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src/hotspot/share/runtime/threadSMR.cpp
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rev 48227 : 8193135: get rid of redundant _smr_ prefix/infix in ThreadSMRSupport stuff
Reviewed-by:
rev 48228 : 8193135 - with code moves
@@ -29,135 +29,135 @@
#include "runtime/threadSMR.inline.hpp"
#include "services/threadService.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/resourceHash.hpp"
-Monitor* ThreadsSMRSupport::_smr_delete_lock =
- new Monitor(Monitor::special, "smr_delete_lock",
+Monitor* ThreadsSMRSupport::_delete_lock =
+ new Monitor(Monitor::special, "Thread_SMR_delete_lock",
false /* allow_vm_block */,
Monitor::_safepoint_check_never);
// The '_cnt', '_max' and '_times" fields are enabled via
// -XX:+EnableThreadSMRStatistics:
-// # of parallel threads in _smr_delete_lock->wait().
+// # of parallel threads in _delete_lock->wait().
// Impl note: Hard to imagine > 64K waiting threads so this could be 16-bit,
// but there is no nice 16-bit _FORMAT support.
-uint ThreadsSMRSupport::_smr_delete_lock_wait_cnt = 0;
+uint ThreadsSMRSupport::_delete_lock_wait_cnt = 0;
-// Max # of parallel threads in _smr_delete_lock->wait().
-// Impl note: See _smr_delete_lock_wait_cnt note.
-uint ThreadsSMRSupport::_smr_delete_lock_wait_max = 0;
-
-// Flag to indicate when an _smr_delete_lock->notify() is needed.
-// Impl note: See _smr_delete_lock_wait_cnt note.
-volatile uint ThreadsSMRSupport::_smr_delete_notify = 0;
+// Max # of parallel threads in _delete_lock->wait().
+// Impl note: See _delete_lock_wait_cnt note.
+uint ThreadsSMRSupport::_delete_lock_wait_max = 0;
+
+// Flag to indicate when an _delete_lock->notify() is needed.
+// Impl note: See _delete_lock_wait_cnt note.
+volatile uint ThreadsSMRSupport::_delete_notify = 0;
// # of threads deleted over VM lifetime.
// Impl note: Atomically incremented over VM lifetime so use unsigned for more
// range. Unsigned 64-bit would be more future proof, but 64-bit atomic inc
// isn't available everywhere (or is it?).
-volatile uint ThreadsSMRSupport::_smr_deleted_thread_cnt = 0;
+volatile uint ThreadsSMRSupport::_deleted_thread_cnt = 0;
// Max time in millis to delete a thread.
// Impl note: 16-bit might be too small on an overloaded machine. Use
// unsigned since this is a time value. Set via Atomic::cmpxchg() in a
// loop for correctness.
-volatile uint ThreadsSMRSupport::_smr_deleted_thread_time_max = 0;
+volatile uint ThreadsSMRSupport::_deleted_thread_time_max = 0;
// Cumulative time in millis to delete threads.
// Impl note: Atomically added to over VM lifetime so use unsigned for more
// range. Unsigned 64-bit would be more future proof, but 64-bit atomic inc
// isn't available everywhere (or is it?).
-volatile uint ThreadsSMRSupport::_smr_deleted_thread_times = 0;
+volatile uint ThreadsSMRSupport::_deleted_thread_times = 0;
-ThreadsList* volatile ThreadsSMRSupport::_smr_java_thread_list = new ThreadsList(0);
+ThreadsList* volatile ThreadsSMRSupport::_java_thread_list = new ThreadsList(0);
// # of ThreadsLists allocated over VM lifetime.
// Impl note: We allocate a new ThreadsList for every thread create and
// every thread delete so we need a bigger type than the
-// _smr_deleted_thread_cnt field.
-uint64_t ThreadsSMRSupport::_smr_java_thread_list_alloc_cnt = 1;
+// _deleted_thread_cnt field.
+uint64_t ThreadsSMRSupport::_java_thread_list_alloc_cnt = 1;
// # of ThreadsLists freed over VM lifetime.
-// Impl note: See _smr_java_thread_list_alloc_cnt note.
-uint64_t ThreadsSMRSupport::_smr_java_thread_list_free_cnt = 0;
+// Impl note: See _java_thread_list_alloc_cnt note.
+uint64_t ThreadsSMRSupport::_java_thread_list_free_cnt = 0;
// Max size ThreadsList allocated.
// Impl note: Max # of threads alive at one time should fit in unsigned 32-bit.
-uint ThreadsSMRSupport::_smr_java_thread_list_max = 0;
+uint ThreadsSMRSupport::_java_thread_list_max = 0;
// Max # of nested ThreadsLists for a thread.
// Impl note: Hard to imagine > 64K nested ThreadsLists so this could be
// 16-bit, but there is no nice 16-bit _FORMAT support.
-uint ThreadsSMRSupport::_smr_nested_thread_list_max = 0;
+uint ThreadsSMRSupport::_nested_thread_list_max = 0;
// # of ThreadsListHandles deleted over VM lifetime.
// Impl note: Atomically incremented over VM lifetime so use unsigned for
// more range. There will be fewer ThreadsListHandles than threads so
// unsigned 32-bit should be fine.
-volatile uint ThreadsSMRSupport::_smr_tlh_cnt = 0;
+volatile uint ThreadsSMRSupport::_tlh_cnt = 0;
// Max time in millis to delete a ThreadsListHandle.
// Impl note: 16-bit might be too small on an overloaded machine. Use
// unsigned since this is a time value. Set via Atomic::cmpxchg() in a
// loop for correctness.
-volatile uint ThreadsSMRSupport::_smr_tlh_time_max = 0;
+volatile uint ThreadsSMRSupport::_tlh_time_max = 0;
// Cumulative time in millis to delete ThreadsListHandles.
// Impl note: Atomically added to over VM lifetime so use unsigned for more
// range. Unsigned 64-bit would be more future proof, but 64-bit atomic inc
// isn't available everywhere (or is it?).
-volatile uint ThreadsSMRSupport::_smr_tlh_times = 0;
+volatile uint ThreadsSMRSupport::_tlh_times = 0;
-ThreadsList* ThreadsSMRSupport::_smr_to_delete_list = NULL;
+ThreadsList* ThreadsSMRSupport::_to_delete_list = NULL;
// # of parallel ThreadsLists on the to-delete list.
// Impl note: Hard to imagine > 64K ThreadsLists needing to be deleted so
// this could be 16-bit, but there is no nice 16-bit _FORMAT support.
-uint ThreadsSMRSupport::_smr_to_delete_list_cnt = 0;
+uint ThreadsSMRSupport::_to_delete_list_cnt = 0;
// Max # of parallel ThreadsLists on the to-delete list.
-// Impl note: See _smr_to_delete_list_cnt note.
-uint ThreadsSMRSupport::_smr_to_delete_list_max = 0;
+// Impl note: See _to_delete_list_cnt note.
+uint ThreadsSMRSupport::_to_delete_list_max = 0;
// 'inline' functions first so the definitions are before first use:
-inline void ThreadsSMRSupport::add_smr_deleted_thread_times(uint add_value) {
- Atomic::add(add_value, &_smr_deleted_thread_times);
+inline void ThreadsSMRSupport::add_deleted_thread_times(uint add_value) {
+ Atomic::add(add_value, &_deleted_thread_times);
}
-inline void ThreadsSMRSupport::inc_smr_deleted_thread_cnt() {
- Atomic::inc(&_smr_deleted_thread_cnt);
+inline void ThreadsSMRSupport::inc_deleted_thread_cnt() {
+ Atomic::inc(&_deleted_thread_cnt);
}
-inline void ThreadsSMRSupport::inc_smr_java_thread_list_alloc_cnt() {
- _smr_java_thread_list_alloc_cnt++;
+inline void ThreadsSMRSupport::inc_java_thread_list_alloc_cnt() {
+ _java_thread_list_alloc_cnt++;
}
-inline void ThreadsSMRSupport::update_smr_deleted_thread_time_max(uint new_value) {
+inline void ThreadsSMRSupport::update_deleted_thread_time_max(uint new_value) {
while (true) {
- uint cur_value = _smr_deleted_thread_time_max;
+ uint cur_value = _deleted_thread_time_max;
if (new_value <= cur_value) {
// No need to update max value so we're done.
break;
}
- if (Atomic::cmpxchg(new_value, &_smr_deleted_thread_time_max, cur_value) == cur_value) {
+ if (Atomic::cmpxchg(new_value, &_deleted_thread_time_max, cur_value) == cur_value) {
// Updated max value so we're done. Otherwise try it all again.
break;
}
}
}
-inline void ThreadsSMRSupport::update_smr_java_thread_list_max(uint new_value) {
- if (new_value > _smr_java_thread_list_max) {
- _smr_java_thread_list_max = new_value;
+inline void ThreadsSMRSupport::update_java_thread_list_max(uint new_value) {
+ if (new_value > _java_thread_list_max) {
+ _java_thread_list_max = new_value;
}
}
-inline ThreadsList* ThreadsSMRSupport::xchg_smr_java_thread_list(ThreadsList* new_list) {
- return (ThreadsList*)Atomic::xchg(new_list, &_smr_java_thread_list);
+inline ThreadsList* ThreadsSMRSupport::xchg_java_thread_list(ThreadsList* new_list) {
+ return (ThreadsList*)Atomic::xchg(new_list, &_java_thread_list);
}
// Hash table of pointers found by a scan. Used for collecting hazard
// pointers (ThreadsList references). Also used for collecting JavaThreads
@@ -266,11 +266,11 @@
// hazard ptr.
if (thread->cmpxchg_threads_hazard_ptr(NULL, current_list) == current_list) return;
}
// The current JavaThread has a hazard ptr (ThreadsList reference)
- // which might be _smr_java_thread_list or it might be an older
+ // which might be _java_thread_list or it might be an older
// ThreadsList that has been removed but not freed. In either case,
// the hazard ptr is protecting all the JavaThreads on that
// ThreadsList.
AddThreadHazardPointerThreadClosure add_cl(_table);
current_list->threads_do(&add_cl);
@@ -345,11 +345,11 @@
}
// If the hazard ptr is unverified, then ignore it.
if (Thread::is_hazard_ptr_tagged(current_list)) return;
// The current JavaThread has a hazard ptr (ThreadsList reference)
- // which might be _smr_java_thread_list or it might be an older
+ // which might be _java_thread_list or it might be an older
// ThreadsList that has been removed but not freed. In either case,
// the hazard ptr is protecting all the JavaThreads on that
// ThreadsList, but we only care about matching a specific JavaThread.
JavaThreadIterator jti(current_list);
for (JavaThread *p = jti.first(); p != NULL; p = jti.next()) {
@@ -474,11 +474,11 @@
ThreadsListHandle::~ThreadsListHandle() {
ThreadsSMRSupport::release_stable_list(_self);
if (EnableThreadSMRStatistics) {
_timer.stop();
uint millis = (uint)_timer.milliseconds();
- ThreadsSMRSupport::update_smr_tlh_stats(millis);
+ ThreadsSMRSupport::update_tlh_stats(millis);
}
}
// Convert an internal thread reference to a JavaThread found on the
// associated ThreadsList. This ThreadsListHandle "protects" the
@@ -572,29 +572,29 @@
"cannot have a nested hazard ptr with a NULL regular hazard ptr");
ThreadsList* threads;
// Stable recording of a hazard ptr for SMR. This code does not use
- // locks so its use of the _smr_java_thread_list & _threads_hazard_ptr
+ // locks so its use of the _java_thread_list & _threads_hazard_ptr
// fields is racy relative to code that uses those fields with locks.
// OrderAccess and Atomic functions are used to deal with those races.
//
while (true) {
- threads = get_smr_java_thread_list();
+ threads = get_java_thread_list();
// Publish a tagged hazard ptr to denote that the hazard ptr is not
// yet verified as being stable. Due to the fence after the hazard
// ptr write, it will be sequentially consistent w.r.t. the
// sequentially consistent writes of the ThreadsList, even on
// non-multiple copy atomic machines where stores can be observed
// in different order from different observer threads.
ThreadsList* unverified_threads = Thread::tag_hazard_ptr(threads);
self->set_threads_hazard_ptr(unverified_threads);
- // If _smr_java_thread_list has changed, we have lost a race with
+ // If _java_thread_list has changed, we have lost a race with
// Threads::add() or Threads::remove() and have to try again.
- if (get_smr_java_thread_list() != threads) {
+ if (get_java_thread_list() != threads) {
continue;
}
// We try to remove the tag which will verify the hazard ptr as
// being stable. This exchange can race with a scanning thread
@@ -632,58 +632,134 @@
NestedThreadsList* node;
{
// Only grab the Threads_lock if we don't already own it.
MutexLockerEx ml(Threads_lock->owned_by_self() ? NULL : Threads_lock);
- node = new NestedThreadsList(get_smr_java_thread_list());
+ node = new NestedThreadsList(get_java_thread_list());
// We insert at the front of the list to match up with the delete
// in release_stable_list().
node->set_next(self->get_nested_threads_hazard_ptr());
self->set_nested_threads_hazard_ptr(node);
if (EnableThreadSMRStatistics) {
self->inc_nested_threads_hazard_ptr_cnt();
- if (self->nested_threads_hazard_ptr_cnt() > _smr_nested_thread_list_max) {
- _smr_nested_thread_list_max = self->nested_threads_hazard_ptr_cnt();
+ if (self->nested_threads_hazard_ptr_cnt() > _nested_thread_list_max) {
+ _nested_thread_list_max = self->nested_threads_hazard_ptr_cnt();
}
}
}
log_debug(thread, smr)("tid=" UINTX_FORMAT ": ThreadsSMRSupport::acquire_stable_list: add NestedThreadsList node containing ThreadsList=" INTPTR_FORMAT, os::current_thread_id(), p2i(node->t_list()));
return node->t_list();
}
void ThreadsSMRSupport::add_thread(JavaThread *thread){
- ThreadsList *new_list = ThreadsList::add_thread(ThreadsSMRSupport::get_smr_java_thread_list(), thread);
+ ThreadsList *new_list = ThreadsList::add_thread(ThreadsSMRSupport::get_java_thread_list(), thread);
if (EnableThreadSMRStatistics) {
- ThreadsSMRSupport::inc_smr_java_thread_list_alloc_cnt();
- ThreadsSMRSupport::update_smr_java_thread_list_max(new_list->length());
+ ThreadsSMRSupport::inc_java_thread_list_alloc_cnt();
+ ThreadsSMRSupport::update_java_thread_list_max(new_list->length());
}
- // Initial _smr_java_thread_list will not generate a "Threads::add" mesg.
+ // Initial _java_thread_list will not generate a "Threads::add" mesg.
log_debug(thread, smr)("tid=" UINTX_FORMAT ": Threads::add: new ThreadsList=" INTPTR_FORMAT, os::current_thread_id(), p2i(new_list));
- ThreadsList *old_list = ThreadsSMRSupport::xchg_smr_java_thread_list(new_list);
- ThreadsSMRSupport::smr_free_list(old_list);
+ ThreadsList *old_list = ThreadsSMRSupport::xchg_java_thread_list(new_list);
+ ThreadsSMRSupport::free_list(old_list);
}
-// set_smr_delete_notify() and clear_smr_delete_notify() are called
-// under the protection of the smr_delete_lock, but we also use an
+// set_delete_notify() and clear_delete_notify() are called
+// under the protection of the delete_lock, but we also use an
// Atomic operation to ensure the memory update is seen earlier than
-// when the smr_delete_lock is dropped.
+// when the delete_lock is dropped.
//
-void ThreadsSMRSupport::clear_smr_delete_notify() {
- Atomic::dec(&_smr_delete_notify);
+void ThreadsSMRSupport::clear_delete_notify() {
+ Atomic::dec(&_delete_notify);
+}
+
+bool ThreadsSMRSupport::delete_notify() {
+ // Use load_acquire() in order to see any updates to _delete_notify
+ // earlier than when delete_lock is grabbed.
+ return (OrderAccess::load_acquire(&_delete_notify) != 0);
+}
+
+// Safely free a ThreadsList after a Threads::add() or Threads::remove().
+// The specified ThreadsList may not get deleted during this call if it
+// is still in-use (referenced by a hazard ptr). Other ThreadsLists
+// in the chain may get deleted by this call if they are no longer in-use.
+void ThreadsSMRSupport::free_list(ThreadsList* threads) {
+ assert_locked_or_safepoint(Threads_lock);
+
+ threads->set_next_list(_to_delete_list);
+ _to_delete_list = threads;
+ if (EnableThreadSMRStatistics) {
+ _to_delete_list_cnt++;
+ if (_to_delete_list_cnt > _to_delete_list_max) {
+ _to_delete_list_max = _to_delete_list_cnt;
+ }
+ }
+
+ // Hash table size should be first power of two higher than twice the length of the ThreadsList
+ int hash_table_size = MIN2((int)get_java_thread_list()->length(), 32) << 1;
+ hash_table_size--;
+ hash_table_size |= hash_table_size >> 1;
+ hash_table_size |= hash_table_size >> 2;
+ hash_table_size |= hash_table_size >> 4;
+ hash_table_size |= hash_table_size >> 8;
+ hash_table_size |= hash_table_size >> 16;
+ hash_table_size++;
+
+ // Gather a hash table of the current hazard ptrs:
+ ThreadScanHashtable *scan_table = new ThreadScanHashtable(hash_table_size);
+ ScanHazardPtrGatherThreadsListClosure scan_cl(scan_table);
+ Threads::threads_do(&scan_cl);
+
+ // Walk through the linked list of pending freeable ThreadsLists
+ // and free the ones that are not referenced from hazard ptrs.
+ ThreadsList* current = _to_delete_list;
+ ThreadsList* prev = NULL;
+ ThreadsList* next = NULL;
+ bool threads_is_freed = false;
+ while (current != NULL) {
+ next = current->next_list();
+ if (!scan_table->has_entry((void*)current)) {
+ // This ThreadsList is not referenced by a hazard ptr.
+ if (prev != NULL) {
+ prev->set_next_list(next);
+ }
+ if (_to_delete_list == current) {
+ _to_delete_list = next;
+ }
+
+ log_debug(thread, smr)("tid=" UINTX_FORMAT ": ThreadsSMRSupport::free_list: threads=" INTPTR_FORMAT " is freed.", os::current_thread_id(), p2i(current));
+ if (current == threads) threads_is_freed = true;
+ delete current;
+ if (EnableThreadSMRStatistics) {
+ _java_thread_list_free_cnt++;
+ _to_delete_list_cnt--;
+ }
+ } else {
+ prev = current;
+ }
+ current = next;
+ }
+
+ if (!threads_is_freed) {
+ // Only report "is not freed" on the original call to
+ // free_list() for this ThreadsList.
+ log_debug(thread, smr)("tid=" UINTX_FORMAT ": ThreadsSMRSupport::free_list: threads=" INTPTR_FORMAT " is not freed.", os::current_thread_id(), p2i(threads));
+ }
+
+ delete scan_table;
}
// Return true if the specified JavaThread is protected by a hazard
// pointer (ThreadsList reference). Otherwise, returns false.
//
bool ThreadsSMRSupport::is_a_protected_JavaThread(JavaThread *thread) {
assert_locked_or_safepoint(Threads_lock);
// Hash table size should be first power of two higher than twice
// the length of the Threads list.
- int hash_table_size = MIN2((int)get_smr_java_thread_list()->length(), 32) << 1;
+ int hash_table_size = MIN2((int)get_java_thread_list()->length(), 32) << 1;
hash_table_size--;
hash_table_size |= hash_table_size >> 1;
hash_table_size |= hash_table_size >> 2;
hash_table_size |= hash_table_size >> 4;
hash_table_size |= hash_table_size >> 8;
@@ -734,14 +810,14 @@
// After releasing the hazard ptr, other threads may go ahead and
// free up some memory temporarily used by a ThreadsList snapshot.
self->set_threads_hazard_ptr(NULL);
// We use double-check locking to reduce traffic on the system
- // wide smr_delete_lock.
- if (ThreadsSMRSupport::smr_delete_notify()) {
+ // wide Thread-SMR delete_lock.
+ if (ThreadsSMRSupport::delete_notify()) {
// An exiting thread might be waiting in smr_delete(); we need to
- // check with smr_delete_lock to be sure.
+ // check with delete_lock to be sure.
release_stable_list_wake_up((char *) "regular hazard ptr");
}
}
// Release a nested stable ThreadsList; this is rare so it uses
@@ -770,59 +846,59 @@
self->dec_nested_threads_hazard_ptr_cnt();
}
}
// An exiting thread might be waiting in smr_delete(); we need to
- // check with smr_delete_lock to be sure.
+ // check with delete_lock to be sure.
release_stable_list_wake_up((char *) "nested hazard ptr");
log_debug(thread, smr)("tid=" UINTX_FORMAT ": ThreadsSMRSupport::release_stable_list: delete NestedThreadsList node containing ThreadsList=" INTPTR_FORMAT, os::current_thread_id(), p2i(node->t_list()));
delete node;
}
// Wake up portion of the release stable ThreadsList protocol;
-// uses the smr_delete_lock().
+// uses the delete_lock().
//
void ThreadsSMRSupport::release_stable_list_wake_up(char *log_str) {
assert(log_str != NULL, "sanity check");
- // Note: smr_delete_lock is held in smr_delete() for the entire
+ // Note: delete_lock is held in smr_delete() for the entire
// hazard ptr search so that we do not lose this notify() if
// the exiting thread has to wait. That code path also holds
- // Threads_lock (which was grabbed before smr_delete_lock) so that
+ // Threads_lock (which was grabbed before delete_lock) so that
// threads_do() can be called. This means the system can't start a
// safepoint which means this thread can't take too long to get to
- // a safepoint because of being blocked on smr_delete_lock.
+ // a safepoint because of being blocked on delete_lock.
//
- MonitorLockerEx ml(ThreadsSMRSupport::smr_delete_lock(), Monitor::_no_safepoint_check_flag);
- if (ThreadsSMRSupport::smr_delete_notify()) {
+ MonitorLockerEx ml(ThreadsSMRSupport::delete_lock(), Monitor::_no_safepoint_check_flag);
+ if (ThreadsSMRSupport::delete_notify()) {
// Notify any exiting JavaThreads that are waiting in smr_delete()
// that we've released a ThreadsList.
ml.notify_all();
log_debug(thread, smr)("tid=" UINTX_FORMAT ": ThreadsSMRSupport::release_stable_list notified %s", os::current_thread_id(), log_str);
}
}
void ThreadsSMRSupport::remove_thread(JavaThread *thread) {
- ThreadsList *new_list = ThreadsList::remove_thread(ThreadsSMRSupport::get_smr_java_thread_list(), thread);
+ ThreadsList *new_list = ThreadsList::remove_thread(ThreadsSMRSupport::get_java_thread_list(), thread);
if (EnableThreadSMRStatistics) {
- ThreadsSMRSupport::inc_smr_java_thread_list_alloc_cnt();
+ ThreadsSMRSupport::inc_java_thread_list_alloc_cnt();
// This list is smaller so no need to check for a "longest" update.
}
- // Final _smr_java_thread_list will not generate a "Threads::remove" mesg.
+ // Final _java_thread_list will not generate a "Threads::remove" mesg.
log_debug(thread, smr)("tid=" UINTX_FORMAT ": Threads::remove: new ThreadsList=" INTPTR_FORMAT, os::current_thread_id(), p2i(new_list));
- ThreadsList *old_list = ThreadsSMRSupport::xchg_smr_java_thread_list(new_list);
- ThreadsSMRSupport::smr_free_list(old_list);
+ ThreadsList *old_list = ThreadsSMRSupport::xchg_java_thread_list(new_list);
+ ThreadsSMRSupport::free_list(old_list);
}
-// See note for clear_smr_delete_notify().
+// See note for clear_delete_notify().
//
-void ThreadsSMRSupport::set_smr_delete_notify() {
- Atomic::inc(&_smr_delete_notify);
+void ThreadsSMRSupport::set_delete_notify() {
+ Atomic::inc(&_delete_notify);
}
// Safely delete a JavaThread when it is no longer in use by a
// ThreadsListHandle.
//
@@ -840,20 +916,20 @@
// No safepoint check because this JavaThread is not on the
// Threads list.
MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
// Cannot use a MonitorLockerEx helper here because we have
// to drop the Threads_lock first if we wait.
- ThreadsSMRSupport::smr_delete_lock()->lock_without_safepoint_check();
- // Set the smr_delete_notify flag after we grab smr_delete_lock
+ ThreadsSMRSupport::delete_lock()->lock_without_safepoint_check();
+ // Set the delete_notify flag after we grab delete_lock
// and before we scan hazard ptrs because we're doing
// double-check locking in release_stable_list().
- ThreadsSMRSupport::set_smr_delete_notify();
+ ThreadsSMRSupport::set_delete_notify();
if (!is_a_protected_JavaThread(thread)) {
// This is the common case.
- ThreadsSMRSupport::clear_smr_delete_notify();
- ThreadsSMRSupport::smr_delete_lock()->unlock();
+ ThreadsSMRSupport::clear_delete_notify();
+ ThreadsSMRSupport::delete_lock()->unlock();
break;
}
if (!has_logged_once) {
has_logged_once = true;
log_debug(thread, smr)("tid=" UINTX_FORMAT ": ThreadsSMRSupport::smr_delete: thread=" INTPTR_FORMAT " is not deleted.", os::current_thread_id(), p2i(thread));
@@ -863,26 +939,26 @@
}
}
} // We have to drop the Threads_lock to wait or delete the thread
if (EnableThreadSMRStatistics) {
- _smr_delete_lock_wait_cnt++;
- if (_smr_delete_lock_wait_cnt > _smr_delete_lock_wait_max) {
- _smr_delete_lock_wait_max = _smr_delete_lock_wait_cnt;
+ _delete_lock_wait_cnt++;
+ if (_delete_lock_wait_cnt > _delete_lock_wait_max) {
+ _delete_lock_wait_max = _delete_lock_wait_cnt;
}
}
// Wait for a release_stable_list() call before we check again. No
// safepoint check, no timeout, and not as suspend equivalent flag
// because this JavaThread is not on the Threads list.
- ThreadsSMRSupport::smr_delete_lock()->wait(Mutex::_no_safepoint_check_flag, 0,
+ ThreadsSMRSupport::delete_lock()->wait(Mutex::_no_safepoint_check_flag, 0,
!Mutex::_as_suspend_equivalent_flag);
if (EnableThreadSMRStatistics) {
- _smr_delete_lock_wait_cnt--;
+ _delete_lock_wait_cnt--;
}
- ThreadsSMRSupport::clear_smr_delete_notify();
- ThreadsSMRSupport::smr_delete_lock()->unlock();
+ ThreadsSMRSupport::clear_delete_notify();
+ ThreadsSMRSupport::delete_lock()->unlock();
// Retry the whole scenario.
}
if (ThreadLocalHandshakes) {
// The thread is about to be deleted so cancel any handshake.
@@ -891,170 +967,93 @@
delete thread;
if (EnableThreadSMRStatistics) {
timer.stop();
uint millis = (uint)timer.milliseconds();
- ThreadsSMRSupport::inc_smr_deleted_thread_cnt();
- ThreadsSMRSupport::add_smr_deleted_thread_times(millis);
- ThreadsSMRSupport::update_smr_deleted_thread_time_max(millis);
+ ThreadsSMRSupport::inc_deleted_thread_cnt();
+ ThreadsSMRSupport::add_deleted_thread_times(millis);
+ ThreadsSMRSupport::update_deleted_thread_time_max(millis);
}
log_debug(thread, smr)("tid=" UINTX_FORMAT ": ThreadsSMRSupport::smr_delete: thread=" INTPTR_FORMAT " is deleted.", os::current_thread_id(), p2i(thread));
}
-bool ThreadsSMRSupport::smr_delete_notify() {
- // Use load_acquire() in order to see any updates to _smr_delete_notify
- // earlier than when smr_delete_lock is grabbed.
- return (OrderAccess::load_acquire(&_smr_delete_notify) != 0);
-}
-
-// Safely free a ThreadsList after a Threads::add() or Threads::remove().
-// The specified ThreadsList may not get deleted during this call if it
-// is still in-use (referenced by a hazard ptr). Other ThreadsLists
-// in the chain may get deleted by this call if they are no longer in-use.
-void ThreadsSMRSupport::smr_free_list(ThreadsList* threads) {
- assert_locked_or_safepoint(Threads_lock);
-
- threads->set_next_list(_smr_to_delete_list);
- _smr_to_delete_list = threads;
- if (EnableThreadSMRStatistics) {
- _smr_to_delete_list_cnt++;
- if (_smr_to_delete_list_cnt > _smr_to_delete_list_max) {
- _smr_to_delete_list_max = _smr_to_delete_list_cnt;
- }
- }
-
- // Hash table size should be first power of two higher than twice the length of the ThreadsList
- int hash_table_size = MIN2((int)get_smr_java_thread_list()->length(), 32) << 1;
- hash_table_size--;
- hash_table_size |= hash_table_size >> 1;
- hash_table_size |= hash_table_size >> 2;
- hash_table_size |= hash_table_size >> 4;
- hash_table_size |= hash_table_size >> 8;
- hash_table_size |= hash_table_size >> 16;
- hash_table_size++;
-
- // Gather a hash table of the current hazard ptrs:
- ThreadScanHashtable *scan_table = new ThreadScanHashtable(hash_table_size);
- ScanHazardPtrGatherThreadsListClosure scan_cl(scan_table);
- Threads::threads_do(&scan_cl);
-
- // Walk through the linked list of pending freeable ThreadsLists
- // and free the ones that are not referenced from hazard ptrs.
- ThreadsList* current = _smr_to_delete_list;
- ThreadsList* prev = NULL;
- ThreadsList* next = NULL;
- bool threads_is_freed = false;
- while (current != NULL) {
- next = current->next_list();
- if (!scan_table->has_entry((void*)current)) {
- // This ThreadsList is not referenced by a hazard ptr.
- if (prev != NULL) {
- prev->set_next_list(next);
- }
- if (_smr_to_delete_list == current) {
- _smr_to_delete_list = next;
- }
-
- log_debug(thread, smr)("tid=" UINTX_FORMAT ": ThreadsSMRSupport::smr_free_list: threads=" INTPTR_FORMAT " is freed.", os::current_thread_id(), p2i(current));
- if (current == threads) threads_is_freed = true;
- delete current;
- if (EnableThreadSMRStatistics) {
- _smr_java_thread_list_free_cnt++;
- _smr_to_delete_list_cnt--;
- }
- } else {
- prev = current;
- }
- current = next;
- }
-
- if (!threads_is_freed) {
- // Only report "is not freed" on the original call to
- // smr_free_list() for this ThreadsList.
- log_debug(thread, smr)("tid=" UINTX_FORMAT ": ThreadsSMRSupport::smr_free_list: threads=" INTPTR_FORMAT " is not freed.", os::current_thread_id(), p2i(threads));
- }
-
- delete scan_table;
-}
-
// Debug, logging, and printing stuff at the end:
// Log Threads class SMR info.
-void ThreadsSMRSupport::log_smr_statistics() {
+void ThreadsSMRSupport::log_statistics() {
LogTarget(Info, thread, smr) log;
if (log.is_enabled()) {
LogStream out(log);
- print_smr_info_on(&out);
+ print_info_on(&out);
}
}
// Print Threads class SMR info.
-void ThreadsSMRSupport::print_smr_info_on(outputStream* st) {
+void ThreadsSMRSupport::print_info_on(outputStream* st) {
// Only grab the Threads_lock if we don't already own it
// and if we are not reporting an error.
MutexLockerEx ml((Threads_lock->owned_by_self() || VMError::is_error_reported()) ? NULL : Threads_lock);
st->print_cr("Threads class SMR info:");
- st->print_cr("_smr_java_thread_list=" INTPTR_FORMAT ", length=%u, "
- "elements={", p2i(_smr_java_thread_list),
- _smr_java_thread_list->length());
- print_smr_info_elements_on(st, _smr_java_thread_list);
+ st->print_cr("_java_thread_list=" INTPTR_FORMAT ", length=%u, "
+ "elements={", p2i(_java_thread_list),
+ _java_thread_list->length());
+ print_info_elements_on(st, _java_thread_list);
st->print_cr("}");
- if (_smr_to_delete_list != NULL) {
- st->print_cr("_smr_to_delete_list=" INTPTR_FORMAT ", length=%u, "
- "elements={", p2i(_smr_to_delete_list),
- _smr_to_delete_list->length());
- print_smr_info_elements_on(st, _smr_to_delete_list);
+ if (_to_delete_list != NULL) {
+ st->print_cr("_to_delete_list=" INTPTR_FORMAT ", length=%u, "
+ "elements={", p2i(_to_delete_list),
+ _to_delete_list->length());
+ print_info_elements_on(st, _to_delete_list);
st->print_cr("}");
- for (ThreadsList *t_list = _smr_to_delete_list->next_list();
+ for (ThreadsList *t_list = _to_delete_list->next_list();
t_list != NULL; t_list = t_list->next_list()) {
st->print("next-> " INTPTR_FORMAT ", length=%u, "
"elements={", p2i(t_list), t_list->length());
- print_smr_info_elements_on(st, t_list);
+ print_info_elements_on(st, t_list);
st->print_cr("}");
}
}
if (!EnableThreadSMRStatistics) {
return;
}
- st->print_cr("_smr_java_thread_list_alloc_cnt=" UINT64_FORMAT ","
- "_smr_java_thread_list_free_cnt=" UINT64_FORMAT ","
- "_smr_java_thread_list_max=%u, "
- "_smr_nested_thread_list_max=%u",
- _smr_java_thread_list_alloc_cnt,
- _smr_java_thread_list_free_cnt,
- _smr_java_thread_list_max,
- _smr_nested_thread_list_max);
- if (_smr_tlh_cnt > 0) {
- st->print_cr("_smr_tlh_cnt=%u"
- ", _smr_tlh_times=%u"
- ", avg_smr_tlh_time=%0.2f"
- ", _smr_tlh_time_max=%u",
- _smr_tlh_cnt, _smr_tlh_times,
- ((double) _smr_tlh_times / _smr_tlh_cnt),
- _smr_tlh_time_max);
- }
- if (_smr_deleted_thread_cnt > 0) {
- st->print_cr("_smr_deleted_thread_cnt=%u"
- ", _smr_deleted_thread_times=%u"
- ", avg_smr_deleted_thread_time=%0.2f"
- ", _smr_deleted_thread_time_max=%u",
- _smr_deleted_thread_cnt, _smr_deleted_thread_times,
- ((double) _smr_deleted_thread_times / _smr_deleted_thread_cnt),
- _smr_deleted_thread_time_max);
- }
- st->print_cr("_smr_delete_lock_wait_cnt=%u, _smr_delete_lock_wait_max=%u",
- _smr_delete_lock_wait_cnt, _smr_delete_lock_wait_max);
- st->print_cr("_smr_to_delete_list_cnt=%u, _smr_to_delete_list_max=%u",
- _smr_to_delete_list_cnt, _smr_to_delete_list_max);
+ st->print_cr("_java_thread_list_alloc_cnt=" UINT64_FORMAT ","
+ "_java_thread_list_free_cnt=" UINT64_FORMAT ","
+ "_java_thread_list_max=%u, "
+ "_nested_thread_list_max=%u",
+ _java_thread_list_alloc_cnt,
+ _java_thread_list_free_cnt,
+ _java_thread_list_max,
+ _nested_thread_list_max);
+ if (_tlh_cnt > 0) {
+ st->print_cr("_tlh_cnt=%u"
+ ", _tlh_times=%u"
+ ", avg_tlh_time=%0.2f"
+ ", _tlh_time_max=%u",
+ _tlh_cnt, _tlh_times,
+ ((double) _tlh_times / _tlh_cnt),
+ _tlh_time_max);
+ }
+ if (_deleted_thread_cnt > 0) {
+ st->print_cr("_deleted_thread_cnt=%u"
+ ", _deleted_thread_times=%u"
+ ", avg_deleted_thread_time=%0.2f"
+ ", _deleted_thread_time_max=%u",
+ _deleted_thread_cnt, _deleted_thread_times,
+ ((double) _deleted_thread_times / _deleted_thread_cnt),
+ _deleted_thread_time_max);
+ }
+ st->print_cr("_delete_lock_wait_cnt=%u, _delete_lock_wait_max=%u",
+ _delete_lock_wait_cnt, _delete_lock_wait_max);
+ st->print_cr("_to_delete_list_cnt=%u, _to_delete_list_max=%u",
+ _to_delete_list_cnt, _to_delete_list_max);
}
// Print ThreadsList elements (4 per line).
-void ThreadsSMRSupport::print_smr_info_elements_on(outputStream* st,
- ThreadsList* t_list) {
+void ThreadsSMRSupport::print_info_elements_on(outputStream* st, ThreadsList* t_list) {
uint cnt = 0;
JavaThreadIterator jti(t_list);
for (JavaThread *jt = jti.first(); jt != NULL; jt = jti.next()) {
st->print(INTPTR_FORMAT, p2i(jt));
if (cnt < t_list->length() - 1) {
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