drm/i915: Release the active tracker tree upon idling

ickle · ickle · commit a42375af0a30 · 2019-02-05T17:14:33.000Z
As soon as we detect that the active tracker is idle and we prepare to call the retire callback, release the storage for our tree of per-timeline nodes. We expect these to be infrequently used and quick to allocate, so there is little benefit in keeping the tree cached and we would prefer to return the pages back to the system in a timely fashion. This also means that when we finalize the struct as a whole, we know as the activity tracker must be idle, the tree has already been released. Indeed we can reduce i915_active_fini() just to the assertions that there is nothing to do. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190205130005.2807-3-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c
@@ -16,12 +16,29 @@ struct active_node {
 	u64 timeline;
 };
 
+static void
+__active_park(struct i915_active *ref)
+{
+	struct active_node *it, *n;
+
+	rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
+		GEM_BUG_ON(i915_gem_active_isset(&it->base));
+		kfree(it);
+	}
+	ref->tree = RB_ROOT;
+}
+
 static void
 __active_retire(struct i915_active *ref)
 {
 	GEM_BUG_ON(!ref->count);
-	if (!--ref->count)
-		ref->retire(ref);
+	if (--ref->count)
+		return;
+
+	/* return the unused nodes to our slabcache */
+	__active_park(ref);
+
+	ref->retire(ref);
 }
 
 static void
@@ -210,18 +227,14 @@ int i915_request_await_active(struct i915_request *rq, struct i915_active *ref)
 	return 0;
 }
 
+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)
 void i915_active_fini(struct i915_active *ref)
 {
-	struct active_node *it, *n;
-
 	GEM_BUG_ON(i915_gem_active_isset(&ref->last));
-
-	rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
-		GEM_BUG_ON(i915_gem_active_isset(&it->base));
-		kfree(it);
-	}
-	ref->tree = RB_ROOT;
+	GEM_BUG_ON(!RB_EMPTY_ROOT(&ref->tree));
+	GEM_BUG_ON(ref->count);
 }
+#endif
 
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 #include "selftests/i915_active.c"
diff --git a/drivers/gpu/drm/i915/i915_active.h b/drivers/gpu/drm/i915/i915_active.h
@@ -64,6 +64,10 @@ i915_active_is_idle(const struct i915_active *ref)
 	return !ref->count;
 }
 
+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)
 void i915_active_fini(struct i915_active *ref);
+#else
+static inline void i915_active_fini(struct i915_active *ref) { }
+#endif
 
 #endif /* _I915_ACTIVE_H_ */

Original file line number	Diff line number	Diff line change
`@@ -64,6 +64,10 @@ i915_active_is_idle(const struct i915_active *ref)`
`64`	`64`	`return !ref->count;`
`65`	`65`	`}`
`66`	`66`
	`67`	`+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)`
`67`	`68`	`void i915_active_fini(struct i915_active *ref);`
	`69`	`+#else`
	`70`	`+static inline void i915_active_fini(struct i915_active *ref) { }`
	`71`	`+#endif`
`68`	`72`
`69`	`73`	`#endif /* _I915_ACTIVE_H_ */`