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path: root/drivers/gpu/drm/i915/i915_request.c
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Diffstat (limited to 'drivers/gpu/drm/i915/i915_request.c')
-rw-r--r--drivers/gpu/drm/i915/i915_request.c69
1 files changed, 54 insertions, 15 deletions
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index a53777dd371c..1c5506822dc7 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -194,6 +194,27 @@ static void free_capture_list(struct i915_request *request)
}
}
+static void remove_from_engine(struct i915_request *rq)
+{
+ struct intel_engine_cs *engine, *locked;
+
+ /*
+ * Virtual engines complicate acquiring the engine timeline lock,
+ * as their rq->engine pointer is not stable until under that
+ * engine lock. The simple ploy we use is to take the lock then
+ * check that the rq still belongs to the newly locked engine.
+ */
+ locked = READ_ONCE(rq->engine);
+ spin_lock(&locked->active.lock);
+ while (unlikely(locked != (engine = READ_ONCE(rq->engine)))) {
+ spin_unlock(&locked->active.lock);
+ spin_lock(&engine->active.lock);
+ locked = engine;
+ }
+ list_del(&rq->sched.link);
+ spin_unlock(&locked->active.lock);
+}
+
static bool i915_request_retire(struct i915_request *rq)
{
struct i915_active_request *active, *next;
@@ -259,9 +280,7 @@ static bool i915_request_retire(struct i915_request *rq)
* request that we have removed from the HW and put back on a run
* queue.
*/
- spin_lock(&rq->engine->active.lock);
- list_del(&rq->sched.link);
- spin_unlock(&rq->engine->active.lock);
+ remove_from_engine(rq);
spin_lock(&rq->lock);
i915_request_mark_complete(rq);
@@ -358,9 +377,10 @@ __i915_request_await_execution(struct i915_request *rq,
return 0;
}
-void __i915_request_submit(struct i915_request *request)
+bool __i915_request_submit(struct i915_request *request)
{
struct intel_engine_cs *engine = request->engine;
+ bool result = false;
GEM_TRACE("%s fence %llx:%lld, current %d\n",
engine->name,
@@ -370,6 +390,25 @@ void __i915_request_submit(struct i915_request *request)
GEM_BUG_ON(!irqs_disabled());
lockdep_assert_held(&engine->active.lock);
+ /*
+ * With the advent of preempt-to-busy, we frequently encounter
+ * requests that we have unsubmitted from HW, but left running
+ * until the next ack and so have completed in the meantime. On
+ * resubmission of that completed request, we can skip
+ * updating the payload, and execlists can even skip submitting
+ * the request.
+ *
+ * We must remove the request from the caller's priority queue,
+ * and the caller must only call us when the request is in their
+ * priority queue, under the active.lock. This ensures that the
+ * request has *not* yet been retired and we can safely move
+ * the request into the engine->active.list where it will be
+ * dropped upon retiring. (Otherwise if resubmit a *retired*
+ * request, this would be a horrible use-after-free.)
+ */
+ if (i915_request_completed(request))
+ goto xfer;
+
if (i915_gem_context_is_banned(request->gem_context))
i915_request_skip(request, -EIO);
@@ -393,13 +432,18 @@ void __i915_request_submit(struct i915_request *request)
i915_sw_fence_signaled(&request->semaphore))
engine->saturated |= request->sched.semaphores;
- /* We may be recursing from the signal callback of another i915 fence */
- spin_lock_nested(&request->lock, SINGLE_DEPTH_NESTING);
+ engine->emit_fini_breadcrumb(request,
+ request->ring->vaddr + request->postfix);
- list_move_tail(&request->sched.link, &engine->active.requests);
+ trace_i915_request_execute(request);
+ engine->serial++;
+ result = true;
+
+xfer: /* We may be recursing from the signal callback of another i915 fence */
+ spin_lock_nested(&request->lock, SINGLE_DEPTH_NESTING);
- GEM_BUG_ON(test_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags));
- set_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags);
+ if (!test_and_set_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags))
+ list_move_tail(&request->sched.link, &engine->active.requests);
if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags) &&
!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &request->fence.flags) &&
@@ -410,12 +454,7 @@ void __i915_request_submit(struct i915_request *request)
spin_unlock(&request->lock);
- engine->emit_fini_breadcrumb(request,
- request->ring->vaddr + request->postfix);
-
- engine->serial++;
-
- trace_i915_request_execute(request);
+ return result;
}
void i915_request_submit(struct i915_request *request)