From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750984AbdKLLXs (ORCPT ); Sun, 12 Nov 2017 06:23:48 -0500 Received: from mail-lf0-f65.google.com ([209.85.215.65]:54900 "EHLO mail-lf0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750735AbdKLLXp (ORCPT ); Sun, 12 Nov 2017 06:23:45 -0500 X-Google-Smtp-Source: AGs4zMZwSOAWlrLzKBTWN9I8Vsa/XaSnGySH620pNLXBKw0uCTchg8Ul4Y+EOSDWuAjrONWLdM5/Bg== Subject: Re: [PATCH 10/10] gpu: host1x: Optionally block when acquiring channel From: Dmitry Osipenko To: Mikko Perttunen , Mikko Perttunen , thierry.reding@gmail.com, jonathanh@nvidia.com Cc: dri-devel@lists.freedesktop.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org References: <20171105110118.15142-1-mperttunen@nvidia.com> <20171105110118.15142-11-mperttunen@nvidia.com> <9c5676eb-ba6f-c187-29e4-7b331bd3962f@gmail.com> <38340901-7016-3444-5ace-64159b32f1c7@kapsi.fi> <1b35ec93-167b-3436-0ff2-5e2e0886aea7@gmail.com> Message-ID: <775a2536-b225-2d96-3954-7efab6bc5c3e@gmail.com> Date: Sun, 12 Nov 2017 14:23:42 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11.11.2017 00:15, Dmitry Osipenko wrote: > On 07.11.2017 18:29, Dmitry Osipenko wrote: >> On 07.11.2017 16:11, Mikko Perttunen wrote: >>> On 05.11.2017 19:14, Dmitry Osipenko wrote: >>>> On 05.11.2017 14:01, Mikko Perttunen wrote: >>>>> Add an option to host1x_channel_request to interruptibly wait for a >>>>> free channel. This allows IOCTLs that acquire a channel to block >>>>> the userspace. >>>>> >>>> >>>> Wouldn't it be more optimal to request channel and block after job's pining, >>>> when all patching and checks are completed? Note that right now we have locking >>>> around submission in DRM, which I suppose should go away by making locking fine >>>> grained. >>> >>> That would be possible, but I don't think it should matter much since contention >>> here should not be the common case. >>> >>>> >>>> Or maybe it would be more optimal to just iterate over channels, like I >>>> suggested before [0]? >>> >>> Somehow I hadn't noticed this before, but this would break the invariant of >>> having one client/class per channel. >>> >> >> Yes, currently there is a weak relation of channel and clients device, but seems >> channels device is only used for printing dev_* messages and device could be >> borrowed from the channels job. I don't see any real point of hardwiring channel >> to a specific device or client. > > Although, it won't work with syncpoint assignment to channel. On the other hand.. it should work if one syncpoint could be assigned to multiple channels, couldn't it?