From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756196AbYH0Ng0 (ORCPT ); Wed, 27 Aug 2008 09:36:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755113AbYH0NgR (ORCPT ); Wed, 27 Aug 2008 09:36:17 -0400 Received: from smtp108.mail.mud.yahoo.com ([209.191.85.218]:34854 "HELO smtp108.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754982AbYH0NgR (ORCPT ); Wed, 27 Aug 2008 09:36:17 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:X-YMail-OSG:X-Yahoo-Newman-Property:From:To:Subject:Date:User-Agent:Cc:References:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-Disposition:Message-Id; b=JyitovVYemAsXE/M7nB2CNVVA01y2neBPs9vg0ysOLnh/k4BNX4dPDpeSig98DDgfoBMKv6mlD/pF1UQYoRiZi5dOhMGRr3X5bQN5MEV6+bLq2dzBJ5HOygp+2t8sF7Zylp9e5iJohlbx8yJMiIZUC76AXd2yeK4qfNZDkv7RC8= ; X-YMail-OSG: PvzPnE8VM1nj58ZTbwsZjHBBj.2tARI0DeT9dIr547yPVTIHehjPD3RnmxUjguw4dggR8O6BmioxAk2wL3L9DVFrpaY_pOGlZM6LeOvbMfaTgD7_ksJyD3vjXXwJ8uREzS8t8EOtmf9RkVQJsQsfak1I X-Yahoo-Newman-Property: ymail-3 From: Nick Piggin To: Eric Anholt , Dave Airlie , linux-arch@vger.kernel.org Subject: Re: [PATCH] Export kmap_atomic_pfn for DRM-GEM. Date: Wed, 27 Aug 2008 23:36:05 +1000 User-Agent: KMail/1.9.5 Cc: linux-kernel@vger.kernel.org References: <1219779789-8368-1-git-send-email-eric@anholt.net> <1219779789-8368-2-git-send-email-eric@anholt.net> <1219779789-8368-3-git-send-email-eric@anholt.net> In-Reply-To: <1219779789-8368-3-git-send-email-eric@anholt.net> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200808272336.05736.nickpiggin@yahoo.com.au> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 27 August 2008 05:43, Eric Anholt wrote: > The driver would like to map IO space directly for copying data in when > appropriate, to avoid CPU cache flushing for streaming writes. > kmap_atomic_pfn lets us avoid IPIs associated with ioremap for this > process. > > Signed-off-by: Eric Anholt > --- > arch/x86/mm/highmem_32.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c > index 165c871..d52e91d 100644 > --- a/arch/x86/mm/highmem_32.c > +++ b/arch/x86/mm/highmem_32.c > @@ -137,6 +137,7 @@ void *kmap_atomic_pfn(unsigned long pfn, enum km_type > type) > > return (void*) vaddr; > } > +EXPORT_SYMBOL(kmap_atomic_pfn); > > struct page *kmap_atomic_to_page(void *ptr) > { I wonder if you ever tested my vmap rework patches with this issue? It seems somewhat x86 specific and also not conceptually so clean to use kmap_atomic_pfn for this. vmap may not be used by all architectures but I think it might be able to cover some of them. As I said, there are some other possible improvements that can be made to my vmap rewrite if performance isn't good enough, but I simply have not seen numbers... Thanks, Nick