[PATCH 5/5] drm/amd/sched: signal and free remaining fences in amd_sched_entity_fini
Nicolai Hähnle
nicolai.haehnle at amd.com
Mon Oct 9 11:04:30 UTC 2017
On 09.10.2017 12:59, Christian König wrote:
> Nicolai, how hard would it be to handle ENODEV as failure for all
> currently existing contexts?
Impossible? "All currently existing contexts" is not a well-defined
concept when multiple drivers co-exist in the same process.
And what would be the purpose of this? If it's to support VRAM loss,
having a per-context VRAM loss counter would enable each context to
signal ECANCELED separately.
Cheers,
Nicolai
>
> Monk, would it be ok with you when we return ENODEV only for existing
> context when VRAM is lost and/or we have a strict mode GPU reset? E.g.
> newly created contexts would continue work as they should.
>
> Regards,
> Christian.
>
> Am 09.10.2017 um 12:49 schrieb Nicolai Hähnle:
>> Hi Monk,
>>
>> Yes, you're right, we're only using ECANCELED internally. But as a
>> consequence, Mesa would already handle a kernel error of ECANCELED on
>> context loss correctly :)
>>
>> Cheers,
>> Nicolai
>>
>> On 09.10.2017 12:35, Liu, Monk wrote:
>>> Hi Christian
>>>
>>> You reject some of my patches that returns -ENODEV, with the cause
>>> that MESA doesn't do the handling on -ENODEV
>>>
>>> But if Nicolai can confirm that MESA do have a handling on
>>> -ECANCELED, then we need to overall align our error code, on detail
>>> below IOCTL can return error code:
>>>
>>> Amdgpu_cs_ioctl
>>> Amdgpu_cs_wait_ioctl
>>> Amdgpu_cs_wait_fences_ioctl
>>> Amdgpu_info_ioctl
>>>
>>>
>>> My patches is:
>>> return -ENODEV on cs_ioctl if the context is detected guilty,
>>> also return -ENODEV on cs_wait|cs_wait_fences if the fence is
>>> signaled but with error -ETIME,
>>> also return -ENODEV on info_ioctl so UMD can query if gpu reset
>>> happened after the process created (because for strict mode we block
>>> process instead of context)
>>>
>>>
>>> according to Nicolai:
>>>
>>> amdgpu_cs_ioctl *can* return -ECANCELED, but to be frankly speaking,
>>> kernel part doesn't have any place with "-ECANCELED" so this solution
>>> on MESA side doesn't align with *current* amdgpu driver,
>>> which only return 0 on success or -EINVALID on other error but
>>> definitely no "-ECANCELED" error code,
>>>
>>> so if we talking about community rules we shouldn't let MESA handle
>>> -ECANCELED , we should have a unified error code
>>>
>>> + Marek
>>>
>>> BR Monk
>>>
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: Haehnle, Nicolai
>>> Sent: 2017年10月9日 18:14
>>> To: Koenig, Christian <Christian.Koenig at amd.com>; Liu, Monk
>>> <Monk.Liu at amd.com>; Nicolai Hähnle <nhaehnle at gmail.com>;
>>> amd-gfx at lists.freedesktop.org
>>> Subject: Re: [PATCH 5/5] drm/amd/sched: signal and free remaining
>>> fences in amd_sched_entity_fini
>>>
>>> On 09.10.2017 10:02, Christian König wrote:
>>>>> For gpu reset patches (already submitted to pub) I would make kernel
>>>>> return -ENODEV if the waiting fence (in cs_wait or wait_fences IOCTL)
>>>>> founded as error, that way UMD would run into robust extension path
>>>>> and considering the GPU hang occurred,
>>>> Well that is only closed source behavior which is completely
>>>> irrelevant for upstream development.
>>>>
>>>> As far as I know we haven't pushed the change to return -ENODEV
>>>> upstream.
>>>
>>> FWIW, radeonsi currently expects -ECANCELED on CS submissions and
>>> treats those as context lost. Perhaps we could use the same error on
>>> fences?
>>> That makes more sense to me than -ENODEV.
>>>
>>> Cheers,
>>> Nicolai
>>>
>>>>
>>>> Regards,
>>>> Christian.
>>>>
>>>> Am 09.10.2017 um 08:42 schrieb Liu, Monk:
>>>>> Christian
>>>>>
>>>>>> It would be really nice to have an error code set on
>>>>>> s_fence->finished before it is signaled, use dma_fence_set_error()
>>>>>> for this.
>>>>> For gpu reset patches (already submitted to pub) I would make kernel
>>>>> return -ENODEV if the waiting fence (in cs_wait or wait_fences IOCTL)
>>>>> founded as error, that way UMD would run into robust extension path
>>>>> and considering the GPU hang occurred,
>>>>>
>>>>> Don't know if this is expected for the case of normal process being
>>>>> killed or crashed like Nicolai hit ... since there is no gpu hang hit
>>>>>
>>>>>
>>>>> BR Monk
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> -----Original Message-----
>>>>> From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On
>>>>> Behalf Of Christian K?nig
>>>>> Sent: 2017年9月28日 23:01
>>>>> To: Nicolai Hähnle <nhaehnle at gmail.com>;
>>>>> amd-gfx at lists.freedesktop.org
>>>>> Cc: Haehnle, Nicolai <Nicolai.Haehnle at amd.com>
>>>>> Subject: Re: [PATCH 5/5] drm/amd/sched: signal and free remaining
>>>>> fences in amd_sched_entity_fini
>>>>>
>>>>> Am 28.09.2017 um 16:55 schrieb Nicolai Hähnle:
>>>>>> From: Nicolai Hähnle <nicolai.haehnle at amd.com>
>>>>>>
>>>>>> Highly concurrent Piglit runs can trigger a race condition where a
>>>>>> pending SDMA job on a buffer object is never executed because the
>>>>>> corresponding process is killed (perhaps due to a crash). Since the
>>>>>> job's fences were never signaled, the buffer object was effectively
>>>>>> leaked. Worse, the buffer was stuck wherever it happened to be at
>>>>>> the time, possibly in VRAM.
>>>>>>
>>>>>> The symptom was user space processes stuck in interruptible waits
>>>>>> with kernel stacks like:
>>>>>>
>>>>>> [<ffffffffbc5e6722>] dma_fence_default_wait+0x112/0x250
>>>>>> [<ffffffffbc5e6399>] dma_fence_wait_timeout+0x39/0xf0
>>>>>> [<ffffffffbc5e82d2>]
>>>>>> reservation_object_wait_timeout_rcu+0x1c2/0x300
>>>>>> [<ffffffffc03ce56f>] ttm_bo_cleanup_refs_and_unlock+0xff/0x1a0
>>>>>> [ttm]
>>>>>> [<ffffffffc03cf1ea>] ttm_mem_evict_first+0xba/0x1a0 [ttm]
>>>>>> [<ffffffffc03cf611>] ttm_bo_mem_space+0x341/0x4c0 [ttm]
>>>>>> [<ffffffffc03cfc54>] ttm_bo_validate+0xd4/0x150 [ttm]
>>>>>> [<ffffffffc03cffbd>] ttm_bo_init_reserved+0x2ed/0x420 [ttm]
>>>>>> [<ffffffffc042f523>] amdgpu_bo_create_restricted+0x1f3/0x470
>>>>>> [amdgpu]
>>>>>> [<ffffffffc042f9fa>] amdgpu_bo_create+0xda/0x220 [amdgpu]
>>>>>> [<ffffffffc04349ea>] amdgpu_gem_object_create+0xaa/0x140
>>>>>> [amdgpu]
>>>>>> [<ffffffffc0434f97>] amdgpu_gem_create_ioctl+0x97/0x120
>>>>>> [amdgpu]
>>>>>> [<ffffffffc037ddba>] drm_ioctl+0x1fa/0x480 [drm]
>>>>>> [<ffffffffc041904f>] amdgpu_drm_ioctl+0x4f/0x90 [amdgpu]
>>>>>> [<ffffffffbc23db33>] do_vfs_ioctl+0xa3/0x5f0
>>>>>> [<ffffffffbc23e0f9>] SyS_ioctl+0x79/0x90
>>>>>> [<ffffffffbc864ffb>] entry_SYSCALL_64_fastpath+0x1e/0xad
>>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
>>>>>>
>>>>>> Signed-off-by: Nicolai Hähnle <nicolai.haehnle at amd.com>
>>>>>> Acked-by: Christian König <christian.koenig at amd.com>
>>>>>> ---
>>>>>> drivers/gpu/drm/amd/scheduler/gpu_scheduler.c | 7 ++++++-
>>>>>> 1 file changed, 6 insertions(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
>>>>>> b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
>>>>>> index 54eb77cffd9b..32a99e980d78 100644
>>>>>> --- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
>>>>>> +++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
>>>>>> @@ -220,22 +220,27 @@ void amd_sched_entity_fini(struct
>>>>>> amd_gpu_scheduler *sched,
>>>>>> amd_sched_entity_is_idle(entity));
>>>>>> amd_sched_rq_remove_entity(rq, entity);
>>>>>> if (r) {
>>>>>> struct amd_sched_job *job;
>>>>>> /* Park the kernel for a moment to make sure it isn't
>>>>>> processing
>>>>>> * our enity.
>>>>>> */
>>>>>> kthread_park(sched->thread);
>>>>>> kthread_unpark(sched->thread);
>>>>>> - while (kfifo_out(&entity->job_queue, &job, sizeof(job)))
>>>>>> + while (kfifo_out(&entity->job_queue, &job, sizeof(job))) {
>>>>>> + struct amd_sched_fence *s_fence = job->s_fence;
>>>>>> + amd_sched_fence_scheduled(s_fence);
>>>>> It would be really nice to have an error code set on
>>>>> s_fence->finished before it is signaled, use dma_fence_set_error()
>>>>> for this.
>>>>>
>>>>> Additional to that it would be nice to note in the subject line that
>>>>> this is a rather important bug fix.
>>>>>
>>>>> With that fixed the whole series is Reviewed-by: Christian König
>>>>> <christian.koenig at amd.com>.
>>>>>
>>>>> Regards,
>>>>> Christian.
>>>>>
>>>>>> + amd_sched_fence_finished(s_fence);
>>>>>> + dma_fence_put(&s_fence->finished);
>>>>>> sched->ops->free_job(job);
>>>>>> + }
>>>>>> }
>>>>>> kfifo_free(&entity->job_queue);
>>>>>> }
>>>>>> static void amd_sched_entity_wakeup(struct dma_fence *f, struct
>>>>>> dma_fence_cb *cb)
>>>>>> {
>>>>>> struct amd_sched_entity *entity =
>>>>>> container_of(cb, struct amd_sched_entity, cb);
>>>>>> entity->dependency = NULL;
>>>>>
>>>>> _______________________________________________
>>>>> amd-gfx mailing list
>>>>> amd-gfx at lists.freedesktop.org
>>>>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
>>>>> _______________________________________________
>>>>> amd-gfx mailing list
>>>>> amd-gfx at lists.freedesktop.org
>>>>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
>>>>
>>>>
>>>
>>
>
More information about the amd-gfx
mailing list