From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751353AbcFXO7m (ORCPT ); Fri, 24 Jun 2016 10:59:42 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:38412 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751001AbcFXO7l convert rfc822-to-8bit (ORCPT ); Fri, 24 Jun 2016 10:59:41 -0400 Date: Fri, 24 Jun 2016 11:59:33 -0300 From: Gustavo Padovan To: Christian =?iso-8859-1?Q?K=F6nig?= Cc: Gustavo Padovan , Christian =?iso-8859-1?Q?K=F6nig?= , dri-devel@lists.freedesktop.org, marcheu@google.com, Daniel Stone , seanpaul@google.com, Daniel Vetter , linux-kernel@vger.kernel.org, laurent.pinchart@ideasonboard.com, Gustavo Padovan , John Harrison , m.chehab@samsung.com Subject: Re: [RFC 0/5] rework fences on struct sync_file Message-ID: <20160624145933.GF2508@joana> References: <1466695790-2833-1-git-send-email-gustavo@padovan.org> <576CFD0B.6000501@amd.com> <20160624131724.GA2503@joana> <576D4032.3000001@vodafone.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8BIT In-Reply-To: <576D4032.3000001@vodafone.de> User-Agent: Mutt/1.6.1 (2016-04-27) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2016-06-24 Christian König : > Am 24.06.2016 um 15:17 schrieb Gustavo Padovan: > > Hi Christian, > > > > 2016-06-24 Christian König : > > > > > Am 23.06.2016 um 17:29 schrieb Gustavo Padovan: > > > > From: Gustavo Padovan > > > > > > > > Hi all, > > > > > > > > This is an attempt to improve fence support on Sync File. The basic idea > > > > is to have only sync_file->fence and store all fences there, either as > > > > normal fences or fence_arrays. That way we can remove some potential > > > > duplication when using fence_array with sync_file: the duplication of the array > > > > of fences and the duplication of fence_add_callback() for all fences. > > > > > > > > Now when creating a new sync_file during the merge process sync_file_set_fence() > > > > will set sync_file->fence based on the number of fences for that sync_file. If > > > > there is more than one fence a fence_array is created. One important advantage > > > > approach is that we only add one fence callback now, no matter how many fences > > > > there are in a sync_file - the individual callbacks are added by fence_array. > > > > > > > > Two fence ops had to be created to help abstract the difference between handling > > > > fences and fences_arrays: .teardown() and .get_fences(). The former run needed > > > > on fence_array, and the latter just return a copy of all fences in the fence. > > > > I'm not so sure about adding those two, speacially .get_fences(). What do you > > > > think? > > > Clearly not a good idea to add this a fence ops, cause those are specialized > > > functions for only a certain fence implementation (the fence_array). > > Are you refering only to .get_fences()? > > That comment was only for the get_fences() operation, but the teardown() > callback looks very suspicious to me as well. > > Can you explain once more why that should be necessary? When the sync_file owner exits we need to clean up it and that means releasing the fence too, however with fence_array we can't just call fence_put() as a extra reference to array->base for each fence is held when enabling signalling. Thus we need a prior step, that I called teardown(), to remove the callback for not signaled fences and put the extra references. Another way to do this would be: if (fence_is_array(sync_file->fence)) fence_array_destroy(to_fence_array(sync_file->fence)); else fence_put(sync_file_fence); This would avoid the extra ops, maybe we should go this way. Gustavo