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From: Chris Wilson <chris@chris-wilson.co.uk>
To: intel-gfx@lists.freedesktop.org
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Subject: [Intel-gfx] [PATCH 7/9] drm/i915/gt: Drop atomic for engine->fw_active tracking
Date: Tue, 16 Jun 2020 09:41:39 +0100	[thread overview]
Message-ID: <20200616084141.3722-7-chris@chris-wilson.co.uk> (raw)
In-Reply-To: <20200616084141.3722-1-chris@chris-wilson.co.uk>

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@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_lrc.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 be1730773db8..39471674a40f 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -1531,7 +1531,7 @@ void intel_engine_dump(struct intel_engine_cs *engine,
 	drm_printf(m, "\tLatency: %luus\n",
 		   ewma__engine_latency_read(&engine->latency));
 	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 31cf60cef5a8..ca124f229f65 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -335,7 +335,7 @@ 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_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 8b3959207c02..09ec7242fbcb 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1380,7 +1380,7 @@ __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);
@@ -1451,7 +1451,7 @@ static inline void __execlists_schedule_out(struct i915_request *rq)
 	intel_context_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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  parent reply	other threads:[~2020-06-16  8:42 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-16  8:41 [Intel-gfx] [PATCH 1/9] drm/i915/selftests: Exercise far preemption rollbacks Chris Wilson
2020-06-16  8:41 ` [Intel-gfx] [PATCH 2/9] drm/i915/selftests: Use friendly request names for live_timeslice_rewind Chris Wilson
2020-06-16  8:56   ` Mika Kuoppala
2020-06-16  8:41 ` [Intel-gfx] [PATCH 3/9] drm/i915/selftests: Enable selftesting of busy-stats Chris Wilson
2020-06-16  9:03   ` Mika Kuoppala
2020-06-16 10:38     ` Chris Wilson
2020-06-16  8:41 ` [Intel-gfx] [PATCH 4/9] drm/i915/execlists: Replace direct submit with direct call to tasklet Chris Wilson
2020-06-16  9:35   ` Mika Kuoppala
2020-06-16  8:41 ` [Intel-gfx] [PATCH 5/9] drm/i915/execlists: Defer schedule_out until after the next dequeue Chris Wilson
2020-06-16  8:41 ` [Intel-gfx] [PATCH 6/9] drm/i915/gt: ce->inflight updates are now serialised Chris Wilson
2020-06-16  8:41 ` Chris Wilson [this message]
2020-06-16  8:41 ` [Intel-gfx] [PATCH 8/9] drm/i915/gt: Extract busy-stats for ring-scheduler Chris Wilson
2020-06-16  8:41 ` [Intel-gfx] [PATCH 9/9] drm/i915/gt: Convert stats.active to plain unsigned int Chris Wilson
2020-06-16  8:55 ` [Intel-gfx] [PATCH 1/9] drm/i915/selftests: Exercise far preemption rollbacks Mika Kuoppala
2020-06-16  9:09   ` Chris Wilson
2020-06-16  9:45     ` Mika Kuoppala
2020-06-16 18:04 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for series starting with [1/9] " Patchwork
2020-06-16 18:37 ` [Intel-gfx] ✗ Fi.CI.BAT: failure " Patchwork

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