From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: Re: [PATCH 10/10] gpu: host1x: Optionally block when acquiring channel Date: Sat, 11 Nov 2017 00:15:11 +0300 Message-ID: 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> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1b35ec93-167b-3436-0ff2-5e2e0886aea7-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Content-Language: en-US Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Mikko Perttunen , Mikko Perttunen , thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org Cc: dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: dri-devel@lists.freedesktop.org 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.