texture_cache: find a deleted image's view entries without a scan

Deleting an image erased the channels' descriptor -> view entries
pointing to its views by scanning every channel's map (Mario Kart
World: ~5,000 entries, 50-130 us per deleted image, dozens a frame
while the collector runs). The cache keeps, per view, the (channel,
descriptor) entries that point to it and erases just those, skipping
entries of channels that are gone or that point to another view since.

(cherry picked from commit c3d22e8e09dacf39000c742d03dfc7517bd6f343)

1 files changed, 21 insertions, 10 deletions

diff --git a/src/video_core/texture_cache/texture_cache.h b/src/video_core/texture_cache/texture_cache.h
index c8aaf8dff5..279668813f 100644
--- a/src/video_core/texture_cache/texture_cache.h
+++ b/src/video_core/texture_cache/texture_cache.h
@@ -689,8 +689,13 @@ ImageViewId TextureCache<P>::VisitImageView(u32 index, bool compute) {
         if (IsValidEntry(*gpu_memory, descriptor)) {
             // Is new (registered view) on the texture cache side?
             const auto [pair, is_new_tc] = channel_state->image_views.try_emplace(descriptor);
-            if (is_new_tc)
+            if (is_new_tc) {
                 pair->second = CreateImageView(descriptor);
+                if (pair->second != NULL_IMAGE_VIEW_ID) {
+                    image_view_descriptors[pair->second].emplace_back(current_channel_id,
+                                                                      descriptor);
+                }
+            }
             PrepareImageView(pair->second, false, false);
             channel_state->image_view_ids.insert_or_assign(map_index, pair->second);
             return pair->second;
@@ -2917,17 +2922,23 @@ void TextureCache<P>::DeleteImage(ImageId image_id, bool immediate_delete) {
 
 template <class P>
 void TextureCache<P>::RemoveImageViewReferences(std::span<const ImageViewId> removed_views) {
-    for (size_t c : active_channel_ids) {
-        auto& channel_info = channel_storage[c];
-        auto it = channel_info.image_views.begin();
-        while (it != channel_info.image_views.end()) {
-            const auto found = std::ranges::find(removed_views, it->second);
-            if (found != removed_views.end()) {
-                it = channel_info.image_views.erase(it);
-            } else {
-                ++it;
+    for (const ImageViewId removed : removed_views) {
+        const auto refs = image_view_descriptors.find(removed);
+        if (refs == image_view_descriptors.end()) {
+            continue;
+        }
+        for (const auto& [channel, descriptor] : refs->second) {
+            // The channel may be gone, or its entry point to another view since.
+            if (std::ranges::find(active_channel_ids, channel) == active_channel_ids.end()) {
+                continue;
+            }
+            auto& image_views = channel_storage[channel].image_views;
+            if (const auto it = image_views.find(descriptor);
+                it != image_views.end() && it->second == removed) {
+                image_views.erase(it);
             }
         }
+        image_view_descriptors.erase(refs);
     }
 }