[Offload] Improve `olDestroyQueue` logic (#153041)

Previously, `olDestroyQueue` would not actually destroy the queue,
instead leaving it for the device to clean up when it was destroyed.
Now, the queue is either released immediately if it is complete or put
into a list of "pending" queues if it is not. Whenever we create a new
queue, we check this list to see if any are now completed. If there are
any we release their resources and use them instead of pulling from
the pool.

This prevents long running programs that create and drop many queues
without syncing them from leaking memory all over the place.

1 files changed, 9 insertions, 6 deletions

diff --git a/offload/plugins-nextgen/common/src/PluginInterface.cpp b/offload/plugins-nextgen/common/src/PluginInterface.cpp
index 4363a4f7c06c..e5a313d5e9bb 100644
--- a/offload/plugins-nextgen/common/src/PluginInterface.cpp
+++ b/offload/plugins-nextgen/common/src/PluginInterface.cpp
@@ -1341,16 +1341,19 @@ Error PinnedAllocationMapTy::unlockUnmappedHostBuffer(void *HstPtr) {
 
 Error GenericDeviceTy::synchronize(__tgt_async_info *AsyncInfo,
                                    bool ReleaseQueue) {
+  if (!AsyncInfo)
+    return Plugin::error(ErrorCode::INVALID_ARGUMENT,
+                         "invalid async info queue");
+
   SmallVector<void *> AllocsToDelete{};
   {
     std::lock_guard<std::mutex> AllocationGuard{AsyncInfo->Mutex};
 
-    if (!AsyncInfo || !AsyncInfo->Queue)
-      return Plugin::error(ErrorCode::INVALID_ARGUMENT,
-                           "invalid async info queue");
-
-    if (auto Err = synchronizeImpl(*AsyncInfo, ReleaseQueue))
-      return Err;
+    // This can be false when no work has been added to the AsyncInfo. In which
+    // case, the device has nothing to synchronize.
+    if (AsyncInfo->Queue)
+      if (auto Err = synchronizeImpl(*AsyncInfo, ReleaseQueue))
+        return Err;
 
     std::swap(AllocsToDelete, AsyncInfo->AssociatedAllocations);
   }