Prepare to allow the execlists submission to be run from underneath a
hardirq timer context (and not just the current softirq context) as is
required for fast preemption resets and context switches.
Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/intel_lrc.c | 42 ++++++++++++++++++++++----------
1 file changed, 29 insertions(+), 13 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index f9f4064dec0e..15c373ea5b7e 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -357,10 +357,13 @@ execlists_unwind_incomplete_requests(struct
intel_engine_execlists *execlists)
{
struct intel_engine_cs *engine =
container_of(execlists, typeof(*engine), execlists);
+ unsigned long flags;
+
+ spin_lock_irqsave(&engine->timeline.lock, flags);
- spin_lock_irq(&engine->timeline.lock);
__unwind_incomplete_requests(engine);
- spin_unlock_irq(&engine->timeline.lock);
+
+ spin_unlock_irqrestore(&engine->timeline.lock, flags);
}
static inline void
@@ -554,7 +557,7 @@ static void inject_preempt_context(struct intel_engine_cs
*engine)
execlists_set_active(&engine->execlists, EXECLISTS_ACTIVE_PREEMPT);
}
-static void execlists_dequeue(struct intel_engine_cs *engine)
+static bool __execlists_dequeue(struct intel_engine_cs *engine)
{
struct intel_engine_execlists * const execlists = &engine->execlists;
struct execlist_port *port = execlists->port;
@@ -564,6 +567,8 @@ static void execlists_dequeue(struct intel_engine_cs
*engine)
struct rb_node *rb;
bool submit = false;
+ lockdep_assert_held(&engine->timeline.lock);
+
/* Hardware submission is through 2 ports. Conceptually each port
* has a (RING_START, RING_HEAD, RING_TAIL) tuple. RING_START is
* static for a context, and unique to each, so we only execute
@@ -585,7 +590,6 @@ static void execlists_dequeue(struct intel_engine_cs
*engine)
* and context switches) submission.
*/
- spin_lock_irq(&engine->timeline.lock);
rb = execlists->first;
GEM_BUG_ON(rb_first(&execlists->queue) != rb);
@@ -600,7 +604,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
EXECLISTS_ACTIVE_USER));
GEM_BUG_ON(!port_count(&port[0]));
if (port_count(&port[0]) > 1)
- goto unlock;
+ return false;
/*
* If we write to ELSP a second time before the HW has had
@@ -610,11 +614,11 @@ static void execlists_dequeue(struct intel_engine_cs
*engine)
* the HW to indicate that it has had a chance to respond.
*/
if (!execlists_is_active(execlists, EXECLISTS_ACTIVE_HWACK))
- goto unlock;
+ return false;
if (need_preempt(engine, last, execlists->queue_priority)) {
inject_preempt_context(engine);
- goto unlock;
+ return false;
}
/*
@@ -639,7 +643,7 @@ static void execlists_dequeue(struct intel_engine_cs
*engine)
* priorities of the ports haven't been switch.
*/
if (port_count(&port[1]))
- goto unlock;
+ return false;
/*
* WaIdleLiteRestore:bdw,skl
@@ -744,13 +748,25 @@ static void execlists_dequeue(struct intel_engine_cs
*engine)
/* We must always keep the beast fed if we have work piled up */
GEM_BUG_ON(execlists->first && !port_isset(execlists->port));
-unlock:
- spin_unlock_irq(&engine->timeline.lock);
-
- if (submit) {
+ /* Re-evaluate the executing context setup after each preemptive kick */
+ if (last)
execlists_user_begin(execlists, execlists->port);
+
+ return submit;
+}
+
+static void execlists_dequeue(struct intel_engine_cs *engine)
+{
+ struct intel_engine_execlists * const execlists = &engine->execlists;
+ unsigned long flags;
+ bool submit;
+
+ spin_lock_irqsave(&engine->timeline.lock, flags);
+ submit = __execlists_dequeue(engine);
+ spin_unlock_irqrestore(&engine->timeline.lock, flags);
+
+ if (submit)
execlists_submit_ports(engine);
- }
