< prev index next >
src/hotspot/share/gc/shared/oopStorage.cpp
Print this page
rev 50278 : [mq]: fix
@@ -38,10 +38,11 @@
#include "runtime/stubRoutines.hpp"
#include "runtime/thread.hpp"
#include "utilities/align.hpp"
#include "utilities/count_trailing_zeros.hpp"
#include "utilities/debug.hpp"
+#include "utilities/globalCounter.inline.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/macros.hpp"
#include "utilities/ostream.hpp"
#include "utilities/spinYield.hpp"
@@ -499,52 +500,10 @@
replace_active_array(new_array);
relinquish_block_array(old_array);
return true;
}
-OopStorage::ProtectActive::ProtectActive() : _enter(0), _exit() {}
-
-// Begin read-side critical section.
-uint OopStorage::ProtectActive::read_enter() {
- return Atomic::add(2u, &_enter);
-}
-
-// End read-side critical section.
-void OopStorage::ProtectActive::read_exit(uint enter_value) {
- Atomic::add(2u, &_exit[enter_value & 1]);
-}
-
-// Wait until all readers that entered the critical section before
-// synchronization have exited that critical section.
-void OopStorage::ProtectActive::write_synchronize() {
- SpinYield spinner;
- // Determine old and new exit counters, based on bit0 of the
- // on-entry _enter counter.
- uint value = OrderAccess::load_acquire(&_enter);
- volatile uint* new_ptr = &_exit[(value + 1) & 1];
- // Atomically change the in-use exit counter to the new counter, by
- // adding 1 to the _enter counter (flipping bit0 between 0 and 1)
- // and initializing the new exit counter to that enter value. Note:
- // The new exit counter is not being used by read operations until
- // this change succeeds.
- uint old;
- do {
- old = value;
- *new_ptr = ++value;
- value = Atomic::cmpxchg(value, &_enter, old);
- } while (old != value);
- // Readers that entered the critical section before we changed the
- // selected exit counter will use the old exit counter. Readers
- // entering after the change will use the new exit counter. Wait
- // for all the critical sections started before the change to
- // complete, e.g. for the value of old_ptr to catch up with old.
- volatile uint* old_ptr = &_exit[old & 1];
- while (old != OrderAccess::load_acquire(old_ptr)) {
- spinner.wait();
- }
-}
-
// Make new_array the _active_array. Increments new_array's refcount
// to account for the new reference. The assignment is atomic wrto
// obtain_active_array; once this function returns, it is safe for the
// caller to relinquish the old array.
void OopStorage::replace_active_array(ActiveArray* new_array) {
@@ -552,26 +511,25 @@
// Update new_array refcount to account for the new reference.
new_array->increment_refcount();
// Install new_array, ensuring its initialization is complete first.
OrderAccess::release_store(&_active_array, new_array);
// Wait for any readers that could read the old array from _active_array.
- _protect_active.write_synchronize();
- // All obtain critical sections that could see the old array have
- // completed, having incremented the refcount of the old array. The
+ GlobalCounter::write_synchronize();
+ // All obtain_actuve_array critical sections that could see the old array
+ // have completed, having incremented the refcount of the old array. The
// caller can now safely relinquish the old array.
}
// Atomically (wrto replace_active_array) get the active array and
// increment its refcount. This provides safe access to the array,
// even if an allocate operation expands and replaces the value of
// _active_array. The caller must relinquish the array when done
// using it.
OopStorage::ActiveArray* OopStorage::obtain_active_array() const {
- uint enter_value = _protect_active.read_enter();
+ GlobalCounter::CriticalSection cs(Thread::current());
ActiveArray* result = OrderAccess::load_acquire(&_active_array);
result->increment_refcount();
- _protect_active.read_exit(enter_value);
return result;
}
// Decrement refcount of array and destroy if refcount is zero.
void OopStorage::relinquish_block_array(ActiveArray* array) const {
< prev index next >