In Xe, the new Intel GPU driver, a choice has made to have a 1 to 1
mapping between a drm_gpu_scheduler and drm_sched_entity. At first this
seems a bit odd but let us explain the reasoning below.
1. In Xe the submission order from multiple drm_sched_entity is not
guaranteed to be the same completion even if targeting the same hardware
engine. This is because in Xe we have a firmware scheduler, the GuC,
which allowed to reorder, timeslice, and preempt submissions. If a using
shared drm_gpu_scheduler across multiple drm_sched_entity, the TDR falls
apart as the TDR expects submission order == completion order. Using a
dedicated drm_gpu_scheduler per drm_sched_entity solve this problem.
2. In Xe submissions are done via programming a ring buffer (circular
buffer), a drm_gpu_scheduler provides a limit on number of jobs, if the
limit of number jobs is set to RING_SIZE / MAX_SIZE_PER_JOB we get flow
control on the ring for free.
A problem with this design is currently a drm_gpu_scheduler uses a
kthread for submission / job cleanup. This doesn't scale if a large
number of drm_gpu_scheduler are used. To work around the scaling issue,
use a worker rather than kthread for submission / job cleanup.
v2:
- (Rob Clark) Fix msm build
- Pass in run work queue
v3:
- (Boris) don't have loop in worker
v4:
- (Tvrtko) break out submit ready, stop, start helpers into own patch
v5:
- (Boris) default to ordered work queue
v6:
- (Luben / checkpatch) fix alignment in msm_ringbuffer.c
- (Luben) s/drm_sched_submit_queue/drm_sched_wqueue_enqueue
- (Luben) Update comment for drm_sched_wqueue_enqueue
- (Luben) Positive check for submit_wq in drm_sched_init
- (Luben) s/alloc_submit_wq/own_submit_wq
v7:
- (Luben) s/drm_sched_wqueue_enqueue/drm_sched_run_job_queue
v8:
- (Luben) Adjust var names / comments
Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
Reviewed-by: Luben Tuikov <luben.tuikov@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +-
drivers/gpu/drm/etnaviv/etnaviv_sched.c | 2 +-
drivers/gpu/drm/lima/lima_sched.c | 2 +-
drivers/gpu/drm/msm/msm_ringbuffer.c | 2 +-
drivers/gpu/drm/nouveau/nouveau_sched.c | 2 +-
drivers/gpu/drm/panfrost/panfrost_job.c | 2 +-
drivers/gpu/drm/scheduler/sched_main.c | 131 +++++++++++----------
drivers/gpu/drm/v3d/v3d_sched.c | 10 +-
include/drm/gpu_scheduler.h | 14 ++-
9 files changed, 86 insertions(+), 81 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index d20c12aae66b..f493ffa1feec 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -2491,7 +2491,7 @@ static int amdgpu_device_init_schedulers(struct amdgpu_device *adev)
break;
}
- r = drm_sched_init(&ring->sched, &amdgpu_sched_ops,
+ r = drm_sched_init(&ring->sched, &amdgpu_sched_ops, NULL,
DRM_SCHED_PRIORITY_COUNT,
ring->num_hw_submission, 0,
timeout, adev->reset_domain->wq,
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_sched.c b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
index 9b79f218e21a..c4b04b0dee16 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_sched.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
@@ -134,7 +134,7 @@ int etnaviv_sched_init(struct etnaviv_gpu *gpu)
{
int ret;
- ret = drm_sched_init(&gpu->sched, &etnaviv_sched_ops,
+ ret = drm_sched_init(&gpu->sched, &etnaviv_sched_ops, NULL,
DRM_SCHED_PRIORITY_COUNT,
etnaviv_hw_jobs_limit, etnaviv_job_hang_limit,
msecs_to_jiffies(500), NULL, NULL,
diff --git a/drivers/gpu/drm/lima/lima_sched.c b/drivers/gpu/drm/lima/lima_sched.c
index 295f0353a02e..aa030e1f7cda 100644
--- a/drivers/gpu/drm/lima/lima_sched.c
+++ b/drivers/gpu/drm/lima/lima_sched.c
@@ -488,7 +488,7 @@ int lima_sched_pipe_init(struct lima_sched_pipe *pipe, const char *name)
INIT_WORK(&pipe->recover_work, lima_sched_recover_work);
- return drm_sched_init(&pipe->base, &lima_sched_ops,
+ return drm_sched_init(&pipe->base, &lima_sched_ops, NULL,
DRM_SCHED_PRIORITY_COUNT,
1,
lima_job_hang_limit,
diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.c b/drivers/gpu/drm/msm/msm_ringbuffer.c
index 95257ab0185d..4968568e3b54 100644
--- a/drivers/gpu/drm/msm/msm_ringbuffer.c
+++ b/drivers/gpu/drm/msm/msm_ringbuffer.c
@@ -94,7 +94,7 @@ struct msm_ringbuffer *msm_ringbuffer_new(struct msm_gpu *gpu, int id,
/* currently managing hangcheck ourselves: */
sched_timeout = MAX_SCHEDULE_TIMEOUT;
- ret = drm_sched_init(&ring->sched, &msm_sched_ops,
+ ret = drm_sched_init(&ring->sched, &msm_sched_ops, NULL,
DRM_SCHED_PRIORITY_COUNT,
num_hw_submissions, 0, sched_timeout,
NULL, NULL, to_msm_bo(ring->bo)->name, gpu->dev->dev);
diff --git a/drivers/gpu/drm/nouveau/nouveau_sched.c b/drivers/gpu/drm/nouveau/nouveau_sched.c
index 7c376c4ccdcf..c4ba56b1a6dd 100644
--- a/drivers/gpu/drm/nouveau/nouveau_sched.c
+++ b/drivers/gpu/drm/nouveau/nouveau_sched.c
@@ -435,7 +435,7 @@ int nouveau_sched_init(struct nouveau_drm *drm)
if (!drm->sched_wq)
return -ENOMEM;
- return drm_sched_init(sched, &nouveau_sched_ops,
+ return drm_sched_init(sched, &nouveau_sched_ops, NULL,
DRM_SCHED_PRIORITY_COUNT,
NOUVEAU_SCHED_HW_SUBMISSIONS, 0, job_hang_limit,
NULL, NULL, "nouveau_sched", drm->dev->dev);
diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index ecd2e035147f..6d89e24322db 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -852,7 +852,7 @@ int panfrost_job_init(struct panfrost_device *pfdev)
js->queue[j].fence_context = dma_fence_context_alloc(1);
ret = drm_sched_init(&js->queue[j].sched,
- &panfrost_sched_ops,
+ &panfrost_sched_ops, NULL,
DRM_SCHED_PRIORITY_COUNT,
nentries, 0,
msecs_to_jiffies(JOB_TIMEOUT_MS),
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 54c1c5fe01ba..d1ae05bded15 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -48,7 +48,6 @@
* through the jobs entity pointer.
*/
-#include <linux/kthread.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/completion.h>
@@ -256,6 +255,16 @@ drm_sched_rq_select_entity_fifo(struct drm_sched_rq *rq)
return rb ? rb_entry(rb, struct drm_sched_entity, rb_tree_node) : NULL;
}
+/**
+ * drm_sched_run_job_queue - enqueue run-job work
+ * @sched: scheduler instance
+ */
+static void drm_sched_run_job_queue(struct drm_gpu_scheduler *sched)
+{
+ if (!READ_ONCE(sched->pause_submit))
+ queue_work(sched->submit_wq, &sched->work_run_job);
+}
+
/**
* drm_sched_job_done - complete a job
* @s_job: pointer to the job which is done
@@ -275,7 +284,7 @@ static void drm_sched_job_done(struct drm_sched_job *s_job, int result)
dma_fence_get(&s_fence->finished);
drm_sched_fence_finished(s_fence, result);
dma_fence_put(&s_fence->finished);
- wake_up_interruptible(&sched->wake_up_worker);
+ drm_sched_run_job_queue(sched);
}
/**
@@ -874,7 +883,7 @@ static bool drm_sched_can_queue(struct drm_gpu_scheduler *sched)
void drm_sched_wakeup_if_can_queue(struct drm_gpu_scheduler *sched)
{
if (drm_sched_can_queue(sched))
- wake_up_interruptible(&sched->wake_up_worker);
+ drm_sched_run_job_queue(sched);
}
/**
@@ -985,60 +994,41 @@ drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
EXPORT_SYMBOL(drm_sched_pick_best);
/**
- * drm_sched_blocked - check if the scheduler is blocked
+ * drm_sched_run_job_work - main scheduler thread
*
- * @sched: scheduler instance
- *
- * Returns true if blocked, otherwise false.
+ * @w: run job work
*/
-static bool drm_sched_blocked(struct drm_gpu_scheduler *sched)
+static void drm_sched_run_job_work(struct work_struct *w)
{
- if (kthread_should_park()) {
- kthread_parkme();
- return true;
- }
-
- return false;
-}
-
-/**
- * drm_sched_main - main scheduler thread
- *
- * @param: scheduler instance
- *
- * Returns 0.
- */
-static int drm_sched_main(void *param)
-{
- struct drm_gpu_scheduler *sched = (struct drm_gpu_scheduler *)param;
+ struct drm_gpu_scheduler *sched =
+ container_of(w, struct drm_gpu_scheduler, work_run_job);
+ struct drm_sched_entity *entity;
+ struct drm_sched_job *cleanup_job;
int r;
- sched_set_fifo_low(current);
+ if (READ_ONCE(sched->pause_submit))
+ return;
- while (!kthread_should_stop()) {
- struct drm_sched_entity *entity = NULL;
- struct drm_sched_fence *s_fence;
- struct drm_sched_job *sched_job;
- struct dma_fence *fence;
- struct drm_sched_job *cleanup_job = NULL;
+ cleanup_job = drm_sched_get_cleanup_job(sched);
+ entity = drm_sched_select_entity(sched);
- wait_event_interruptible(sched->wake_up_worker,
- (cleanup_job = drm_sched_get_cleanup_job(sched)) ||
- (!drm_sched_blocked(sched) &&
- (entity = drm_sched_select_entity(sched))) ||
- kthread_should_stop());
+ if (!entity && !cleanup_job)
+ return; /* No more work */
- if (cleanup_job)
- sched->ops->free_job(cleanup_job);
+ if (cleanup_job)
+ sched->ops->free_job(cleanup_job);
- if (!entity)
- continue;
+ if (entity) {
+ struct dma_fence *fence;
+ struct drm_sched_fence *s_fence;
+ struct drm_sched_job *sched_job;
sched_job = drm_sched_entity_pop_job(entity);
-
if (!sched_job) {
complete_all(&entity->entity_idle);
- continue;
+ if (!cleanup_job)
+ return; /* No more work */
+ goto again;
}
s_fence = sched_job->s_fence;
@@ -1069,7 +1059,9 @@ static int drm_sched_main(void *param)
wake_up(&sched->job_scheduled);
}
- return 0;
+
+again:
+ drm_sched_run_job_queue(sched);
}
/**
@@ -1077,6 +1069,8 @@ static int drm_sched_main(void *param)
*
* @sched: scheduler instance
* @ops: backend operations for this scheduler
+ * @submit_wq: workqueue to use for submission. If NULL, an ordered wq is
+ * allocated and used
* @num_rqs: number of runqueues, one for each priority, up to DRM_SCHED_PRIORITY_COUNT
* @hw_submission: number of hw submissions that can be in flight
* @hang_limit: number of times to allow a job to hang before dropping it
@@ -1091,6 +1085,7 @@ static int drm_sched_main(void *param)
*/
int drm_sched_init(struct drm_gpu_scheduler *sched,
const struct drm_sched_backend_ops *ops,
+ struct workqueue_struct *submit_wq,
u32 num_rqs, uint32_t hw_submission, unsigned int hang_limit,
long timeout, struct workqueue_struct *timeout_wq,
atomic_t *score, const char *name, struct device *dev)
@@ -1121,14 +1116,22 @@ int drm_sched_init(struct drm_gpu_scheduler *sched,
return 0;
}
+ if (submit_wq) {
+ sched->submit_wq = submit_wq;
+ sched->own_submit_wq = false;
+ } else {
+ sched->submit_wq = alloc_ordered_workqueue(name, 0);
+ if (!sched->submit_wq)
+ return -ENOMEM;
+
+ sched->own_submit_wq = true;
+ }
+ ret = -ENOMEM;
sched->sched_rq = kmalloc_array(num_rqs, sizeof(*sched->sched_rq),
GFP_KERNEL | __GFP_ZERO);
- if (!sched->sched_rq) {
- drm_err(sched, "%s: out of memory for sched_rq\n", __func__);
- return -ENOMEM;
- }
+ if (!sched->sched_rq)
+ goto Out_free;
sched->num_rqs = num_rqs;
- ret = -ENOMEM;
for (i = DRM_SCHED_PRIORITY_MIN; i < sched->num_rqs; i++) {
sched->sched_rq[i] = kzalloc(sizeof(*sched->sched_rq[i]), GFP_KERNEL);
if (!sched->sched_rq[i])
@@ -1136,31 +1139,26 @@ int drm_sched_init(struct drm_gpu_scheduler *sched,
drm_sched_rq_init(sched, sched->sched_rq[i]);
}
- init_waitqueue_head(&sched->wake_up_worker);
init_waitqueue_head(&sched->job_scheduled);
INIT_LIST_HEAD(&sched->pending_list);
spin_lock_init(&sched->job_list_lock);
atomic_set(&sched->hw_rq_count, 0);
INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
+ INIT_WORK(&sched->work_run_job, drm_sched_run_job_work);
atomic_set(&sched->_score, 0);
atomic64_set(&sched->job_id_count, 0);
-
- /* Each scheduler will run on a seperate kernel thread */
- sched->thread = kthread_run(drm_sched_main, sched, sched->name);
- if (IS_ERR(sched->thread)) {
- ret = PTR_ERR(sched->thread);
- sched->thread = NULL;
- DRM_DEV_ERROR(sched->dev, "Failed to create scheduler for %s.\n", name);
- goto Out_unroll;
- }
+ sched->pause_submit = false;
sched->ready = true;
return 0;
Out_unroll:
for (--i ; i >= DRM_SCHED_PRIORITY_MIN; i--)
kfree(sched->sched_rq[i]);
+Out_free:
kfree(sched->sched_rq);
sched->sched_rq = NULL;
+ if (sched->own_submit_wq)
+ destroy_workqueue(sched->submit_wq);
drm_err(sched, "%s: Failed to setup GPU scheduler--out of memory\n", __func__);
return ret;
}
@@ -1178,8 +1176,7 @@ void drm_sched_fini(struct drm_gpu_scheduler *sched)
struct drm_sched_entity *s_entity;
int i;
- if (sched->thread)
- kthread_stop(sched->thread);
+ drm_sched_wqueue_stop(sched);
for (i = sched->num_rqs - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
struct drm_sched_rq *rq = sched->sched_rq[i];
@@ -1202,6 +1199,8 @@ void drm_sched_fini(struct drm_gpu_scheduler *sched)
/* Confirm no work left behind accessing device structures */
cancel_delayed_work_sync(&sched->work_tdr);
+ if (sched->own_submit_wq)
+ destroy_workqueue(sched->submit_wq);
sched->ready = false;
kfree(sched->sched_rq);
sched->sched_rq = NULL;
@@ -1262,7 +1261,7 @@ EXPORT_SYMBOL(drm_sched_increase_karma);
*/
bool drm_sched_wqueue_ready(struct drm_gpu_scheduler *sched)
{
- return !!sched->thread;
+ return sched->ready;
}
EXPORT_SYMBOL(drm_sched_wqueue_ready);
@@ -1273,7 +1272,8 @@ EXPORT_SYMBOL(drm_sched_wqueue_ready);
*/
void drm_sched_wqueue_stop(struct drm_gpu_scheduler *sched)
{
- kthread_park(sched->thread);
+ WRITE_ONCE(sched->pause_submit, true);
+ cancel_work_sync(&sched->work_run_job);
}
EXPORT_SYMBOL(drm_sched_wqueue_stop);
@@ -1284,6 +1284,7 @@ EXPORT_SYMBOL(drm_sched_wqueue_stop);
*/
void drm_sched_wqueue_start(struct drm_gpu_scheduler *sched)
{
- kthread_unpark(sched->thread);
+ WRITE_ONCE(sched->pause_submit, false);
+ queue_work(sched->submit_wq, &sched->work_run_job);
}
EXPORT_SYMBOL(drm_sched_wqueue_start);
diff --git a/drivers/gpu/drm/v3d/v3d_sched.c b/drivers/gpu/drm/v3d/v3d_sched.c
index 038e1ae589c7..0b6696b0d882 100644
--- a/drivers/gpu/drm/v3d/v3d_sched.c
+++ b/drivers/gpu/drm/v3d/v3d_sched.c
@@ -388,7 +388,7 @@ v3d_sched_init(struct v3d_dev *v3d)
int ret;
ret = drm_sched_init(&v3d->queue[V3D_BIN].sched,
- &v3d_bin_sched_ops,
+ &v3d_bin_sched_ops, NULL,
DRM_SCHED_PRIORITY_COUNT,
hw_jobs_limit, job_hang_limit,
msecs_to_jiffies(hang_limit_ms), NULL,
@@ -397,7 +397,7 @@ v3d_sched_init(struct v3d_dev *v3d)
return ret;
ret = drm_sched_init(&v3d->queue[V3D_RENDER].sched,
- &v3d_render_sched_ops,
+ &v3d_render_sched_ops, NULL,
DRM_SCHED_PRIORITY_COUNT,
hw_jobs_limit, job_hang_limit,
msecs_to_jiffies(hang_limit_ms), NULL,
@@ -406,7 +406,7 @@ v3d_sched_init(struct v3d_dev *v3d)
goto fail;
ret = drm_sched_init(&v3d->queue[V3D_TFU].sched,
- &v3d_tfu_sched_ops,
+ &v3d_tfu_sched_ops, NULL,
DRM_SCHED_PRIORITY_COUNT,
hw_jobs_limit, job_hang_limit,
msecs_to_jiffies(hang_limit_ms), NULL,
@@ -416,7 +416,7 @@ v3d_sched_init(struct v3d_dev *v3d)
if (v3d_has_csd(v3d)) {
ret = drm_sched_init(&v3d->queue[V3D_CSD].sched,
- &v3d_csd_sched_ops,
+ &v3d_csd_sched_ops, NULL,
DRM_SCHED_PRIORITY_COUNT,
hw_jobs_limit, job_hang_limit,
msecs_to_jiffies(hang_limit_ms), NULL,
@@ -425,7 +425,7 @@ v3d_sched_init(struct v3d_dev *v3d)
goto fail;
ret = drm_sched_init(&v3d->queue[V3D_CACHE_CLEAN].sched,
- &v3d_cache_clean_sched_ops,
+ &v3d_cache_clean_sched_ops, NULL,
DRM_SCHED_PRIORITY_COUNT,
hw_jobs_limit, job_hang_limit,
msecs_to_jiffies(hang_limit_ms), NULL,
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index 1d5a20af4a06..e0e7c4eb57d9 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -474,17 +474,16 @@ struct drm_sched_backend_ops {
* @num_rqs: Number of run-queues. This is at most DRM_SCHED_PRIORITY_COUNT,
* as there's usually one run-queue per priority, but could be less.
* @sched_rq: An allocated array of run-queues of size @num_rqs;
- * @wake_up_worker: the wait queue on which the scheduler sleeps until a job
- * is ready to be scheduled.
* @job_scheduled: once @drm_sched_entity_do_release is called the scheduler
* waits on this wait queue until all the scheduled jobs are
* finished.
* @hw_rq_count: the number of jobs currently in the hardware queue.
* @job_id_count: used to assign unique id to the each job.
+ * @submit_wq: workqueue used to queue @work_run_job
* @timeout_wq: workqueue used to queue @work_tdr
+ * @work_run_job: work which calls run_job op of each scheduler.
* @work_tdr: schedules a delayed call to @drm_sched_job_timedout after the
* timeout interval is over.
- * @thread: the kthread on which the scheduler which run.
* @pending_list: the list of jobs which are currently in the job queue.
* @job_list_lock: lock to protect the pending_list.
* @hang_limit: once the hangs by a job crosses this limit then it is marked
@@ -493,6 +492,8 @@ struct drm_sched_backend_ops {
* @_score: score used when the driver doesn't provide one
* @ready: marks if the underlying HW is ready to work
* @free_guilty: A hit to time out handler to free the guilty job.
+ * @pause_submit: pause queuing of @work_run_job on @submit_wq
+ * @own_submit_wq: scheduler owns allocation of @submit_wq
* @dev: system &struct device
*
* One scheduler is implemented for each hardware ring.
@@ -504,13 +505,13 @@ struct drm_gpu_scheduler {
const char *name;
u32 num_rqs;
struct drm_sched_rq **sched_rq;
- wait_queue_head_t wake_up_worker;
wait_queue_head_t job_scheduled;
atomic_t hw_rq_count;
atomic64_t job_id_count;
+ struct workqueue_struct *submit_wq;
struct workqueue_struct *timeout_wq;
+ struct work_struct work_run_job;
struct delayed_work work_tdr;
- struct task_struct *thread;
struct list_head pending_list;
spinlock_t job_list_lock;
int hang_limit;
@@ -518,11 +519,14 @@ struct drm_gpu_scheduler {
atomic_t _score;
bool ready;
bool free_guilty;
+ bool pause_submit;
+ bool own_submit_wq;
struct device *dev;
};
int drm_sched_init(struct drm_gpu_scheduler *sched,
const struct drm_sched_backend_ops *ops,
+ struct workqueue_struct *submit_wq,
u32 num_rqs, uint32_t hw_submission, unsigned int hang_limit,
long timeout, struct workqueue_struct *timeout_wq,
atomic_t *score, const char *name, struct device *dev);
--
2.34.1
