From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
In a patch named "drm/i915: Return immediately if trylock fails for
direct-reclaim" Chris Wilson implicitly suggests it is safe to use a plain
mutex_lock instead of trylock on the I915_SHRINK_ACTIVE code paths.
Explore this to see how the lockdep traces will look.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_shrinker.c | 11 ++---------
1 file changed, 2 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c
index 97deec775f40..2d4a54851c0a 100644
--- a/drivers/gpu/drm/i915/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c
@@ -47,15 +47,8 @@ shrinker_lock(struct drm_i915_private *i915, unsigned int flags, bool *unlock)
case MUTEX_TRYLOCK_FAILED:
*unlock = false;
if (flags & I915_SHRINK_ACTIVE) {
- preempt_disable();
- do {
- cpu_relax();
- if (mutex_trylock(&i915->drm.struct_mutex)) {
- *unlock = true;
- break;
- }
- } while (!need_resched());
- preempt_enable();
+ mutex_lock(&i915->drm.struct_mutex);
+ *unlock = true;
}
return *unlock;
--
2.19.1
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