From: "Christian König" <deathsimple@vodafone.de> To: "Maarten Lankhorst" <maarten.lankhorst@canonical.com>, "Christian König" <christian.koenig@amd.com>, "Daniel Vetter" <daniel.vetter@ffwll.ch> Cc: Thomas Hellstrom <thellstrom@vmware.com>, nouveau <nouveau@lists.freedesktop.org>, LKML <linux-kernel@vger.kernel.org>, dri-devel <dri-devel@lists.freedesktop.org>, Ben Skeggs <bskeggs@redhat.com>, "Deucher, Alexander" <alexander.deucher@amd.com> Subject: Re: [Nouveau] [PATCH 09/17] drm/radeon: use common fence implementation for fences Date: Wed, 23 Jul 2014 09:58:16 +0200 [thread overview] Message-ID: <53CF6B18.5070107@vodafone.de> (raw) In-Reply-To: <53CF699D.9070902@canonical.com> > Regardless of the fence implementation, why would it be a good idea to do a full lockup recovery when some other driver is > calling your wait function? That doesn't seem to be a nice thing to do, so I think a timeout is the best error you could return here, > other drivers have to deal with that anyway. The problem is that we need to guarantee that the lockup will be resolved eventually. Just imagine an application using prime is locking up Radeon and because of that gets killed by the user. Nothing else in the system would use the Radeon hardware any more and so radeon gets only called by another driver waiting patiently for radeon to finish rendering which never happens because the whole thing is locked up and we don't get a chance to recover. Christian. Am 23.07.2014 09:51, schrieb Maarten Lankhorst: > op 23-07-14 09:37, Christian König schreef: >> Am 23.07.2014 09:31, schrieb Daniel Vetter: >>> On Wed, Jul 23, 2014 at 9:26 AM, Christian König >>> <deathsimple@vodafone.de> wrote: >>>> It's not a locking problem I'm talking about here. Radeons lockup handling >>>> kicks in when anything calls into the driver from the outside, if you have a >>>> fence wait function that's called from the outside but doesn't handle >>>> lockups you essentially rely on somebody else calling another radeon >>>> function for the lockup to be resolved. >>> So you don't have a timer in radeon that periodically checks whether >>> progress is still being made? That's the approach we're using in i915, >>> together with some tricks to kick any stuck waiters so that we can >>> reliably step in and grab locks for the reset. >> We tried this approach, but it didn't worked at all. >> >> I already considered trying it again because of the upcoming fence implementation, but reconsidering that when a driver is forced to change it's handling because of the fence implementation that's just another hint that there is something wrong here. > As far as I can tell it wouldn't need to be reworked for the fence implementation currently, only the moment you want to allow callers outside of radeon. :-) > Doing a GPU lockup recovery in the wait function would be messy even right now, you would hit a deadlock in ttm_bo_delayed_delete -> ttm_bo_cleanup_refs_and_unlock. > > Regardless of the fence implementation, why would it be a good idea to do a full lockup recovery when some other driver is > calling your wait function? That doesn't seem to be a nice thing to do, so I think a timeout is the best error you could return here, > other drivers have to deal with that anyway. > > ~Maarten >
WARNING: multiple messages have this Message-ID (diff)
From: "Christian König" <deathsimple-ANTagKRnAhcb1SvskN2V4Q@public.gmane.org> To: "Maarten Lankhorst" <maarten.lankhorst-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>, "Christian König" <christian.koenig-5C7GfCeVMHo@public.gmane.org>, "Daniel Vetter" <daniel.vetter-/w4YWyX8dFk@public.gmane.org> Cc: Thomas Hellstrom <thellstrom-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>, nouveau <nouveau-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org>, LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, dri-devel <dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org>, Ben Skeggs <bskeggs-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, "Deucher, Alexander" <alexander.deucher-5C7GfCeVMHo@public.gmane.org> Subject: Re: [PATCH 09/17] drm/radeon: use common fence implementation for fences Date: Wed, 23 Jul 2014 09:58:16 +0200 [thread overview] Message-ID: <53CF6B18.5070107@vodafone.de> (raw) In-Reply-To: <53CF699D.9070902-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org> > Regardless of the fence implementation, why would it be a good idea to do a full lockup recovery when some other driver is > calling your wait function? That doesn't seem to be a nice thing to do, so I think a timeout is the best error you could return here, > other drivers have to deal with that anyway. The problem is that we need to guarantee that the lockup will be resolved eventually. Just imagine an application using prime is locking up Radeon and because of that gets killed by the user. Nothing else in the system would use the Radeon hardware any more and so radeon gets only called by another driver waiting patiently for radeon to finish rendering which never happens because the whole thing is locked up and we don't get a chance to recover. Christian. Am 23.07.2014 09:51, schrieb Maarten Lankhorst: > op 23-07-14 09:37, Christian König schreef: >> Am 23.07.2014 09:31, schrieb Daniel Vetter: >>> On Wed, Jul 23, 2014 at 9:26 AM, Christian König >>> <deathsimple@vodafone.de> wrote: >>>> It's not a locking problem I'm talking about here. Radeons lockup handling >>>> kicks in when anything calls into the driver from the outside, if you have a >>>> fence wait function that's called from the outside but doesn't handle >>>> lockups you essentially rely on somebody else calling another radeon >>>> function for the lockup to be resolved. >>> So you don't have a timer in radeon that periodically checks whether >>> progress is still being made? That's the approach we're using in i915, >>> together with some tricks to kick any stuck waiters so that we can >>> reliably step in and grab locks for the reset. >> We tried this approach, but it didn't worked at all. >> >> I already considered trying it again because of the upcoming fence implementation, but reconsidering that when a driver is forced to change it's handling because of the fence implementation that's just another hint that there is something wrong here. > As far as I can tell it wouldn't need to be reworked for the fence implementation currently, only the moment you want to allow callers outside of radeon. :-) > Doing a GPU lockup recovery in the wait function would be messy even right now, you would hit a deadlock in ttm_bo_delayed_delete -> ttm_bo_cleanup_refs_and_unlock. > > Regardless of the fence implementation, why would it be a good idea to do a full lockup recovery when some other driver is > calling your wait function? That doesn't seem to be a nice thing to do, so I think a timeout is the best error you could return here, > other drivers have to deal with that anyway. > > ~Maarten > _______________________________________________ Nouveau mailing list Nouveau@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/nouveau
next prev parent reply other threads:[~2014-07-23 7:58 UTC|newest] Thread overview: 165+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-07-09 12:29 [PATCH 00/17] Convert TTM to the new fence interface Maarten Lankhorst 2014-07-09 12:29 ` [PATCH 01/17] drm/ttm: add interruptible parameter to ttm_eu_reserve_buffers Maarten Lankhorst 2014-07-09 12:29 ` [PATCH 02/17] drm/ttm: kill off some members to ttm_validate_buffer Maarten Lankhorst 2014-07-09 12:29 ` [PATCH 03/17] drm/nouveau: add reservation to nouveau_gem_ioctl_cpu_prep Maarten Lankhorst 2014-07-09 12:29 ` [PATCH 04/17] drm/nouveau: require reservations for nouveau_fence_sync and nouveau_bo_fence Maarten Lankhorst 2014-07-09 12:29 ` [PATCH 05/17] drm/ttm: call ttm_bo_wait while inside a reservation Maarten Lankhorst 2014-07-09 12:29 ` [PATCH 06/17] drm/ttm: kill fence_lock Maarten Lankhorst 2014-07-09 12:29 ` [PATCH 07/17] drm/nouveau: rework to new fence interface Maarten Lankhorst 2014-07-09 12:29 ` [PATCH 08/17] drm/radeon: add timeout argument to radeon_fence_wait_seq Maarten Lankhorst 2014-07-09 12:29 ` Maarten Lankhorst 2014-07-09 12:29 ` [PATCH 09/17] drm/radeon: use common fence implementation for fences Maarten Lankhorst 2014-07-09 12:57 ` Deucher, Alexander 2014-07-09 12:57 ` Deucher, Alexander 2014-07-09 13:23 ` [PATCH v2 " Maarten Lankhorst 2014-07-09 13:23 ` Maarten Lankhorst 2014-07-10 17:27 ` Alex Deucher 2014-07-10 17:27 ` Alex Deucher 2014-07-22 4:05 ` [PATCH " Dave Airlie 2014-07-22 4:05 ` Dave Airlie 2014-07-22 4:05 ` Dave Airlie 2014-07-22 8:43 ` Christian König 2014-07-22 8:43 ` Christian König 2014-07-22 11:46 ` Daniel Vetter 2014-07-22 11:46 ` Daniel Vetter 2014-07-22 11:52 ` Daniel Vetter 2014-07-22 11:52 ` Daniel Vetter 2014-07-22 11:57 ` Daniel Vetter 2014-07-22 11:57 ` Daniel Vetter 2014-07-22 12:19 ` Christian König 2014-07-22 12:19 ` Christian König 2014-07-22 13:26 ` [Nouveau] " Daniel Vetter 2014-07-22 13:26 ` Daniel Vetter 2014-07-22 13:45 ` Christian König 2014-07-22 13:45 ` Christian König 2014-07-22 14:44 ` [Nouveau] " Maarten Lankhorst 2014-07-22 14:44 ` Maarten Lankhorst 2014-07-22 15:02 ` [Nouveau] " Christian König 2014-07-22 15:18 ` Maarten Lankhorst 2014-07-22 15:17 ` Daniel Vetter 2014-07-22 15:17 ` Daniel Vetter 2014-07-22 15:35 ` [Nouveau] " Christian König 2014-07-22 15:35 ` Christian König 2014-07-22 15:42 ` Daniel Vetter 2014-07-22 15:42 ` Daniel Vetter 2014-07-22 15:59 ` Christian König 2014-07-22 15:59 ` Christian König 2014-07-22 16:21 ` Daniel Vetter 2014-07-22 16:21 ` Daniel Vetter 2014-07-22 16:39 ` Christian König 2014-07-22 16:39 ` Christian König 2014-07-22 16:52 ` Daniel Vetter 2014-07-22 16:52 ` Daniel Vetter 2014-07-22 16:43 ` Daniel Vetter 2014-07-22 16:43 ` Daniel Vetter 2014-07-23 6:40 ` Maarten Lankhorst 2014-07-23 6:40 ` Maarten Lankhorst 2014-07-23 6:52 ` Christian König 2014-07-23 6:52 ` Christian König 2014-07-23 7:02 ` [Nouveau] " Daniel Vetter 2014-07-23 7:02 ` Daniel Vetter 2014-07-23 7:06 ` [Nouveau] " Maarten Lankhorst 2014-07-23 7:06 ` Maarten Lankhorst 2014-07-23 7:09 ` Daniel Vetter 2014-07-23 7:09 ` Daniel Vetter 2014-07-23 7:15 ` Christian König 2014-07-23 7:15 ` Christian König 2014-07-23 7:32 ` [Nouveau] " Maarten Lankhorst 2014-07-23 7:32 ` Maarten Lankhorst 2014-07-23 7:41 ` Christian König 2014-07-23 7:41 ` Christian König 2014-07-23 7:26 ` [Nouveau] " Christian König 2014-07-23 7:26 ` Christian König 2014-07-23 7:31 ` Daniel Vetter 2014-07-23 7:31 ` Daniel Vetter 2014-07-23 7:37 ` Christian König 2014-07-23 7:37 ` Christian König 2014-07-23 7:51 ` [Nouveau] " Maarten Lankhorst 2014-07-23 7:51 ` Maarten Lankhorst 2014-07-23 7:58 ` Christian König [this message] 2014-07-23 7:58 ` Christian König 2014-07-23 8:07 ` [Nouveau] " Daniel Vetter 2014-07-23 8:07 ` Daniel Vetter 2014-07-23 8:20 ` [Nouveau] " Christian König 2014-07-23 8:20 ` Christian König 2014-07-23 8:25 ` Maarten Lankhorst 2014-07-23 8:25 ` Maarten Lankhorst 2014-07-23 8:42 ` [Nouveau] " Daniel Vetter 2014-07-23 8:42 ` Daniel Vetter 2014-07-23 8:46 ` Christian König 2014-07-23 8:46 ` Christian König 2014-07-23 8:54 ` [Nouveau] " Daniel Vetter 2014-07-23 8:54 ` Daniel Vetter 2014-07-23 9:27 ` [Nouveau] " Christian König 2014-07-23 9:27 ` Christian König 2014-07-23 9:30 ` [Nouveau] " Daniel Vetter 2014-07-23 9:30 ` Daniel Vetter 2014-07-23 9:36 ` [Nouveau] " Christian König 2014-07-23 9:36 ` Christian König 2014-07-23 9:38 ` [Nouveau] " Maarten Lankhorst 2014-07-23 9:38 ` Maarten Lankhorst 2014-07-23 9:39 ` Christian König 2014-07-23 9:39 ` Christian König 2014-07-23 9:39 ` [Nouveau] " Daniel Vetter 2014-07-23 9:39 ` Daniel Vetter 2014-07-23 9:44 ` Daniel Vetter 2014-07-23 9:44 ` Daniel Vetter 2014-07-23 9:47 ` [Nouveau] " Christian König 2014-07-23 9:47 ` Christian König 2014-07-23 9:52 ` Daniel Vetter 2014-07-23 9:52 ` Daniel Vetter 2014-07-23 9:55 ` [Nouveau] " Maarten Lankhorst 2014-07-23 9:55 ` Maarten Lankhorst 2014-07-23 10:13 ` [Nouveau] " Christian König 2014-07-23 10:13 ` Christian König 2014-07-23 10:52 ` [Nouveau] " Daniel Vetter 2014-07-23 10:52 ` Daniel Vetter 2014-07-23 12:36 ` Christian König 2014-07-23 12:36 ` Christian König 2014-07-23 12:42 ` Daniel Vetter 2014-07-23 12:42 ` Daniel Vetter 2014-07-23 13:16 ` Maarten Lankhorst 2014-07-23 13:16 ` Maarten Lankhorst 2014-07-23 14:05 ` [Nouveau] " Maarten Lankhorst 2014-07-23 14:05 ` Maarten Lankhorst 2014-07-24 13:47 ` [Nouveau] " Christian König 2014-07-24 13:47 ` Christian König 2014-07-23 8:01 ` Daniel Vetter 2014-07-23 8:01 ` Daniel Vetter 2014-07-23 8:31 ` Christian König 2014-07-23 8:31 ` Christian König 2014-07-23 12:35 ` Rob Clark 2014-07-23 12:35 ` Rob Clark 2014-07-22 14:05 ` Maarten Lankhorst 2014-07-22 14:24 ` Christian König 2014-07-22 14:27 ` Maarten Lankhorst 2014-07-22 14:39 ` Christian König 2014-07-22 14:47 ` Maarten Lankhorst 2014-07-22 15:16 ` Christian König 2014-07-22 15:19 ` Daniel Vetter 2014-07-22 15:19 ` Daniel Vetter 2014-07-22 15:42 ` Alex Deucher 2014-07-22 15:42 ` Alex Deucher 2014-07-22 15:48 ` Daniel Vetter 2014-07-22 15:48 ` Daniel Vetter 2014-07-22 19:14 ` Jesse Barnes 2014-07-22 19:14 ` Jesse Barnes 2014-07-23 9:47 ` [Nouveau] " Daniel Vetter 2014-07-23 9:47 ` Daniel Vetter 2014-07-23 15:37 ` [Nouveau] " Jesse Barnes 2014-07-23 15:37 ` Jesse Barnes 2014-07-22 11:51 ` Maarten Lankhorst 2014-07-22 11:51 ` Maarten Lankhorst 2014-07-09 12:29 ` [PATCH 10/17] drm/qxl: rework to new fence interface Maarten Lankhorst 2014-07-09 12:30 ` [PATCH 11/17] drm/vmwgfx: get rid of different types of fence_flags entirely Maarten Lankhorst 2014-07-09 12:30 ` [PATCH 12/17] drm/vmwgfx: rework to new fence interface Maarten Lankhorst 2014-07-09 12:30 ` [PATCH 13/17] drm/ttm: flip the switch, and convert to dma_fence Maarten Lankhorst 2014-07-09 12:30 ` [PATCH 14/17] drm/nouveau: use rcu in nouveau_gem_ioctl_cpu_prep Maarten Lankhorst 2014-07-09 12:30 ` [PATCH 15/17] drm/radeon: use rcu waits in some ioctls Maarten Lankhorst 2014-07-09 12:30 ` [PATCH 16/17] drm/vmwgfx: use rcu in vmw_user_dmabuf_synccpu_grab Maarten Lankhorst 2014-07-09 12:30 ` [PATCH 17/17] drm/ttm: use rcu in core ttm Maarten Lankhorst 2014-07-09 13:09 ` [PATCH 00/17] Convert TTM to the new fence interface Mike Lothian 2014-07-09 13:21 ` Maarten Lankhorst 2014-07-09 13:21 ` Maarten Lankhorst 2014-07-10 21:37 ` Thomas Hellström 2014-07-10 21:37 ` Thomas Hellström
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