From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Hellstrom Subject: Re: [PATCH 4/4] drm/ttm: Optimize reservation slightly Date: Mon, 05 Nov 2012 15:09:26 +0100 Message-ID: <5097C896.80805@vmware.com> References: <1352122278-12896-1-git-send-email-thellstrom@vmware.com> <1352122278-12896-5-git-send-email-thellstrom@vmware.com> <5097C6A1.9000405@canonical.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5097C6A1.9000405@canonical.com> Sender: linux-kernel-owner@vger.kernel.org To: Maarten Lankhorst Cc: airlied@gmail.com, airlied@redhat.com, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.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