[RFC v4 14/16] drm/sched: Remove FIFO and RR and simplify to a single run queue
Tvrtko Ursulin
tvrtko.ursulin at igalia.com
Fri Apr 25 10:20:32 UTC 2025
If the new fair policy is at least as good as FIFO and we can afford to
remove round-robin, we can simplify the scheduler code by making the
scheduler to run queue relationship always 1:1 and remove some code.
Also, now that the FIFO policy is gone the tree of entities is not a FIFO
tree any more so rename it to just the tree.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
Cc: Christian König <christian.koenig at amd.com>
Cc: Danilo Krummrich <dakr at kernel.org>
Cc: Matthew Brost <matthew.brost at intel.com>
Cc: Philipp Stanner <phasta at kernel.org>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_job.c | 23 ++--
drivers/gpu/drm/scheduler/sched_entity.c | 29 +----
drivers/gpu/drm/scheduler/sched_internal.h | 9 +-
drivers/gpu/drm/scheduler/sched_main.c | 133 +++++----------------
drivers/gpu/drm/scheduler/sched_rq.c | 53 +++-----
include/drm/gpu_scheduler.h | 13 +-
6 files changed, 62 insertions(+), 198 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
index acb21fc8b3ce..9440af58073b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
@@ -459,25 +459,22 @@ drm_sched_entity_queue_pop(struct drm_sched_entity *entity)
void amdgpu_job_stop_all_jobs_on_sched(struct drm_gpu_scheduler *sched)
{
+ struct drm_sched_rq *rq = sched->rq;
+ struct drm_sched_entity *s_entity;
struct drm_sched_job *s_job;
- struct drm_sched_entity *s_entity = NULL;
- int i;
/* Signal all jobs not yet scheduled */
- 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) {
- while ((s_job = drm_sched_entity_queue_pop(s_entity))) {
- struct drm_sched_fence *s_fence = s_job->s_fence;
+ spin_lock(&rq->lock);
+ list_for_each_entry(s_entity, &rq->entities, list) {
+ while ((s_job = drm_sched_entity_queue_pop(s_entity))) {
+ struct drm_sched_fence *s_fence = s_job->s_fence;
- dma_fence_signal(&s_fence->scheduled);
- dma_fence_set_error(&s_fence->finished, -EHWPOISON);
- dma_fence_signal(&s_fence->finished);
- }
+ dma_fence_signal(&s_fence->scheduled);
+ dma_fence_set_error(&s_fence->finished, -EHWPOISON);
+ dma_fence_signal(&s_fence->finished);
}
- spin_unlock(&rq->lock);
}
+ spin_unlock(&rq->lock);
/* Signal all jobs already scheduled to HW */
list_for_each_entry(s_job, &sched->pending_list, list) {
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 4481d5645138..d149df2a2050 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -98,8 +98,6 @@ int drm_sched_entity_init(struct drm_sched_entity *entity,
entity->guilty = guilty;
entity->num_sched_list = num_sched_list;
entity->priority = priority;
- entity->rq_priority = drm_sched_policy == DRM_SCHED_POLICY_FAIR ?
- DRM_SCHED_PRIORITY_KERNEL : priority;
/*
* It's perfectly valid to initialize an entity without having a valid
* scheduler attached. It's just not valid to use the scheduler before it
@@ -109,30 +107,14 @@ int drm_sched_entity_init(struct drm_sched_entity *entity,
RCU_INIT_POINTER(entity->last_scheduled, NULL);
RB_CLEAR_NODE(&entity->rb_tree_node);
- if (num_sched_list && !sched_list[0]->sched_rq) {
+ if (num_sched_list && !sched_list[0]->rq) {
/* Since every entry covered by num_sched_list
* should be non-NULL and therefore we warn drivers
* not to do this and to fix their DRM calling order.
*/
pr_warn("%s: called with uninitialized scheduler\n", __func__);
} else if (num_sched_list) {
- enum drm_sched_priority p = entity->priority;
-
- /*
- * The "priority" of an entity cannot exceed the number of
- * run-queues of a scheduler. Protect against num_rqs being 0,
- * by converting to signed. Choose the lowest priority
- * available.
- */
- if (p >= sched_list[0]->num_user_rqs) {
- dev_err(sched_list[0]->dev, "entity with out-of-bounds priority:%u num_user_rqs:%u\n",
- p, sched_list[0]->num_user_rqs);
- p = max_t(s32,
- (s32)sched_list[0]->num_user_rqs - 1,
- (s32)DRM_SCHED_PRIORITY_KERNEL);
- entity->priority = p;
- }
- entity->rq = sched_list[0]->sched_rq[entity->rq_priority];
+ entity->rq = sched_list[0]->rq;
}
init_completion(&entity->entity_idle);
@@ -580,7 +562,7 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
spin_lock(&entity->lock);
sched = drm_sched_pick_best(entity->sched_list, entity->num_sched_list);
- rq = sched ? sched->sched_rq[entity->rq_priority] : NULL;
+ rq = sched ? sched->rq : NULL;
if (rq != entity->rq) {
drm_sched_rq_remove_entity(entity->rq, entity);
entity->rq = rq;
@@ -604,7 +586,6 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job)
{
struct drm_sched_entity *entity = sched_job->entity;
bool first;
- ktime_t submit_ts;
trace_drm_sched_job(sched_job, entity);
atomic_inc(entity->rq->sched->score);
@@ -613,16 +594,14 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job)
/*
* After the sched_job is pushed into the entity queue, it may be
* completed and freed up at any time. We can no longer access it.
- * Make sure to set the submit_ts first, to avoid a race.
*/
- sched_job->submit_ts = submit_ts = ktime_get();
first = spsc_queue_push(&entity->job_queue, &sched_job->queue_node);
/* first job wakes up scheduler */
if (first) {
struct drm_gpu_scheduler *sched;
- sched = drm_sched_rq_add_entity(entity, submit_ts);
+ sched = drm_sched_rq_add_entity(entity);
if (sched)
drm_sched_wakeup(sched);
}
diff --git a/drivers/gpu/drm/scheduler/sched_internal.h b/drivers/gpu/drm/scheduler/sched_internal.h
index b675941b58a0..2d55f265a092 100644
--- a/drivers/gpu/drm/scheduler/sched_internal.h
+++ b/drivers/gpu/drm/scheduler/sched_internal.h
@@ -15,13 +15,6 @@ struct drm_sched_entity_stats {
u64 vruntime;
};
-/* Used to choose between FIFO and RR job-scheduling */
-extern int drm_sched_policy;
-
-#define DRM_SCHED_POLICY_RR 0
-#define DRM_SCHED_POLICY_FIFO 1
-#define DRM_SCHED_POLICY_FAIR 2
-
bool drm_sched_can_queue(struct drm_gpu_scheduler *sched,
struct drm_sched_entity *entity);
void drm_sched_wakeup(struct drm_gpu_scheduler *sched);
@@ -32,7 +25,7 @@ struct drm_sched_entity *
drm_sched_rq_select_entity(struct drm_gpu_scheduler *sched,
struct drm_sched_rq *rq);
struct drm_gpu_scheduler *
-drm_sched_rq_add_entity(struct drm_sched_entity *entity, ktime_t ts);
+drm_sched_rq_add_entity(struct drm_sched_entity *entity);
void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
struct drm_sched_entity *entity);
void drm_sched_rq_pop_entity(struct drm_sched_entity *entity);
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index d63c10c19f21..a2be0a097e75 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -83,15 +83,6 @@
#define CREATE_TRACE_POINTS
#include "gpu_scheduler_trace.h"
-int drm_sched_policy = DRM_SCHED_POLICY_FAIR;
-
-/**
- * DOC: sched_policy (int)
- * Used to override default entities scheduling policy in a run queue.
- */
-MODULE_PARM_DESC(sched_policy, "Specify the scheduling policy for entities on a run-queue, " __stringify(DRM_SCHED_POLICY_RR) " = Round Robin, " __stringify(DRM_SCHED_POLICY_FIFO) " = FIFO, " __stringify(DRM_SCHED_POLICY_FAIR) " = Fair (default).");
-module_param_named(sched_policy, drm_sched_policy, int, 0444);
-
static u32 drm_sched_available_credits(struct drm_gpu_scheduler *sched)
{
u32 credits;
@@ -835,34 +826,6 @@ void drm_sched_wakeup(struct drm_gpu_scheduler *sched)
drm_sched_run_job_queue(sched);
}
-/**
- * drm_sched_select_entity - Select next entity to process
- *
- * @sched: scheduler instance
- *
- * Return an entity to process or NULL if none are found.
- *
- * Note, that we break out of the for-loop when "entity" is non-null, which can
- * also be an error-pointer--this assures we don't process lower priority
- * run-queues. See comments in the respectively called functions.
- */
-static struct drm_sched_entity *
-drm_sched_select_entity(struct drm_gpu_scheduler *sched)
-{
- struct drm_sched_entity *entity = NULL;
- int i;
-
- /* Start with the highest priority.
- */
- for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) {
- entity = drm_sched_rq_select_entity(sched, sched->sched_rq[i]);
- if (entity)
- break;
- }
-
- return IS_ERR(entity) ? NULL : entity;
-}
-
/**
* drm_sched_get_finished_job - fetch the next finished job to be destroyed
*
@@ -979,8 +942,8 @@ static void drm_sched_run_job_work(struct work_struct *w)
int r;
/* Find entity with a ready job */
- entity = drm_sched_select_entity(sched);
- if (!entity)
+ entity = drm_sched_rq_select_entity(sched, sched->rq);
+ if (IS_ERR_OR_NULL(entity))
return; /* No more work */
sched_job = drm_sched_entity_pop_job(entity);
@@ -1045,8 +1008,6 @@ static struct workqueue_struct *drm_sched_alloc_wq(const char *name)
*/
int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_init_args *args)
{
- int i;
-
sched->ops = args->ops;
sched->credit_limit = args->credit_limit;
sched->name = args->name;
@@ -1056,13 +1017,7 @@ int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_init_
sched->score = args->score ? args->score : &sched->_score;
sched->dev = args->dev;
- if (args->num_rqs > DRM_SCHED_PRIORITY_COUNT) {
- /* This is a gross violation--tell drivers what the problem is.
- */
- dev_err(sched->dev, "%s: num_rqs cannot be greater than DRM_SCHED_PRIORITY_COUNT\n",
- __func__);
- return -EINVAL;
- } else if (sched->sched_rq) {
+ if (sched->rq) {
/* Not an error, but warn anyway so drivers can
* fine-tune their DRM calling order, and return all
* is good.
@@ -1082,21 +1037,11 @@ int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_init_
sched->own_submit_wq = true;
}
- sched->num_user_rqs = args->num_rqs;
- sched->num_rqs = drm_sched_policy != DRM_SCHED_POLICY_FAIR ?
- args->num_rqs : 1;
- sched->sched_rq = kmalloc_array(sched->num_rqs,
- sizeof(*sched->sched_rq),
- GFP_KERNEL | __GFP_ZERO);
- if (!sched->sched_rq)
+ sched->rq = kmalloc(sizeof(*sched->rq), GFP_KERNEL | __GFP_ZERO);
+ if (!sched->rq)
goto Out_check_own;
- for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) {
- sched->sched_rq[i] = kzalloc(sizeof(*sched->sched_rq[i]), GFP_KERNEL);
- if (!sched->sched_rq[i])
- goto Out_unroll;
- drm_sched_rq_init(sched, sched->sched_rq[i]);
- }
+ drm_sched_rq_init(sched, sched->rq);
init_waitqueue_head(&sched->job_scheduled);
INIT_LIST_HEAD(&sched->pending_list);
@@ -1111,12 +1056,7 @@ int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_init_
sched->ready = true;
return 0;
-Out_unroll:
- for (--i ; i >= DRM_SCHED_PRIORITY_KERNEL; i--)
- kfree(sched->sched_rq[i]);
- kfree(sched->sched_rq);
- sched->sched_rq = NULL;
Out_check_own:
if (sched->own_submit_wq)
destroy_workqueue(sched->submit_wq);
@@ -1148,25 +1088,21 @@ EXPORT_SYMBOL(drm_sched_init);
*/
void drm_sched_fini(struct drm_gpu_scheduler *sched)
{
+
+ struct drm_sched_rq *rq = sched->rq;
struct drm_sched_entity *s_entity;
- int i;
drm_sched_wqueue_stop(sched);
- 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)
- /*
- * Prevents reinsertion and marks job_queue as idle,
- * it will be removed from the rq in drm_sched_entity_fini()
- * eventually
- */
- s_entity->stopped = true;
- spin_unlock(&rq->lock);
- kfree(sched->sched_rq[i]);
- }
+ spin_lock(&rq->lock);
+ list_for_each_entry(s_entity, &rq->entities, list)
+ /*
+ * Prevents reinsertion and marks job_queue as idle,
+ * it will be removed from the rq in drm_sched_entity_fini()
+ * eventually
+ */
+ s_entity->stopped = true;
+ spin_unlock(&rq->lock);
/* Wakeup everyone stuck in drm_sched_entity_flush for this scheduler */
wake_up_all(&sched->job_scheduled);
@@ -1177,8 +1113,8 @@ void drm_sched_fini(struct drm_gpu_scheduler *sched)
if (sched->own_submit_wq)
destroy_workqueue(sched->submit_wq);
sched->ready = false;
- kfree(sched->sched_rq);
- sched->sched_rq = NULL;
+ kfree(sched->rq);
+ sched->rq = NULL;
}
EXPORT_SYMBOL(drm_sched_fini);
@@ -1193,35 +1129,28 @@ EXPORT_SYMBOL(drm_sched_fini);
*/
void drm_sched_increase_karma(struct drm_sched_job *bad)
{
- int i;
- struct drm_sched_entity *tmp;
- struct drm_sched_entity *entity;
struct drm_gpu_scheduler *sched = bad->sched;
+ struct drm_sched_entity *entity, *tmp;
+ struct drm_sched_rq *rq = sched->rq;
/* don't change @bad's karma if it's from KERNEL RQ,
* because sometimes GPU hang would cause kernel jobs (like VM updating jobs)
* corrupt but keep in mind that kernel jobs always considered good.
*/
- if (bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
- atomic_inc(&bad->karma);
+ if (bad->s_priority == DRM_SCHED_PRIORITY_KERNEL)
+ return;
- for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) {
- struct drm_sched_rq *rq = sched->sched_rq[i];
+ atomic_inc(&bad->karma);
- spin_lock(&rq->lock);
- list_for_each_entry_safe(entity, tmp, &rq->entities, list) {
- if (bad->s_fence->scheduled.context ==
- entity->fence_context) {
- if (entity->guilty)
- atomic_set(entity->guilty, 1);
- break;
- }
- }
- spin_unlock(&rq->lock);
- if (&entity->list != &rq->entities)
- break;
+ spin_lock(&rq->lock);
+ list_for_each_entry_safe(entity, tmp, &rq->entities, list) {
+ if (bad->s_fence->scheduled.context == entity->fence_context) {
+ if (entity->guilty)
+ atomic_set(entity->guilty, 1);
+ break;
}
}
+ spin_unlock(&rq->lock);
}
EXPORT_SYMBOL(drm_sched_increase_karma);
diff --git a/drivers/gpu/drm/scheduler/sched_rq.c b/drivers/gpu/drm/scheduler/sched_rq.c
index fd1cf89911e6..69ccdbd5af6c 100644
--- a/drivers/gpu/drm/scheduler/sched_rq.c
+++ b/drivers/gpu/drm/scheduler/sched_rq.c
@@ -16,7 +16,7 @@ drm_sched_entity_compare_before(struct rb_node *a, const struct rb_node *b)
return ktime_before(ea->oldest_job_waiting, eb->oldest_job_waiting);
}
-static void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity,
+static void drm_sched_rq_remove_tree_locked(struct drm_sched_entity *entity,
struct drm_sched_rq *rq)
{
lockdep_assert_held(&entity->lock);
@@ -28,7 +28,7 @@ static void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity,
}
}
-static void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity,
+static void drm_sched_rq_update_tree_locked(struct drm_sched_entity *entity,
struct drm_sched_rq *rq,
ktime_t ts)
{
@@ -40,7 +40,7 @@ static void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity,
lockdep_assert_held(&entity->lock);
lockdep_assert_held(&rq->lock);
- drm_sched_rq_remove_fifo_locked(entity, rq);
+ drm_sched_rq_remove_tree_locked(entity, rq);
entity->oldest_job_waiting = ts;
@@ -65,16 +65,6 @@ void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
rq->sched = sched;
}
-static ktime_t
-drm_sched_rq_get_rr_deadline(struct drm_sched_rq *rq)
-{
- lockdep_assert_held(&rq->lock);
-
- rq->rr_deadline = ktime_add_ns(rq->rr_deadline, 1);
-
- return rq->rr_deadline;
-}
-
static ktime_t
drm_sched_rq_get_min_vruntime(struct drm_sched_rq *rq)
{
@@ -103,10 +93,11 @@ drm_sched_rq_get_min_vruntime(struct drm_sched_rq *rq)
* Returns a DRM scheduler pre-selected to handle this entity.
*/
struct drm_gpu_scheduler *
-drm_sched_rq_add_entity(struct drm_sched_entity *entity, ktime_t ts)
+drm_sched_rq_add_entity(struct drm_sched_entity *entity)
{
struct drm_gpu_scheduler *sched;
struct drm_sched_rq *rq;
+ ktime_t ts;
/* Add the entity to the run queue */
spin_lock(&entity->lock);
@@ -126,14 +117,9 @@ drm_sched_rq_add_entity(struct drm_sched_entity *entity, ktime_t ts)
list_add_tail(&entity->list, &rq->entities);
}
- if (drm_sched_policy == DRM_SCHED_POLICY_FAIR) {
- ts = drm_sched_rq_get_min_vruntime(rq);
- ts = drm_sched_entity_restore_vruntime(entity, ts);
- } else if (drm_sched_policy == DRM_SCHED_POLICY_RR) {
- ts = drm_sched_rq_get_rr_deadline(rq);
- }
-
- drm_sched_rq_update_fifo_locked(entity, rq, ts);
+ ts = drm_sched_rq_get_min_vruntime(rq);
+ ts = drm_sched_entity_restore_vruntime(entity, ts);
+ drm_sched_rq_update_tree_locked(entity, rq, ts);
spin_unlock(&rq->lock);
spin_unlock(&entity->lock);
@@ -162,7 +148,7 @@ void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
atomic_dec(rq->sched->score);
list_del_init(&entity->list);
- drm_sched_rq_remove_fifo_locked(entity, rq);
+ drm_sched_rq_remove_tree_locked(entity, rq);
spin_unlock(&rq->lock);
}
@@ -183,23 +169,14 @@ void drm_sched_rq_pop_entity(struct drm_sched_entity *entity)
if (next_job) {
ktime_t ts;
- if (drm_sched_policy == DRM_SCHED_POLICY_FAIR)
- ts = drm_sched_entity_get_job_ts(entity);
- else if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
- ts = next_job->submit_ts;
- else
- ts = drm_sched_rq_get_rr_deadline(rq);
-
- drm_sched_rq_update_fifo_locked(entity, rq, ts);
+ ts = drm_sched_entity_get_job_ts(entity);
+ drm_sched_rq_update_tree_locked(entity, rq, ts);
} else {
- drm_sched_rq_remove_fifo_locked(entity, rq);
+ ktime_t min_vruntime;
- if (drm_sched_policy == DRM_SCHED_POLICY_FAIR) {
- ktime_t min_vruntime;
-
- min_vruntime = drm_sched_rq_get_min_vruntime(rq);
- drm_sched_entity_save_vruntime(entity, min_vruntime);
- }
+ drm_sched_rq_remove_tree_locked(entity, rq);
+ min_vruntime = drm_sched_rq_get_min_vruntime(rq);
+ drm_sched_entity_save_vruntime(entity, min_vruntime);
}
spin_unlock(&rq->lock);
spin_unlock(&entity->lock);
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index c6169cbf909b..e9ff24c076aa 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -151,8 +151,6 @@ struct drm_sched_entity {
*/
struct spsc_queue job_queue;
- enum drm_sched_priority rq_priority;
-
/**
* @fence_seq:
*
@@ -339,13 +337,6 @@ struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f);
struct drm_sched_job {
u64 id;
- /**
- * @submit_ts:
- *
- * When the job was pushed into the entity queue.
- */
- ktime_t submit_ts;
-
/**
* @sched:
*
@@ -557,9 +548,7 @@ struct drm_gpu_scheduler {
atomic_t credit_count;
long timeout;
const char *name;
- u32 num_rqs;
- u32 num_user_rqs;
- struct drm_sched_rq **sched_rq;
+ struct drm_sched_rq *rq;
wait_queue_head_t job_scheduled;
atomic64_t job_id_count;
struct workqueue_struct *submit_wq;
--
2.48.0
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