From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758446AbZEMKKM (ORCPT ); Wed, 13 May 2009 06:10:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757922AbZEMKJ6 (ORCPT ); Wed, 13 May 2009 06:09:58 -0400 Received: from cantor2.suse.de ([195.135.220.15]:35079 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752384AbZEMKJ6 (ORCPT ); Wed, 13 May 2009 06:09:58 -0400 Message-ID: <4A0A9C70.6090803@novell.com> Date: Wed, 13 May 2009 19:09:52 +0900 From: Tejun Heo User-Agent: Thunderbird 2.0.0.19 (X11/20081227) MIME-Version: 1.0 To: Jan Beulich Cc: Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: remap allocator for per-CPU memory References: <4A09B23B02000078000007F1@vpn.id2.novell.com> <4A09991E.9010903@kernel.org> In-Reply-To: <4A09991E.9010903@kernel.org> X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Tejun Heo wrote: > Jan Beulich wrote: >> Didn't the addition of this allocator introduce another case that >> needs special treatment in pageattr.c? Since large pages are used >> for mapping the allocated memory, but only part of the initially >> allocated large pages are actually retained, there's now the >> potential for TLB aliases with different cache attributes for those >> parts of these pages that get passed back through free_bootmem(). > > Hmmm.... yes, the large page mapping and the returned part of it would > alias each other. What changes should be made for it? Dunno much > about how pageattr works. Okay, just glanced over the pageattr code. I don't think we need any special provisions for this as long as the TLB is fine with having overlapping PMD and PTE mappings with different attributes (please note that these two mappings aren't occupying the same linear addresses - they're aliases). This is allowed, right? Thanks. -- tejun