drm/i915/gem: Drop lru bumping on display unpinning

Simplify the frontbuffer unpin by removing the lock requirement. The LRU
bumping was primarily to protect the GTT from being evicted and from
frontbuffers being eagerly shrunk. Now we protect frontbuffers from the
shrinker, and we avoid accidentally evicting from the GTT, so the
benefit from bumping LRU is no more, and we can save more time by not.

Reported-and-tested-by: Matti Hämäläinen <ccr@tnsp.org>
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2905
Fixes: c1793ba86a41 ("drm/i915: Add ww locking to pin_to_display_plane, v2.")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210119214336.1463-6-chris@chris-wilson.co.uk
(cherry picked from commit 14ca83eece9565a2d2177291ceb122982dc38420)
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: <stable@vger.kernel.org> # v5.10+
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 3939624..61be6be 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -2309,7 +2309,7 @@ intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb,
                 */
                ret = i915_vma_pin_fence(vma);
                if (ret != 0 && INTEL_GEN(dev_priv) < 4) {
-                       i915_gem_object_unpin_from_display_plane(vma);
+                       i915_vma_unpin(vma);
                        vma = ERR_PTR(ret);
                        goto err;
                }
@@ -2327,12 +2327,9 @@ err:
 
 void intel_unpin_fb_vma(struct i915_vma *vma, unsigned long flags)
 {
-       i915_gem_object_lock(vma->obj, NULL);
        if (flags & PLANE_HAS_FENCE)
                i915_vma_unpin_fence(vma);
-       i915_gem_object_unpin_from_display_plane(vma);
-       i915_gem_object_unlock(vma->obj);
-
+       i915_vma_unpin(vma);
        i915_vma_put(vma);
 }
 

diff --git a/drivers/gpu/drm/i915/display/intel_overlay.c b/drivers/gpu/drm/i915/display/intel_overlay.c
index 52b4f61..0095c8c 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_overlay.c
+++ b/drivers/gpu/drm/i915/display/intel_overlay.c
@@ -359,7 +359,7 @@ static void intel_overlay_release_old_vma(struct intel_overlay *overlay)
        intel_frontbuffer_flip_complete(overlay->i915,
                                        INTEL_FRONTBUFFER_OVERLAY(overlay->crtc->pipe));
 
-       i915_gem_object_unpin_from_display_plane(vma);
+       i915_vma_unpin(vma);
        i915_vma_put(vma);
 }
 
@@ -860,7 +860,7 @@ static int intel_overlay_do_put_image(struct intel_overlay *overlay,
        return 0;
 
 out_unpin:
-       i915_gem_object_unpin_from_display_plane(vma);
+       i915_vma_unpin(vma);
 out_pin_section:
        atomic_dec(&dev_priv->gpu_error.pending_fb_pin);
 

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_domain.c b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
index fcce690..3d435bf 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_domain.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
@@ -387,48 +387,6 @@ err:
        return vma;
 }
 
-static void i915_gem_object_bump_inactive_ggtt(struct drm_i915_gem_object *obj)
-{
-       struct drm_i915_private *i915 = to_i915(obj->base.dev);
-       struct i915_vma *vma;
-
-       if (list_empty(&obj->vma.list))
-               return;
-
-       mutex_lock(&i915->ggtt.vm.mutex);
-       spin_lock(&obj->vma.lock);
-       for_each_ggtt_vma(vma, obj) {
-               if (!drm_mm_node_allocated(&vma->node))
-                       continue;
-
-               GEM_BUG_ON(vma->vm != &i915->ggtt.vm);
-               list_move_tail(&vma->vm_link, &vma->vm->bound_list);
-       }
-       spin_unlock(&obj->vma.lock);
-       mutex_unlock(&i915->ggtt.vm.mutex);
-
-       if (i915_gem_object_is_shrinkable(obj)) {
-               unsigned long flags;
-
-               spin_lock_irqsave(&i915->mm.obj_lock, flags);
-
-               if (obj->mm.madv == I915_MADV_WILLNEED &&
-                   !atomic_read(&obj->mm.shrink_pin))
-                       list_move_tail(&obj->mm.link, &i915->mm.shrink_list);
-
-               spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
-       }
-}
-
-void
-i915_gem_object_unpin_from_display_plane(struct i915_vma *vma)
-{
-       /* Bump the LRU to try and avoid premature eviction whilst flipping  */
-       i915_gem_object_bump_inactive_ggtt(vma->obj);
-
-       i915_vma_unpin(vma);
-}
-
 /**
  * Moves a single object to the CPU read, and possibly write domain.
  * @obj: object to act on
@@ -569,9 +527,6 @@ i915_gem_set_domain_ioctl(struct drm_device *dev, void *data,
        else
                err = i915_gem_object_set_to_cpu_domain(obj, write_domain);
 
-       /* And bump the LRU for this access */
-       i915_gem_object_bump_inactive_ggtt(obj);
-
        i915_gem_object_unlock(obj);
 
        if (write_domain)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index be14486..4556afe 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -486,7 +486,6 @@ i915_gem_object_pin_to_display_plane(struct drm_i915_gem_object *obj,
                                     u32 alignment,
                                     const struct i915_ggtt_view *view,
                                     unsigned int flags);
-void i915_gem_object_unpin_from_display_plane(struct i915_vma *vma);
 
 void i915_gem_object_make_unshrinkable(struct drm_i915_gem_object *obj);
 void i915_gem_object_make_shrinkable(struct drm_i915_gem_object *obj);