Merge "Improve the thread flip."
diff --git a/runtime/gc/collector/concurrent_copying.cc b/runtime/gc/collector/concurrent_copying.cc
index 7afe6f9..42816a0 100644
--- a/runtime/gc/collector/concurrent_copying.cc
+++ b/runtime/gc/collector/concurrent_copying.cc
@@ -435,10 +435,8 @@
gc_barrier_->Init(self, 0);
ThreadFlipVisitor thread_flip_visitor(this, heap_->use_tlab_);
FlipCallback flip_callback(this);
- heap_->ThreadFlipBegin(self); // Sync with JNI critical calls.
size_t barrier_count = Runtime::Current()->FlipThreadRoots(
&thread_flip_visitor, &flip_callback, this);
- heap_->ThreadFlipEnd(self);
{
ScopedThreadStateChange tsc(self, kWaitingForCheckPointsToRun);
gc_barrier_->Increment(self, barrier_count);
diff --git a/runtime/gc/heap.cc b/runtime/gc/heap.cc
index 39f26e7..638c1d8 100644
--- a/runtime/gc/heap.cc
+++ b/runtime/gc/heap.cc
@@ -878,9 +878,13 @@
MutexLock mu(self, *thread_flip_lock_);
bool has_waited = false;
uint64_t wait_start = NanoTime();
- while (thread_flip_running_) {
- has_waited = true;
- thread_flip_cond_->Wait(self);
+ if (thread_flip_running_) {
+ TimingLogger::ScopedTiming split("IncrementDisableThreadFlip",
+ GetCurrentGcIteration()->GetTimings());
+ while (thread_flip_running_) {
+ has_waited = true;
+ thread_flip_cond_->Wait(self);
+ }
}
++disable_thread_flip_count_;
if (has_waited) {
diff --git a/runtime/thread-inl.h b/runtime/thread-inl.h
index 3aa1fc2..216d8a7 100644
--- a/runtime/thread-inl.h
+++ b/runtime/thread-inl.h
@@ -224,6 +224,7 @@
thread_to_pass = this;
}
MutexLock mu(thread_to_pass, *Locks::thread_suspend_count_lock_);
+ ScopedTransitioningToRunnable scoped_transitioning_to_runnable(this);
old_state_and_flags.as_int = tls32_.state_and_flags.as_int;
DCHECK_EQ(old_state_and_flags.as_struct.state, old_state);
while ((old_state_and_flags.as_struct.flags & kSuspendRequest) != 0) {
diff --git a/runtime/thread.cc b/runtime/thread.cc
index b35a614..0457ba0 100644
--- a/runtime/thread.cc
+++ b/runtime/thread.cc
@@ -1217,10 +1217,8 @@
ScopedTrace trace(__FUNCTION__);
VLOG(threads) << this << " self-suspending";
// Make thread appear suspended to other threads, release mutator_lock_.
- tls32_.suspended_at_suspend_check = true;
// Transition to suspended and back to runnable, re-acquire share on mutator_lock_.
ScopedThreadSuspension(this, kSuspended);
- tls32_.suspended_at_suspend_check = false;
VLOG(threads) << this << " self-reviving";
}
@@ -1635,7 +1633,7 @@
}
tlsPtr_.flip_function = nullptr;
tlsPtr_.thread_local_mark_stack = nullptr;
- tls32_.suspended_at_suspend_check = false;
+ tls32_.is_transitioning_to_runnable = false;
}
bool Thread::IsStillStarting() const {
@@ -1773,7 +1771,7 @@
CHECK(tlsPtr_.checkpoint_function == nullptr);
CHECK_EQ(checkpoint_overflow_.size(), 0u);
CHECK(tlsPtr_.flip_function == nullptr);
- CHECK_EQ(tls32_.suspended_at_suspend_check, false);
+ CHECK_EQ(tls32_.is_transitioning_to_runnable, false);
// Make sure we processed all deoptimization requests.
CHECK(tlsPtr_.deoptimization_context_stack == nullptr) << "Missed deoptimization";
diff --git a/runtime/thread.h b/runtime/thread.h
index 840b781..1c2d4ab 100644
--- a/runtime/thread.h
+++ b/runtime/thread.h
@@ -1085,8 +1085,12 @@
return tlsPtr_.nested_signal_state;
}
- bool IsSuspendedAtSuspendCheck() const {
- return tls32_.suspended_at_suspend_check;
+ bool IsTransitioningToRunnable() const {
+ return tls32_.is_transitioning_to_runnable;
+ }
+
+ void SetIsTransitioningToRunnable(bool value) {
+ tls32_.is_transitioning_to_runnable = value;
}
void PushVerifier(verifier::MethodVerifier* verifier);
@@ -1264,7 +1268,7 @@
suspend_count(0), debug_suspend_count(0), thin_lock_thread_id(0), tid(0),
daemon(is_daemon), throwing_OutOfMemoryError(false), no_thread_suspension(0),
thread_exit_check_count(0), handling_signal_(false),
- suspended_at_suspend_check(false), ready_for_debug_invoke(false),
+ is_transitioning_to_runnable(false), ready_for_debug_invoke(false),
debug_method_entry_(false), is_gc_marking(false), weak_ref_access_enabled(true),
disable_thread_flip_count(0) {
}
@@ -1306,10 +1310,10 @@
// True if signal is being handled by this thread.
bool32_t handling_signal_;
- // True if the thread is suspended in FullSuspendCheck(). This is
- // used to distinguish runnable threads that are suspended due to
- // a normal suspend check from other threads.
- bool32_t suspended_at_suspend_check;
+ // True if the thread is in TransitionFromSuspendedToRunnable(). This is used to distinguish the
+ // non-runnable threads (eg. kNative, kWaiting) that are about to transition to runnable from
+ // the rest of them.
+ bool32_t is_transitioning_to_runnable;
// True if the thread has been suspended by a debugger event. This is
// used to invoke method from the debugger which is only allowed when
@@ -1588,6 +1592,26 @@
Thread* const self_;
};
+class ScopedTransitioningToRunnable : public ValueObject {
+ public:
+ explicit ScopedTransitioningToRunnable(Thread* self)
+ : self_(self) {
+ DCHECK_EQ(self, Thread::Current());
+ if (kUseReadBarrier) {
+ self_->SetIsTransitioningToRunnable(true);
+ }
+ }
+
+ ~ScopedTransitioningToRunnable() {
+ if (kUseReadBarrier) {
+ self_->SetIsTransitioningToRunnable(false);
+ }
+ }
+
+ private:
+ Thread* const self_;
+};
+
std::ostream& operator<<(std::ostream& os, const Thread& thread);
std::ostream& operator<<(std::ostream& os, const StackedShadowFrameType& thread);
diff --git a/runtime/thread_list.cc b/runtime/thread_list.cc
index 419ecec..688514c 100644
--- a/runtime/thread_list.cc
+++ b/runtime/thread_list.cc
@@ -405,6 +405,8 @@
Locks::thread_suspend_count_lock_->AssertNotHeld(self);
CHECK_NE(self->GetState(), kRunnable);
+ collector->GetHeap()->ThreadFlipBegin(self); // Sync with JNI critical calls.
+
SuspendAllInternal(self, self, nullptr);
// Run the flip callback for the collector.
@@ -414,26 +416,31 @@
collector->RegisterPause(NanoTime() - start_time);
// Resume runnable threads.
- std::vector<Thread*> runnable_threads;
+ size_t runnable_thread_count = 0;
std::vector<Thread*> other_threads;
{
+ TimingLogger::ScopedTiming split2("ResumeRunnableThreads", collector->GetTimings());
MutexLock mu(self, *Locks::thread_list_lock_);
MutexLock mu2(self, *Locks::thread_suspend_count_lock_);
--suspend_all_count_;
for (const auto& thread : list_) {
+ // Set the flip function for all threads because Thread::DumpState/DumpJavaStack() (invoked by
+ // a checkpoint) may cause the flip function to be run for a runnable/suspended thread before
+ // a runnable thread runs it for itself or we run it for a suspended thread below.
+ thread->SetFlipFunction(thread_flip_visitor);
if (thread == self) {
continue;
}
- // Set the flip function for both runnable and suspended threads
- // because Thread::DumpState/DumpJavaStack() (invoked by a
- // checkpoint) may cause the flip function to be run for a
- // runnable/suspended thread before a runnable threads runs it
- // for itself or we run it for a suspended thread below.
- thread->SetFlipFunction(thread_flip_visitor);
- if (thread->IsSuspendedAtSuspendCheck()) {
+ // Resume early the threads that were runnable but are suspended just for this thread flip or
+ // about to transition from non-runnable (eg. kNative at the SOA entry in a JNI function) to
+ // runnable (both cases waiting inside Thread::TransitionFromSuspendedToRunnable), or waiting
+ // for the thread flip to end at the JNI critical section entry (kWaitingForGcThreadFlip),
+ ThreadState state = thread->GetState();
+ if (state == kWaitingForGcThreadFlip ||
+ thread->IsTransitioningToRunnable()) {
// The thread will resume right after the broadcast.
thread->ModifySuspendCount(self, -1, nullptr, false);
- runnable_threads.push_back(thread);
+ ++runnable_thread_count;
} else {
other_threads.push_back(thread);
}
@@ -441,8 +448,11 @@
Thread::resume_cond_->Broadcast(self);
}
+ collector->GetHeap()->ThreadFlipEnd(self);
+
// Run the closure on the other threads and let them resume.
{
+ TimingLogger::ScopedTiming split3("FlipOtherThreads", collector->GetTimings());
ReaderMutexLock mu(self, *Locks::mutator_lock_);
for (const auto& thread : other_threads) {
Closure* flip_func = thread->GetFlipFunction();
@@ -451,11 +461,15 @@
}
}
// Run it for self.
- thread_flip_visitor->Run(self);
+ Closure* flip_func = self->GetFlipFunction();
+ if (flip_func != nullptr) {
+ flip_func->Run(self);
+ }
}
// Resume other threads.
{
+ TimingLogger::ScopedTiming split4("ResumeOtherThreads", collector->GetTimings());
MutexLock mu2(self, *Locks::thread_suspend_count_lock_);
for (const auto& thread : other_threads) {
thread->ModifySuspendCount(self, -1, nullptr, false);
@@ -463,7 +477,7 @@
Thread::resume_cond_->Broadcast(self);
}
- return runnable_threads.size() + other_threads.size() + 1; // +1 for self.
+ return runnable_thread_count + other_threads.size() + 1; // +1 for self.
}
void ThreadList::SuspendAll(const char* cause, bool long_suspend) {