[Intel-gfx] [PATCH] drm/i915: Make closing request flush mandatory

Chris Wilson chris at chris-wilson.co.uk
Tue Jun 12 10:51:35 UTC 2018


For symmetry, simplicity and ensuring the request is always truly idle
upon its completion, always emit the closing flush prior to emitting the
request breadcrumb. Previously, we would only emit the flush if we had
started a user batch, but this just leaves all the other paths open to
speculation (do they affect the GPU caches or not?) With mm switching, a
key requirement is that the GPU is flushed and invalidated before hand,
so for absolute safety, we want that closing flush be mandatory.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem.c                |  4 ++--
 drivers/gpu/drm/i915/i915_gem_context.c        |  9 +--------
 drivers/gpu/drm/i915/i915_gem_execbuffer.c     |  4 ++--
 drivers/gpu/drm/i915/i915_request.c            | 18 ++----------------
 drivers/gpu/drm/i915/i915_request.h            |  4 +---
 drivers/gpu/drm/i915/selftests/huge_pages.c    |  2 +-
 .../drm/i915/selftests/i915_gem_coherency.c    |  4 ++--
 .../gpu/drm/i915/selftests/i915_gem_context.c  |  4 ++--
 drivers/gpu/drm/i915/selftests/i915_request.c  |  2 +-
 .../gpu/drm/i915/selftests/intel_hangcheck.c   | 16 ++++++++--------
 drivers/gpu/drm/i915/selftests/intel_lrc.c     |  2 +-
 .../gpu/drm/i915/selftests/intel_workarounds.c |  2 +-
 12 files changed, 24 insertions(+), 47 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 93efd92362db..8dd4d35655af 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3213,7 +3213,7 @@ void i915_gem_reset(struct drm_i915_private *dev_priv,
 			rq = i915_request_alloc(engine,
 						dev_priv->kernel_context);
 			if (!IS_ERR(rq))
-				__i915_request_add(rq, false);
+				i915_request_add(rq);
 		}
 	}
 
@@ -5332,7 +5332,7 @@ static int __intel_engines_record_defaults(struct drm_i915_private *i915)
 		if (engine->init_context)
 			err = engine->init_context(rq);
 
-		__i915_request_add(rq, true);
+		i915_request_add(rq);
 		if (err)
 			goto err_active;
 	}
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index b2c7ac1b074d..ef6ea4bcd773 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -700,14 +700,7 @@ int i915_gem_switch_to_kernel_context(struct drm_i915_private *i915)
 			i915_timeline_sync_set(rq->timeline, &prev->fence);
 		}
 
-		/*
-		 * Force a flush after the switch to ensure that all rendering
-		 * and operations prior to switching to the kernel context hits
-		 * memory. This should be guaranteed by the previous request,
-		 * but an extra layer of paranoia before we declare the system
-		 * idle (on suspend etc) is advisable!
-		 */
-		__i915_request_add(rq, true);
+		i915_request_add(rq);
 	}
 
 	return 0;
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 2d2eb3075960..60dc2a865f5f 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -921,7 +921,7 @@ static void reloc_gpu_flush(struct reloc_cache *cache)
 	i915_gem_object_unpin_map(cache->rq->batch->obj);
 	i915_gem_chipset_flush(cache->rq->i915);
 
-	__i915_request_add(cache->rq, true);
+	i915_request_add(cache->rq);
 	cache->rq = NULL;
 }
 
@@ -2438,7 +2438,7 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 	trace_i915_request_queue(eb.request, eb.batch_flags);
 	err = eb_submit(&eb);
 err_request:
-	__i915_request_add(eb.request, err == 0);
+	i915_request_add(eb.request);
 	add_to_client(eb.request, file);
 
 	if (fences)
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 9092f5464c24..e1dbb544046f 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1018,14 +1018,13 @@ i915_request_await_object(struct i915_request *to,
  * request is not being tracked for completion but the work itself is
  * going to happen on the hardware. This would be a Bad Thing(tm).
  */
-void __i915_request_add(struct i915_request *request, bool flush_caches)
+void i915_request_add(struct i915_request *request)
 {
 	struct intel_engine_cs *engine = request->engine;
 	struct i915_timeline *timeline = request->timeline;
 	struct intel_ring *ring = request->ring;
 	struct i915_request *prev;
 	u32 *cs;
-	int err;
 
 	GEM_TRACE("%s fence %llx:%d\n",
 		  engine->name, request->fence.context, request->fence.seqno);
@@ -1046,20 +1045,7 @@ void __i915_request_add(struct i915_request *request, bool flush_caches)
 	 * know that it is time to use that space up.
 	 */
 	request->reserved_space = 0;
-
-	/*
-	 * Emit any outstanding flushes - execbuf can fail to emit the flush
-	 * after having emitted the batchbuffer command. Hence we need to fix
-	 * things up similar to emitting the lazy request. The difference here
-	 * is that the flush _must_ happen before the next request, no matter
-	 * what.
-	 */
-	if (flush_caches) {
-		err = engine->emit_flush(request, EMIT_FLUSH);
-
-		/* Not allowed to fail! */
-		WARN(err, "engine->emit_flush() failed: %d!\n", err);
-	}
+	engine->emit_flush(request, EMIT_FLUSH);
 
 	/*
 	 * Record the position of the start of the breadcrumb so that
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index 0e9aba53d0e4..7ee220ded9c9 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -253,9 +253,7 @@ int i915_request_await_object(struct i915_request *to,
 int i915_request_await_dma_fence(struct i915_request *rq,
 				 struct dma_fence *fence);
 
-void __i915_request_add(struct i915_request *rq, bool flush_caches);
-#define i915_request_add(rq) \
-	__i915_request_add(rq, false)
+void i915_request_add(struct i915_request *rq);
 
 void __i915_request_submit(struct i915_request *request);
 void i915_request_submit(struct i915_request *request);
diff --git a/drivers/gpu/drm/i915/selftests/huge_pages.c b/drivers/gpu/drm/i915/selftests/huge_pages.c
index 7846ea4a99bc..fbe4324116d7 100644
--- a/drivers/gpu/drm/i915/selftests/huge_pages.c
+++ b/drivers/gpu/drm/i915/selftests/huge_pages.c
@@ -1003,7 +1003,7 @@ static int gpu_write(struct i915_vma *vma,
 	reservation_object_unlock(vma->resv);
 
 err_request:
-	__i915_request_add(rq, err == 0);
+	i915_request_add(rq);
 
 	return err;
 }
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_coherency.c b/drivers/gpu/drm/i915/selftests/i915_gem_coherency.c
index 340a98c0c804..a4900091ae3d 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_coherency.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_coherency.c
@@ -199,7 +199,7 @@ static int gpu_set(struct drm_i915_gem_object *obj,
 
 	cs = intel_ring_begin(rq, 4);
 	if (IS_ERR(cs)) {
-		__i915_request_add(rq, false);
+		i915_request_add(rq);
 		i915_vma_unpin(vma);
 		return PTR_ERR(cs);
 	}
@@ -229,7 +229,7 @@ static int gpu_set(struct drm_i915_gem_object *obj,
 	reservation_object_add_excl_fence(obj->resv, &rq->fence);
 	reservation_object_unlock(obj->resv);
 
-	__i915_request_add(rq, true);
+	i915_request_add(rq);
 
 	return 0;
 }
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
index 708e8d721448..836f1af8b833 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
@@ -182,12 +182,12 @@ static int gpu_fill(struct drm_i915_gem_object *obj,
 	reservation_object_add_excl_fence(obj->resv, &rq->fence);
 	reservation_object_unlock(obj->resv);
 
-	__i915_request_add(rq, true);
+	i915_request_add(rq);
 
 	return 0;
 
 err_request:
-	__i915_request_add(rq, false);
+	i915_request_add(rq);
 err_batch:
 	i915_vma_unpin(batch);
 err_vma:
diff --git a/drivers/gpu/drm/i915/selftests/i915_request.c b/drivers/gpu/drm/i915/selftests/i915_request.c
index a3a89aadeccb..f5d00332bb31 100644
--- a/drivers/gpu/drm/i915/selftests/i915_request.c
+++ b/drivers/gpu/drm/i915/selftests/i915_request.c
@@ -466,7 +466,7 @@ empty_request(struct intel_engine_cs *engine,
 		goto out_request;
 
 out_request:
-	__i915_request_add(request, err == 0);
+	i915_request_add(request);
 	return err ? ERR_PTR(err) : request;
 }
 
diff --git a/drivers/gpu/drm/i915/selftests/intel_hangcheck.c b/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
index 390a157b37c3..fe7d3190ebfe 100644
--- a/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
+++ b/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
@@ -245,7 +245,7 @@ hang_create_request(struct hang *h, struct intel_engine_cs *engine)
 
 	err = emit_recurse_batch(h, rq);
 	if (err) {
-		__i915_request_add(rq, false);
+		i915_request_add(rq);
 		return ERR_PTR(err);
 	}
 
@@ -318,7 +318,7 @@ static int igt_hang_sanitycheck(void *arg)
 		*h.batch = MI_BATCH_BUFFER_END;
 		i915_gem_chipset_flush(i915);
 
-		__i915_request_add(rq, true);
+		i915_request_add(rq);
 
 		timeout = i915_request_wait(rq,
 					    I915_WAIT_LOCKED,
@@ -464,7 +464,7 @@ static int __igt_reset_engine(struct drm_i915_private *i915, bool active)
 				}
 
 				i915_request_get(rq);
-				__i915_request_add(rq, true);
+				i915_request_add(rq);
 				mutex_unlock(&i915->drm.struct_mutex);
 
 				if (!wait_until_running(&h, rq)) {
@@ -742,7 +742,7 @@ static int __igt_reset_engines(struct drm_i915_private *i915,
 				}
 
 				i915_request_get(rq);
-				__i915_request_add(rq, true);
+				i915_request_add(rq);
 				mutex_unlock(&i915->drm.struct_mutex);
 
 				if (!wait_until_running(&h, rq)) {
@@ -942,7 +942,7 @@ static int igt_wait_reset(void *arg)
 	}
 
 	i915_request_get(rq);
-	__i915_request_add(rq, true);
+	i915_request_add(rq);
 
 	if (!wait_until_running(&h, rq)) {
 		struct drm_printer p = drm_info_printer(i915->drm.dev);
@@ -1037,7 +1037,7 @@ static int igt_reset_queue(void *arg)
 		}
 
 		i915_request_get(prev);
-		__i915_request_add(prev, true);
+		i915_request_add(prev);
 
 		count = 0;
 		do {
@@ -1051,7 +1051,7 @@ static int igt_reset_queue(void *arg)
 			}
 
 			i915_request_get(rq);
-			__i915_request_add(rq, true);
+			i915_request_add(rq);
 
 			/*
 			 * XXX We don't handle resetting the kernel context
@@ -1184,7 +1184,7 @@ static int igt_handle_error(void *arg)
 	}
 
 	i915_request_get(rq);
-	__i915_request_add(rq, true);
+	i915_request_add(rq);
 
 	if (!wait_until_running(&h, rq)) {
 		struct drm_printer p = drm_info_printer(i915->drm.dev);
diff --git a/drivers/gpu/drm/i915/selftests/intel_lrc.c b/drivers/gpu/drm/i915/selftests/intel_lrc.c
index 0b6da08c8cae..ea27c7cfbf96 100644
--- a/drivers/gpu/drm/i915/selftests/intel_lrc.c
+++ b/drivers/gpu/drm/i915/selftests/intel_lrc.c
@@ -155,7 +155,7 @@ spinner_create_request(struct spinner *spin,
 
 	err = emit_recurse_batch(spin, rq, arbitration_command);
 	if (err) {
-		__i915_request_add(rq, false);
+		i915_request_add(rq);
 		return ERR_PTR(err);
 	}
 
diff --git a/drivers/gpu/drm/i915/selftests/intel_workarounds.c b/drivers/gpu/drm/i915/selftests/intel_workarounds.c
index f1cfb0fb6bea..e1ea2d2bedd2 100644
--- a/drivers/gpu/drm/i915/selftests/intel_workarounds.c
+++ b/drivers/gpu/drm/i915/selftests/intel_workarounds.c
@@ -75,7 +75,7 @@ read_nonprivs(struct i915_gem_context *ctx, struct intel_engine_cs *engine)
 	i915_gem_object_get(result);
 	i915_gem_object_set_active_reference(result);
 
-	__i915_request_add(rq, true);
+	i915_request_add(rq);
 	i915_vma_unpin(vma);
 
 	return result;
-- 
2.17.1



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