[PATCH 2/2] drm/amd/sched: add schuduling policy

[Chunming Zhou]

if high priority rq is full, then process with low priority could be starve.
Add policy for this problem, the high proiority can ahead of next priority 
queue,
the ratio is 2 : 1.

Change-Id: I58f4a6b9cdce8689b18dd8e83dd6e2cf5f99d5fb
Signed-off-by: Chunming Zhou <david1.z...@amd.com>
---
 drivers/gpu/drm/amd/scheduler/gpu_scheduler.c | 26 +++++++++++++++++++++++---
 drivers/gpu/drm/amd/scheduler/gpu_scheduler.h |  2 ++
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c 
b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
index 0f439dd..4637b6f 100644
--- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
+++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
@@ -35,11 +35,16 @@
 static void amd_sched_process_job(struct fence *f, struct fence_cb *cb);
 
 /* Initialize a given run queue struct */
-static void amd_sched_rq_init(struct amd_sched_rq *rq)
+static void amd_sched_rq_init(struct amd_gpu_scheduler *sched, enum
+                             amd_sched_priority pri)
 {
+       struct amd_sched_rq *rq = &sched->sched_rq[pri];
+
        spin_lock_init(&rq->lock);
        INIT_LIST_HEAD(&rq->entities);
        rq->current_entity = NULL;
+       rq->wait_base = pri * 2;
+       rq->wait = rq->wait_base;
 }
 
 static void amd_sched_rq_add_entity(struct amd_sched_rq *rq,
@@ -494,17 +499,32 @@ static void amd_sched_wakeup(struct amd_gpu_scheduler 
*sched)
 {
        struct amd_sched_entity *entity;
        int i;
+       bool skip;
 
        if (!amd_sched_ready(sched))
                return NULL;
 
+retry:
+       skip = false;
        /* Kernel run queue has higher priority than normal run queue*/
        for (i = AMD_SCHED_PRIORITY_MAX - 1; i >= AMD_SCHED_PRIORITY_MIN; i--) {
+               if ((i > AMD_SCHED_PRIORITY_MIN) &&
+                   (sched->sched_rq[i - 1].wait >= 
sched->sched_rq[i].wait_base)) {
+                       sched->sched_rq[i - 1].wait = sched->sched_rq[i - 
1].wait_base;
+                       skip = true;
+                       continue;
+               }
                entity = amd_sched_rq_select_entity(&sched->sched_rq[i]);
-               if (entity)
+               if (entity) {
+                       if (i > AMD_SCHED_PRIORITY_MIN)
+                               sched->sched_rq[i - 1].wait++;
                        break;
+               }
        }
 
+       if (!entity && skip)
+               goto retry;
+
        return entity;
 }
 
@@ -608,7 +628,7 @@ int amd_sched_init(struct amd_gpu_scheduler *sched,
        sched->name = name;
        sched->timeout = timeout;
        for (i = AMD_SCHED_PRIORITY_MIN; i < AMD_SCHED_PRIORITY_MAX; i++)
-               amd_sched_rq_init(&sched->sched_rq[i]);
+               amd_sched_rq_init(sched, i);
 
        init_waitqueue_head(&sched->wake_up_worker);
        init_waitqueue_head(&sched->job_scheduled);
diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h 
b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
index 99f0240..4caed30 100644
--- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
+++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
@@ -64,6 +64,8 @@ struct amd_sched_rq {
        spinlock_t              lock;
        struct list_head        entities;
        struct amd_sched_entity *current_entity;
+       int wait_base;
+       int wait;
 };
 
 struct amd_sched_fence {
-- 
1.9.1

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