In the next patch, we will begin processing the CSB from inside the
submission path (underneath an irqsoff section, and even from inside
interrupt handlers). This means that updating the execlists->port[] will
no longer be serialised by the tasklet but needs to be locked by the
engine->timeline.lock instead. Pull dequeue and submit under the same
lock for protection. (An alternate future plan is to keep the in/out
arrays separate for concurrent processing and reduced lock coverage.)
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_lrc.c | 32 ++++++++++++--------------------
1 file changed, 12 insertions(+), 20 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 02ee3b12507f..b5c809201c7a 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -567,7 +567,7 @@ static void complete_preempt_context(struct intel_engine_execlists *execlists)
execlists_clear_active(execlists, EXECLISTS_ACTIVE_PREEMPT);
}
-static bool __execlists_dequeue(struct intel_engine_cs *engine)
+static void __execlists_dequeue(struct intel_engine_cs *engine)
{
struct intel_engine_execlists * const execlists = &engine->execlists;
struct execlist_port *port = execlists->port;
@@ -622,11 +622,11 @@ static bool __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))
- return false;
+ return;
if (need_preempt(engine, last, execlists->queue_priority)) {
inject_preempt_context(engine);
- return false;
+ return;
}
/*
@@ -651,7 +651,7 @@ static bool __execlists_dequeue(struct intel_engine_cs *engine)
* priorities of the ports haven't been switch.
*/
if (port_count(&port[1]))
- return false;
+ return;
/*
* WaIdleLiteRestore:bdw,skl
@@ -751,8 +751,10 @@ static bool __execlists_dequeue(struct intel_engine_cs *engine)
port != execlists->port ? rq_prio(last) : INT_MIN;
execlists->first = rb;
- if (submit)
+ if (submit) {
port_assign(port, last);
+ execlists_submit_ports(engine);
+ }
/* We must always keep the beast fed if we have work piled up */
GEM_BUG_ON(execlists->first && !port_isset(execlists->port));
@@ -761,24 +763,19 @@ static bool __execlists_dequeue(struct intel_engine_cs *engine)
if (last)
execlists_user_begin(execlists, execlists->port);
- return submit;
+ /* If the engine is now idle, so should be the flag; and vice versa. */
+ GEM_BUG_ON(execlists_is_active(&engine->execlists,
+ EXECLISTS_ACTIVE_USER) ==
+ !port_isset(engine->execlists.port));
}
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);
+ __execlists_dequeue(engine);
spin_unlock_irqrestore(&engine->timeline.lock, flags);
-
- if (submit)
- execlists_submit_ports(engine);
-
- GEM_BUG_ON(port_isset(execlists->port) &&
- !execlists_is_active(execlists, EXECLISTS_ACTIVE_USER));
}
void
@@ -1161,11 +1158,6 @@ static void execlists_submission_tasklet(unsigned long data)
if (!execlists_is_active(&engine->execlists, EXECLISTS_ACTIVE_PREEMPT))
execlists_dequeue(engine);
-
- /* If the engine is now idle, so should be the flag; and vice versa. */
- GEM_BUG_ON(execlists_is_active(&engine->execlists,
- EXECLISTS_ACTIVE_USER) ==
- !port_isset(engine->execlists.port));
}
static void queue_request(struct intel_engine_cs *engine,
