[PATCH 2/9] drm/i915: Pull the unconditional GPU cache invalidation into request construction

Chris Wilson chris at chris-wilson.co.uk
Fri Nov 17 23:16:29 UTC 2017


As the request now may implicitly invoke a context-switch, we should
follow that with a GPU TLB invalidation. Also even before using GGTT, we
should invalidate the TLBs for any updates (as well as the ppgtt
invalidates that are unconditionally applied by execbuf). Since we
almost always require the TLB invalidate, do it unconditionally on
request allocation and so we can remove it from all other paths.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_gem_execbuffer.c        |  7 +------
 drivers/gpu/drm/i915/i915_gem_render_state.c      |  4 ----
 drivers/gpu/drm/i915/i915_gem_request.c           | 24 ++++++++++++++++++-----
 drivers/gpu/drm/i915/selftests/huge_pages.c       |  4 ----
 drivers/gpu/drm/i915/selftests/i915_gem_context.c |  4 ----
 drivers/gpu/drm/i915/selftests/i915_gem_request.c | 10 ----------
 drivers/gpu/drm/i915/selftests/intel_hangcheck.c  |  4 ----
 7 files changed, 20 insertions(+), 37 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 53ccb27bfe91..b7895788bc75 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1111,10 +1111,6 @@ static int __reloc_gpu_alloc(struct i915_execbuffer *eb,
 	if (err)
 		goto err_request;
 
-	err = eb->engine->emit_flush(rq, EMIT_INVALIDATE);
-	if (err)
-		goto err_request;
-
 	err = i915_switch_context(rq);
 	if (err)
 		goto err_request;
@@ -1818,8 +1814,7 @@ static int eb_move_to_gpu(struct i915_execbuffer *eb)
 	/* Unconditionally flush any chipset caches (for streaming writes). */
 	i915_gem_chipset_flush(eb->i915);
 
-	/* Unconditionally invalidate GPU caches and TLBs. */
-	return eb->engine->emit_flush(eb->request, EMIT_INVALIDATE);
+	return 0;
 }
 
 static bool i915_gem_check_execbuffer(struct drm_i915_gem_execbuffer2 *exec)
diff --git a/drivers/gpu/drm/i915/i915_gem_render_state.c b/drivers/gpu/drm/i915/i915_gem_render_state.c
index c2723a06fbb4..f7fc0df251ac 100644
--- a/drivers/gpu/drm/i915/i915_gem_render_state.c
+++ b/drivers/gpu/drm/i915/i915_gem_render_state.c
@@ -208,10 +208,6 @@ int i915_gem_render_state_emit(struct drm_i915_gem_request *rq)
 	if (err)
 		goto err_unpin;
 
-	err = engine->emit_flush(rq, EMIT_INVALIDATE);
-	if (err)
-		goto err_unpin;
-
 	err = engine->emit_bb_start(rq,
 				    so.batch_offset, so.batch_size,
 				    I915_DISPATCH_SECURE);
diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index e0d6221022a8..91eae1b20c42 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -703,17 +703,31 @@ i915_gem_request_alloc(struct intel_engine_cs *engine,
 	req->reserved_space = MIN_SPACE_FOR_ADD_REQUEST;
 	GEM_BUG_ON(req->reserved_space < engine->emit_breadcrumb_sz);
 
-	ret = engine->request_alloc(req);
-	if (ret)
-		goto err_ctx;
-
-	/* Record the position of the start of the request so that
+	/*
+	 * Record the position of the start of the request so that
 	 * should we detect the updated seqno part-way through the
 	 * GPU processing the request, we never over-estimate the
 	 * position of the head.
 	 */
 	req->head = req->ring->emit;
 
+	/* Unconditionally invalidate GPU caches and TLBs. */
+	ret = engine->emit_flush(req, EMIT_INVALIDATE);
+	if (ret)
+		goto err_ctx;
+
+	ret = engine->request_alloc(req);
+	if (ret) {
+		/*
+		 * Past the point-of-no-return. Since we may have updated
+		 * global state after partially completing the request alloc,
+		 * we need to commit any commands so far emitted in the
+		 * request to the HW.
+		 */
+		__i915_add_request(req, false);
+		return ERR_PTR(ret);
+	}
+
 	/* Check that we didn't interrupt ourselves with a new request */
 	GEM_BUG_ON(req->timeline->seqno != req->fence.seqno);
 	return req;
diff --git a/drivers/gpu/drm/i915/selftests/huge_pages.c b/drivers/gpu/drm/i915/selftests/huge_pages.c
index 01af540b6ef9..159a2cb68765 100644
--- a/drivers/gpu/drm/i915/selftests/huge_pages.c
+++ b/drivers/gpu/drm/i915/selftests/huge_pages.c
@@ -989,10 +989,6 @@ static int gpu_write(struct i915_vma *vma,
 	i915_vma_unpin(batch);
 	i915_vma_close(batch);
 
-	err = rq->engine->emit_flush(rq, EMIT_INVALIDATE);
-	if (err)
-		goto err_request;
-
 	err = i915_switch_context(rq);
 	if (err)
 		goto err_request;
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
index c82780a9d455..4ff30b9af1fe 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
@@ -158,10 +158,6 @@ static int gpu_fill(struct drm_i915_gem_object *obj,
 		goto err_batch;
 	}
 
-	err = engine->emit_flush(rq, EMIT_INVALIDATE);
-	if (err)
-		goto err_request;
-
 	err = i915_switch_context(rq);
 	if (err)
 		goto err_request;
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_request.c b/drivers/gpu/drm/i915/selftests/i915_gem_request.c
index 6bce99050e94..d7bf53ff8f84 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_request.c
@@ -459,10 +459,6 @@ empty_request(struct intel_engine_cs *engine,
 	if (IS_ERR(request))
 		return request;
 
-	err = engine->emit_flush(request, EMIT_INVALIDATE);
-	if (err)
-		goto out_request;
-
 	err = i915_switch_context(request);
 	if (err)
 		goto out_request;
@@ -675,9 +671,6 @@ static int live_all_engines(void *arg)
 			goto out_request;
 		}
 
-		err = engine->emit_flush(request[id], EMIT_INVALIDATE);
-		GEM_BUG_ON(err);
-
 		err = i915_switch_context(request[id]);
 		GEM_BUG_ON(err);
 
@@ -797,9 +790,6 @@ static int live_sequential_engines(void *arg)
 			}
 		}
 
-		err = engine->emit_flush(request[id], EMIT_INVALIDATE);
-		GEM_BUG_ON(err);
-
 		err = i915_switch_context(request[id]);
 		GEM_BUG_ON(err);
 
diff --git a/drivers/gpu/drm/i915/selftests/intel_hangcheck.c b/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
index 71ce06680d66..145bdc26553c 100644
--- a/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
+++ b/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
@@ -114,10 +114,6 @@ static int emit_recurse_batch(struct hang *h,
 	if (err)
 		goto unpin_vma;
 
-	err = rq->engine->emit_flush(rq, EMIT_INVALIDATE);
-	if (err)
-		goto unpin_hws;
-
 	err = i915_switch_context(rq);
 	if (err)
 		goto unpin_hws;
-- 
2.15.0



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