Ideally, we want to atomically flush and disable the tasklet before
resetting the GPU. At present, we rely on being the only part to touch
our tasklet and serialisation of the reset process to ensure that we can
suspend the tasklet from the mix of reset/wedge pathways. In this patch,
we move the tasklet abuse into its own function and tweak it such that
we only do a synchronous operation the first time it is disabled around
the reset. This allows us to avoid the sync inside a softirq context in
subsequent patches.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
Cc: Michał Winiarski <michal.winiarski@xxxxxxxxx>
CC: Michel Thierry <michel.thierry@xxxxxxxxx>
Cc: Jeff McGee <jeff.mcgee@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem.c | 2 --
drivers/gpu/drm/i915/i915_tasklet.h | 14 ++++++++++++++
drivers/gpu/drm/i915/intel_engine_cs.c | 4 ++--
3 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 98481e150e61..8d27e78b052c 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3043,8 +3043,6 @@ i915_gem_reset_prepare_engine(struct intel_engine_cs *engine)
* common case of recursively being called from set-wedged from inside
* i915_reset.
*/
- if (i915_tasklet_is_enabled(&engine->execlists.tasklet))
- i915_tasklet_flush(&engine->execlists.tasklet);
i915_tasklet_disable(&engine->execlists.tasklet);
/*
diff --git a/drivers/gpu/drm/i915/i915_tasklet.h b/drivers/gpu/drm/i915/i915_tasklet.h
index c9f41a5ebb91..d8263892f385 100644
--- a/drivers/gpu/drm/i915/i915_tasklet.h
+++ b/drivers/gpu/drm/i915/i915_tasklet.h
@@ -59,10 +59,24 @@ static inline void i915_tasklet_enable(struct i915_tasklet *t)
}
static inline void i915_tasklet_disable(struct i915_tasklet *t)
+{
+ if (i915_tasklet_is_enabled(t))
+ i915_tasklet_flush(t);
+
+ if (atomic_inc_return(&t->base.count) == 1)
+ tasklet_unlock_wait(&t->base);
+}
+
+static inline void i915_tasklet_lock(struct i915_tasklet *t)
{
tasklet_disable(&t->base);
}
+static inline void i915_tasklet_unlock(struct i915_tasklet *t)
+{
+ tasklet_enable(&t->base);
+}
+
static inline void i915_tasklet_set_func(struct i915_tasklet *t,
void (*func)(unsigned long data),
unsigned long data)
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index 5f1118ea96d8..3c8a0c3245f3 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -1478,7 +1478,7 @@ int intel_enable_engine_stats(struct intel_engine_cs *engine)
if (!intel_engine_supports_stats(engine))
return -ENODEV;
- i915_tasklet_disable(&execlists->tasklet);
+ i915_tasklet_lock(&execlists->tasklet);
write_seqlock_irqsave(&engine->stats.lock, flags);
if (unlikely(engine->stats.enabled == ~0)) {
@@ -1504,7 +1504,7 @@ int intel_enable_engine_stats(struct intel_engine_cs *engine)
unlock:
write_sequnlock_irqrestore(&engine->stats.lock, flags);
- i915_tasklet_enable(&execlists->tasklet);
+ i915_tasklet_unlock(&execlists->tasklet);
return err;
}
--
2.17.0
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