[Intel-gfx] [PATCH 2/3] drm/i915: Automatic i915_switch_context for legacy

Chris Wilson chris at chris-wilson.co.uk
Fri Nov 10 22:50:03 UTC 2017


During request construction, after pinning the context we know whether
or not we have to emit a context switch. So move this common operation
from every caller into i915_gem_request_alloc() itself.

v2: Always submit the request if we emitted some commands during request
construction, as typically it also involves changes in global state.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem.c                   |  2 +-
 drivers/gpu/drm/i915/i915_gem_context.c           |  7 +------
 drivers/gpu/drm/i915/i915_gem_execbuffer.c        |  8 --------
 drivers/gpu/drm/i915/i915_gem_request.c           | 18 +++++++++++++-----
 drivers/gpu/drm/i915/intel_ringbuffer.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 ----
 8 files changed, 19 insertions(+), 38 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index a2e5a54128c1..bf4995f93357 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -5001,7 +5001,7 @@ static int __intel_engines_record_defaults(struct drm_i915_private *i915)
 			goto out_ctx;
 		}
 
-		err = i915_switch_context(rq);
+		err = 0;
 		if (engine->init_context)
 			err = engine->init_context(rq);
 
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 2db040695035..c1efbaf02bf2 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -842,8 +842,7 @@ int i915_switch_context(struct drm_i915_gem_request *req)
 	struct intel_engine_cs *engine = req->engine;
 
 	lockdep_assert_held(&req->i915->drm.struct_mutex);
-	if (i915_modparams.enable_execlists)
-		return 0;
+	GEM_BUG_ON(i915_modparams.enable_execlists);
 
 	if (!req->ctx->engine[engine->id].state) {
 		struct i915_gem_context *to = req->ctx;
@@ -899,7 +898,6 @@ int i915_gem_switch_to_kernel_context(struct drm_i915_private *dev_priv)
 
 	for_each_engine(engine, dev_priv, id) {
 		struct drm_i915_gem_request *req;
-		int ret;
 
 		if (engine_has_idle_kernel_context(engine))
 			continue;
@@ -922,10 +920,7 @@ int i915_gem_switch_to_kernel_context(struct drm_i915_private *dev_priv)
 								 GFP_KERNEL);
 		}
 
-		ret = i915_switch_context(req);
 		i915_add_request(req);
-		if (ret)
-			return ret;
 	}
 
 	return 0;
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 435ed95df144..85c7e8afe26e 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1115,10 +1115,6 @@ static int __reloc_gpu_alloc(struct i915_execbuffer *eb,
 	if (err)
 		goto err_request;
 
-	err = i915_switch_context(rq);
-	if (err)
-		goto err_request;
-
 	err = eb->engine->emit_bb_start(rq,
 					batch->node.start, PAGE_SIZE,
 					cache->gen > 5 ? 0 : I915_DISPATCH_SECURE);
@@ -1965,10 +1961,6 @@ static int eb_submit(struct i915_execbuffer *eb)
 	if (err)
 		return err;
 
-	err = i915_switch_context(eb->request);
-	if (err)
-		return err;
-
 	if (eb->args->flags & I915_EXEC_GEN7_SOL_RESET) {
 		err = i915_reset_gen7_sol_offsets(eb->request);
 		if (err)
diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index e0d6221022a8..445495f9893c 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -624,6 +624,10 @@ i915_gem_request_alloc(struct intel_engine_cs *engine,
 	if (ret)
 		goto err_unpin;
 
+	ret = intel_ring_wait_for_space(ring, MIN_SPACE_FOR_ADD_REQUEST);
+	if (ret)
+		goto err_unreserve;
+
 	/* Move the oldest request to the slab-cache (if not in use!) */
 	req = list_first_entry_or_null(&engine->timeline->requests,
 				       typeof(*req), link);
@@ -703,10 +707,6 @@ 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
 	 * should we detect the updated seqno part-way through the
 	 * GPU processing the request, we never over-estimate the
@@ -714,16 +714,24 @@ i915_gem_request_alloc(struct intel_engine_cs *engine,
 	 */
 	req->head = req->ring->emit;
 
+	ret = engine->request_alloc(req);
+	if (ret)
+		goto err_ctx;
+
 	/* Check that we didn't interrupt ourselves with a new request */
 	GEM_BUG_ON(req->timeline->seqno != req->fence.seqno);
 	return req;
 
 err_ctx:
+	if (req->ring->emit != req->head) {
+		__i915_add_request(req, false);
+		return ERR_PTR(ret);
+	}
+
 	/* Make sure we didn't add ourselves to external state before freeing */
 	GEM_BUG_ON(!list_empty(&req->active_list));
 	GEM_BUG_ON(!list_empty(&req->priotree.signalers_list));
 	GEM_BUG_ON(!list_empty(&req->priotree.waiters_list));
-
 	kmem_cache_free(dev_priv->requests, req);
 err_unreserve:
 	unreserve_engine(engine);
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 12e734b29463..be98868115bf 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1592,6 +1592,10 @@ static int ring_request_alloc(struct drm_i915_gem_request *request)
 	if (ret)
 		return ret;
 
+	ret = i915_switch_context(request);
+	if (ret)
+		return ret;
+
 	request->reserved_space -= LEGACY_REQUEST_SIZE;
 	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 def5052862ae..61fcfa2c4dfd 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
@@ -162,10 +162,6 @@ static int gpu_fill(struct drm_i915_gem_object *obj,
 	if (err)
 		goto err_request;
 
-	err = i915_switch_context(rq);
-	if (err)
-		goto err_request;
-
 	flags = 0;
 	if (INTEL_GEN(vm->i915) <= 5)
 		flags |= I915_DISPATCH_SECURE;
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_request.c b/drivers/gpu/drm/i915/selftests/i915_gem_request.c
index a999161e8db1..9a35ebd5c876 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_request.c
@@ -463,10 +463,6 @@ empty_request(struct intel_engine_cs *engine,
 	if (err)
 		goto out_request;
 
-	err = i915_switch_context(request);
-	if (err)
-		goto out_request;
-
 	err = engine->emit_bb_start(request,
 				    batch->node.start,
 				    batch->node.size,
@@ -678,9 +674,6 @@ static int live_all_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);
-
 		err = engine->emit_bb_start(request[id],
 					    batch->node.start,
 					    batch->node.size,
@@ -800,9 +793,6 @@ 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);
-
 		err = engine->emit_bb_start(request[id],
 					    batch->node.start,
 					    batch->node.size,
diff --git a/drivers/gpu/drm/i915/selftests/intel_hangcheck.c b/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
index 71ce06680d66..cafe39e2e0f7 100644
--- a/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
+++ b/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
@@ -118,10 +118,6 @@ static int emit_recurse_batch(struct hang *h,
 	if (err)
 		goto unpin_hws;
 
-	err = i915_switch_context(rq);
-	if (err)
-		goto unpin_hws;
-
 	i915_vma_move_to_active(vma, rq, 0);
 	if (!i915_gem_object_has_active_reference(vma->obj)) {
 		i915_gem_object_get(vma->obj);
-- 
2.15.0



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