The start of the scheduler, add a hook into request submission for the
scheduler to see the arrival of new requests and prepare its runqueues.
Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_drv.c | 4 ++++
drivers/gpu/drm/i915/i915_gem_request.c | 13 +++++++++++++
drivers/gpu/drm/i915/intel_engine_cs.c | 3 +++
drivers/gpu/drm/i915/intel_ringbuffer.h | 9 +++++++++
include/uapi/drm/i915_drm.h | 5 +++++
5 files changed, 34 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index dd02ad69eb7b..11b9f6c38699 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -323,6 +323,10 @@ static int i915_getparam(struct drm_device *dev, void
*data,
*/
value = i915_gem_mmap_gtt_version();
break;
+ case I915_PARAM_HAS_SCHEDULER:
+ value = dev_priv->engine[RCS] &&
+ dev_priv->engine[RCS]->schedule;
+ break;
case I915_PARAM_MMAP_VERSION:
/* Remember to bump this if the version changes! */
case I915_PARAM_HAS_GEM:
diff --git a/drivers/gpu/drm/i915/i915_gem_request.c
b/drivers/gpu/drm/i915/i915_gem_request.c
index 2232f86b892d..864ab686af33 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -737,6 +737,19 @@ void __i915_add_request(struct drm_i915_gem_request
*request, bool flush_caches)
i915_gem_mark_busy(engine);
+ /* Let the backend know a new request has arrived that may need
+ * to adjust the existing execution schedule due to a high priority
+ * request - i.e. we may want to preempt the current request in order
+ * to run a high priority dependency chain *before* we can execute this
+ * request.
+ *
+ * This is called before the request is ready to run so that we can
+ * decide whether to preempt the entire chain so that it is ready to
+ * run at the earliest possible convenience.
+ */
+ if (engine->schedule)
+ engine->schedule(request, 0);
+
local_bh_disable();
i915_sw_fence_commit(&request->submit);
local_bh_enable(); /* Kick the execlists tasklet if just scheduled */
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c
b/drivers/gpu/drm/i915/intel_engine_cs.c
index 94de3d66733d..3e8ecbd9b95d 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -102,6 +102,9 @@ intel_engine_setup(struct drm_i915_private *dev_priv,
engine->mmio_base = info->mmio_base;
engine->irq_shift = info->irq_shift;
+ /* Nothing to do here, execute in order of dependencies */
+ engine->schedule = NULL;
+
dev_priv->engine[id] = engine;
return 0;
}
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h
b/drivers/gpu/drm/i915/intel_ringbuffer.h
index dcb145c67e89..97e162efe557 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -267,6 +267,15 @@ struct intel_engine_cs {
*/
void (*submit_request)(struct drm_i915_gem_request *req);
+ /* Call when the priority on a request has changed and it and its
+ * dependencies may need rescheduling. Note the request itself may
+ * not be ready to run!
+ *
+ * Called under the struct_mutex.
+ */
+ void (*schedule)(struct drm_i915_gem_request *request,
+ int priority);
+
/* Some chipsets are not quite as coherent as advertised and need
* an expensive kick to force a true read of the up-to-date seqno.
* However, the up-to-date seqno is not always required and the last
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index a1d04d8bc80a..f51d429feaae 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -402,6 +402,11 @@ typedef struct drm_i915_irq_wait {
*/
#define I915_PARAM_HAS_EXEC_FENCE 42
+/* Query whether DRM_I915_GEM_EXECBUFFER2 supports user defined execution
+ * priorities and the driver will attempt to execute batches in priority order.
+ */
+#define I915_PARAM_HAS_SCHEDULER 43
+
typedef struct drm_i915_getparam {
__s32 param;
/*
--
2.10.1
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