tasklet_kill() ensures that we _yield_ the processor until a remote
tasklet is completed. However, this leads to a starvation condition as
being at the bottom of the scheduler's runqueue means that anything else
is able to run, including all hogs keeping the tasklet occupied.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/gt/intel_engine_cs.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index f62550d95a60..101f54467c1e 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -1178,10 +1178,6 @@ void intel_engine_flush_submission(struct intel_engine_cs *engine)
if (!t->func)
return;
- /* Synchronise and wait for the tasklet on another CPU */
- tasklet_kill(t);
-
- /* Having cancelled the tasklet, ensure that is run */
local_bh_disable();
if (tasklet_trylock(t)) {
/* Must wait for any GPU reset in progress. */
@@ -1190,6 +1186,9 @@ void intel_engine_flush_submission(struct intel_engine_cs *engine)
tasklet_unlock(t);
}
local_bh_enable();
+
+ /* Synchronise and wait for the tasklet on another CPU */
+ tasklet_unlock_wait(t);
}
/**
--
2.20.1
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