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Fix scripting AssemblyLoadContext not getting unloaded

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This commit is contained in:
Ari Vuollet
2024-04-22 00:11:24 +03:00
committed by Ari Vuollet
parent 83c3201ef8
commit beff9d5241
8 changed files with 159 additions and 58 deletions
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28
Source/Engine/Engine/NativeInterop.Managed.cs
View File

@@ -176,6 +176,7 @@ namespace FlaxEngine.Interop
_managedHandle.Free();
_unmanagedData = IntPtr.Zero;
}
_arrayType = _elementType = null;
ManagedArrayPool.Put(this);
}
@@ -442,22 +443,25 @@ namespace FlaxEngine.Interop
/// <summary>
/// Tries to free all references to old weak handles so GC can collect them.
/// </summary>
internal static void TryCollectWeakHandles()
internal static void TryCollectWeakHandles(bool force = false)
{
if (weakHandleAccumulator < nextWeakPoolCollection)
return;
if (!force)
{
if (weakHandleAccumulator < nextWeakPoolCollection)
return;
nextWeakPoolCollection = weakHandleAccumulator + 1000;
nextWeakPoolCollection = weakHandleAccumulator + 1000;
// Try to swap pools after garbage collection or whenever the pool gets too large
var gc0CollectionCount = GC.CollectionCount(0);
if (gc0CollectionCount < nextWeakPoolGCCollection && weakPool.Count < WeakPoolCollectionSizeThreshold)
return;
nextWeakPoolGCCollection = gc0CollectionCount + 1;
// Try to swap pools after garbage collection or whenever the pool gets too large
var gc0CollectionCount = GC.CollectionCount(0);
if (gc0CollectionCount < nextWeakPoolGCCollection && weakPool.Count < WeakPoolCollectionSizeThreshold)
return;
nextWeakPoolGCCollection = gc0CollectionCount + 1;
// Prevent huge allocations from swapping the pools in the middle of the operation
if (System.Diagnostics.Stopwatch.GetElapsedTime(lastWeakPoolCollectionTime).TotalMilliseconds < WeakPoolCollectionTimeThreshold)
return;
// Prevent huge allocations from swapping the pools in the middle of the operation
if (System.Diagnostics.Stopwatch.GetElapsedTime(lastWeakPoolCollectionTime).TotalMilliseconds < WeakPoolCollectionTimeThreshold)
return;
}
lastWeakPoolCollectionTime = System.Diagnostics.Stopwatch.GetTimestamp();
// Swap the pools and release the oldest pool for GC

107
Source/Engine/Engine/NativeInterop.Unmanaged.cs
View File

@@ -1054,7 +1054,49 @@ namespace FlaxEngine.Interop
}
[UnmanagedCallersOnly]
internal static void ReloadScriptingAssemblyLoadContext()
internal static void CreateScriptingAssemblyLoadContext()
{
#if FLAX_EDITOR
if (scriptingAssemblyLoadContext != null)
{
// Wait for previous ALC to finish unloading, track it without holding strong references to it
GCHandle weakRef = GCHandle.Alloc(scriptingAssemblyLoadContext, GCHandleType.WeakTrackResurrection);
scriptingAssemblyLoadContext = null;
#if true
// In case the ALC doesn't unload properly: https://learn.microsoft.com/en-us/dotnet/standard/assembly/unloadability#debug-unloading-issues
while (true)
#else
for (int attempts = 5; attempts > 0; attempts--)
#endif
{
GC.Collect();
GC.WaitForPendingFinalizers();
if (!IsHandleAlive(weakRef))
break;
System.Threading.Thread.Sleep(1);
}
if (IsHandleAlive(weakRef))
Debug.LogWarning("Scripting AssemblyLoadContext was not unloaded.");
weakRef.Free();
static bool IsHandleAlive(GCHandle weakRef)
{
// Checking the target in scope somehow holds a reference to it...?
return weakRef.Target != null;
}
}
scriptingAssemblyLoadContext = new AssemblyLoadContext("Flax", isCollectible: true);
scriptingAssemblyLoadContext.Resolving += OnScriptingAssemblyLoadContextResolving;
#else
scriptingAssemblyLoadContext = new AssemblyLoadContext("Flax", isCollectible: false);
#endif
DelegateHelpers.InitMethods();
}
[UnmanagedCallersOnly]
internal static void UnloadScriptingAssemblyLoadContext()
{
#if FLAX_EDITOR
// Clear all caches which might hold references to assemblies in collectible ALC
@@ -1072,24 +1114,73 @@ namespace FlaxEngine.Interop
handle.Free();
propertyHandleCacheCollectible.Clear();
foreach (var key in assemblyHandles.Keys.Where(x => x.IsCollectible))
assemblyHandles.Remove(key);
foreach (var key in assemblyOwnedNativeLibraries.Keys.Where(x => x.IsCollectible))
assemblyOwnedNativeLibraries.Remove(key);
_typeSizeCache.Clear();
foreach (var pair in classAttributesCacheCollectible)
pair.Value.Free();
classAttributesCacheCollectible.Clear();
ArrayFactory.marshalledTypes.Clear();
ArrayFactory.arrayTypes.Clear();
ArrayFactory.createArrayDelegates.Clear();
FlaxEngine.Json.JsonSerializer.ResetCache();
DelegateHelpers.Release();
// Ensure both pools are empty
ManagedHandle.ManagedHandlePool.TryCollectWeakHandles(true);
ManagedHandle.ManagedHandlePool.TryCollectWeakHandles(true);
GC.Collect();
GC.WaitForPendingFinalizers();
{
// HACK: Workaround for TypeDescriptor holding references to collectible types (https://github.com/dotnet/runtime/issues/30656)
Type TypeDescriptionProviderType = typeof(System.ComponentModel.TypeDescriptionProvider);
MethodInfo clearCacheMethod = TypeDescriptionProviderType?.Assembly.GetType("System.ComponentModel.ReflectionCachesUpdateHandler")?.GetMethod("ClearCache");
if (clearCacheMethod != null)
clearCacheMethod.Invoke(null, new object[] { null });
else
{
MethodInfo beforeUpdateMethod = TypeDescriptionProviderType?.Assembly.GetType("System.ComponentModel.ReflectionCachesUpdateHandler")?.GetMethod("BeforeUpdate");
if (beforeUpdateMethod != null)
beforeUpdateMethod.Invoke(null, new object[] { null });
}
Type TypeDescriptorType = typeof(System.ComponentModel.TypeDescriptor);
object s_internalSyncObject = TypeDescriptorType?.GetField("s_internalSyncObject", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic)?.GetValue(null);
System.Collections.Hashtable s_defaultProviders = (System.Collections.Hashtable)TypeDescriptorType?.GetField("s_defaultProviders", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic)?.GetValue(null);
if (s_internalSyncObject != null && s_defaultProviders != null)
{
lock (s_internalSyncObject)
s_defaultProviders.Clear();
}
object s_providerTable = TypeDescriptorType?.GetField("s_providerTable", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic)?.GetValue(null);
System.Collections.Hashtable s_providerTypeTable = (System.Collections.Hashtable)TypeDescriptorType?.GetField("s_providerTypeTable", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic)?.GetValue(null);
if (s_providerTable != null && s_providerTypeTable != null)
{
lock (s_providerTable)
s_providerTypeTable.Clear();
TypeDescriptorType.GetField("s_providerTable", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic)
?.FieldType.GetMethods(BindingFlags.Instance | BindingFlags.Public).FirstOrDefault(x => x.Name == "Clear")
?.Invoke(s_providerTable, new object[] { });
}
}
// Unload the ALC
bool unloading = true;
scriptingAssemblyLoadContext.Unloading += (alc) => { unloading = false; };
scriptingAssemblyLoadContext.Unload();
scriptingAssemblyLoadContext.Resolving -= OnScriptingAssemblyLoadContextResolving;
while (unloading)
System.Threading.Thread.Sleep(1);
InitScriptingAssemblyLoadContext();
DelegateHelpers.InitMethods();
GC.Collect();
GC.WaitForPendingFinalizers();
#endif
}

42
Source/Engine/Engine/NativeInterop.cs
View File

@@ -73,19 +73,6 @@ namespace FlaxEngine.Interop
return nativeLibrary;
}
private static void InitScriptingAssemblyLoadContext()
{
#if FLAX_EDITOR
var isCollectible = true;
#else
var isCollectible = false;
#endif
scriptingAssemblyLoadContext = new AssemblyLoadContext("Flax", isCollectible);
#if FLAX_EDITOR
scriptingAssemblyLoadContext.Resolving += OnScriptingAssemblyLoadContextResolving;
#endif
}
[UnmanagedCallersOnly]
internal static unsafe void Init()
{
@@ -97,8 +84,6 @@ namespace FlaxEngine.Interop
System.Threading.Thread.CurrentThread.CurrentCulture = CultureInfo.InvariantCulture;
System.Threading.Thread.CurrentThread.CurrentUICulture = CultureInfo.InvariantCulture;
InitScriptingAssemblyLoadContext();
DelegateHelpers.InitMethods();
}
#if FLAX_EDITOR
@@ -1475,11 +1460,11 @@ namespace FlaxEngine.Interop
internal static class ArrayFactory
{
private delegate Array CreateArrayDelegate(long size);
internal delegate Array CreateArrayDelegate(long size);
private static ConcurrentDictionary<Type, Type> marshalledTypes = new ConcurrentDictionary<Type, Type>(1, 3);
private static ConcurrentDictionary<Type, Type> arrayTypes = new ConcurrentDictionary<Type, Type>(1, 3);
private static ConcurrentDictionary<Type, CreateArrayDelegate> createArrayDelegates = new ConcurrentDictionary<Type, CreateArrayDelegate>(1, 3);
internal static ConcurrentDictionary<Type, Type> marshalledTypes = new ConcurrentDictionary<Type, Type>(1, 3);
internal static ConcurrentDictionary<Type, Type> arrayTypes = new ConcurrentDictionary<Type, Type>(1, 3);
internal static ConcurrentDictionary<Type, CreateArrayDelegate> createArrayDelegates = new ConcurrentDictionary<Type, CreateArrayDelegate>(1, 3);
internal static Type GetMarshalledType(Type elementType)
{
@@ -1645,17 +1630,6 @@ namespace FlaxEngine.Interop
return RegisterType(type, true).typeHolder;
}
internal static (TypeHolder typeHolder, ManagedHandle handle) GetTypeHolderAndManagedHandle(Type type)
{
if (managedTypes.TryGetValue(type, out (TypeHolder typeHolder, ManagedHandle handle) tuple))
return tuple;
#if FLAX_EDITOR
if (managedTypesCollectible.TryGetValue(type, out tuple))
return tuple;
#endif
return RegisterType(type, true);
}
/// <summary>
/// Returns a static ManagedHandle to TypeHolder for given Type, and caches it if needed.
/// </summary>
@@ -1781,6 +1755,14 @@ namespace FlaxEngine.Interop
#endif
}
internal static void Release()
{
MakeNewCustomDelegateFunc = null;
#if FLAX_EDITOR
MakeNewCustomDelegateFuncCollectible = null;
#endif
}
internal static Type MakeNewCustomDelegate(Type[] parameters)
{
#if FLAX_EDITOR

11
Source/Engine/Scripting/ManagedCLR/MCore.h
View File

@@ -45,9 +45,16 @@ public:
/// </summary>
static void UnloadEngine();
/// <summary>
/// Creates the assembly load context for assemblies used by Scripting.
/// </summary>
static void CreateScriptingAssemblyLoadContext();
#if USE_EDITOR
// Called by Scripting in a middle of hot-reload (after unloading modules but before loading them again).
static void ReloadScriptingAssemblyLoadContext();
/// <summary>
/// Called by Scripting in a middle of hot-reload (after unloading modules but before loading them again).
/// </summary>
static void UnloadScriptingAssemblyLoadContext();
#endif
public:

12
Source/Engine/Scripting/Runtime/DotNet.cpp
View File

@@ -330,9 +330,15 @@ void MCore::UnloadEngine()
ShutdownHostfxr();
}
void MCore::CreateScriptingAssemblyLoadContext()
{
static void* CreateScriptingAssemblyLoadContextPtr = GetStaticMethodPointer(TEXT("CreateScriptingAssemblyLoadContext"));
CallStaticMethod<void>(CreateScriptingAssemblyLoadContextPtr);
}
#if USE_EDITOR
void MCore::ReloadScriptingAssemblyLoadContext()
void MCore::UnloadScriptingAssemblyLoadContext()
{
// Clear any cached class attributes (see https://github.com/FlaxEngine/FlaxEngine/issues/1108)
for (auto e : CachedClassHandles)
@@ -377,8 +383,8 @@ void MCore::ReloadScriptingAssemblyLoadContext()
}
}
static void* ReloadScriptingAssemblyLoadContextPtr = GetStaticMethodPointer(TEXT("ReloadScriptingAssemblyLoadContext"));
CallStaticMethod<void>(ReloadScriptingAssemblyLoadContextPtr);
static void* UnloadScriptingAssemblyLoadContextPtr = GetStaticMethodPointer(TEXT("UnloadScriptingAssemblyLoadContext"));
CallStaticMethod<void>(UnloadScriptingAssemblyLoadContextPtr);
}
#endif

6
Source/Engine/Scripting/Runtime/Mono.cpp
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@@ -715,9 +715,13 @@ void MCore::UnloadEngine()
#endif
}
void MCore::CreateScriptingAssemblyLoadContext()
{
}
#if USE_EDITOR
void MCore::ReloadScriptingAssemblyLoadContext()
void MCore::UnloadScriptingAssemblyLoadContext()
{
}

6
Source/Engine/Scripting/Runtime/None.cpp
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@@ -58,9 +58,13 @@ void MCore::UnloadEngine()
MRootDomain = nullptr;
}
void MCore::CreateScriptingAssemblyLoadContext()
{
}
#if USE_EDITOR
void MCore::ReloadScriptingAssemblyLoadContext()
void MCore::UnloadScriptingAssemblyLoadContext()
{
}

5
Source/Engine/Scripting/Scripting.cpp
View File

@@ -182,6 +182,8 @@ bool ScriptingService::Init()
return true;
}
MCore::CreateScriptingAssemblyLoadContext();
// Cache root domain
_rootDomain = MCore::GetRootDomain();
@@ -710,7 +712,8 @@ void Scripting::Reload(bool canTriggerSceneReload)
_hasGameModulesLoaded = false;
// Release and create a new assembly load context for user assemblies
MCore::ReloadScriptingAssemblyLoadContext();
MCore::UnloadScriptingAssemblyLoadContext();
MCore::CreateScriptingAssemblyLoadContext();
// Give GC a try to cleanup old user objects and the other mess
MCore::GC::Collect();