[PATCH 11/38] drm/i915/gt: Drop atomic for engine->fw_active tracking
Chris Wilson
chris at chris-wilson.co.uk
Tue Jan 5 10:25:25 UTC 2021
Since schedule-in/out is now entirely serialised by the tasklet bitlock,
we do not need to worry about concurrent in/out operations and so reduce
the atomic operations to plain instructions.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/gt/intel_engine_cs.c | 2 +-
drivers/gpu/drm/i915/gt/intel_engine_types.h | 2 +-
drivers/gpu/drm/i915/gt/intel_execlists_submission.c | 4 ++--
3 files changed, 4 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 e325d559f29a..5ead72c1b7d2 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -1657,7 +1657,7 @@ void intel_engine_dump(struct intel_engine_cs *engine,
ktime_to_ms(intel_engine_get_busy_time(engine,
&dummy)));
drm_printf(m, "\tForcewake: %x domains, %d active\n",
- engine->fw_domain, atomic_read(&engine->fw_active));
+ engine->fw_domain, READ_ONCE(engine->fw_active));
rcu_read_lock();
rq = READ_ONCE(engine->heartbeat.systole);
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
index df62e793e747..75c9093b5e7f 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -319,7 +319,7 @@ struct intel_engine_cs {
* as possible.
*/
enum forcewake_domains fw_domain;
- atomic_t fw_active;
+ unsigned int fw_active;
unsigned long context_tag;
diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
index 1418512a7e11..4af2a60766e8 100644
--- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
+++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
@@ -550,7 +550,7 @@ __execlists_schedule_in(struct i915_request *rq)
ce->lrc.ccid |= engine->execlists.ccid;
__intel_gt_pm_get(engine->gt);
- if (engine->fw_domain && !atomic_fetch_inc(&engine->fw_active))
+ if (engine->fw_domain && !engine->fw_active++)
intel_uncore_forcewake_get(engine->uncore, engine->fw_domain);
execlists_context_status_change(rq, INTEL_CONTEXT_SCHEDULE_IN);
intel_engine_context_in(engine);
@@ -660,7 +660,7 @@ static inline void __execlists_schedule_out(struct i915_request *rq)
lrc_update_runtime(ce);
intel_engine_context_out(engine);
execlists_context_status_change(rq, INTEL_CONTEXT_SCHEDULE_OUT);
- if (engine->fw_domain && !atomic_dec_return(&engine->fw_active))
+ if (engine->fw_domain && !--engine->fw_active)
intel_uncore_forcewake_put(engine->uncore, engine->fw_domain);
intel_gt_pm_put_async(engine->gt);
--
2.20.1
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