From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754118Ab0JTVmd (ORCPT ); Wed, 20 Oct 2010 17:42:33 -0400 Received: from terminus.zytor.com ([198.137.202.10]:41080 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751720Ab0JTVmc (ORCPT ); Wed, 20 Oct 2010 17:42:32 -0400 Message-ID: <4CBF6234.9090402@zytor.com> Date: Wed, 20 Oct 2010 14:42:12 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc13 Thunderbird/3.1.4 MIME-Version: 1.0 To: Eric Dumazet CC: Andi Kleen , Shaohua Li , lkml , Ingo Molnar , "Chen, Tim C" Subject: Re: [PATCH 1/2]percpu: introduce read mostly percpu API References: <1287544022.4571.7.camel@sli10-conroe.sh.intel.com> <1287551880.2700.79.camel@edumazet-laptop> <20101020073511.GC20124@basil.fritz.box> <1287561234.2328.1.camel@edumazet-laptop> <4CBF616E.1080501@zytor.com> In-Reply-To: <4CBF616E.1080501@zytor.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/20/2010 02:38 PM, H. Peter Anvin wrote: > On 10/20/2010 12:53 AM, Eric Dumazet wrote: >> >> My question was more a rethoric one. I understand for sure the intent. >> >> All this should be explained in changelog, so that people know >> when/where use this new class of per_cpu variables ;) >> > > Changelog really isn't the best place for this, a Documentation file > would be better. > > I'm trying to grok the intended semantic of the shared_aligned section > right now... I'm not sure if there is a significant difference between > the read mostly and the shared aligned section? > >>From the looks of it, it's a manual way to do what the linker would, quite frankly, do better with SORT_BY_ALIGNMENT() -- although by separating it out it might still be a win to avoid lots of "N+1"-sized sections aligned to N. -hpa