[PATCH 1/5] drm/amdgpu:keep ctx alive till all job finished
Christian König
deathsimple at vodafone.de
Wed May 3 13:34:22 UTC 2017
> Can we guarantee the pde/pte and PRT/CSA are all alive (BO, mappings) when resubmitting the timeout job (assume this time out job can signal after the resubmit)?
Yes, that's why we add all fences of each command submission to the
PD/PT BOs.
Regards,
Christian.
Am 03.05.2017 um 15:31 schrieb Liu, Monk:
> Even we release the ctx as usual way,
> Can we guarantee the pde/pte and PRT/CSA are all alive (BO, mappings) when resubmitting the timeout job (assume this time out job can signal after the resubmit)?
>
> You know App can submit a command a release all BO and free_ctx, close FD/VM, and exit very soon, it just doesn't wait for the fence signal
>
> BR Monk
>
> -----Original Message-----
> From: Christian König [mailto:deathsimple at vodafone.de]
> Sent: Wednesday, May 03, 2017 8:50 PM
> To: Liu, Monk <Monk.Liu at amd.com>; amd-gfx at lists.freedesktop.org
> Subject: Re: [PATCH 1/5] drm/amdgpu:keep ctx alive till all job finished
>
>> and the ironic thing is I want to alive as well (especially CSA, PTR)
> Yes, and exactly that is the danger I was talking about. We messed up the tear down oder with that and try to access resources which are already freed when the job is now scheduled.
>
> I would rather say we should get completely rid of the ctx kref counting, that was a rather bad idea in the first place.
>
> Regards,
> Christian.
>
> Am 03.05.2017 um 11:36 schrieb Liu, Monk:
>> Since I get one more kref for ctx when creating jobs, so amdgpu_ctx_mgr_fini(&fpriv->ctx_mgr) here won't actually waiting ... because the " amdgpu_ctx_do_release"
>> Won't going to run (kref > 0 before all job signaled).
>>
>> That way amdgpu_driver_postclose_kms() can continue go on , So
>> actually " UVD and VCE handle, the PRT VAs, the CSA and even the whole
>> VM structure" won't be kept alive , and the ironic thing is I want to
>> alive as well (especially CSA, PTR)
>>
>>
>> BR Monk
>>
>>
>>
>>
>> -----Original Message-----
>> From: Christian König [mailto:deathsimple at vodafone.de]
>> Sent: Wednesday, May 03, 2017 5:19 PM
>> To: Liu, Monk <Monk.Liu at amd.com>; amd-gfx at lists.freedesktop.org
>> Subject: Re: [PATCH 1/5] drm/amdgpu:keep ctx alive till all job
>> finished
>>
>>>> I'm afraid not: CSA is gone with the VM, and VM is gone after app close our FD, I don't see amdgpu_vm_fini() is depended on context living or not ...
>> See the teardown order in amdgpu_driver_postclose_kms():
>>> amdgpu_ctx_mgr_fini(&fpriv->ctx_mgr);
>>>
>>> amdgpu_uvd_free_handles(adev, file_priv);
>>> amdgpu_vce_free_handles(adev, file_priv);
>>>
>>> amdgpu_vm_bo_rmv(adev, fpriv->prt_va);
>>>
>>> if (amdgpu_sriov_vf(adev)) {
>>> /* TODO: how to handle reserve failure */
>>> BUG_ON(amdgpu_bo_reserve(adev->virt.csa_obj, false));
>>> amdgpu_vm_bo_rmv(adev, fpriv->vm.csa_bo_va);
>>> fpriv->vm.csa_bo_va = NULL;
>>> amdgpu_bo_unreserve(adev->virt.csa_obj);
>>> }
>>>
>>> amdgpu_vm_fini(adev, &fpriv->vm);
>> amdgpu_ctx_mgr_fini() waits for scheduling to finish and releases all contexts of the current fd.
>>
>> If we don't release the context here because some jobs are still executed we need to keep the UVD and VCE handle, the PRT VAs, the CSA and even the whole VM structure alive.
>>
>>> I'll see if dma_fence could solve my issue, but I wish you can give
>>> me your detail idea
>> Please take a look at David's idea of using the fence_context to find which jobs and entity to skip, that is even better than mine about the fence status and should be trivial to implement because all the data is already present we just need to use it.
>>
>> Regards,
>> Christian.
>>
>> Am 03.05.2017 um 11:08 schrieb Liu, Monk:
>>> 1,My idea is that userspace should rather gather the feedback during the next command submission. This has the advantage that you don't need to keep userspace alive till all jobs are done.
>>>
>>>> No, we need to clean the hw ring (cherry-pick out guilty entities' job in all rings) after gpu reset, and we need fackly signal all sched_fence in the guity entity as well, and we need mark context as guilty so the next IOCTL on it will return -ENODEV.
>>>> I don't understand how your idea can solve my request ...
>>> 2,You need to keep quite a bunch of stuff alive (VM, CSA) when you don't tear down the ctx immediately.
>>>
>>>> I'm afraid not: CSA is gone with the VM, and VM is gone after app close our FD, I don't see amdgpu_vm_fini() is depended on context living or not ...
>>> 3, struct fence was renamed to struct dma_fence on newer kernels and a status field added to exactly this purpose.
>>>
>>> The Intel guys did this because they ran into the exactly same problem.
>>>
>>>> I'll see if dma_fence could solve my issue, but I wish you can give
>>>> me your detail idea
>>> BR Monk
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: Christian König [mailto:deathsimple at vodafone.de]
>>> Sent: Wednesday, May 03, 2017 4:59 PM
>>> To: Liu, Monk <Monk.Liu at amd.com>; amd-gfx at lists.freedesktop.org
>>> Subject: Re: [PATCH 1/5] drm/amdgpu:keep ctx alive till all job
>>> finished
>>>
>>>> 1, This is necessary otherwise how can I access entity pointer after
>>>> a job timedout
>>> No that isn't necessary.
>>>
>>> The problem with your idea is that you want to actively push the
>>> feedback/status from the job execution back to userspace when an
>>> error
>>> (timeout) happens.
>>>
>>> My idea is that userspace should rather gather the feedback during the next command submission. This has the advantage that you don't need to keep userspace alive till all jobs are done.
>>>
>>>> , and why it is dangerous ?
>>> You need to keep quite a bunch of stuff alive (VM, CSA) when you don't tear down the ctx immediately.
>>>
>>> We could split ctx tear down into freeing the resources and freeing the structure, but I think just gathering the information needed on CS is easier to do.
>>>
>>>> 2, what's the status field in the fences you were referring to ? I
>>>> need to judge if it could satisfy my requirement
>>> struct fence was renamed to struct dma_fence on newer kernels and a status field added to exactly this purpose.
>>>
>>> The Intel guys did this because they ran into the exactly same problem.
>>>
>>> Regards,
>>> Christian.
>>>
>>> Am 03.05.2017 um 05:30 schrieb Liu, Monk:
>>>> 1, This is necessary otherwise how can I access entity pointer after a job timedout , and why it is dangerous ?
>>>> 2, what's the status field in the fences you were referring to ? I
>>>> need to judge if it could satisfy my requirement
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Christian König [mailto:deathsimple at vodafone.de]
>>>> Sent: Monday, May 01, 2017 10:48 PM
>>>> To: Liu, Monk <Monk.Liu at amd.com>; amd-gfx at lists.freedesktop.org
>>>> Subject: Re: [PATCH 1/5] drm/amdgpu:keep ctx alive till all job
>>>> finished
>>>>
>>>> Am 01.05.2017 um 09:22 schrieb Monk Liu:
>>>>> for TDR guilty context feature, we need access ctx/s_entity field
>>>>> member through sched job pointer,so ctx must keep alive till all
>>>>> job from it signaled.
>>>> NAK, that is unnecessary and quite dangerous.
>>>>
>>>> Instead we have the designed status field in the fences which should be checked for that.
>>>>
>>>> Regards,
>>>> Christian.
>>>>
>>>>> Change-Id: Ib87e9502f7a5c8c054c7e56956d7f7ad75998e43
>>>>> Signed-off-by: Monk Liu <Monk.Liu at amd.com>
>>>>> ---
>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu.h | 6 +++++-
>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 2 +-
>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c | 9 +++++++++
>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_job.c | 9 +++++++--
>>>>> drivers/gpu/drm/amd/scheduler/gpu_scheduler.c | 6 ------
>>>>> drivers/gpu/drm/amd/scheduler/gpu_scheduler.h | 1 +
>>>>> 6 files changed, 23 insertions(+), 10 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>>>> index e330009..8e031d6 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>>>> @@ -760,10 +760,12 @@ struct amdgpu_ib {
>>>>> uint32_t flags;
>>>>> };
>>>>>
>>>>> +struct amdgpu_ctx;
>>>>> +
>>>>> extern const struct amd_sched_backend_ops amdgpu_sched_ops;
>>>>>
>>>>> int amdgpu_job_alloc(struct amdgpu_device *adev, unsigned num_ibs,
>>>>> - struct amdgpu_job **job, struct amdgpu_vm *vm);
>>>>> + struct amdgpu_job **job, struct amdgpu_vm *vm, struct
>>>>> +amdgpu_ctx *ctx);
>>>>> int amdgpu_job_alloc_with_ib(struct amdgpu_device *adev, unsigned size,
>>>>> struct amdgpu_job **job);
>>>>>
>>>>> @@ -802,6 +804,7 @@ struct amdgpu_ctx_mgr {
>>>>>
>>>>> struct amdgpu_ctx *amdgpu_ctx_get(struct amdgpu_fpriv *fpriv, uint32_t id);
>>>>> int amdgpu_ctx_put(struct amdgpu_ctx *ctx);
>>>>> +struct amdgpu_ctx *amdgpu_ctx_kref_get(struct amdgpu_ctx *ctx);
>>>>>
>>>>> uint64_t amdgpu_ctx_add_fence(struct amdgpu_ctx *ctx, struct amdgpu_ring *ring,
>>>>> struct fence *fence); @@ -1129,6 +1132,7 @@ struct
>>>>> amdgpu_job {
>>>>> struct amdgpu_sync sync;
>>>>> struct amdgpu_ib *ibs;
>>>>> struct fence *fence; /* the hw fence */
>>>>> + struct amdgpu_ctx *ctx;
>>>>> uint32_t preamble_status;
>>>>> uint32_t num_ibs;
>>>>> void *owner;
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>>>> index 699f5fe..267fb65 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>>>> @@ -234,7 +234,7 @@ int amdgpu_cs_parser_init(struct amdgpu_cs_parser *p, void *data)
>>>>> }
>>>>> }
>>>>>
>>>>> - ret = amdgpu_job_alloc(p->adev, num_ibs, &p->job, vm);
>>>>> + ret = amdgpu_job_alloc(p->adev, num_ibs, &p->job, vm, p->ctx);
>>>>> if (ret)
>>>>> goto free_all_kdata;
>>>>>
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
>>>>> index b4bbbb3..81438af 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
>>>>> @@ -25,6 +25,13 @@
>>>>> #include <drm/drmP.h>
>>>>> #include "amdgpu.h"
>>>>>
>>>>> +struct amdgpu_ctx *amdgpu_ctx_kref_get(struct amdgpu_ctx *ctx) {
>>>>> + if (ctx)
>>>>> + kref_get(&ctx->refcount);
>>>>> + return ctx;
>>>>> +}
>>>>> +
>>>>> static int amdgpu_ctx_init(struct amdgpu_device *adev, struct amdgpu_ctx *ctx)
>>>>> {
>>>>> unsigned i, j;
>>>>> @@ -56,6 +63,8 @@ static int amdgpu_ctx_init(struct amdgpu_device *adev, struct amdgpu_ctx *ctx)
>>>>> rq, amdgpu_sched_jobs);
>>>>> if (r)
>>>>> goto failed;
>>>>> +
>>>>> + ctx->rings[i].entity.ptr_guilty = &ctx->guilty; /* kernel entity
>>>>> +doesn't have ptr_guilty */
>>>>> }
>>>>>
>>>>> return 0;
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
>>>>> index 690ef3d..208da11 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
>>>>> @@ -40,7 +40,7 @@ static void amdgpu_job_timedout(struct amd_sched_job *s_job)
>>>>> }
>>>>>
>>>>> int amdgpu_job_alloc(struct amdgpu_device *adev, unsigned num_ibs,
>>>>> - struct amdgpu_job **job, struct amdgpu_vm *vm)
>>>>> + struct amdgpu_job **job, struct amdgpu_vm *vm, struct
>>>>> +amdgpu_ctx *ctx)
>>>>> {
>>>>> size_t size = sizeof(struct amdgpu_job);
>>>>>
>>>>> @@ -57,6 +57,7 @@ int amdgpu_job_alloc(struct amdgpu_device *adev, unsigned num_ibs,
>>>>> (*job)->vm = vm;
>>>>> (*job)->ibs = (void *)&(*job)[1];
>>>>> (*job)->num_ibs = num_ibs;
>>>>> + (*job)->ctx = amdgpu_ctx_kref_get(ctx);
>>>>>
>>>>> amdgpu_sync_create(&(*job)->sync);
>>>>>
>>>>> @@ -68,7 +69,7 @@ int amdgpu_job_alloc_with_ib(struct amdgpu_device *adev, unsigned size,
>>>>> {
>>>>> int r;
>>>>>
>>>>> - r = amdgpu_job_alloc(adev, 1, job, NULL);
>>>>> + r = amdgpu_job_alloc(adev, 1, job, NULL, NULL);
>>>>> if (r)
>>>>> return r;
>>>>>
>>>>> @@ -94,6 +95,10 @@ void amdgpu_job_free_resources(struct amdgpu_job *job)
>>>>> static void amdgpu_job_free_cb(struct amd_sched_job *s_job)
>>>>> {
>>>>> struct amdgpu_job *job = container_of(s_job, struct
>>>>> amdgpu_job, base);
>>>>> + struct amdgpu_ctx *ctx = job->ctx;
>>>>> +
>>>>> + if (ctx)
>>>>> + amdgpu_ctx_put(ctx);
>>>>>
>>>>> fence_put(job->fence);
>>>>> amdgpu_sync_free(&job->sync); diff --git
>>>>> a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
>>>>> b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
>>>>> index 6f4e31f..9100ca8 100644
>>>>> --- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
>>>>> +++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
>>>>> @@ -208,12 +208,6 @@ void amd_sched_entity_fini(struct amd_gpu_scheduler *sched,
>>>>> if (!amd_sched_entity_is_initialized(sched, entity))
>>>>> return;
>>>>>
>>>>> - /**
>>>>> - * The client will not queue more IBs during this fini, consume existing
>>>>> - * queued IBs
>>>>> - */
>>>>> - wait_event(sched->job_scheduled, amd_sched_entity_is_idle(entity));
>>>>> -
>>>>> amd_sched_rq_remove_entity(rq, entity);
>>>>> kfifo_free(&entity->job_queue);
>>>>> }
>>>>> diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
>>>>> b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
>>>>> index 8cb41d3..ccbbcb0 100644
>>>>> --- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
>>>>> +++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
>>>>> @@ -49,6 +49,7 @@ struct amd_sched_entity {
>>>>>
>>>>> struct fence *dependency;
>>>>> struct fence_cb cb;
>>>>> + bool *ptr_guilty;
>>>>> };
>>>>>
>>>>> /**
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