[PATCH 7/9] drm/i915/gt: Remove breadcrumb interrupt shadow
Chris Wilson
chris at chris-wilson.co.uk
Sat Jul 18 20:00:55 UTC 2020
Work too much.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 106 ++++++++++----------
drivers/gpu/drm/i915/gt/intel_breadcrumbs.h | 1 -
drivers/gpu/drm/i915/gt/intel_engine_pm.c | 1 -
3 files changed, 53 insertions(+), 55 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
index 971184a7033c..496fc397f669 100644
--- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
+++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
@@ -55,32 +55,72 @@ static void irq_disable(struct intel_engine_cs *engine)
spin_unlock(&engine->gt->irq_lock);
}
+static void __intel_breadcrumbs_arm_irq(struct intel_breadcrumbs *b)
+{
+ lockdep_assert_held(&b->irq_lock);
+
+ if (b->irq_armed)
+ return;
+
+ GEM_BUG_ON(!b->irq_engine);
+ if (!intel_gt_pm_get_if_awake(b->irq_engine->gt))
+ return;
+
+ /*
+ * The breadcrumb irq will be disarmed on the interrupt after the
+ * waiters are signaled. This gives us a single interrupt window in
+ * which we can add a new waiter and avoid the cost of re-enabling
+ * the irq.
+ */
+ b->irq_armed = true;
+
+ /*
+ * Since we are waiting on a request, the GPU should be busy
+ * and should have its own rpm reference. This is tracked
+ * by i915->gt.awake, we can forgo holding our own wakref
+ * for the interrupt as before i915->gt.awake is released (when
+ * the driver is idle) we disarm the breadcrumbs.
+ */
+
+ if (!b->irq_enabled++)
+ irq_enable(b->irq_engine);
+}
+
static void __intel_breadcrumbs_disarm_irq(struct intel_breadcrumbs *b)
{
lockdep_assert_held(&b->irq_lock);
- if (!b->irq_engine)
+ if (!b->irq_armed || !b->irq_engine)
return;
GEM_BUG_ON(!b->irq_enabled);
if (!--b->irq_enabled)
irq_disable(b->irq_engine);
- WRITE_ONCE(b->irq_armed, false);
+ b->irq_armed = false;
intel_gt_pm_put_async(b->irq_engine->gt);
}
-void intel_breadcrumbs_park(struct intel_breadcrumbs *b)
+static void add_signaling_context(struct intel_breadcrumbs *b,
+ struct intel_context *ce)
{
- unsigned long flags;
+ intel_context_get(ce);
- if (!READ_ONCE(b->irq_armed))
- return;
+ if (list_empty(&b->signalers))
+ __intel_breadcrumbs_arm_irq(b);
- spin_lock_irqsave(&b->irq_lock, flags);
- if (b->irq_armed)
+ list_add_tail(&ce->signal_link, &b->signalers);
+}
+
+static void remove_signaling_context(struct intel_breadcrumbs *b,
+ struct intel_context *ce)
+{
+ list_del(&ce->signal_link);
+
+ if (list_empty(&b->signalers))
__intel_breadcrumbs_disarm_irq(b);
- spin_unlock_irqrestore(&b->irq_lock, flags);
+
+ intel_context_put(ce);
}
static inline bool __request_completed(const struct i915_request *rq)
@@ -159,9 +199,6 @@ static void signal_irq_work(struct irq_work *work)
spin_lock(&b->irq_lock);
- if (b->irq_armed && list_empty(&b->signalers))
- __intel_breadcrumbs_disarm_irq(b);
-
list_splice_init(&b->signaled_requests, &signal);
list_for_each_entry_safe(ce, cn, &b->signalers, signal_link) {
@@ -194,9 +231,8 @@ static void signal_irq_work(struct irq_work *work)
/* Advance the list to the first incomplete request */
__list_del_many(&ce->signals, pos);
if (&ce->signals == pos) { /* now empty */
- list_del(&ce->signal_link);
+ remove_signaling_context(b, ce);
add_retire(b, ce->timeline);
- intel_context_put(ce);
}
}
}
@@ -218,37 +254,6 @@ static void signal_irq_work(struct irq_work *work)
}
}
-static void __intel_breadcrumbs_arm_irq(struct intel_breadcrumbs *b)
-{
- lockdep_assert_held(&b->irq_lock);
-
- if (b->irq_armed)
- return;
-
- GEM_BUG_ON(!b->irq_engine);
- if (!intel_gt_pm_get_if_awake(b->irq_engine->gt))
- return;
-
- /*
- * The breadcrumb irq will be disarmed on the interrupt after the
- * waiters are signaled. This gives us a single interrupt window in
- * which we can add a new waiter and avoid the cost of re-enabling
- * the irq.
- */
- WRITE_ONCE(b->irq_armed, true);
-
- /*
- * Since we are waiting on a request, the GPU should be busy
- * and should have its own rpm reference. This is tracked
- * by i915->gt.awake, we can forgo holding our own wakref
- * for the interrupt as before i915->gt.awake is released (when
- * the driver is idle) we disarm the breadcrumbs.
- */
-
- if (!b->irq_enabled++)
- irq_enable(b->irq_engine);
-}
-
struct intel_breadcrumbs *
intel_breadcrumbs_create(struct intel_engine_cs *irq_engine)
{
@@ -332,10 +337,7 @@ static void insert_breadcrumb(struct i915_request *rq,
* the list.
*/
if (list_empty(&ce->signals)) {
- intel_context_get(ce);
- list_add_tail(&ce->signal_link, &b->signalers);
-
- __intel_breadcrumbs_arm_irq(b);
+ add_signaling_context(b, ce);
pos = &ce->signals;
} else {
list_for_each_prev(pos, &ce->signals) {
@@ -426,10 +428,8 @@ void i915_request_cancel_breadcrumb(struct i915_request *rq)
struct intel_context *ce = rq->context;
list_del(&rq->signal_link);
- if (list_empty(&ce->signals)) {
- list_del(&ce->signal_link);
- intel_context_put(ce);
- }
+ if (list_empty(&ce->signals))
+ remove_signaling_context(b, ce);
clear_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags);
i915_request_put(rq);
diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h
index 0d25f793159e..7a82dfe69e4f 100644
--- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h
+++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h
@@ -19,7 +19,6 @@ intel_breadcrumbs_create(struct intel_engine_cs *irq_engine);
void intel_breadcrumbs_free(struct intel_breadcrumbs *b);
void intel_breadcrumbs_reset(struct intel_breadcrumbs *b);
-void intel_breadcrumbs_park(struct intel_breadcrumbs *b);
static inline void
intel_engine_signal_breadcrumbs(struct intel_engine_cs *engine)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
index f7b2e07e2229..f729c5cf0a60 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
@@ -248,7 +248,6 @@ static int __engine_park(struct intel_wakeref *wf)
call_idle_barriers(engine); /* cleanup after wedging */
intel_engine_park_heartbeat(engine);
- intel_breadcrumbs_park(engine->breadcrumbs);
/* Must be reset upon idling, or we may miss the busy wakeup. */
GEM_BUG_ON(engine->execlists.queue_priority_hint != INT_MIN);
--
2.20.1
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