[Intel-gfx] [PATCH 15/26] drm/i915: Remove waiting & retiring from shrinker paths

[Chris Wilson]

i915_gem_wait_for_idle() and i915_retire_requests() introduce a
dependency on the timeline->mutex. This is problematic as we want to
later perform allocations underneath i915_active.mutex, forming a link
between the shrinker, the timeline and active mutexes. Nip this cycle in
the bud by removing the acquisition of the timeline mutex (i.e.
retiring) from inside the shrinker.

Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/gem/i915_gem_shrinker.c | 10 ----------
 drivers/gpu/drm/i915/i915_timeline.c         |  3 ---
 2 files changed, 13 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c 
b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
index 3a926a8755c6..1bbc690494c7 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
@@ -169,7 +169,6 @@ i915_gem_shrink(struct drm_i915_private *i915,
         */
 
        trace_i915_gem_shrink(i915, target, shrink);
-       i915_retire_requests(i915);
 
        /*
         * Unbinding of objects will require HW access; Let us not wake the
@@ -269,8 +268,6 @@ i915_gem_shrink(struct drm_i915_private *i915,
        if (shrink & I915_SHRINK_BOUND)
                intel_runtime_pm_put(&i915->runtime_pm, wakeref);
 
-       i915_retire_requests(i915);
-
        shrinker_unlock(i915, unlock);
 
        if (nr_scanned)
@@ -427,12 +424,6 @@ i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned 
long event, void *ptr
        if (!shrinker_lock(i915, 0, &unlock))
                return NOTIFY_DONE;
 
-       /* Force everything onto the inactive lists */
-       if (i915_gem_wait_for_idle(i915,
-                                  I915_WAIT_LOCKED,
-                                  MAX_SCHEDULE_TIMEOUT))
-               goto out;
-
        with_intel_runtime_pm(&i915->runtime_pm, wakeref)
                freed_pages += i915_gem_shrink(i915, -1UL, NULL,
                                               I915_SHRINK_BOUND |
@@ -455,7 +446,6 @@ i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned 
long event, void *ptr
        }
        mutex_unlock(&i915->ggtt.vm.mutex);
 
-out:
        shrinker_unlock(i915, unlock);
 
        *(unsigned long *)ptr += freed_pages;
diff --git a/drivers/gpu/drm/i915/i915_timeline.c 
b/drivers/gpu/drm/i915/i915_timeline.c
index c311ce9c6f9d..f3ee264d7dd5 100644
--- a/drivers/gpu/drm/i915/i915_timeline.c
+++ b/drivers/gpu/drm/i915/i915_timeline.c
@@ -270,9 +270,6 @@ void i915_timelines_init(struct drm_i915_private *i915)
 
        spin_lock_init(&gt->hwsp_lock);
        INIT_LIST_HEAD(&gt->hwsp_free_list);
-
-       /* via i915_gem_wait_for_idle() */
-       i915_gem_shrinker_taints_mutex(i915, &gt->mutex);
 }
 
 static void timeline_add_to_active(struct i915_timeline *tl)
-- 
2.20.1

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