From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030357AbWGMUWR (ORCPT ); Thu, 13 Jul 2006 16:22:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030358AbWGMUWR (ORCPT ); Thu, 13 Jul 2006 16:22:17 -0400 Received: from smtp105.mail.mud.yahoo.com ([209.191.85.215]:35184 "HELO smtp105.mail.mud.yahoo.com") by vger.kernel.org with SMTP id S1030357AbWGMUWQ (ORCPT ); Thu, 13 Jul 2006 16:22:16 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=wwTAECo5GOcleHr+qQToGGsIZ1l48uChSNjz0IYJaM8hBnaUguZIweHcVcG7IGE6Ag+M5W/w26SF84kyV31k3APatFXbtsW7ZKsAnRo232iWAsFcb8EFMVuBPJr5LfpiQlR5MUbnSR7BKWtguY/i+lk7JYMAqL29clvy2jka9YE= ; Message-ID: <44B64CC9.7070307@yahoo.com.au> Date: Thu, 13 Jul 2006 23:38:17 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1 X-Accept-Language: en MIME-Version: 1.0 To: Takashi Iwai CC: Russell King , Marc Singer , Linux-Kernel Subject: Re: DMA memory, split_page, BUG_ON(PageCompound()), sound 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> <20060712103241.GA7908@flint.arm.linux.org.uk> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Takashi Iwai wrote: > At Wed, 12 Jul 2006 11:32:41 +0100, >>In which case should ALSA be passing __GFP_COMP to the dma allocator ? Yes, sorry I didn't answer your question: ALSA basically wants to be able to have that memory mmapable by userspace programs, and it doesn't care whether this is via compound pages or split pages. > I would be willing to remove __GFP_COMP if it's not needed :) > Passing this flag is really confusing. The driver doesn't use the > compound pages at all but it was added just to enable mmap support. > So, Nick's proposal appears reasonable to me. I don't think it would be hard. Just need a bit of thinking about how to go about composing some sort of GFP_USERMAP that can easily be handled by all allocators, without costing performance or being too intrusive. I suspect I won't have time to wade into such an exercise until after OLS. But I could give a quick review for anyone who does ;) -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com