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8193135: get rid of redundant _smr_ prefix/infix in ThreadSMRSupport stuff

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Reviewed-by: stefank, gtriantafill, coleenp
This commit is contained in:
Daniel D. Daugherty 2017-12-08 15:24:47 -05:00
parent 3f561e29a9
commit b0138d81ad
7 changed files with 281 additions and 281 deletions
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4
src/hotspot/share/runtime/java.cpp
View File

@ -357,7 +357,7 @@ void print_statistics() {
MemTracker::final_report(tty);
}
ThreadsSMRSupport::log_smr_statistics();
ThreadsSMRSupport::log_statistics();
}
#else // PRODUCT MODE STATISTICS
@ -399,7 +399,7 @@ void print_statistics() {
Method::print_touched_methods(tty);
}
ThreadsSMRSupport::log_smr_statistics();
ThreadsSMRSupport::log_statistics();
}
#endif

8
src/hotspot/share/runtime/thread.cpp
View File

@ -3473,7 +3473,7 @@ static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
// All JavaThreads
#define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_smr_java_thread_list(), X)
#define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
// All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
void Threads::threads_do(ThreadClosure* tc) {
@ -4382,7 +4382,7 @@ void Threads::remove(JavaThread* p) {
// that we do not remove thread without safepoint code notice
{ MutexLocker ml(Threads_lock);
assert(ThreadsSMRSupport::get_smr_java_thread_list()->includes(p), "p must be present");
assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
// Maintain fast thread list
ThreadsSMRSupport::remove_thread(p);
@ -4610,7 +4610,7 @@ void Threads::print_on(outputStream* st, bool print_stacks,
}
#endif // INCLUDE_SERVICES
ThreadsSMRSupport::print_smr_info_on(st);
ThreadsSMRSupport::print_info_on(st);
st->cr();
ALL_JAVA_THREADS(p) {
@ -4679,7 +4679,7 @@ class PrintOnErrorClosure : public ThreadClosure {
// memory (even in resource area), it might deadlock the error handler.
void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
int buflen) {
ThreadsSMRSupport::print_smr_info_on(st);
ThreadsSMRSupport::print_info_on(st);
st->cr();
bool found_current = false;

431
src/hotspot/share/runtime/threadSMR.cpp
View File

@ -31,131 +31,131 @@
#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;
// 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 _smr_delete_lock->notify() is needed.
// Impl note: See _smr_delete_lock_wait_cnt note.
volatile uint ThreadsSMRSupport::_smr_delete_notify = 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);
}
@ -268,7 +268,7 @@ class ScanHazardPtrGatherProtectedThreadsClosure : public ThreadClosure {
}
// 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.
@ -347,7 +347,7 @@ class ScanHazardPtrPrintMatchingThreadsClosure : public ThreadClosure {
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.
@ -476,7 +476,7 @@ ThreadsListHandle::~ThreadsListHandle() {
if (EnableThreadSMRStatistics) {
_timer.stop();
uint millis = (uint)_timer.milliseconds();
ThreadsSMRSupport::update_smr_tlh_stats(millis);
ThreadsSMRSupport::update_tlh_stats(millis);
}
}
@ -574,12 +574,12 @@ ThreadsList *ThreadsSMRSupport::acquire_stable_list_fast_path(Thread *self) {
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
@ -590,9 +590,9 @@ ThreadsList *ThreadsSMRSupport::acquire_stable_list_fast_path(Thread *self) {
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;
}
@ -634,15 +634,15 @@ ThreadsList *ThreadsSMRSupport::acquire_stable_list_nested_path(Thread *self) {
{
// 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();
}
}
}
@ -652,25 +652,101 @@ ThreadsList *ThreadsSMRSupport::acquire_stable_list_nested_path(Thread *self) {
}
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
@ -681,7 +757,7 @@ bool ThreadsSMRSupport::is_a_protected_JavaThread(JavaThread *thread) {
// 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;
@ -736,10 +812,10 @@ void ThreadsSMRSupport::release_stable_list_fast_path(Thread *self) {
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");
}
}
@ -772,7 +848,7 @@ void ThreadsSMRSupport::release_stable_list_nested_path(Thread *self) {
}
// 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()));
@ -781,21 +857,21 @@ void ThreadsSMRSupport::release_stable_list_nested_path(Thread *self) {
}
// 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();
@ -804,23 +880,23 @@ void ThreadsSMRSupport::release_stable_list_wake_up(char *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
@ -842,16 +918,16 @@ void ThreadsSMRSupport::smr_delete(JavaThread *thread) {
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) {
@ -865,22 +941,22 @@ void ThreadsSMRSupport::smr_delete(JavaThread *thread) {
} // 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.
}
@ -893,166 +969,89 @@ void ThreadsSMRSupport::smr_delete(JavaThread *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);
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 (_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);
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("_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("_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()) {

81
src/hotspot/share/runtime/threadSMR.hpp
View File

@ -81,67 +81,68 @@
//
class ThreadsSMRSupport : AllStatic {
// The coordination between ThreadsSMRSupport::release_stable_list() and
// ThreadsSMRSupport::smr_delete() uses the smr_delete_lock in order to
// ThreadsSMRSupport::smr_delete() uses the delete_lock in order to
// reduce the traffic on the Threads_lock.
static Monitor* _smr_delete_lock;
static Monitor* _delete_lock;
// The '_cnt', '_max' and '_times" fields are enabled via
// -XX:+EnableThreadSMRStatistics (see thread.cpp for a
// description about each field):
static uint _smr_delete_lock_wait_cnt;
static uint _smr_delete_lock_wait_max;
// The smr_delete_notify flag is used for proper double-check
// locking in order to reduce the traffic on the smr_delete_lock.
static volatile uint _smr_delete_notify;
static volatile uint _smr_deleted_thread_cnt;
static volatile uint _smr_deleted_thread_time_max;
static volatile uint _smr_deleted_thread_times;
static ThreadsList* volatile _smr_java_thread_list;
static uint64_t _smr_java_thread_list_alloc_cnt;
static uint64_t _smr_java_thread_list_free_cnt;
static uint _smr_java_thread_list_max;
static uint _smr_nested_thread_list_max;
static volatile uint _smr_tlh_cnt;
static volatile uint _smr_tlh_time_max;
static volatile uint _smr_tlh_times;
static ThreadsList* _smr_to_delete_list;
static uint _smr_to_delete_list_cnt;
static uint _smr_to_delete_list_max;
static uint _delete_lock_wait_cnt;
static uint _delete_lock_wait_max;
// The delete_notify flag is used for proper double-check
// locking in order to reduce the traffic on the system wide
// Thread-SMR delete_lock.
static volatile uint _delete_notify;
static volatile uint _deleted_thread_cnt;
static volatile uint _deleted_thread_time_max;
static volatile uint _deleted_thread_times;
static ThreadsList* volatile _java_thread_list;
static uint64_t _java_thread_list_alloc_cnt;
static uint64_t _java_thread_list_free_cnt;
static uint _java_thread_list_max;
static uint _nested_thread_list_max;
static volatile uint _tlh_cnt;
static volatile uint _tlh_time_max;
static volatile uint _tlh_times;
static ThreadsList* _to_delete_list;
static uint _to_delete_list_cnt;
static uint _to_delete_list_max;
static ThreadsList *acquire_stable_list_fast_path(Thread *self);
static ThreadsList *acquire_stable_list_nested_path(Thread *self);
static void add_smr_deleted_thread_times(uint add_value);
static void add_smr_tlh_times(uint add_value);
static void clear_smr_delete_notify();
static void inc_smr_deleted_thread_cnt();
static void inc_smr_java_thread_list_alloc_cnt();
static void inc_smr_tlh_cnt();
static void add_deleted_thread_times(uint add_value);
static void add_tlh_times(uint add_value);
static void clear_delete_notify();
static Monitor* delete_lock() { return _delete_lock; }
static bool delete_notify();
static void free_list(ThreadsList* threads);
static void inc_deleted_thread_cnt();
static void inc_java_thread_list_alloc_cnt();
static void inc_tlh_cnt();
static bool is_a_protected_JavaThread(JavaThread *thread);
static void release_stable_list_fast_path(Thread *self);
static void release_stable_list_nested_path(Thread *self);
static void release_stable_list_wake_up(char *log_str);
static void set_smr_delete_notify();
static Monitor* smr_delete_lock() { return _smr_delete_lock; }
static bool smr_delete_notify();
static void smr_free_list(ThreadsList* threads);
static void update_smr_deleted_thread_time_max(uint new_value);
static void update_smr_java_thread_list_max(uint new_value);
static void update_smr_tlh_time_max(uint new_value);
static ThreadsList* xchg_smr_java_thread_list(ThreadsList* new_list);
static void set_delete_notify();
static void update_deleted_thread_time_max(uint new_value);
static void update_java_thread_list_max(uint new_value);
static void update_tlh_time_max(uint new_value);
static ThreadsList* xchg_java_thread_list(ThreadsList* new_list);
public:
static ThreadsList *acquire_stable_list(Thread *self, bool is_ThreadsListSetter);
static void add_thread(JavaThread *thread);
static ThreadsList* get_smr_java_thread_list();
static ThreadsList* get_java_thread_list();
static bool is_a_protected_JavaThread_with_lock(JavaThread *thread);
static void release_stable_list(Thread *self);
static void remove_thread(JavaThread *thread);
static void smr_delete(JavaThread *thread);
static void update_smr_tlh_stats(uint millis);
static void update_tlh_stats(uint millis);
// Logging and printing support:
static void log_smr_statistics();
static void print_smr_info_elements_on(outputStream* st, ThreadsList* t_list);
static void print_smr_info_on(outputStream* st);
static void log_statistics();
static void print_info_elements_on(outputStream* st, ThreadsList* t_list);
static void print_info_on(outputStream* st);
};
// A fast list of JavaThreads.

28
src/hotspot/share/runtime/threadSMR.inline.hpp
View File

@ -53,24 +53,24 @@ inline void ThreadsList::threads_do(T *cl) const {
}
// These three inlines are private to ThreadsSMRSupport, but
// they are called by public inline update_smr_tlh_stats() below:
// they are called by public inline update_tlh_stats() below:
inline void ThreadsSMRSupport::add_smr_tlh_times(uint add_value) {
Atomic::add(add_value, &_smr_tlh_times);
inline void ThreadsSMRSupport::add_tlh_times(uint add_value) {
Atomic::add(add_value, &_tlh_times);
}
inline void ThreadsSMRSupport::inc_smr_tlh_cnt() {
Atomic::inc(&_smr_tlh_cnt);
inline void ThreadsSMRSupport::inc_tlh_cnt() {
Atomic::inc(&_tlh_cnt);
}
inline void ThreadsSMRSupport::update_smr_tlh_time_max(uint new_value) {
inline void ThreadsSMRSupport::update_tlh_time_max(uint new_value) {
while (true) {
uint cur_value = _smr_tlh_time_max;
uint cur_value = _tlh_time_max;
if (new_value <= cur_value) {
// No need to update max value so we're done.
break;
}
if (Atomic::cmpxchg(new_value, &_smr_tlh_time_max, cur_value) == cur_value) {
if (Atomic::cmpxchg(new_value, &_tlh_time_max, cur_value) == cur_value) {
// Updated max value so we're done. Otherwise try it all again.
break;
}
@ -85,8 +85,8 @@ inline ThreadsList* ThreadsListSetter::list() {
return ret;
}
inline ThreadsList* ThreadsSMRSupport::get_smr_java_thread_list() {
return (ThreadsList*)OrderAccess::load_acquire(&_smr_java_thread_list);
inline ThreadsList* ThreadsSMRSupport::get_java_thread_list() {
return (ThreadsList*)OrderAccess::load_acquire(&_java_thread_list);
}
inline bool ThreadsSMRSupport::is_a_protected_JavaThread_with_lock(JavaThread *thread) {
@ -94,10 +94,10 @@ inline bool ThreadsSMRSupport::is_a_protected_JavaThread_with_lock(JavaThread *t
return is_a_protected_JavaThread(thread);
}
inline void ThreadsSMRSupport::update_smr_tlh_stats(uint millis) {
ThreadsSMRSupport::inc_smr_tlh_cnt();
ThreadsSMRSupport::add_smr_tlh_times(millis);
ThreadsSMRSupport::update_smr_tlh_time_max(millis);
inline void ThreadsSMRSupport::update_tlh_stats(uint millis) {
ThreadsSMRSupport::inc_tlh_cnt();
ThreadsSMRSupport::add_tlh_times(millis);
ThreadsSMRSupport::update_tlh_time_max(millis);
}
#endif // SHARE_VM_RUNTIME_THREADSMR_INLINE_HPP

2
test/hotspot/jtreg/runtime/ErrorHandling/NestedThreadsListHandleInErrorHandlingTest.java
View File

@ -89,7 +89,7 @@ public class NestedThreadsListHandleInErrorHandlingTest {
// We should have a section of Threads class SMR info:
Pattern.compile("Threads class SMR info:"),
// We should have one nested ThreadsListHandle:
Pattern.compile(".*, _smr_nested_thread_list_max=1"),
Pattern.compile(".*, _nested_thread_list_max=1"),
// The current thread (marked with '=>') in the threads list
// should show a hazard ptr:
Pattern.compile("=>.* JavaThread \"main\" .*_threads_hazard_ptr=0x[0-9A-Fa-f][0-9A-Fa-f]*, _nested_threads_hazard_ptr_cnt=1, _nested_threads_hazard_ptrs=0x.*"),

8
test/hotspot/jtreg/runtime/Thread/TestThreadDumpSMRInfo.java
View File

@ -45,7 +45,7 @@ public class TestThreadDumpSMRInfo {
// Here's a sample "Threads class SMR info" section:
//
// Threads class SMR info:
// _smr_java_thread_list=0x0000000000ce8da0, length=23, elements={
// _java_thread_list=0x0000000000ce8da0, length=23, elements={
// 0x000000000043a800, 0x0000000000aee800, 0x0000000000b06800, 0x0000000000b26000,
// 0x0000000000b28800, 0x0000000000b2b000, 0x0000000000b2e000, 0x0000000000b30000,
// 0x0000000000b32800, 0x0000000000b35000, 0x0000000000b3f000, 0x0000000000b41800,
@ -53,9 +53,9 @@ public class TestThreadDumpSMRInfo {
// 0x0000000000b55800, 0x0000000000b57800, 0x0000000000b5a000, 0x0000000000b5c800,
// 0x0000000000cc8800, 0x0000000000fd9800, 0x0000000000ef4800
// }
// _smr_java_thread_list_alloc_cnt=24, _smr_java_thread_list_free_cnt=23, _smr_java_thread_list_max=23, _smr_nested_thread_list_max=0
// _smr_delete_lock_wait_cnt=0, _smr_delete_lock_wait_max=0
// _smr_to_delete_list_cnt=0, _smr_to_delete_list_max=1
// _java_thread_list_alloc_cnt=24, _java_thread_list_free_cnt=23, _java_thread_list_max=23, _nested_thread_list_max=0
// _delete_lock_wait_cnt=0, _delete_lock_wait_max=0
// _to_delete_list_cnt=0, _to_delete_list_max=1
final static String HEADER_STR = "Threads class SMR info:";