On 2023-11-24 04:38, Christian König wrote:
> Am 24.11.23 um 09:22 schrieb Luben Tuikov:
>> On 2023-11-24 03:04, Christian König wrote:
>>> Am 24.11.23 um 06:27 schrieb Luben Tuikov:
>>>> Reverse run-queue priority enumeration such that the higest priority is now 0,
>>>> and for each consecutive integer the prioirty diminishes.
>>>>
>>>> Run-queues correspond to priorities. To an external observer a scheduler
>>>> created with a single run-queue, and another created with
>>>> DRM_SCHED_PRIORITY_COUNT number of run-queues, should always schedule
>>>> sched->sched_rq[0] with the same "priority", as that index run-queue exists in
>>>> both schedulers, i.e. a scheduler with one run-queue or many. This patch makes
>>>> it so.
>>>>
>>>> In other words, the "priority" of sched->sched_rq[n], n >= 0, is the same for
>>>> any scheduler created with any allowable number of run-queues (priorities), 0
>>>> to DRM_SCHED_PRIORITY_COUNT.
>>>>
>>>> Cc: Rob Clark <robdclark@xxxxxxxxx>
>>>> Cc: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
>>>> Cc: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
>>>> Cc: Danilo Krummrich <dakr@xxxxxxxxxx>
>>>> Cc: Alex Deucher <alexander.deucher@xxxxxxx>
>>>> Cc: Christian König <christian.koenig@xxxxxxx>
>>>> Cc: linux-arm-msm@xxxxxxxxxxxxxxx
>>>> Cc: freedreno@xxxxxxxxxxxxxxxxxxxxx
>>>> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
>>>> Signed-off-by: Luben Tuikov <ltuikov89@xxxxxxxxx>
>>>> ---
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_job.c | 2 +-
>>>> drivers/gpu/drm/msm/msm_gpu.h | 2 +-
>>>> drivers/gpu/drm/scheduler/sched_entity.c | 7 ++++---
>>>> drivers/gpu/drm/scheduler/sched_main.c | 15 +++++++--------
>>>> include/drm/gpu_scheduler.h | 6 +++---
>>>> 5 files changed, 16 insertions(+), 16 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
>>>> index 1a25931607c514..71a5cf37b472d4 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
>>>> @@ -325,7 +325,7 @@ void amdgpu_job_stop_all_jobs_on_sched(struct drm_gpu_scheduler *sched)
>>>> int i;
>>>>
>>>> /* Signal all jobs not yet scheduled */
>>>> - for (i = sched->num_rqs - 1; i >= DRM_SCHED_PRIORITY_LOW; i--) {
>>>> + for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) {
>>>> struct drm_sched_rq *rq = sched->sched_rq[i];
>>>> spin_lock(&rq->lock);
>>>> list_for_each_entry(s_entity, &rq->entities, list) {
>>>> diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h
>>>> index eb0c97433e5f8a..2bfcb222e35338 100644
>>>> --- a/drivers/gpu/drm/msm/msm_gpu.h
>>>> +++ b/drivers/gpu/drm/msm/msm_gpu.h
>>>> @@ -347,7 +347,7 @@ struct msm_gpu_perfcntr {
>>>> * DRM_SCHED_PRIORITY_KERNEL priority level is treated specially in some
>>>> * cases, so we don't use it (no need for kernel generated jobs).
>>>> */
>>>> -#define NR_SCHED_PRIORITIES (1 + DRM_SCHED_PRIORITY_HIGH - DRM_SCHED_PRIORITY_LOW)
>>>> +#define NR_SCHED_PRIORITIES (1 + DRM_SCHED_PRIORITY_LOW - DRM_SCHED_PRIORITY_HIGH)
>>>>
>>>> /**
>>>> * struct msm_file_private - per-drm_file context
>>>> diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
>>>> index cb7445be3cbb4e..6e2b02e45e3a32 100644
>>>> --- a/drivers/gpu/drm/scheduler/sched_entity.c
>>>> +++ b/drivers/gpu/drm/scheduler/sched_entity.c
>>>> @@ -81,14 +81,15 @@ int drm_sched_entity_init(struct drm_sched_entity *entity,
>>>> */
>>>> pr_warn("%s: called with uninitialized scheduler\n", __func__);
>>>> } else if (num_sched_list) {
>>>> - /* The "priority" of an entity cannot exceed the number
>>>> - * of run-queues of a scheduler.
>>>> + /* The "priority" of an entity cannot exceed the number of
>>>> + * run-queues of a scheduler. Choose the lowest priority
>>>> + * available.
>>>> */
>>>> if (entity->priority >= sched_list[0]->num_rqs) {
>>>> drm_err(sched_list[0], "entity with out-of-bounds priority:%u num_rqs:%u\n",
>>>> entity->priority, sched_list[0]->num_rqs);
>>>> entity->priority = max_t(s32, (s32) sched_list[0]->num_rqs - 1,
>>>> - (s32) DRM_SCHED_PRIORITY_LOW);
>>>> + (s32) DRM_SCHED_PRIORITY_KERNEL);
>>> That seems to be a no-op. You basically say max_T(.., num_rqs - 1, 0),
>>> this will always be num_rqs - 1
>> This protects against num_rqs being equal to 0, in which case we select KERNEL (0).
>
> Ah! That's also why convert it to signed! I was already wondering why
> you do this.
I thought it was clear since we're doing,
num_rqs - 1
and there's no guarantee that the result would be non-negative even if the variable
num_rqs was non-negative. But I've added an explanation of what's going on here.
>>
>> This comes from "[PATCH] drm/sched: Fix bounds limiting when given a malformed entity"
>> which I sent yesterday (Message-ID: <20231123122422.167832-2-ltuikov89@xxxxxxxxx>).
>
> I can't find that one in my inbox anywhere, but was able to find it in
> patchwork.
Did you check your gmail?
>> Could you R-B that patch too?
>
> I would add a comment cause the intention of max_t(s32 is really not
> obvious here.
>
> With that done feel free to add my rb to both patches.
Done.
--
Regards,
Luben
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