Currently, we check we can send a pulse prior to disabling the heartbeat to verify that we can change the heartbeat, but since we may re-evaluate execution upon changing the heartbeat interval we need another pulse afterwards to refresh execution.
v2: Tvrtko asked if we could reduce the double pulse to a single, which opened up a discussion of how we should handle the pulse-error after attempting to change the property, and the desire to serialise adjustment of the property with its validating pulse, and unwind upon failure.
Fixes: 9a40bddd47ca ("drm/i915/gt: Expose heartbeat interval via sysfs") Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Joonas Lahtinen joonas.lahtinen@linux.intel.com Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com Cc: stable@vger.kernel.org # v5.7+ --- .../gpu/drm/i915/gt/intel_engine_heartbeat.c | 105 +++++++++++------- 1 file changed, 66 insertions(+), 39 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c index 8ffdf676c0a0..eda475f50fa7 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c @@ -177,36 +177,81 @@ void intel_engine_init_heartbeat(struct intel_engine_cs *engine) INIT_DELAYED_WORK(&engine->heartbeat.work, heartbeat); }
+static 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; + + lockdep_assert_held(&ce->timeline->mutex); + GEM_BUG_ON(intel_engine_has_preemption(engine)); + GEM_BUG_ON(intel_engine_pm_is_awake(engine)); + + intel_context_enter(ce); + rq = __i915_request_create(ce, GFP_NOWAIT | __GFP_NOWARN); + intel_context_exit(ce); + if (IS_ERR(rq)) + return PTR_ERR(rq); + + __set_bit(I915_FENCE_FLAG_SENTINEL, &rq->fence.flags); + idle_pulse(engine, rq); + + __i915_request_commit(rq); + __i915_request_queue(rq, &attr); + GEM_BUG_ON(rq->sched.attr.priority < I915_PRIORITY_BARRIER); + + return 0; +} + +static unsigned long set_heartbeat(struct intel_engine_cs *engine, + unsigned long delay) +{ + unsigned long old; + + old = xchg(&engine->props.heartbeat_interval_ms, delay); + if (delay) + intel_engine_unpark_heartbeat(engine); + else + intel_engine_park_heartbeat(engine); + + return old; +} + int intel_engine_set_heartbeat(struct intel_engine_cs *engine, unsigned long delay) { - int err; + struct intel_context *ce = engine->kernel_context; + int err = 0;
- /* Send one last pulse before to cleanup persistent hogs */ - if (!delay && IS_ACTIVE(CONFIG_DRM_I915_PREEMPT_TIMEOUT)) { - err = intel_engine_pulse(engine); - if (err) - return err; - } + if (!delay && !intel_engine_has_preempt_reset(engine)) + return -ENODEV; + + intel_engine_pm_get(engine); + + err = mutex_lock_interruptible(&ce->timeline->mutex); + if (err) + return err;
- WRITE_ONCE(engine->props.heartbeat_interval_ms, delay); + if (delay != engine->props.heartbeat_interval_ms) { + unsigned long saved = set_heartbeat(engine, delay);
- if (intel_engine_pm_get_if_awake(engine)) { - if (delay) - intel_engine_unpark_heartbeat(engine); - else - intel_engine_park_heartbeat(engine); - intel_engine_pm_put(engine); + /* recheck current execution */ + if (intel_engine_has_preemption(engine)) { + err = __intel_engine_pulse(engine); + if (err) + set_heartbeat(engine, saved); + } }
- return 0; + mutex_unlock(&ce->timeline->mutex); + intel_engine_pm_put(engine); + + return err; }
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;
if (!intel_engine_has_preemption(engine)) @@ -215,30 +260,12 @@ int intel_engine_pulse(struct intel_engine_cs *engine) if (!intel_engine_pm_get_if_awake(engine)) return 0;
- if (mutex_lock_interruptible(&ce->timeline->mutex)) { - err = -EINTR; - goto out_rpm; + err = -EINTR; + if (!mutex_lock_interruptible(&ce->timeline->mutex)) { + err = __intel_engine_pulse(engine); + mutex_unlock(&ce->timeline->mutex); }
- 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; - } - - __set_bit(I915_FENCE_FLAG_SENTINEL, &rq->fence.flags); - idle_pulse(engine, rq); - - __i915_request_commit(rq); - __i915_request_queue(rq, &attr); - GEM_BUG_ON(rq->sched.attr.priority < I915_PRIORITY_BARRIER); - err = 0; - -out_unlock: - mutex_unlock(&ce->timeline->mutex); -out_rpm: intel_engine_pm_put(engine); return err; }