From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751233AbWGLKct (ORCPT ); Wed, 12 Jul 2006 06:32:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751240AbWGLKct (ORCPT ); Wed, 12 Jul 2006 06:32:49 -0400 Received: from caramon.arm.linux.org.uk ([212.18.232.186]:6924 "EHLO caramon.arm.linux.org.uk") by vger.kernel.org with ESMTP id S1751233AbWGLKcs (ORCPT ); Wed, 12 Jul 2006 06:32:48 -0400 Date: Wed, 12 Jul 2006 11:32:41 +0100 From: Russell King To: Nick Piggin Cc: Marc Singer , Linux-Kernel Subject: Re: DMA memory, split_page, BUG_ON(PageCompound()), sound Message-ID: <20060712103241.GA7908@flint.arm.linux.org.uk> Mail-Followup-To: Nick Piggin , Marc Singer , Linux-Kernel References: <20060709000703.GA9806@cerise.buici.com> <44B0774E.5010103@yahoo.com.au> <20060710025103.GC28166@cerise.buici.com> <44B1FAE4.9070903@yahoo.com.au> <20060710162600.GB18728@flint.arm.linux.org.uk> <44B28F93.9020304@yahoo.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <44B28F93.9020304@yahoo.com.au> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 11, 2006 at 03:34:11AM +1000, Nick Piggin wrote: > Russell King wrote: > >On Mon, Jul 10, 2006 at 04:59:48PM +1000, Nick Piggin wrote: > > > >>I guess you could do it a number of ways. Maybe having GFP_USERMAP > >>set __GFP_USERMAP|__GFP_COMP, and the arm dma memory allocator can > >>strip the __GFP_COMP. > >> > >>If you get an explicit __GFP_COMP passed down, the allocator doesn't > >>know whether that was because they want a user mappable area, or > >>really want a compound page (in which case, stripping __GFP_COMP is > >>the wrong thing to do). > > > > > >So I'll mask off __GFP_COMP for the time being in the ARM dma allocator > >with a note to this effect? > > I believe that should do the trick, yes (AFAIK, nobody yet is > explicitly relying on a compound page from the dma allocator). In which case should ALSA be passing __GFP_COMP to the dma allocator ? -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core