Merge tag 'drm-msm-next-2021-04-11' of https://gitlab.freedesktop.org/drm/msm into drm-next

msm-next from Rob:
* Big DSI phy/pll cleanup. Includes some clk patches, acked by
  maintainer
* Initial support for sc7280
* compatibles fixes for sm8150/sm8250
* cleanups for all dpu gens to use same bandwidth scaling paths (\o/)
* various shrinker path lock contention optimizations
* unpin/swap support for GEM objects (disabled by default, enable with
  msm.enable_eviction=1 .. due to various combinations of iommu drivers
  with older gens I want to get more testing on hw I don't have in front
  of me before enabling by default)
* The usual assortment of misc fixes and cleanups

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
From: Rob Clark <robdclark@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/CAF6AEGvL=4aw15qoY8fbKG9FCgnx8Y-dCtf7xiFwTQSHopwSQg@mail.gmail.com

1 files changed, 116 insertions, 50 deletions

diff --git a/drivers/gpu/drm/msm/msm_gem_shrinker.c b/drivers/gpu/drm/msm/msm_gem_shrinker.c
index 9d5248be746f..1187ecf9d647 100644
--- a/drivers/gpu/drm/msm/msm_gem_shrinker.c
+++ b/drivers/gpu/drm/msm/msm_gem_shrinker.c
@@ -9,57 +9,140 @@
 #include "msm_gpu.h"
 #include "msm_gpu_trace.h"
 
+/* Default disabled for now until it has some more testing on the different
+ * iommu combinations that can be paired with the driver:
+ */
+bool enable_eviction = false;
+MODULE_PARM_DESC(enable_eviction, "Enable swappable GEM buffers");
+module_param(enable_eviction, bool, 0600);
+
+static bool can_swap(void)
+{
+	return enable_eviction && get_nr_swap_pages() > 0;
+}
+
 static unsigned long
 msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
 {
 	struct msm_drm_private *priv =
 		container_of(shrinker, struct msm_drm_private, shrinker);
-	struct msm_gem_object *msm_obj;
-	unsigned long count = 0;
+	unsigned count = priv->shrinkable_count;
 
-	mutex_lock(&priv->mm_lock);
+	if (can_swap())
+		count += priv->evictable_count;
 
-	list_for_each_entry(msm_obj, &priv->inactive_dontneed, mm_list) {
-		if (!msm_gem_trylock(&msm_obj->base))
-			continue;
-		if (is_purgeable(msm_obj))
-			count += msm_obj->base.size >> PAGE_SHIFT;
-		msm_gem_unlock(&msm_obj->base);
-	}
+	return count;
+}
 
-	mutex_unlock(&priv->mm_lock);
+static bool
+purge(struct msm_gem_object *msm_obj)
+{
+	if (!is_purgeable(msm_obj))
+		return false;
 
-	return count;
+	/*
+	 * This will move the obj out of still_in_list to
+	 * the purged list
+	 */
+	msm_gem_purge(&msm_obj->base);
+
+	return true;
+}
+
+static bool
+evict(struct msm_gem_object *msm_obj)
+{
+	if (is_unevictable(msm_obj))
+		return false;
+
+	msm_gem_evict(&msm_obj->base);
+
+	return true;
 }
 
 static unsigned long
-msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
+scan(struct msm_drm_private *priv, unsigned nr_to_scan, struct list_head *list,
+		bool (*shrink)(struct msm_gem_object *msm_obj))
 {
-	struct msm_drm_private *priv =
-		container_of(shrinker, struct msm_drm_private, shrinker);
-	struct msm_gem_object *msm_obj;
-	unsigned long freed = 0;
+	unsigned freed = 0;
+	struct list_head still_in_list;
+
+	INIT_LIST_HEAD(&still_in_list);
 
 	mutex_lock(&priv->mm_lock);
 
-	list_for_each_entry(msm_obj, &priv->inactive_dontneed, mm_list) {
-		if (freed >= sc->nr_to_scan)
+	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;
-		if (!msm_gem_trylock(&msm_obj->base))
+
+		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;
-		if (is_purgeable(msm_obj)) {
-			msm_gem_purge(&msm_obj->base);
+
+		/*
+		 * 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);
+	unsigned long freed;
+
+	freed = scan(priv, sc->nr_to_scan, &priv->inactive_dontneed, purge);
+
 	if (freed > 0)
 		trace_msm_gem_purge(freed << PAGE_SHIFT);
 
-	return freed;
+	if (can_swap() && freed < sc->nr_to_scan) {
+		int evicted = scan(priv, sc->nr_to_scan - freed,
+				&priv->inactive_willneed, evict);
+
+		if (evicted > 0)
+			trace_msm_gem_evict(evicted << PAGE_SHIFT);
+
+		freed += evicted;
+	}
+
+	return (freed > 0) ? freed : SHRINK_STOP;
 }
 
 /* since we don't know any better, lets bail after a few
@@ -68,26 +151,15 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
  */
 static const int vmap_shrink_limit = 15;
 
-static unsigned
-vmap_shrink(struct list_head *mm_list)
+static bool
+vmap_shrink(struct msm_gem_object *msm_obj)
 {
-	struct msm_gem_object *msm_obj;
-	unsigned unmapped = 0;
+	if (!is_vunmapable(msm_obj))
+		return false;
 
-	list_for_each_entry(msm_obj, mm_list, mm_list) {
-		if (!msm_gem_trylock(&msm_obj->base))
-			continue;
-		if (is_vunmapable(msm_obj)) {
-			msm_gem_vunmap(&msm_obj->base);
-			unmapped++;
-		}
-		msm_gem_unlock(&msm_obj->base);
+	msm_gem_vunmap(&msm_obj->base);
 
-		if (++unmapped >= vmap_shrink_limit)
-			break;
-	}
-
-	return unmapped;
+	return true;
 }
 
 static int
@@ -103,17 +175,11 @@ msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
 	};
 	unsigned idx, unmapped = 0;
 
-	mutex_lock(&priv->mm_lock);
-
-	for (idx = 0; mm_lists[idx]; idx++) {
-		unmapped += vmap_shrink(mm_lists[idx]);
-
-		if (unmapped >= vmap_shrink_limit)
-			break;
+	for (idx = 0; mm_lists[idx] && unmapped < vmap_shrink_limit; idx++) {
+		unmapped += scan(priv, vmap_shrink_limit - unmapped,
+				mm_lists[idx], vmap_shrink);
 	}
 
-	mutex_unlock(&priv->mm_lock);
-
 	*(unsigned long *)ptr += unmapped;
 
 	if (unmapped > 0)