From 8db6f99a3e488b0b673575d65b92c019587f48d9 Mon Sep 17 00:00:00 2001
From: Dzmitry Malyshau <kvark@fastmail.com>
Date: Thu, 1 Jul 2021 02:02:16 -0400
Subject: [PATCH] Suspect new resources for destruction only after the current
 submission is tracked

---
 wgpu-core/src/device/life.rs  | 29 +++++++++++++++--------------
 wgpu-core/src/device/mod.rs   | 11 ++---------
 wgpu-core/src/device/queue.rs | 27 +++++++++++++++++----------
 3 files changed, 34 insertions(+), 33 deletions(-)

diff --git a/wgpu-core/src/device/life.rs b/wgpu-core/src/device/life.rs
index 6eb933c407..63270106af 100644
--- a/wgpu-core/src/device/life.rs
+++ b/wgpu-core/src/device/life.rs
@@ -230,6 +230,15 @@ impl<A: hal::Api> LifetimeTracker<A> {
             }
         }
 
+        self.active.alloc().init(ActiveSubmission {
+            index,
+            last_resources,
+            mapped: Vec::new(),
+            encoders,
+        });
+    }
+
+    pub fn post_submit(&mut self) {
         self.suspected_resources.buffers.extend(
             self.future_suspected_buffers
                 .drain(..)
@@ -240,13 +249,6 @@ impl<A: hal::Api> LifetimeTracker<A> {
                 .drain(..)
                 .map(|stored| stored.value),
         );
-
-        self.active.alloc().init(ActiveSubmission {
-            index,
-            last_resources,
-            mapped: Vec::new(),
-            encoders,
-        });
     }
 
     pub(crate) fn map(&mut self, value: id::Valid<id::BufferId>, ref_count: RefCount) {
@@ -310,13 +312,6 @@ impl<A: HalApi> LifetimeTracker<A> {
         id: id::Valid<id::TextureViewId>,
         view: resource::TextureView<A>,
     ) {
-        match view.source {
-            resource::TextureViewSource::Native(source_id) => {
-                self.suspected_resources.textures.push(source_id.value);
-            }
-            resource::TextureViewSource::SwapChain { .. } => {}
-        };
-
         let submit_index = view.life_guard.submission_index.load(Ordering::Acquire);
         self.active
             .iter_mut()
@@ -392,6 +387,12 @@ impl<A: HalApi> LifetimeTracker<A> {
                     }
 
                     if let Some(res) = hub.texture_views.unregister_locked(id.0, &mut *guard) {
+                        match res.source {
+                            resource::TextureViewSource::Native(ref source_id) => {
+                                self.suspected_resources.textures.push(source_id.value);
+                            }
+                            resource::TextureViewSource::SwapChain { .. } => {}
+                        };
                         self.schedule_texture_view_for_destruction(id, res);
                     }
                 }
diff --git a/wgpu-core/src/device/mod.rs b/wgpu-core/src/device/mod.rs
index b60808929f..26d224b5ce 100644
--- a/wgpu-core/src/device/mod.rs
+++ b/wgpu-core/src/device/mod.rs
@@ -333,19 +333,12 @@ impl<A: HalApi> Device<A> {
         })
     }
 
-    fn lock_life_internal<'this, 'token: 'this>(
-        tracker: &'this Mutex<life::LifetimeTracker<A>>,
-        _token: &mut Token<'token, Self>,
-    ) -> MutexGuard<'this, life::LifetimeTracker<A>> {
-        tracker.lock()
-    }
-
     fn lock_life<'this, 'token: 'this>(
         &'this self,
         //TODO: fix this - the token has to be borrowed for the lock
-        token: &mut Token<'token, Self>,
+        _token: &mut Token<'token, Self>,
     ) -> MutexGuard<'this, life::LifetimeTracker<A>> {
-        Self::lock_life_internal(&self.life_tracker, token)
+        self.life_tracker.lock()
     }
 
     pub(crate) fn schedule_rogue_texture_view_for_destruction<'this, 'token: 'this>(
diff --git a/wgpu-core/src/device/queue.rs b/wgpu-core/src/device/queue.rs
index 130070aecd..a68766a835 100644
--- a/wgpu-core/src/device/queue.rs
+++ b/wgpu-core/src/device/queue.rs
@@ -808,14 +808,6 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
                 }
             }
 
-            let callbacks = match device.maintain(&hub, false, &mut token) {
-                Ok(callbacks) => callbacks,
-                Err(WaitIdleError::Device(err)) => return Err(QueueSubmitError::Queue(err)),
-                Err(WaitIdleError::StuckGpu) => return Err(QueueSubmitError::StuckGpu),
-            };
-
-            device.temp_suspected.clear();
-
             profiling::scope!("cleanup");
             if let Some(pending_execution) = device.pending_writes.post_submit(
                 &device.command_allocator,
@@ -824,12 +816,27 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
             ) {
                 active_executions.push(pending_execution);
             }
-            super::Device::lock_life_internal(&device.life_tracker, &mut token).track_submission(
+
+            // this will register the new submission to the life time tracker
+            let mut pending_write_resources = mem::take(&mut device.pending_writes.temp_resources);
+            device.lock_life(&mut token).track_submission(
                 submit_index,
-                device.pending_writes.temp_resources.drain(..),
+                pending_write_resources.drain(..),
                 active_executions,
             );
 
+            // This will schedule destruction of all resources that are no longer needed
+            // by the user but used in the command stream, among other things.
+            let callbacks = match device.maintain(&hub, false, &mut token) {
+                Ok(callbacks) => callbacks,
+                Err(WaitIdleError::Device(err)) => return Err(QueueSubmitError::Queue(err)),
+                Err(WaitIdleError::StuckGpu) => return Err(QueueSubmitError::StuckGpu),
+            };
+
+            device.pending_writes.temp_resources = pending_write_resources;
+            device.temp_suspected.clear();
+            device.lock_life(&mut token).post_submit();
+
             callbacks
         };