[PATCH v4 03/18] drm/sched: Add dependency tracking
Daniel Vetter
daniel.vetter at ffwll.ch
Mon Jul 12 17:53:37 UTC 2021
Instead of just a callback we can just glue in the gem helpers that
panfrost, v3d and lima currently use. There's really not that many
ways to skin this cat.
On the naming bikeshed: The idea for using _await_ to denote adding
dependencies to a job comes from i915, where that's used quite
extensively all over the place, in lots of datastructures.
v2/3: Rebased.
Reviewed-by: Steven Price <steven.price at arm.com> (v1)
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
Cc: David Airlie <airlied at linux.ie>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Sumit Semwal <sumit.semwal at linaro.org>
Cc: "Christian König" <christian.koenig at amd.com>
Cc: Andrey Grodzovsky <andrey.grodzovsky at amd.com>
Cc: Lee Jones <lee.jones at linaro.org>
Cc: Nirmoy Das <nirmoy.aiemd at gmail.com>
Cc: Boris Brezillon <boris.brezillon at collabora.com>
Cc: Luben Tuikov <luben.tuikov at amd.com>
Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: Jack Zhang <Jack.Zhang1 at amd.com>
Cc: linux-media at vger.kernel.org
Cc: linaro-mm-sig at lists.linaro.org
---
drivers/gpu/drm/scheduler/sched_entity.c | 18 +++-
drivers/gpu/drm/scheduler/sched_main.c | 103 +++++++++++++++++++++++
include/drm/gpu_scheduler.h | 31 ++++++-
3 files changed, 146 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 89e3f6eaf519..381fbf462ea7 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -211,6 +211,19 @@ static void drm_sched_entity_kill_jobs_cb(struct dma_fence *f,
job->sched->ops->free_job(job);
}
+static struct dma_fence *
+drm_sched_job_dependency(struct drm_sched_job *job,
+ struct drm_sched_entity *entity)
+{
+ if (!xa_empty(&job->dependencies))
+ return xa_erase(&job->dependencies, job->last_dependency++);
+
+ if (job->sched->ops->dependency)
+ return job->sched->ops->dependency(job, entity);
+
+ return NULL;
+}
+
/**
* drm_sched_entity_kill_jobs - Make sure all remaining jobs are killed
*
@@ -229,7 +242,7 @@ static void drm_sched_entity_kill_jobs(struct drm_sched_entity *entity)
struct drm_sched_fence *s_fence = job->s_fence;
/* Wait for all dependencies to avoid data corruptions */
- while ((f = job->sched->ops->dependency(job, entity)))
+ while ((f = drm_sched_job_dependency(job, entity)))
dma_fence_wait(f, false);
drm_sched_fence_scheduled(s_fence);
@@ -419,7 +432,6 @@ static bool drm_sched_entity_add_dependency_cb(struct drm_sched_entity *entity)
*/
struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity)
{
- struct drm_gpu_scheduler *sched = entity->rq->sched;
struct drm_sched_job *sched_job;
sched_job = to_drm_sched_job(spsc_queue_peek(&entity->job_queue));
@@ -427,7 +439,7 @@ struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity)
return NULL;
while ((entity->dependency =
- sched->ops->dependency(sched_job, entity))) {
+ drm_sched_job_dependency(sched_job, entity))) {
trace_drm_sched_job_wait_dep(sched_job, entity->dependency);
if (drm_sched_entity_add_dependency_cb(entity))
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 454cb6164bdc..84c30badb78e 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -603,6 +603,8 @@ int drm_sched_job_init(struct drm_sched_job *job,
INIT_LIST_HEAD(&job->list);
+ xa_init_flags(&job->dependencies, XA_FLAGS_ALLOC);
+
return 0;
}
EXPORT_SYMBOL(drm_sched_job_init);
@@ -637,6 +639,98 @@ void drm_sched_job_arm(struct drm_sched_job *job)
}
EXPORT_SYMBOL(drm_sched_job_arm);
+/**
+ * drm_sched_job_await_fence - adds the fence as a job dependency
+ * @job: scheduler job to add the dependencies to
+ * @fence: the dma_fence to add to the list of dependencies.
+ *
+ * Note that @fence is consumed in both the success and error cases.
+ *
+ * Returns:
+ * 0 on success, or an error on failing to expand the array.
+ */
+int drm_sched_job_await_fence(struct drm_sched_job *job,
+ struct dma_fence *fence)
+{
+ struct dma_fence *entry;
+ unsigned long index;
+ u32 id = 0;
+ int ret;
+
+ if (!fence)
+ return 0;
+
+ /* Deduplicate if we already depend on a fence from the same context.
+ * This lets the size of the array of deps scale with the number of
+ * engines involved, rather than the number of BOs.
+ */
+ xa_for_each(&job->dependencies, index, entry) {
+ if (entry->context != fence->context)
+ continue;
+
+ if (dma_fence_is_later(fence, entry)) {
+ dma_fence_put(entry);
+ xa_store(&job->dependencies, index, fence, GFP_KERNEL);
+ } else {
+ dma_fence_put(fence);
+ }
+ return 0;
+ }
+
+ ret = xa_alloc(&job->dependencies, &id, fence, xa_limit_32b, GFP_KERNEL);
+ if (ret != 0)
+ dma_fence_put(fence);
+
+ return ret;
+}
+EXPORT_SYMBOL(drm_sched_job_await_fence);
+
+/**
+ * drm_sched_job_await_implicit - adds implicit dependencies as job dependencies
+ * @job: scheduler job to add the dependencies to
+ * @obj: the gem object to add new dependencies from.
+ * @write: whether the job might write the object (so we need to depend on
+ * shared fences in the reservation object).
+ *
+ * This should be called after drm_gem_lock_reservations() on your array of
+ * GEM objects used in the job but before updating the reservations with your
+ * own fences.
+ *
+ * Returns:
+ * 0 on success, or an error on failing to expand the array.
+ */
+int drm_sched_job_await_implicit(struct drm_sched_job *job,
+ struct drm_gem_object *obj,
+ bool write)
+{
+ int ret;
+ struct dma_fence **fences;
+ unsigned int i, fence_count;
+
+ if (!write) {
+ struct dma_fence *fence = dma_resv_get_excl_unlocked(obj->resv);
+
+ return drm_sched_job_await_fence(job, fence);
+ }
+
+ ret = dma_resv_get_fences(obj->resv, NULL, &fence_count, &fences);
+ if (ret || !fence_count)
+ return ret;
+
+ for (i = 0; i < fence_count; i++) {
+ ret = drm_sched_job_await_fence(job, fences[i]);
+ if (ret)
+ break;
+ }
+
+ for (; i < fence_count; i++)
+ dma_fence_put(fences[i]);
+ kfree(fences);
+ return ret;
+}
+EXPORT_SYMBOL(drm_sched_job_await_implicit);
+
+
/**
* drm_sched_job_cleanup - clean up scheduler job resources
* @job: scheduler job to clean up
@@ -652,6 +746,9 @@ EXPORT_SYMBOL(drm_sched_job_arm);
*/
void drm_sched_job_cleanup(struct drm_sched_job *job)
{
+ struct dma_fence *fence;
+ unsigned long index;
+
if (kref_read(&job->s_fence->finished.refcount)) {
/* drm_sched_job_arm() has been called */
dma_fence_put(&job->s_fence->finished);
@@ -661,6 +758,12 @@ void drm_sched_job_cleanup(struct drm_sched_job *job)
}
job->s_fence = NULL;
+
+ xa_for_each(&job->dependencies, index, fence) {
+ dma_fence_put(fence);
+ }
+ xa_destroy(&job->dependencies);
+
}
EXPORT_SYMBOL(drm_sched_job_cleanup);
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index 83afc3aa8e2f..74fb321dbc44 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -27,9 +27,12 @@
#include <drm/spsc_queue.h>
#include <linux/dma-fence.h>
#include <linux/completion.h>
+#include <linux/xarray.h>
#define MAX_WAIT_SCHED_ENTITY_Q_EMPTY msecs_to_jiffies(1000)
+struct drm_gem_object;
+
struct drm_gpu_scheduler;
struct drm_sched_rq;
@@ -198,6 +201,16 @@ struct drm_sched_job {
enum drm_sched_priority s_priority;
struct drm_sched_entity *entity;
struct dma_fence_cb cb;
+ /**
+ * @dependencies:
+ *
+ * Contains the dependencies as struct dma_fence for this job, see
+ * drm_sched_job_await_fence() and drm_sched_job_await_implicit().
+ */
+ struct xarray dependencies;
+
+ /** @last_dependency: tracks @dependencies as they signal */
+ unsigned long last_dependency;
};
static inline bool drm_sched_invalidate_job(struct drm_sched_job *s_job,
@@ -220,9 +233,14 @@ enum drm_gpu_sched_stat {
*/
struct drm_sched_backend_ops {
/**
- * @dependency: Called when the scheduler is considering scheduling
- * this job next, to get another struct dma_fence for this job to
- * block on. Once it returns NULL, run_job() may be called.
+ * @dependency:
+ *
+ * Called when the scheduler is considering scheduling this job next, to
+ * get another struct dma_fence for this job to block on. Once it
+ * returns NULL, run_job() may be called.
+ *
+ * If a driver exclusively uses drm_sched_job_await_fence() and
+ * drm_sched_job_await_implicit() this can be ommitted and left as NULL.
*/
struct dma_fence *(*dependency)(struct drm_sched_job *sched_job,
struct drm_sched_entity *s_entity);
@@ -349,6 +367,13 @@ int drm_sched_job_init(struct drm_sched_job *job,
struct drm_sched_entity *entity,
void *owner);
void drm_sched_job_arm(struct drm_sched_job *job);
+int drm_sched_job_await_fence(struct drm_sched_job *job,
+ struct dma_fence *fence);
+int drm_sched_job_await_implicit(struct drm_sched_job *job,
+ struct drm_gem_object *obj,
+ bool write);
+
+
void drm_sched_entity_modify_sched(struct drm_sched_entity *entity,
struct drm_gpu_scheduler **sched_list,
unsigned int num_sched_list);
--
2.32.0
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