Fixes a Mutex Issue Preventing Some UE Titles From Booting (#451)

* Optimize guest import, memory, and pthread hot paths

* Fix UE adaptive mutex self-lock handling
This commit is contained in:
Spooks
2026-07-19 13:20:05 -06:00
committed by GitHub
parent 8ef5a54ee4
commit 90c72ebecf
9 changed files with 647 additions and 58 deletions
@@ -712,6 +712,11 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
private readonly Dictionary<ulong, PendingGuestException> _pendingGuestExceptions = new Dictionary<ulong, PendingGuestException>();
// Import dispatch is the hottest managed path in UE titles. Most imports do
// not have an exception queued, so publish the dictionary population and let
// safe points skip _guestThreadGate entirely in the common case.
private int _pendingGuestExceptionCount;
private readonly HashSet<ulong> _activeGuestExceptionDeliveries = new HashSet<ulong>();
private int _guestThreadPumpDepth;
@@ -3948,10 +3953,10 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
// unwinding. Unity can begin its next stop-the-world cycle in
// that window; treating the new raise as part of the old delivery
// strands the collector waiting for an acknowledgement.
_pendingGuestExceptions[threadHandle] = new PendingGuestException(
QueuePendingGuestExceptionLocked(threadHandle, new PendingGuestException(
handler,
exceptionType,
external.ExceptionStackBase);
external.ExceptionStackBase));
return true;
}
@@ -3960,10 +3965,10 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
// managed thread corrupts the worker's control state. Queue the
// request and let that exact executor consume it at its next HLE
// boundary, where the original guest thread is safely paused.
_pendingGuestExceptions[threadHandle] = new PendingGuestException(
QueuePendingGuestExceptionLocked(threadHandle, new PendingGuestException(
handler,
exceptionType,
external.ExceptionStackBase);
external.ExceptionStackBase));
if (logGuestExceptions)
{
Console.Error.WriteLine(
@@ -4008,17 +4013,17 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
}
if (target.ExceptionDeliveryActive)
{
_pendingGuestExceptions[threadHandle] = new PendingGuestException(
QueuePendingGuestExceptionLocked(threadHandle, new PendingGuestException(
handler,
exceptionType,
exceptionStackBase);
exceptionStackBase));
return true;
}
_pendingGuestExceptions[threadHandle] = new PendingGuestException(
QueuePendingGuestExceptionLocked(threadHandle, new PendingGuestException(
handler,
exceptionType,
exceptionStackBase);
exceptionStackBase));
if (logGuestExceptions)
{
Console.Error.WriteLine(
@@ -4179,7 +4184,7 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
RestoreInterruptedGuestThread();
if (target.State == GuestThreadRunState.Blocked &&
!target.ExecutorActive &&
_pendingGuestExceptions.Remove(threadHandle, out var queued))
TryRemovePendingGuestExceptionLocked(threadHandle, out var queued))
{
followUp = queued;
}
@@ -4265,6 +4270,11 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
CpuContext currentContext,
GuestCpuContinuation interruptedContinuation)
{
if (Volatile.Read(ref _pendingGuestExceptionCount) == 0)
{
return;
}
var threadHandle = GuestThreadExecution.CurrentGuestThreadHandle;
if (threadHandle == 0)
{
@@ -4278,7 +4288,7 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
return;
}
if (!_pendingGuestExceptions.Remove(threadHandle, out pending))
if (!TryRemovePendingGuestExceptionLocked(threadHandle, out pending))
{
return;
}
@@ -4340,6 +4350,27 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
}
}
private void QueuePendingGuestExceptionLocked(
ulong threadHandle,
PendingGuestException pending)
{
_pendingGuestExceptions[threadHandle] = pending;
Volatile.Write(ref _pendingGuestExceptionCount, _pendingGuestExceptions.Count);
}
private bool TryRemovePendingGuestExceptionLocked(
ulong threadHandle,
out PendingGuestException pending)
{
if (!_pendingGuestExceptions.Remove(threadHandle, out pending))
{
return false;
}
Volatile.Write(ref _pendingGuestExceptionCount, _pendingGuestExceptions.Count);
return true;
}
private static bool TryWriteGuestExceptionContext(
CpuContext context,
ulong address,
@@ -4434,6 +4465,7 @@ public sealed unsafe partial class DirectExecutionBackend : INativeCpuBackend, I
_guestThreads.Clear();
_externalGuestThreads.Clear();
_pendingGuestExceptions.Clear();
Volatile.Write(ref _pendingGuestExceptionCount, 0);
_activeGuestExceptionDeliveries.Clear();
}