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8209850: Allow NamedThreads to use GlobalCounter critical sections

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Add NamedThreads iterator and make GlobalCounter use it.

Reviewed-by: eosterlund, rehn
This commit is contained in:
Kim Barrett 2018-08-23 18:14:53 -04:00
parent 8b138c684a
commit 23f0fb4cde
11 changed files with 458 additions and 69 deletions
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55
src/hotspot/share/runtime/thread.cpp
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@ -114,6 +114,7 @@
#include "utilities/events.hpp"
#include "utilities/macros.hpp"
#include "utilities/preserveException.hpp"
#include "utilities/singleWriterSynchronizer.hpp"
#include "utilities/vmError.hpp"
#if INCLUDE_JVMCI
#include "jvmci/jvmciCompiler.hpp"
@ -1206,15 +1207,61 @@ void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name
THREAD);
}
// List of all NamedThreads and safe iteration over that list.
class NamedThread::List {
public:
NamedThread* volatile _head;
SingleWriterSynchronizer _protect;
List() : _head(NULL), _protect() {}
};
NamedThread::List NamedThread::_the_list;
NamedThread::Iterator::Iterator() :
_protect_enter(_the_list._protect.enter()),
_current(OrderAccess::load_acquire(&_the_list._head))
{}
NamedThread::Iterator::~Iterator() {
_the_list._protect.exit(_protect_enter);
}
void NamedThread::Iterator::step() {
assert(!end(), "precondition");
_current = OrderAccess::load_acquire(&_current->_next_named_thread);
}
// NamedThread -- non-JavaThread subclasses with multiple
// uniquely named instances should derive from this.
NamedThread::NamedThread() : Thread() {
_name = NULL;
_processed_thread = NULL;
_gc_id = GCId::undefined();
NamedThread::NamedThread() :
Thread(),
_name(NULL),
_processed_thread(NULL),
_gc_id(GCId::undefined()),
_next_named_thread(NULL)
{
// Add this thread to _the_list.
MutexLockerEx lock(NamedThreadsList_lock, Mutex::_no_safepoint_check_flag);
_next_named_thread = _the_list._head;
OrderAccess::release_store(&_the_list._head, this);
}
NamedThread::~NamedThread() {
// Remove this thread from _the_list.
{
MutexLockerEx lock(NamedThreadsList_lock, Mutex::_no_safepoint_check_flag);
NamedThread* volatile* p = &_the_list._head;
for (NamedThread* t = *p; t != NULL; p = &t->_next_named_thread, t = *p) {
if (t == this) {
*p = this->_next_named_thread;
// Wait for any in-progress iterators.
_the_list._protect.synchronize();
break;
}
}
}
if (_name != NULL) {
FREE_C_HEAP_ARRAY(char, _name);
_name = NULL;