To flush idle barriers, and even inflight requests, we want to send a
preemptive 'pulse' along an engine. We use a no-op request along the
pinned kernel_context at high priority so that it should run or else
kick off the stuck requests. We can use this to ensure idle barriers are
immediately flushed, as part of a context cancellation mechanism, or as
part of a heartbeat mechanism to detect and reset a stuck GPU.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/Makefile | 1 +
.../gpu/drm/i915/gt/intel_engine_heartbeat.c | 56 +++++++++++++++++++
.../gpu/drm/i915/gt/intel_engine_heartbeat.h | 14 +++++
drivers/gpu/drm/i915/gt/intel_engine_pm.c | 2 +-
drivers/gpu/drm/i915/i915_priolist_types.h | 1 +
5 files changed, 73 insertions(+), 1 deletion(-)
create mode 100644 drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
create mode 100644 drivers/gpu/drm/i915/gt/intel_engine_heartbeat.h
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index cd9a10ba2516..cfab7c8585b3 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -78,6 +78,7 @@ gt-y += \
gt/intel_breadcrumbs.o \
gt/intel_context.o \
gt/intel_engine_cs.o \
+ gt/intel_engine_heartbeat.o \
gt/intel_engine_pm.o \
gt/intel_engine_pool.o \
gt/intel_engine_sysfs.o \
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
new file mode 100644
index 000000000000..2fc413f9d506
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
+ */
+
+#include "i915_request.h"
+
+#include "intel_context.h"
+#include "intel_engine_heartbeat.h"
+#include "intel_engine_pm.h"
+#include "intel_engine.h"
+#include "intel_gt.h"
+
+static void idle_pulse(struct intel_engine_cs *engine, struct i915_request *rq)
+{
+ engine->wakeref_serial = READ_ONCE(engine->serial) + 1;
+ i915_request_add_active_barriers(rq);
+}
+
+int intel_engine_pulse(struct intel_engine_cs *engine)
+{
+ struct i915_sched_attr attr = { .priority = I915_PRIORITY_BARRIER };
+ struct intel_context *ce = engine->kernel_context;
+ struct i915_request *rq;
+ int err = 0;
+
+ if (!intel_engine_has_preemption(engine))
+ return -ENODEV;
+
+ if (!intel_engine_pm_get_if_awake(engine))
+ return 0;
+
+ if (mutex_lock_interruptible(&ce->timeline->mutex))
+ goto out_rpm;
+
+ intel_context_enter(ce);
+ rq = __i915_request_create(ce, GFP_NOWAIT | __GFP_NOWARN);
+ intel_context_exit(ce);
+ if (IS_ERR(rq)) {
+ err = PTR_ERR(rq);
+ goto out_unlock;
+ }
+
+ rq->flags |= I915_REQUEST_SENTINEL;
+ idle_pulse(engine, rq);
+
+ __i915_request_commit(rq);
+ __i915_request_queue(rq, &attr);
+
+out_unlock:
+ mutex_unlock(&ce->timeline->mutex);
+out_rpm:
+ intel_engine_pm_put(engine);
+ return err;
+}
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.h b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.h
new file mode 100644
index 000000000000..b950451b5998
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.h
@@ -0,0 +1,14 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
+ */
+
+#ifndef INTEL_ENGINE_HEARTBEAT_H
+#define INTEL_ENGINE_HEARTBEAT_H
+
+struct intel_engine_cs;
+
+int intel_engine_pulse(struct intel_engine_cs *engine);
+
+#endif /* INTEL_ENGINE_HEARTBEAT_H */
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
index 67eb6183648a..7d76611d9df1 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
@@ -111,7 +111,7 @@ static bool switch_to_kernel_context(struct intel_engine_cs *engine)
i915_request_add_active_barriers(rq);
/* Install ourselves as a preemption barrier */
- rq->sched.attr.priority = I915_PRIORITY_UNPREEMPTABLE;
+ rq->sched.attr.priority = I915_PRIORITY_BARRIER;
__i915_request_commit(rq);
/* Release our exclusive hold on the engine */
diff --git a/drivers/gpu/drm/i915/i915_priolist_types.h b/drivers/gpu/drm/i915/i915_priolist_types.h
index 21037a2e2038..ae8bb3cb627e 100644
--- a/drivers/gpu/drm/i915/i915_priolist_types.h
+++ b/drivers/gpu/drm/i915/i915_priolist_types.h
@@ -39,6 +39,7 @@ enum {
* active request.
*/
#define I915_PRIORITY_UNPREEMPTABLE INT_MAX
+#define I915_PRIORITY_BARRIER INT_MAX
#define __NO_PREEMPTION (I915_PRIORITY_WAIT)
--
2.23.0
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