From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754325Ab2KEOJb (ORCPT ); Mon, 5 Nov 2012 09:09:31 -0500 Received: from smtp-outbound-2.vmware.com ([208.91.2.13]:37215 "EHLO smtp-outbound-2.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751088Ab2KEOJa (ORCPT ); Mon, 5 Nov 2012 09:09:30 -0500 Message-ID: <5097C896.80805@vmware.com> Date: Mon, 05 Nov 2012 15:09:26 +0100 From: Thomas Hellstrom User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/20121016 Thunderbird/16.0.1 MIME-Version: 1.0 To: Maarten Lankhorst CC: airlied@gmail.com, airlied@redhat.com, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH 4/4] drm/ttm: Optimize reservation slightly References: <1352122278-12896-1-git-send-email-thellstrom@vmware.com> <1352122278-12896-5-git-send-email-thellstrom@vmware.com> <5097C6A1.9000405@canonical.com> In-Reply-To: <5097C6A1.9000405@canonical.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/05/2012 03:01 PM, Maarten Lankhorst wrote: > Hey, > > Op 05-11-12 14:31, Thomas Hellstrom schreef: >> Reservation locking currently always takes place under the LRU spinlock. >> Hence, strictly there is no need for an atomic_cmpxchg call; we can use >> atomic_read followed by atomic_write since nobody else will ever reserve >> without the lru spinlock held. >> At least on Intel this should remove a locked bus cycle on successful >> reserve. >> >> Signed-off-by: Thomas Hellstrom >> > Is that really a good thing to submit when I am busy killing lru lock around reserve? :-) > If your patch series makes it into the same kernel, let's kill this patch. Otherwise it may live at least for a kernel release. It's not a big thing to rebase against, and I won't complain if your patch adds another atomic read-modify-write op here. :) /Thomas