drm/i915: Stop retiring along engine

We no longer track the execution order along the engine and so no longer
need to enforce ordering of retire along the engine.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614164606.15633-2-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 38d112d8aba7704bcad679faf0106f66ac50a0b6..c99136f78af9603cc27045c7913dc5400c9018e2 100644 (file)
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -183,72 +183,23 @@ static void free_capture_list(struct i915_request *request)
        }
 }
 
-static void __retire_engine_request(struct intel_engine_cs *engine,
-                                   struct i915_request *rq)
-{
-       GEM_TRACE("%s(%s) fence %llx:%lld, current %d\n",
-                 __func__, engine->name,
-                 rq->fence.context, rq->fence.seqno,
-                 hwsp_seqno(rq));
-
-       GEM_BUG_ON(!i915_request_completed(rq));
-
-       local_irq_disable();
-
-       spin_lock(&engine->timeline.lock);
-       GEM_BUG_ON(!list_is_first(&rq->link, &engine->timeline.requests));
-       list_del_init(&rq->link);
-       spin_unlock(&engine->timeline.lock);
-
-       spin_lock(&rq->lock);
-       i915_request_mark_complete(rq);
-       if (!i915_request_signaled(rq))
-               dma_fence_signal_locked(&rq->fence);
-       if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &rq->fence.flags))
-               i915_request_cancel_breadcrumb(rq);
-       if (rq->waitboost) {
-               GEM_BUG_ON(!atomic_read(&rq->i915->gt_pm.rps.num_waiters));
-               atomic_dec(&rq->i915->gt_pm.rps.num_waiters);
-       }
-       spin_unlock(&rq->lock);
-
-       local_irq_enable();
-}
-
-static void __retire_engine_upto(struct intel_engine_cs *engine,
-                                struct i915_request *rq)
-{
-       struct i915_request *tmp;
-
-       if (list_empty(&rq->link))
-               return;
-
-       do {
-               tmp = list_first_entry(&engine->timeline.requests,
-                                      typeof(*tmp), link);
-
-               GEM_BUG_ON(tmp->engine != engine);
-               __retire_engine_request(engine, tmp);
-       } while (tmp != rq);
-}
-
-static void i915_request_retire(struct i915_request *request)
+static bool i915_request_retire(struct i915_request *rq)
 {
        struct i915_active_request *active, *next;
 
-       GEM_TRACE("%s fence %llx:%lld, current %d\n",
-                 request->engine->name,
-                 request->fence.context, request->fence.seqno,
-                 hwsp_seqno(request));
+       lockdep_assert_held(&rq->i915->drm.struct_mutex);
+       if (!i915_request_completed(rq))
+               return false;
 
-       lockdep_assert_held(&request->i915->drm.struct_mutex);
-       GEM_BUG_ON(!i915_sw_fence_signaled(&request->submit));
-       GEM_BUG_ON(!i915_request_completed(request));
+       GEM_TRACE("%s fence %llx:%lld, current %d\n",
+                 rq->engine->name,
+                 rq->fence.context, rq->fence.seqno,
+                 hwsp_seqno(rq));
 
-       trace_i915_request_retire(request);
+       GEM_BUG_ON(!i915_sw_fence_signaled(&rq->submit));
+       trace_i915_request_retire(rq);
 
-       advance_ring(request);
-       free_capture_list(request);
+       advance_ring(rq);
 
        /*
         * Walk through the active list, calling retire on each. This allows
@@ -260,7 +211,7 @@ static void i915_request_retire(struct i915_request *request)
         * pass along the auxiliary information (to avoid dereferencing
         * the node after the callback).
         */
-       list_for_each_entry_safe(active, next, &request->active_list, link) {
+       list_for_each_entry_safe(active, next, &rq->active_list, link) {
                /*
                 * In microbenchmarks or focusing upon time inside the kernel,
                 * we may spend an inordinate amount of time simply handling
@@ -276,18 +227,39 @@ static void i915_request_retire(struct i915_request *request)
                INIT_LIST_HEAD(&active->link);
                RCU_INIT_POINTER(active->request, NULL);
 
-               active->retire(active, request);
+               active->retire(active, rq);
+       }
+
+       local_irq_disable();
+
+       spin_lock(&rq->engine->timeline.lock);
+       list_del(&rq->link);
+       spin_unlock(&rq->engine->timeline.lock);
+
+       spin_lock(&rq->lock);
+       i915_request_mark_complete(rq);
+       if (!i915_request_signaled(rq))
+               dma_fence_signal_locked(&rq->fence);
+       if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &rq->fence.flags))
+               i915_request_cancel_breadcrumb(rq);
+       if (rq->waitboost) {
+               GEM_BUG_ON(!atomic_read(&rq->i915->gt_pm.rps.num_waiters));
+               atomic_dec(&rq->i915->gt_pm.rps.num_waiters);
        }
+       spin_unlock(&rq->lock);
+
+       local_irq_enable();
 
-       i915_request_remove_from_client(request);
+       intel_context_exit(rq->hw_context);
+       intel_context_unpin(rq->hw_context);
 
-       __retire_engine_upto(request->engine, request);
+       i915_request_remove_from_client(rq);
 
-       intel_context_exit(request->hw_context);
-       intel_context_unpin(request->hw_context);
+       free_capture_list(rq);
+       i915_sched_node_fini(&rq->sched);
+       i915_request_put(rq);
 
-       i915_sched_node_fini(&request->sched);
-       i915_request_put(request);
+       return true;
 }
 
 void i915_request_retire_upto(struct i915_request *rq)
@@ -309,9 +281,7 @@ void i915_request_retire_upto(struct i915_request *rq)
        do {
                tmp = list_first_entry(&ring->request_list,
                                       typeof(*tmp), ring_link);
-
-               i915_request_retire(tmp);
-       } while (tmp != rq);
+       } while (i915_request_retire(tmp) && tmp != rq);
 }
 
 static void irq_execute_cb(struct irq_work *wrk)
@@ -600,12 +570,9 @@ static void ring_retire_requests(struct intel_ring *ring)
 {
        struct i915_request *rq, *rn;
 
-       list_for_each_entry_safe(rq, rn, &ring->request_list, ring_link) {
-               if (!i915_request_completed(rq))
+       list_for_each_entry_safe(rq, rn, &ring->request_list, ring_link)
+               if (!i915_request_retire(rq))
                        break;
-
-               i915_request_retire(rq);
-       }
 }
 
 static noinline struct i915_request *
@@ -620,6 +587,15 @@ request_alloc_slow(struct intel_context *ce, gfp_t gfp)
        if (!gfpflags_allow_blocking(gfp))
                goto out;
 
+       /* Move our oldest request to the slab-cache (if not in use!) */
+       rq = list_first_entry(&ring->request_list, typeof(*rq), ring_link);
+       i915_request_retire(rq);
+
+       rq = kmem_cache_alloc(global.slab_requests,
+                             gfp | __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
+       if (rq)
+               return rq;
+
        /* Ratelimit ourselves to prevent oom from malicious clients */
        rq = list_last_entry(&ring->request_list, typeof(*rq), ring_link);
        cond_synchronize_rcu(rq->rcustate);
@@ -777,8 +753,7 @@ i915_request_create(struct intel_context *ce)
 
        /* Move our oldest request to the slab-cache (if not in use!) */
        rq = list_first_entry(&ce->ring->request_list, typeof(*rq), ring_link);
-       if (!list_is_last(&rq->ring_link, &ce->ring->request_list) &&
-           i915_request_completed(rq))
+       if (!list_is_last(&rq->ring_link, &ce->ring->request_list))
                i915_request_retire(rq);
 
        intel_context_enter(ce);