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src/hotspot/share/runtime/safepoint.cpp
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rev 47862 : imported patch 10.07.open.rebase_20171110.dcubed
rev 47863 : imported patch 10.08.open.rebase_20171114.rehn
@@ -57,10 +57,11 @@
#include "runtime/stubCodeGenerator.hpp"
#include "runtime/stubRoutines.hpp"
#include "runtime/sweeper.hpp"
#include "runtime/synchronizer.hpp"
#include "runtime/thread.inline.hpp"
+#include "runtime/threadSMR.hpp"
#include "runtime/timerTrace.hpp"
#include "services/runtimeService.hpp"
#include "trace/tracing.hpp"
#include "trace/traceMacros.hpp"
#include "utilities/events.hpp"
@@ -172,11 +173,11 @@
_state = _synchronizing;
if (SafepointMechanism::uses_thread_local_poll()) {
// Arming the per thread poll while having _state != _not_synchronized means safepointing
log_trace(safepoint)("Setting thread local yield flag for threads");
- for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) {
+ for (JavaThreadIteratorWithHandle jtiwh; JavaThread *cur = jtiwh.next(); ) {
// Make sure the threads start polling, it is time to yield.
SafepointMechanism::arm_local_poll(cur); // release store, global state -> local state
}
}
OrderAccess::fence(); // storestore|storeload, global state -> local state
@@ -198,13 +199,16 @@
}
}
// Consider using active_processor_count() ... but that call is expensive.
int ncpus = os::processor_count() ;
+ unsigned int iterations = 0;
+ {
+ JavaThreadIteratorWithHandle jtiwh;
#ifdef ASSERT
- for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) {
+ for (; JavaThread *cur = jtiwh.next(); ) {
assert(cur->safepoint_state()->is_running(), "Illegal initial state");
// Clear the visited flag to ensure that the critical counts are collected properly.
cur->set_visited_for_critical_count(false);
}
#endif // ASSERT
@@ -211,14 +215,14 @@
if (SafepointTimeout)
safepoint_limit_time = os::javaTimeNanos() + (jlong)SafepointTimeoutDelay * MICROUNITS;
// Iterate through all threads until it have been determined how to stop them all at a safepoint
- unsigned int iterations = 0;
int steps = 0 ;
while(still_running > 0) {
- for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) {
+ jtiwh.rewind();
+ for (; JavaThread *cur = jtiwh.next(); ) {
assert(!cur->is_ConcurrentGC_thread(), "A concurrent GC thread is unexpectly being suspended");
ThreadSafepointState *cur_state = cur->safepoint_state();
if (cur_state->is_running()) {
cur_state->examine_state_of_thread();
if (!cur_state->is_running()) {
@@ -325,10 +329,11 @@
iterations ++ ;
}
assert(iterations < (uint)max_jint, "We have been iterating in the safepoint loop too long");
}
+ } // ThreadsListHandle destroyed here.
assert(still_running == 0, "sanity check");
if (PrintSafepointStatistics) {
update_statistics_on_spin_end();
}
@@ -339,11 +344,11 @@
sync_event.set_initialThreadCount(initial_running);
sync_event.set_runningThreadCount(_waiting_to_block);
sync_event.set_iterations(iterations);
sync_event.commit();
}
- } //EventSafepointStateSync
+ } // EventSafepointStateSynchronization destroyed here.
// wait until all threads are stopped
{
EventSafepointWaitBlocked wait_blocked_event;
int initial_waiting_to_block = _waiting_to_block;
@@ -391,12 +396,12 @@
wait_blocked_event.commit();
}
} // EventSafepointWaitBlocked
#ifdef ASSERT
- for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) {
- // make sure all the threads were visited
+ // Make sure all the threads were visited.
+ for (JavaThreadIteratorWithHandle jtiwh; JavaThread *cur = jtiwh.next(); ) {
assert(cur->was_visited_for_critical_count(), "missed a thread");
}
#endif // ASSERT
// Update the count of active JNI critical regions
@@ -450,15 +455,17 @@
if (PrintSafepointStatistics) {
end_statistics(os::javaTimeNanos());
}
+ {
+ JavaThreadIteratorWithHandle jtiwh;
#ifdef ASSERT
// A pending_exception cannot be installed during a safepoint. The threads
// may install an async exception after they come back from a safepoint into
// pending_exception after they unblock. But that should happen later.
- for (JavaThread *cur = Threads::first(); cur; cur = cur->next()) {
+ for (; JavaThread *cur = jtiwh.next(); ) {
assert (!(cur->has_pending_exception() &&
cur->safepoint_state()->is_at_poll_safepoint()),
"safepoint installed a pending exception");
}
#endif // ASSERT
@@ -481,11 +488,12 @@
assert(_state == _synchronized, "must be synchronized before ending safepoint synchronization");
if (SafepointMechanism::uses_thread_local_poll()) {
_state = _not_synchronized;
OrderAccess::storestore(); // global state -> local state
- for (JavaThread *current = Threads::first(); current; current = current->next()) {
+ jtiwh.rewind();
+ for (; JavaThread *current = jtiwh.next(); ) {
ThreadSafepointState* cur_state = current->safepoint_state();
cur_state->restart(); // TSS _running
SafepointMechanism::disarm_local_poll(current); // release store, local state -> polling page
}
log_debug(safepoint)("Leaving safepoint region");
@@ -496,11 +504,12 @@
OrderAccess::fence();
log_debug(safepoint)("Leaving safepoint region");
// Start suspended threads
- for (JavaThread *current = Threads::first(); current; current = current->next()) {
+ jtiwh.rewind();
+ for (; JavaThread *current = jtiwh.next(); ) {
// A problem occurring on Solaris is when attempting to restart threads
// the first #cpus - 1 go well, but then the VMThread is preempted when we get
// to the next one (since it has been running the longest). We then have
// to wait for a cpu to become available before we can continue restarting
// threads.
@@ -520,15 +529,16 @@
}
}
RuntimeService::record_safepoint_end();
- // Release threads lock, so threads can be created/destroyed again. It will also starts all threads
- // blocked in signal_thread_blocked
+ // Release threads lock, so threads can be created/destroyed again.
+ // It will also release all threads blocked in signal_thread_blocked.
Threads_lock->unlock();
-
}
+ } // ThreadsListHandle destroyed here.
+
Universe::heap()->safepoint_synchronize_end();
// record this time so VMThread can keep track how much time has elapsed
// since last safepoint.
_end_of_last_safepoint = os::javaTimeMillis();
@@ -913,12 +923,11 @@
}
tty->print_cr("# SafepointSynchronize::begin: Threads which did not reach the safepoint:");
ThreadSafepointState *cur_state;
ResourceMark rm;
- for (JavaThread *cur_thread = Threads::first(); cur_thread;
- cur_thread = cur_thread->next()) {
+ for (JavaThreadIteratorWithHandle jtiwh; JavaThread *cur_thread = jtiwh.next(); ) {
cur_state = cur_thread->safepoint_state();
if (cur_thread->thread_state() != _thread_blocked &&
((reason == _spinning_timeout && cur_state->is_running()) ||
(reason == _blocking_timeout && !cur_state->has_called_back()))) {
@@ -1425,11 +1434,11 @@
tty->print_cr("not synchronized");
} else if (_state == _synchronizing || _state == _synchronized) {
tty->print_cr("State: %s", (_state == _synchronizing) ? "synchronizing" :
"synchronized");
- for (JavaThread *cur = Threads::first(); cur; cur = cur->next()) {
+ for (JavaThreadIteratorWithHandle jtiwh; JavaThread *cur = jtiwh.next(); ) {
cur->safepoint_state()->print();
}
}
}
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