From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758001AbZEPPPy (ORCPT ); Sat, 16 May 2009 11:15:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753755AbZEPPPq (ORCPT ); Sat, 16 May 2009 11:15:46 -0400 Received: from hera.kernel.org ([140.211.167.34]:55075 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753017AbZEPPPp (ORCPT ); Sat, 16 May 2009 11:15:45 -0400 Message-ID: <4A0ED8D8.2010303@kernel.org> Date: Sun, 17 May 2009 00:16:40 +0900 From: Tejun Heo User-Agent: Thunderbird 2.0.0.19 (X11/20081227) MIME-Version: 1.0 To: suresh.b.siddha@intel.com CC: "JBeulich@novell.com" , "andi@firstfloor.org" , "mingo@elte.hu" , "linux-kernel-owner@vger.kernel.org" , "hpa@zytor.com" , "tglx@linutronix.de" , "linux-kernel@vger.kernel.org" Subject: Re: [GIT PATCH] x86,percpu: fix pageattr handling with remap allocator References: <1242305390-21958-1-git-send-email-tj@kernel.org> <1242436626.27006.8623.camel@localhost.localdomain> In-Reply-To: <1242436626.27006.8623.camel@localhost.localdomain> X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Sat, 16 May 2009 15:15:24 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Suresh. Suresh Siddha wrote: > Tejun, Can you please educate me why we need to map this first > percpu chunk (which is pre-allocated during boot and is physically > contiguous) into vmalloc area? To make areas for each cpu congruent such that the address offset of a percpu symbol for CPU N is always the same from the address for CPU 0. > Perhaps even for the other dynamically allocated secondary chunks? > (as far as I can see, all the chunk allocations seems to be > physically contiguous and later mapped into vmalloc area).. > > That should simplify these things quite a bit(atleast for first > percpu chunk). I am missing something obvious I guess. Hmm... Sorry I don't really follow. Can you please elaborate the question? thanks. -- tejun