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Commit 65e4760e authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Introduce a global_seqno for each request 



Though we will have multiple timelines, we still have a single timeline
of execution. This we can use to provide an execution and retirement order
of requests. This keeps tracking execution of requests simple, and vital
for preserving a single waiter (i.e. so that we can order the waiters so
that only the earliest to wakeup need be woken). To accomplish this we
distinguish the seqno used to order requests per-context (external) and
that used internally for execution.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-26-chris@chris-wilson.co.uk
parent 4680816b

drivers/gpu/drm/i915/i915_debugfs.c

+1 −1
Original line number Diff line number Diff line
@@ -637,7 +637,7 @@ static void print_request(struct seq_file *m, 
	rcu_read_lock();

	task = pid ? pid_task(pid, PIDTYPE_PID) : NULL;

	seq_printf(m, "%s%x [%x:%x] @ %d: %s [%d]\n", prefix,

		   rq->fence.seqno, rq->ctx->hw_id, rq->fence.seqno,

		   rq->global_seqno, rq->ctx->hw_id, rq->fence.seqno,

		   jiffies_to_msecs(jiffies - rq->emitted_jiffies),

		   task ? task->comm : "<unknown>",

		   task ? task->pid : -1);

drivers/gpu/drm/i915/i915_drv.h

+2 −2
Original line number Diff line number Diff line
@@ -4050,7 +4050,7 @@ __i915_request_irq_complete(struct drm_i915_gem_request *req) 
	/* Before we do the heavier coherent read of the seqno,

	 * check the value (hopefully) in the CPU cacheline.

	 */

	if (i915_gem_request_completed(req))

	if (__i915_gem_request_completed(req))

		return true;



	/* Ensure our read of the seqno is coherent so that we
@@ -4101,7 +4101,7 @@ __i915_request_irq_complete(struct drm_i915_gem_request *req) 
			wake_up_process(tsk);

		rcu_read_unlock();



		if (i915_gem_request_completed(req))

		if (__i915_gem_request_completed(req))

			return true;

	}

drivers/gpu/drm/i915/i915_gem.c

+1 −1
Original line number Diff line number Diff line
@@ -2615,7 +2615,7 @@ static void i915_gem_reset_engine(struct intel_engine_cs *engine) 
		return;



	DRM_DEBUG_DRIVER("resetting %s to restart from tail of request 0x%x\n",

			 engine->name, request->fence.seqno);

			 engine->name, request->global_seqno);



	/* Setup the CS to resume from the breadcrumb of the hung request */

	engine->reset_hw(engine, request);

drivers/gpu/drm/i915/i915_gem_request.c

+14 −5
Original line number Diff line number Diff line
@@ -376,7 +376,7 @@ i915_gem_request_alloc(struct intel_engine_cs *engine, 
	 * of being read by __i915_gem_active_get_rcu(). As such,

	 * we have to be very careful when overwriting the contents. During

	 * the RCU lookup, we change chase the request->engine pointer,

	 * read the request->fence.seqno and increment the reference count.

	 * read the request->global_seqno and increment the reference count.

	 *

	 * The reference count is incremented atomically. If it is zero,

	 * the lookup knows the request is unallocated and complete. Otherwise,
@@ -418,6 +418,7 @@ i915_gem_request_alloc(struct intel_engine_cs *engine, 
	INIT_LIST_HEAD(&req->active_list);

	req->i915 = dev_priv;

	req->engine = engine;

	req->global_seqno = seqno;

	req->ctx = i915_gem_context_get(ctx);



	/* No zalloc, must clear what we need by hand */
@@ -475,8 +476,15 @@ i915_gem_request_await_request(struct drm_i915_gem_request *to, 
		return ret < 0 ? ret : 0;

	}



	if (!from->global_seqno) {

		ret = i915_sw_fence_await_dma_fence(&to->submit,

						    &from->fence, 0,

						    GFP_KERNEL);

		return ret < 0 ? ret : 0;

	}



	idx = intel_engine_sync_index(from->engine, to->engine);

	if (from->fence.seqno <= from->engine->semaphore.sync_seqno[idx])

	if (from->global_seqno <= from->engine->semaphore.sync_seqno[idx])

		return 0;



	trace_i915_gem_ring_sync_to(to, from);
@@ -494,7 +502,7 @@ i915_gem_request_await_request(struct drm_i915_gem_request *to, 
			return ret;

	}



	from->engine->semaphore.sync_seqno[idx] = from->fence.seqno;

	from->engine->semaphore.sync_seqno[idx] = from->global_seqno;

	return 0;

}
@@ -774,7 +782,7 @@ bool __i915_spin_request(const struct drm_i915_gem_request *req, 


	timeout_us += local_clock_us(&cpu);

	do {

		if (i915_gem_request_completed(req))

		if (__i915_gem_request_completed(req))

			return true;



		if (signal_pending_state(state, current))
@@ -883,6 +891,7 @@ long i915_wait_request(struct drm_i915_gem_request *req, 


		GEM_BUG_ON(!i915_sw_fence_done(&req->submit));

	}

	GEM_BUG_ON(!req->global_seqno);



	/* Optimistic short spin before touching IRQs */

	if (i915_spin_request(req, state, 5))
@@ -892,7 +901,7 @@ long i915_wait_request(struct drm_i915_gem_request *req, 
	if (flags & I915_WAIT_LOCKED)

		add_wait_queue(&req->i915->gpu_error.wait_queue, &reset);



	intel_wait_init(&wait, req->fence.seqno);

	intel_wait_init(&wait, req->global_seqno);

	if (intel_engine_add_wait(req->engine, &wait))

		/* In order to check that we haven't missed the interrupt

		 * as we enabled it, we need to kick ourselves to do a

drivers/gpu/drm/i915/i915_gem_request.h

+27 −5
Original line number Diff line number Diff line
@@ -87,6 +87,8 @@ struct drm_i915_gem_request { 
	struct i915_sw_fence submit;

	wait_queue_t submitq;



	u32 global_seqno;



	/** GEM sequence number associated with the previous request,

	 * when the HWS breadcrumb is equal to this the GPU is processing

	 * this request.
@@ -163,7 +165,7 @@ void i915_gem_request_retire_upto(struct drm_i915_gem_request *req); 
static inline u32

i915_gem_request_get_seqno(struct drm_i915_gem_request *req)

{

	return req ? req->fence.seqno : 0;

	return req ? req->global_seqno : 0;

}



static inline struct intel_engine_cs *
@@ -248,17 +250,37 @@ static inline bool i915_seqno_passed(u32 seq1, u32 seq2) 
}



static inline bool

i915_gem_request_started(const struct drm_i915_gem_request *req)

__i915_gem_request_started(const struct drm_i915_gem_request *req)

{

	GEM_BUG_ON(!req->global_seqno);

	return i915_seqno_passed(intel_engine_get_seqno(req->engine),

				 req->previous_seqno);

}



static inline bool

i915_gem_request_completed(const struct drm_i915_gem_request *req)

i915_gem_request_started(const struct drm_i915_gem_request *req)

{

	if (!req->global_seqno)

		return false;



	return __i915_gem_request_started(req);

}



static inline bool

__i915_gem_request_completed(const struct drm_i915_gem_request *req)

{

	GEM_BUG_ON(!req->global_seqno);

	return i915_seqno_passed(intel_engine_get_seqno(req->engine),

				 req->fence.seqno);

				 req->global_seqno);

}



static inline bool

i915_gem_request_completed(const struct drm_i915_gem_request *req)

{

	if (!req->global_seqno)

		return false;



	return __i915_gem_request_completed(req);

}



bool __i915_spin_request(const struct drm_i915_gem_request *request,
@@ -266,7 +288,7 @@ bool __i915_spin_request(const struct drm_i915_gem_request *request, 
static inline bool i915_spin_request(const struct drm_i915_gem_request *request,

				     int state, unsigned long timeout_us)

{

	return (i915_gem_request_started(request) &&

	return (__i915_gem_request_started(request) &&

		__i915_spin_request(request, state, timeout_us));

}