Modify the behavior of thread suspend shootouts.
The thread doing the suspension doesn't attempt to suspend the other thread
unless it knows another thread isn't trying to suspend it. Use the suspend
count, and its lock, for this purpose.
Re-enable ThreadStress test.
Bug: 15446488
Change-Id: Idd34410c7b89d8abd6973e5699a15ca699472c78
diff --git a/runtime/native/dalvik_system_VMStack.cc b/runtime/native/dalvik_system_VMStack.cc
index e396dad..2cdc68f 100644
--- a/runtime/native/dalvik_system_VMStack.cc
+++ b/runtime/native/dalvik_system_VMStack.cc
@@ -38,12 +38,7 @@
soa.Self()->TransitionFromRunnableToSuspended(kNative);
ThreadList* thread_list = Runtime::Current()->GetThreadList();
bool timed_out;
- Thread* thread;
- {
- // Take suspend thread lock to avoid races with threads trying to suspend this one.
- MutexLock mu(soa.Self(), *Locks::thread_list_suspend_thread_lock_);
- thread = thread_list->SuspendThreadByPeer(peer, true, false, &timed_out);
- }
+ Thread* thread = thread_list->SuspendThreadByPeer(peer, true, false, &timed_out);
if (thread != nullptr) {
// Must be runnable to create returned array.
CHECK_EQ(soa.Self()->TransitionFromSuspendedToRunnable(), kNative);