drm/msm/gem: Convert to using drm_gem_lru

This converts over to use the shared GEM LRU/shrinker helpers.  Note
that it means we are no longer tracking purgeable or willneed buffers
that are active separately.  But the most recently pinned buffers should
be at the tail of the various LRUs, and the shrinker is already prepared
to encounter objects which are still active.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/496131/
Link: https://lore.kernel.org/r/20220802155152.1727594-11-robdclark@gmail.com

1 files changed, 29 insertions, 88 deletions

diff --git a/drivers/gpu/drm/msm/msm_gem_shrinker.c b/drivers/gpu/drm/msm/msm_gem_shrinker.c
index 0ab058734777..f1e52410f521 100644
--- a/drivers/gpu/drm/msm/msm_gem_shrinker.c
+++ b/drivers/gpu/drm/msm/msm_gem_shrinker.c
@@ -29,121 +29,61 @@ msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
 {
 	struct msm_drm_private *priv =
 		container_of(shrinker, struct msm_drm_private, shrinker);
-	unsigned count = priv->shrinkable_count;
+	unsigned count = priv->lru.dontneed.count;
 
 	if (can_swap())
-		count += priv->evictable_count;
+		count += priv->lru.willneed.count;
 
 	return count;
 }
 
 static bool
-purge(struct msm_gem_object *msm_obj)
+purge(struct drm_gem_object *obj)
 {
-	if (!is_purgeable(msm_obj))
+	if (!is_purgeable(to_msm_bo(obj)))
 		return false;
 
-	if (msm_gem_active(&msm_obj->base))
+	if (msm_gem_active(obj))
 		return false;
 
-	/*
-	 * This will move the obj out of still_in_list to
-	 * the purged list
-	 */
-	msm_gem_purge(&msm_obj->base);
+	msm_gem_purge(obj);
 
 	return true;
 }
 
 static bool
-evict(struct msm_gem_object *msm_obj)
+evict(struct drm_gem_object *obj)
 {
-	if (is_unevictable(msm_obj))
+	if (is_unevictable(to_msm_bo(obj)))
 		return false;
 
-	if (msm_gem_active(&msm_obj->base))
+	if (msm_gem_active(obj))
 		return false;
 
-	msm_gem_evict(&msm_obj->base);
+	msm_gem_evict(obj);
 
 	return true;
 }
 
 static unsigned long
-scan(struct msm_drm_private *priv, unsigned nr_to_scan, struct list_head *list,
-		bool (*shrink)(struct msm_gem_object *msm_obj))
-{
-	unsigned freed = 0;
-	struct list_head still_in_list;
-
-	INIT_LIST_HEAD(&still_in_list);
-
-	mutex_lock(&priv->mm_lock);
-
-	while (freed < nr_to_scan) {
-		struct msm_gem_object *msm_obj = list_first_entry_or_null(
-				list, typeof(*msm_obj), mm_list);
-
-		if (!msm_obj)
-			break;
-
-		list_move_tail(&msm_obj->mm_list, &still_in_list);
-
-		/*
-		 * If it is in the process of being freed, msm_gem_free_object
-		 * can be blocked on mm_lock waiting to remove it.  So just
-		 * skip it.
-		 */
-		if (!kref_get_unless_zero(&msm_obj->base.refcount))
-			continue;
-
-		/*
-		 * Now that we own a reference, we can drop mm_lock for the
-		 * rest of the loop body, to reduce contention with the
-		 * retire_submit path (which could make more objects purgeable)
-		 */
-
-		mutex_unlock(&priv->mm_lock);
-
-		/*
-		 * Note that this still needs to be trylock, since we can
-		 * hit shrinker in response to trying to get backing pages
-		 * for this obj (ie. while it's lock is already held)
-		 */
-		if (!msm_gem_trylock(&msm_obj->base))
-			goto tail;
-
-		if (shrink(msm_obj))
-			freed += msm_obj->base.size >> PAGE_SHIFT;
-
-		msm_gem_unlock(&msm_obj->base);
-
-tail:
-		drm_gem_object_put(&msm_obj->base);
-		mutex_lock(&priv->mm_lock);
-	}
-
-	list_splice_tail(&still_in_list, list);
-	mutex_unlock(&priv->mm_lock);
-
-	return freed;
-}
-
-static unsigned long
 msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
 {
 	struct msm_drm_private *priv =
 		container_of(shrinker, struct msm_drm_private, shrinker);
+	long nr = sc->nr_to_scan;
 	unsigned long freed;
 
-	freed = scan(priv, sc->nr_to_scan, &priv->inactive_dontneed, purge);
+	freed = drm_gem_lru_scan(&priv->lru.dontneed, nr, purge);
+	nr -= freed;
 
 	if (freed > 0)
 		trace_msm_gem_purge(freed << PAGE_SHIFT);
 
-	if (can_swap() && freed < sc->nr_to_scan) {
-		int evicted = scan(priv, sc->nr_to_scan - freed,
-				&priv->inactive_willneed, evict);
+	if (can_swap() && nr > 0) {
+		unsigned long evicted;
+
+		evicted = drm_gem_lru_scan(&priv->lru.willneed, nr, evict);
+		nr -= evicted;
 
 		if (evicted > 0)
 			trace_msm_gem_evict(evicted << PAGE_SHIFT);
@@ -179,12 +119,12 @@ msm_gem_shrinker_shrink(struct drm_device *dev, unsigned long nr_to_scan)
 static const int vmap_shrink_limit = 15;
 
 static bool
-vmap_shrink(struct msm_gem_object *msm_obj)
+vmap_shrink(struct drm_gem_object *obj)
 {
-	if (!is_vunmapable(msm_obj))
+	if (!is_vunmapable(to_msm_bo(obj)))
 		return false;
 
-	msm_gem_vunmap(&msm_obj->base);
+	msm_gem_vunmap(obj);
 
 	return true;
 }
@@ -194,17 +134,18 @@ msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
 {
 	struct msm_drm_private *priv =
 		container_of(nb, struct msm_drm_private, vmap_notifier);
-	struct list_head *mm_lists[] = {
-		&priv->inactive_dontneed,
-		&priv->inactive_willneed,
-		priv->gpu ? &priv->gpu->active_list : NULL,
+	struct drm_gem_lru *lrus[] = {
+		&priv->lru.dontneed,
+		&priv->lru.willneed,
+		&priv->lru.pinned,
 		NULL,
 	};
 	unsigned idx, unmapped = 0;
 
-	for (idx = 0; mm_lists[idx] && unmapped < vmap_shrink_limit; idx++) {
-		unmapped += scan(priv, vmap_shrink_limit - unmapped,
-				mm_lists[idx], vmap_shrink);
+	for (idx = 0; lrus[idx] && unmapped < vmap_shrink_limit; idx++) {
+		unmapped += drm_gem_lru_scan(lrus[idx],
+					     vmap_shrink_limit - unmapped,
+					     vmap_shrink);
 	}
 
 	*(unsigned long *)ptr += unmapped;