[Intel-gfx] [PATCH 01/15] drm/i915: Hold irq-off for the entire fake lock period
Chris Wilson
chris at chris-wilson.co.uk
Fri Aug 23 13:26:46 UTC 2019
Sadly lockdep records when the irqs are re-enabled and then marks up the
fake lock as being irq-unsafe. Our hand is forced and so we must mark up
the entire fake lock critical section as irq-off.
Hopefully this is the last tweak required!
v2: Not quite, we need to mark the timeline spinlock as irqsafe. That
was a genuine bug being hidden by the earlier lockdep splat.
Fixes: d67739268cf0 ("drm/i915/gt: Mark up the nested engine-pm timeline lock as irqsafe")
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>
---
drivers/gpu/drm/i915/gt/intel_engine_pm.c | 28 +++++++++++++++--------
drivers/gpu/drm/i915/gt/intel_reset.c | 9 ++++----
drivers/gpu/drm/i915/gt/intel_timeline.c | 10 ++++----
drivers/gpu/drm/i915/i915_gem.c | 15 ++++++------
drivers/gpu/drm/i915/i915_request.c | 9 ++++----
5 files changed, 42 insertions(+), 29 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
index a372d4ea9370..65b5ca74b394 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
@@ -39,27 +39,32 @@ static int __engine_unpark(struct intel_wakeref *wf)
#if IS_ENABLED(CONFIG_LOCKDEP)
-static inline void __timeline_mark_lock(struct intel_context *ce)
+static inline unsigned long __timeline_mark_lock(struct intel_context *ce)
{
unsigned long flags;
local_irq_save(flags);
mutex_acquire(&ce->timeline->mutex.dep_map, 2, 0, _THIS_IP_);
- local_irq_restore(flags);
+
+ return flags;
}
-static inline void __timeline_mark_unlock(struct intel_context *ce)
+static inline void __timeline_mark_unlock(struct intel_context *ce,
+ unsigned long flags)
{
mutex_release(&ce->timeline->mutex.dep_map, 0, _THIS_IP_);
+ local_irq_restore(flags);
}
#else
-static inline void __timeline_mark_lock(struct intel_context *ce)
+static inline unsigned long __timeline_mark_lock(struct intel_context *ce)
{
+ return 0;
}
-static inline void __timeline_mark_unlock(struct intel_context *ce)
+static inline void __timeline_mark_unlock(struct intel_context *ce,
+ unsigned long flags)
{
}
@@ -68,6 +73,8 @@ static inline void __timeline_mark_unlock(struct intel_context *ce)
static bool switch_to_kernel_context(struct intel_engine_cs *engine)
{
struct i915_request *rq;
+ unsigned long flags;
+ bool result = true;
/* Already inside the kernel context, safe to power down. */
if (engine->wakeref_serial == engine->serial)
@@ -89,12 +96,12 @@ static bool switch_to_kernel_context(struct intel_engine_cs *engine)
* retiring the last request, thus all rings should be empty and
* all timelines idle.
*/
- __timeline_mark_lock(engine->kernel_context);
+ flags = __timeline_mark_lock(engine->kernel_context);
rq = __i915_request_create(engine->kernel_context, GFP_NOWAIT);
if (IS_ERR(rq))
/* Context switch failed, hope for the best! Maybe reset? */
- return true;
+ goto out_unlock;
intel_timeline_enter(rq->timeline);
@@ -110,9 +117,10 @@ static bool switch_to_kernel_context(struct intel_engine_cs *engine)
__intel_wakeref_defer_park(&engine->wakeref);
__i915_request_queue(rq, NULL);
- __timeline_mark_unlock(engine->kernel_context);
-
- return false;
+ result = false;
+out_unlock:
+ __timeline_mark_unlock(engine->kernel_context, flags);
+ return result;
}
static int __engine_park(struct intel_wakeref *wf)
diff --git a/drivers/gpu/drm/i915/gt/intel_reset.c b/drivers/gpu/drm/i915/gt/intel_reset.c
index 077716442c90..b9d84d52e986 100644
--- a/drivers/gpu/drm/i915/gt/intel_reset.c
+++ b/drivers/gpu/drm/i915/gt/intel_reset.c
@@ -792,6 +792,7 @@ static bool __intel_gt_unset_wedged(struct intel_gt *gt)
{
struct intel_gt_timelines *timelines = >->timelines;
struct intel_timeline *tl;
+ unsigned long flags;
if (!test_bit(I915_WEDGED, >->reset.flags))
return true;
@@ -811,7 +812,7 @@ static bool __intel_gt_unset_wedged(struct intel_gt *gt)
*
* No more can be submitted until we reset the wedged bit.
*/
- spin_lock(&timelines->lock);
+ spin_lock_irqsave(&timelines->lock, flags);
list_for_each_entry(tl, &timelines->active_list, link) {
struct i915_request *rq;
@@ -819,7 +820,7 @@ static bool __intel_gt_unset_wedged(struct intel_gt *gt)
if (!rq)
continue;
- spin_unlock(&timelines->lock);
+ spin_unlock_irqrestore(&timelines->lock, flags);
/*
* All internal dependencies (i915_requests) will have
@@ -832,10 +833,10 @@ static bool __intel_gt_unset_wedged(struct intel_gt *gt)
i915_request_put(rq);
/* Restart iteration after droping lock */
- spin_lock(&timelines->lock);
+ spin_lock_irqsave(&timelines->lock, flags);
tl = list_entry(&timelines->active_list, typeof(*tl), link);
}
- spin_unlock(&timelines->lock);
+ spin_unlock_irqrestore(&timelines->lock, flags);
intel_gt_sanitize(gt, false);
diff --git a/drivers/gpu/drm/i915/gt/intel_timeline.c b/drivers/gpu/drm/i915/gt/intel_timeline.c
index 02fbe11b671b..9cb01d9828f1 100644
--- a/drivers/gpu/drm/i915/gt/intel_timeline.c
+++ b/drivers/gpu/drm/i915/gt/intel_timeline.c
@@ -337,6 +337,7 @@ int intel_timeline_pin(struct intel_timeline *tl)
void intel_timeline_enter(struct intel_timeline *tl)
{
struct intel_gt_timelines *timelines = &tl->gt->timelines;
+ unsigned long flags;
lockdep_assert_held(&tl->mutex);
@@ -345,14 +346,15 @@ void intel_timeline_enter(struct intel_timeline *tl)
return;
GEM_BUG_ON(!tl->active_count); /* overflow? */
- spin_lock(&timelines->lock);
+ spin_lock_irqsave(&timelines->lock, flags);
list_add(&tl->link, &timelines->active_list);
- spin_unlock(&timelines->lock);
+ spin_unlock_irqrestore(&timelines->lock, flags);
}
void intel_timeline_exit(struct intel_timeline *tl)
{
struct intel_gt_timelines *timelines = &tl->gt->timelines;
+ unsigned long flags;
lockdep_assert_held(&tl->mutex);
@@ -360,9 +362,9 @@ void intel_timeline_exit(struct intel_timeline *tl)
if (--tl->active_count)
return;
- spin_lock(&timelines->lock);
+ spin_lock_irqsave(&timelines->lock, flags);
list_del(&tl->link);
- spin_unlock(&timelines->lock);
+ spin_unlock_irqrestore(&timelines->lock, flags);
/*
* Since this timeline is idle, all bariers upon which we were waiting
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index eb31b69a316a..ec9a46c276de 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -889,12 +889,13 @@ void i915_gem_runtime_suspend(struct drm_i915_private *i915)
static long
wait_for_timelines(struct drm_i915_private *i915,
- unsigned int flags, long timeout)
+ unsigned int wait, long timeout)
{
struct intel_gt_timelines *timelines = &i915->gt.timelines;
struct intel_timeline *tl;
+ unsigned long flags;
- spin_lock(&timelines->lock);
+ spin_lock_irqsave(&timelines->lock, flags);
list_for_each_entry(tl, &timelines->active_list, link) {
struct i915_request *rq;
@@ -902,7 +903,7 @@ wait_for_timelines(struct drm_i915_private *i915,
if (!rq)
continue;
- spin_unlock(&timelines->lock);
+ spin_unlock_irqrestore(&timelines->lock, flags);
/*
* "Race-to-idle".
@@ -913,19 +914,19 @@ wait_for_timelines(struct drm_i915_private *i915,
* want to complete as quickly as possible to avoid prolonged
* stalls, so allow the gpu to boost to maximum clocks.
*/
- if (flags & I915_WAIT_FOR_IDLE_BOOST)
+ if (wait & I915_WAIT_FOR_IDLE_BOOST)
gen6_rps_boost(rq);
- timeout = i915_request_wait(rq, flags, timeout);
+ timeout = i915_request_wait(rq, wait, timeout);
i915_request_put(rq);
if (timeout < 0)
return timeout;
/* restart after reacquiring the lock */
- spin_lock(&timelines->lock);
+ spin_lock_irqsave(&timelines->lock, flags);
tl = list_entry(&timelines->active_list, typeof(*tl), link);
}
- spin_unlock(&timelines->lock);
+ spin_unlock_irqrestore(&timelines->lock, flags);
return timeout;
}
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index f1a0a57fc6fc..a53777dd371c 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1465,9 +1465,10 @@ bool i915_retire_requests(struct drm_i915_private *i915)
{
struct intel_gt_timelines *timelines = &i915->gt.timelines;
struct intel_timeline *tl, *tn;
+ unsigned long flags;
LIST_HEAD(free);
- spin_lock(&timelines->lock);
+ spin_lock_irqsave(&timelines->lock, flags);
list_for_each_entry_safe(tl, tn, &timelines->active_list, link) {
if (!mutex_trylock(&tl->mutex))
continue;
@@ -1475,11 +1476,11 @@ bool i915_retire_requests(struct drm_i915_private *i915)
intel_timeline_get(tl);
GEM_BUG_ON(!tl->active_count);
tl->active_count++; /* pin the list element */
- spin_unlock(&timelines->lock);
+ spin_unlock_irqrestore(&timelines->lock, flags);
retire_requests(tl);
- spin_lock(&timelines->lock);
+ spin_lock_irqsave(&timelines->lock, flags);
/* Resume iteration after dropping lock */
list_safe_reset_next(tl, tn, link);
@@ -1494,7 +1495,7 @@ bool i915_retire_requests(struct drm_i915_private *i915)
list_add(&tl->link, &free);
}
}
- spin_unlock(&timelines->lock);
+ spin_unlock_irqrestore(&timelines->lock, flags);
list_for_each_entry_safe(tl, tn, &free, link)
__intel_timeline_free(&tl->kref);
--
2.23.0
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