iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

drm/i915/gt: Another tweak for flushing the tasklets

Browse Source 
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@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201220134858.10510-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2020-12-20 13:48:58 +00:00
parent 9bb36cf660
commit 5ec17c7630
3 changed files with 12 additions and 7 deletions

7
drivers/gpu/drm/i915/gt/intel_engine.h

@ -232,7 +232,12 @@ static inline void __intel_engine_reset(struct intel_engine_cs *engine,
bool intel_engines_are_idle(struct intel_gt *gt);
bool intel_engine_is_idle(struct intel_engine_cs *engine);
void intel_engine_flush_submission(struct intel_engine_cs *engine);
void __intel_engine_flush_submission(struct intel_engine_cs *engine, bool sync);
static inline void intel_engine_flush_submission(struct intel_engine_cs *engine)
{
__intel_engine_flush_submission(engine, true);
}
void intel_engines_reset_default_submission(struct intel_gt *gt);

10
drivers/gpu/drm/i915/gt/intel_engine_cs.c

@ -1190,17 +1190,13 @@ static bool ring_is_idle(struct intel_engine_cs *engine)
return idle;
}
void intel_engine_flush_submission(struct intel_engine_cs *engine)
void __intel_engine_flush_submission(struct intel_engine_cs *engine, bool sync)
{
struct tasklet_struct *t = &engine->execlists.tasklet;
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. */
@ -1209,6 +1205,10 @@ 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 */
if (sync)
tasklet_unlock_wait(t);
}
/**

2
drivers/gpu/drm/i915/i915_request.c

@ -1825,7 +1825,7 @@ long i915_request_wait(struct i915_request *rq,
* for unhappy HW.
*/
if (i915_request_is_ready(rq))
intel_engine_flush_submission(rq->engine);
__intel_engine_flush_submission(rq->engine, false);
for (;;) {
set_current_state(state);