Shaohua Li wrote: > [ hpa: moved it *after* the page-aligned section, for obvious > reasons. ] move it after page-aligned section can't guarantee to avoid cache false sharing. we need: . = ALIGN(CACHE_LINE_SIZE); *(.data..percpu..readmostly) . = ALIGN(CACHE_LINE_SIZE); To make sure before/after readmostly section doesn't share cache line with others. The headcache is some arch need L1_CACHE_SIZE and others need (1 << INTERNODE_CACHE_SHIFT). We need change all ARCHs to make this happen.