[PATCH 43/81] drm/i915: Derive GEM requests from dma-fence

Chris Wilson chris at chris-wilson.co.uk
Sat Apr 16 18:11:00 UTC 2016


dma-buf provides a generic fence class for interoperation between
drivers. Internally we use the request structure as a fence, and so with
only a little bit of interfacing we can rebase those requests on top of
dma-buf fences. This will allow us, in the future, to pass those fences
back to userspace or between drivers.

v2: The fence_context needs to be globally unique, not just unique to
this device.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Jesse Barnes <jbarnes at virtuousgeek.org>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/i915_debugfs.c        |   2 +-
 drivers/gpu/drm/i915/i915_gem_request.c    | 110 +++++++++++++++++++++++++----
 drivers/gpu/drm/i915/i915_gem_request.h    |  33 ++++-----
 drivers/gpu/drm/i915/i915_gpu_error.c      |   2 +-
 drivers/gpu/drm/i915/i915_guc_submission.c |   2 +-
 drivers/gpu/drm/i915/i915_trace.h          |   2 +-
 drivers/gpu/drm/i915/intel_breadcrumbs.c   |   3 +-
 drivers/gpu/drm/i915/intel_lrc.c           |   3 +-
 drivers/gpu/drm/i915/intel_ringbuffer.c    |  11 +--
 drivers/gpu/drm/i915/intel_ringbuffer.h    |   1 +
 10 files changed, 130 insertions(+), 39 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 4fa78a23554d..0e7bf67c70da 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -737,7 +737,7 @@ static int i915_gem_request_info(struct seq_file *m, void *data)
 			if (req->pid)
 				task = pid_task(req->pid, PIDTYPE_PID);
 			seq_printf(m, "    %x @ %d: %s [%d]\n",
-				   req->seqno,
+				   req->fence.seqno,
 				   (int) (jiffies - req->emitted_jiffies),
 				   task ? task->comm : "<unknown>",
 				   task ? task->pid : -1);
diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index 121f5ccd0fe4..454a143dbe7d 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -24,6 +24,92 @@
 
 #include "i915_drv.h"
 
+static inline struct drm_i915_gem_request *
+to_i915_request(struct fence *fence)
+{
+	return container_of(fence, struct drm_i915_gem_request, fence);
+}
+
+static const char *i915_fence_get_driver_name(struct fence *fence)
+{
+	return "i915";
+}
+
+static const char *i915_fence_get_timeline_name(struct fence *fence)
+{
+	return to_i915_request(fence)->engine->name;
+}
+
+static bool i915_fence_signaled(struct fence *fence)
+{
+	return i915_gem_request_completed(to_i915_request(fence));
+}
+
+static bool i915_fence_enable_signaling(struct fence *fence)
+{
+	if (i915_fence_signaled(fence))
+		return false;
+
+	return intel_engine_enable_signaling(to_i915_request(fence)) == 0;
+}
+
+static signed long i915_fence_wait(struct fence *fence,
+				   bool interruptible,
+				   signed long timeout_jiffies)
+{
+	s64 timeout_ns, *timeout;
+	int ret;
+
+	if (timeout_jiffies != MAX_SCHEDULE_TIMEOUT) {
+		timeout_ns = jiffies_to_nsecs(timeout_jiffies);
+		timeout = &timeout_ns;
+	} else
+		timeout = NULL;
+
+	ret = __i915_wait_request(to_i915_request(fence),
+				  interruptible, timeout,
+				  NULL);
+	if (ret == -ETIME)
+		return 0;
+
+	if (ret < 0)
+		return ret;
+
+	if (timeout_jiffies != MAX_SCHEDULE_TIMEOUT)
+		timeout_jiffies = nsecs_to_jiffies(timeout_ns);
+
+	return timeout_jiffies;
+}
+
+static void i915_fence_value_str(struct fence *fence, char *str, int size)
+{
+	snprintf(str, size, "%u", fence->seqno);
+}
+
+static void i915_fence_timeline_value_str(struct fence *fence, char *str,
+					  int size)
+{
+	snprintf(str, size, "%u",
+		 intel_engine_get_seqno(to_i915_request(fence)->engine));
+}
+
+static void i915_fence_release(struct fence *fence)
+{
+	struct drm_i915_gem_request *req = to_i915_request(fence);
+	kmem_cache_free(req->i915->requests, req);
+}
+
+static const struct fence_ops i915_fence_ops = {
+	.get_driver_name = i915_fence_get_driver_name,
+	.get_timeline_name = i915_fence_get_timeline_name,
+	.enable_signaling = i915_fence_enable_signaling,
+	.signaled = i915_fence_signaled,
+	.wait = i915_fence_wait,
+	.release = i915_fence_release,
+	.fence_value_str = i915_fence_value_str,
+	.timeline_value_str = i915_fence_timeline_value_str,
+};
+
 static int
 i915_gem_check_wedge(unsigned reset_counter, bool interruptible)
 {
@@ -111,6 +197,7 @@ static int __i915_gem_request_alloc(struct intel_engine_cs *engine,
 	struct drm_i915_private *dev_priv = to_i915(engine);
 	unsigned reset_counter = i915_reset_counter(&dev_priv->gpu_error);
 	struct drm_i915_gem_request *req;
+	u32 seqno;
 	int ret;
 
 	if (!req_out)
@@ -130,11 +217,17 @@ static int __i915_gem_request_alloc(struct intel_engine_cs *engine,
 	if (req == NULL)
 		return -ENOMEM;
 
-	ret = i915_gem_get_seqno(dev_priv, &req->seqno);
+	ret = i915_gem_get_seqno(dev_priv, &seqno);
 	if (ret)
 		goto err;
 
-	kref_init(&req->ref);
+	spin_lock_init(&req->lock);
+	fence_init(&req->fence,
+		   &i915_fence_ops,
+		   &req->lock,
+		   engine->fence_context,
+		   seqno);
+
 	req->i915 = dev_priv;
 	req->engine = engine;
 	req->reset_counter = reset_counter;
@@ -391,7 +484,7 @@ void __i915_add_request(struct drm_i915_gem_request *request,
 	 */
 	request->emitted_jiffies = jiffies;
 	request->previous_seqno = engine->last_submitted_seqno;
-	smp_store_mb(engine->last_submitted_seqno, request->seqno);
+	smp_store_mb(engine->last_submitted_seqno, request->fence.seqno);
 	list_add_tail(&request->list, &engine->request_list);
 
 	/* Record the position of the start of the request so that
@@ -555,7 +648,7 @@ int __i915_wait_request(struct drm_i915_gem_request *req,
 	if (__i915_spin_request(req, state))
 		goto complete;
 
-	intel_wait_init(&wait, req->seqno);
+	intel_wait_init(&wait, req->fence.seqno);
 	set_task_state(wait.task, state);
 	if (intel_engine_add_wait(req->engine, &wait))
 		/* In order to check that we haven't missed the interrupt
@@ -615,7 +708,7 @@ complete:
 			*timeout = 0;
 	}
 
-	if (rps && req->seqno == req->engine->last_submitted_seqno) {
+	if (rps && req->fence.seqno == req->engine->last_submitted_seqno) {
 		/* The GPU is now idle and this client has stalled.
 		 * Since no other client has submitted a request in the
 		 * meantime, assume that this client is the only one
@@ -654,10 +747,3 @@ i915_wait_request(struct drm_i915_gem_request *req)
 	i915_gem_request_retire_upto(req);
 	return 0;
 }
-
-void i915_gem_request_free(struct kref *req_ref)
-{
-	struct drm_i915_gem_request *req =
-		container_of(req_ref, typeof(*req), ref);
-	kmem_cache_free(to_i915(req)->requests, req);
-}
diff --git a/drivers/gpu/drm/i915/i915_gem_request.h b/drivers/gpu/drm/i915/i915_gem_request.h
index 48bff7dc4f90..b07b61905756 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.h
+++ b/drivers/gpu/drm/i915/i915_gem_request.h
@@ -25,6 +25,8 @@
 #ifndef I915_GEM_REQUEST_H
 #define I915_GEM_REQUEST_H
 
+#include <linux/fence.h>
+
 /**
  * Request queue structure.
  *
@@ -36,11 +38,11 @@
  * emission time to be associated with the request for tracking how far ahead
  * of the GPU the submission is.
  *
- * The requests are reference counted, so upon creation they should have an
- * initial reference taken using kref_init
+ * The requests are reference counted.
  */
 struct drm_i915_gem_request {
-	struct kref ref;
+	struct fence fence;
+	spinlock_t lock;
 
 	/** On Which ring this request was generated */
 	struct drm_i915_private *i915;
@@ -53,12 +55,6 @@ struct drm_i915_gem_request {
 	  */
 	u32 previous_seqno;
 
-	 /** GEM sequence number associated with this request,
-	  * when the HWS breadcrumb is equal or greater than this the GPU
-	  * has finished processing this request.
-	  */
-	u32 seqno;
-
 	/** Position in the ringbuffer of the start of the request */
 	u32 head;
 
@@ -142,7 +138,6 @@ __request_to_i915(const struct drm_i915_gem_request *request)
 struct drm_i915_gem_request * __must_check
 i915_gem_request_alloc(struct intel_engine_cs *engine,
 		       struct intel_context *ctx);
-void i915_gem_request_free(struct kref *req_ref);
 int i915_gem_request_add_to_client(struct drm_i915_gem_request *req,
 				   struct drm_file *file);
 void i915_gem_request_retire_upto(struct drm_i915_gem_request *req);
@@ -150,7 +145,7 @@ void i915_gem_request_retire_upto(struct drm_i915_gem_request *req);
 static inline uint32_t
 i915_gem_request_get_seqno(struct drm_i915_gem_request *req)
 {
-	return req ? req->seqno : 0;
+	return req ? req->fence.seqno : 0;
 }
 
 static inline struct intel_engine_cs *
@@ -160,17 +155,23 @@ i915_gem_request_get_engine(struct drm_i915_gem_request *req)
 }
 
 static inline struct drm_i915_gem_request *
+to_request(struct fence *fence)
+{
+	/* We assume that NULL fence/request are interoperable */
+	BUILD_BUG_ON(offsetof(struct drm_i915_gem_request, fence) != 0);
+	return container_of(fence, struct drm_i915_gem_request, fence);
+}
+
+static inline struct drm_i915_gem_request *
 i915_gem_request_reference(struct drm_i915_gem_request *req)
 {
-	if (req)
-		kref_get(&req->ref);
-	return req;
+	return to_request(fence_get(&req->fence));
 }
 
 static inline void
 i915_gem_request_unreference(struct drm_i915_gem_request *req)
 {
-	kref_put(&req->ref, i915_gem_request_free);
+	fence_put(&req->fence);
 }
 
 static inline void i915_gem_request_assign(struct drm_i915_gem_request **pdst,
@@ -221,7 +222,7 @@ static inline bool i915_gem_request_started(struct drm_i915_gem_request *req)
 static inline bool i915_gem_request_completed(struct drm_i915_gem_request *req)
 {
 	return i915_seqno_passed(intel_engine_get_seqno(req->engine),
-				 req->seqno);
+				 req->fence.seqno);
 }
 
 #endif /* I915_GEM_REQUEST_H */
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index 7df9aa1c7642..3be47a6d01be 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -1130,7 +1130,7 @@ static void i915_gem_record_rings(struct drm_device *dev,
 			}
 
 			erq = &error->ring[i].requests[count++];
-			erq->seqno = request->seqno;
+			erq->seqno = request->fence.seqno;
 			erq->jiffies = request->emitted_jiffies;
 			erq->tail = request->postfix;
 		}
diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index c10cb13d0fc9..ae19d9e70a88 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -587,7 +587,7 @@ int i915_guc_submit(struct i915_guc_client *client,
 		client->retcode = 0;
 	}
 	guc->submissions[engine_id] += 1;
-	guc->last_seqno[engine_id] = rq->seqno;
+	guc->last_seqno[engine_id] = rq->fence.seqno;
 
 	return q_ret;
 }
diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h
index 5c0ccd942985..e56b2cf7aaa6 100644
--- a/drivers/gpu/drm/i915/i915_trace.h
+++ b/drivers/gpu/drm/i915/i915_trace.h
@@ -492,7 +492,7 @@ TRACE_EVENT(i915_gem_ring_dispatch,
 			   __entry->ring = engine->id;
 			   __entry->seqno = i915_gem_request_get_seqno(req);
 			   __entry->flags = flags;
-			   intel_engine_enable_signaling(req);
+			   fence_enable_sw_signaling(&req->fence);
 			   ),
 
 	    TP_printk("dev=%u, ring=%u, seqno=%u, flags=%x",
diff --git a/drivers/gpu/drm/i915/intel_breadcrumbs.c b/drivers/gpu/drm/i915/intel_breadcrumbs.c
index d7d19e17318e..3f8725087c87 100644
--- a/drivers/gpu/drm/i915/intel_breadcrumbs.c
+++ b/drivers/gpu/drm/i915/intel_breadcrumbs.c
@@ -379,6 +379,7 @@ static int intel_breadcrumbs_signaler(void *arg)
 			 */
 			intel_engine_remove_wait(engine, &signal->wait);
 
+			fence_signal(&signal->request->fence);
 			i915_gem_request_unreference(signal->request);
 
 			/* Find the next oldest signal. Note that as we have
@@ -445,7 +446,7 @@ int intel_engine_enable_signaling(struct drm_i915_gem_request *request)
 	}
 
 	signal->wait.task = task;
-	signal->wait.seqno = request->seqno;
+	signal->wait.seqno = request->fence.seqno;
 
 	signal->request = i915_gem_request_reference(request);
 
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 69028c0dfce1..717d8373acd6 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1876,7 +1876,7 @@ static int gen8_emit_request(struct drm_i915_gem_request *request)
 				hws_seqno_address(request->engine) |
 				MI_FLUSH_DW_USE_GTT);
 	intel_logical_ring_emit(ringbuf, 0);
-	intel_logical_ring_emit(ringbuf, request->seqno);
+	intel_logical_ring_emit(ringbuf, request->fence.seqno);
 	intel_logical_ring_emit(ringbuf, MI_USER_INTERRUPT);
 	intel_logical_ring_emit(ringbuf, MI_NOOP);
 	return intel_logical_ring_advance_and_submit(request);
@@ -2068,6 +2068,7 @@ logical_ring_setup(struct drm_device *dev, int id,
 	engine->exec_id = exec_id;
 	engine->guc_id = guc_id;
 	engine->mmio_base = mmio_base;
+	engine->fence_context = fence_context_alloc(1);
 
 	/* Intentionally left blank. */
 	engine->buffer = NULL;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 54ee4d636d62..c3c4360ac2b9 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1278,7 +1278,7 @@ static int gen8_rcs_signal(struct drm_i915_gem_request *signaller_req,
 					   PIPE_CONTROL_FLUSH_ENABLE);
 		intel_ring_emit(signaller, lower_32_bits(gtt_offset));
 		intel_ring_emit(signaller, upper_32_bits(gtt_offset));
-		intel_ring_emit(signaller, signaller_req->seqno);
+		intel_ring_emit(signaller, signaller_req->fence.seqno);
 		intel_ring_emit(signaller, 0);
 		intel_ring_emit(signaller, MI_SEMAPHORE_SIGNAL |
 					   MI_SEMAPHORE_TARGET(waiter->id));
@@ -1316,7 +1316,7 @@ static int gen8_xcs_signal(struct drm_i915_gem_request *signaller_req,
 		intel_ring_emit(signaller, lower_32_bits(gtt_offset) |
 					   MI_FLUSH_DW_USE_GTT);
 		intel_ring_emit(signaller, upper_32_bits(gtt_offset));
-		intel_ring_emit(signaller, signaller_req->seqno);
+		intel_ring_emit(signaller, signaller_req->fence.seqno);
 		intel_ring_emit(signaller, MI_SEMAPHORE_SIGNAL |
 					   MI_SEMAPHORE_TARGET(waiter->id));
 		intel_ring_emit(signaller, 0);
@@ -1349,7 +1349,7 @@ static int gen6_signal(struct drm_i915_gem_request *signaller_req,
 		if (i915_mmio_reg_valid(mbox_reg)) {
 			intel_ring_emit(signaller, MI_LOAD_REGISTER_IMM(1));
 			intel_ring_emit_reg(signaller, mbox_reg);
-			intel_ring_emit(signaller, signaller_req->seqno);
+			intel_ring_emit(signaller, signaller_req->fence.seqno);
 		}
 	}
 
@@ -1385,7 +1385,7 @@ gen6_add_request(struct drm_i915_gem_request *req)
 	intel_ring_emit(engine, MI_STORE_DWORD_INDEX);
 	intel_ring_emit(engine,
 			I915_GEM_HWS_INDEX << MI_STORE_DWORD_INDEX_SHIFT);
-	intel_ring_emit(engine, req->seqno);
+	intel_ring_emit(engine, req->fence.seqno);
 	intel_ring_emit(engine, MI_USER_INTERRUPT);
 	__intel_ring_advance(engine);
 
@@ -1591,7 +1591,7 @@ i9xx_add_request(struct drm_i915_gem_request *req)
 	intel_ring_emit(engine, MI_STORE_DWORD_INDEX);
 	intel_ring_emit(engine,
 		       	I915_GEM_HWS_INDEX << MI_STORE_DWORD_INDEX_SHIFT);
-	intel_ring_emit(engine, req->seqno);
+	intel_ring_emit(engine, req->fence.seqno);
 	intel_ring_emit(engine, MI_USER_INTERRUPT);
 	__intel_ring_advance(engine);
 
@@ -2005,6 +2005,7 @@ static int intel_init_ring_buffer(struct drm_device *dev,
 
 	engine->dev = dev;
 	engine->i915 = to_i915(dev);
+	engine->fence_context = fence_context_alloc(1);
 	INIT_LIST_HEAD(&engine->active_list);
 	INIT_LIST_HEAD(&engine->request_list);
 	INIT_LIST_HEAD(&engine->execlist_queue);
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index c0119c7dfa1b..4ef6dce74228 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -159,6 +159,7 @@ struct  intel_engine_cs {
 #define _VCS(n) (VCS + (n))
 	unsigned int exec_id;
 	unsigned int guc_id;
+	unsigned fence_context;
 	u32		mmio_base;
 	struct		drm_device *dev;
 	struct drm_i915_private *i915;
-- 
2.8.0.rc3



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