[PATCH 5/5] drm/amd/sched: signal and free remaining fences in amd_sched_entity_fini
Liu, Monk
Monk.Liu at amd.com
Mon Oct 9 10:35:36 UTC 2017
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;
>>
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