diff -r 0b27f3512f9e -r 37f87013dfd8 src/share/vm/utilities/workgroup.cpp --- a/src/share/vm/utilities/workgroup.cpp Wed Jun 04 13:51:09 2008 -0700 +++ b/src/share/vm/utilities/workgroup.cpp Thu Jun 05 15:57:56 2008 -0700 @@ -28,13 +28,19 @@ // Definitions of WorkGang methods. AbstractWorkGang::AbstractWorkGang(const char* name, - bool are_GC_threads) : + bool are_GC_task_threads, + bool are_ConcurrentGC_threads) : _name(name), - _are_GC_threads(are_GC_threads) { + _are_GC_task_threads(are_GC_task_threads), + _are_ConcurrentGC_threads(are_ConcurrentGC_threads) { + + assert(!(are_GC_task_threads && are_ConcurrentGC_threads), + "They cannot both be STW GC and Concurrent threads" ); + // Other initialization. _monitor = new Monitor(/* priority */ Mutex::leaf, /* name */ "WorkGroup monitor", - /* allow_vm_block */ are_GC_threads); + /* allow_vm_block */ are_GC_task_threads); assert(monitor() != NULL, "Failed to allocate monitor"); _terminate = false; _task = NULL; @@ -44,16 +50,21 @@ } WorkGang::WorkGang(const char* name, - int workers, - bool are_GC_threads) : - AbstractWorkGang(name, are_GC_threads) { + int workers, + bool are_GC_task_threads, + bool are_ConcurrentGC_threads) : + AbstractWorkGang(name, are_GC_task_threads, are_ConcurrentGC_threads) +{ // Save arguments. _total_workers = workers; + if (TraceWorkGang) { tty->print_cr("Constructing work gang %s with %d threads", name, workers); } _gang_workers = NEW_C_HEAP_ARRAY(GangWorker*, workers); - assert(gang_workers() != NULL, "Failed to allocate gang workers"); + if (gang_workers() == NULL) { + vm_exit_out_of_memory(0, "Cannot create GangWorker array."); + } for (int worker = 0; worker < total_workers(); worker += 1) { GangWorker* new_worker = new GangWorker(this, worker); assert(new_worker != NULL, "Failed to allocate GangWorker"); @@ -285,7 +296,11 @@ } bool GangWorker::is_GC_task_thread() const { - return gang()->are_GC_threads(); + return gang()->are_GC_task_threads(); +} + +bool GangWorker::is_ConcurrentGC_thread() const { + return gang()->are_ConcurrentGC_threads(); } void GangWorker::print_on(outputStream* st) const { @@ -312,26 +327,43 @@ WorkGangBarrierSync::WorkGangBarrierSync() : _monitor(Mutex::safepoint, "work gang barrier sync", true), - _n_workers(0), _n_completed(0) { + _n_workers(0), _n_completed(0), _should_reset(false) { } WorkGangBarrierSync::WorkGangBarrierSync(int n_workers, const char* name) : _monitor(Mutex::safepoint, name, true), - _n_workers(n_workers), _n_completed(0) { + _n_workers(n_workers), _n_completed(0), _should_reset(false) { } void WorkGangBarrierSync::set_n_workers(int n_workers) { _n_workers = n_workers; _n_completed = 0; + _should_reset = false; } void WorkGangBarrierSync::enter() { MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag); + if (should_reset()) { + // The should_reset() was set and we are the first worker to enter + // the sync barrier. We will zero the n_completed() count which + // effectively resets the barrier. + zero_completed(); + set_should_reset(false); + } inc_completed(); if (n_completed() == n_workers()) { + // At this point we would like to reset the barrier to be ready in + // case it is used again. However, we cannot set n_completed() to + // 0, even after the notify_all(), given that some other workers + // might still be waiting for n_completed() to become == + // n_workers(). So, if we set n_completed() to 0, those workers + // will get stuck (as they will wake up, see that n_completed() != + // n_workers() and go back to sleep). Instead, we raise the + // should_reset() flag and the barrier will be reset the first + // time a worker enters it again. + set_should_reset(true); monitor()->notify_all(); - } - else { + } else { while (n_completed() != n_workers()) { monitor()->wait(/* no_safepoint_check */ true); } @@ -442,3 +474,122 @@ } return false; } + +bool FreeIdSet::_stat_init = false; +FreeIdSet* FreeIdSet::_sets[NSets]; +bool FreeIdSet::_safepoint; + +FreeIdSet::FreeIdSet(int sz, Monitor* mon) : + _sz(sz), _mon(mon), _hd(0), _waiters(0), _index(-1), _claimed(0) +{ + _ids = new int[sz]; + for (int i = 0; i < sz; i++) _ids[i] = i+1; + _ids[sz-1] = end_of_list; // end of list. + if (_stat_init) { + for (int j = 0; j < NSets; j++) _sets[j] = NULL; + _stat_init = true; + } + // Add to sets. (This should happen while the system is still single-threaded.) + for (int j = 0; j < NSets; j++) { + if (_sets[j] == NULL) { + _sets[j] = this; + _index = j; + break; + } + } + guarantee(_index != -1, "Too many FreeIdSets in use!"); +} + +FreeIdSet::~FreeIdSet() { + _sets[_index] = NULL; +} + +void FreeIdSet::set_safepoint(bool b) { + _safepoint = b; + if (b) { + for (int j = 0; j < NSets; j++) { + if (_sets[j] != NULL && _sets[j]->_waiters > 0) { + Monitor* mon = _sets[j]->_mon; + mon->lock_without_safepoint_check(); + mon->notify_all(); + mon->unlock(); + } + } + } +} + +#define FID_STATS 0 + +int FreeIdSet::claim_par_id() { +#if FID_STATS + thread_t tslf = thr_self(); + tty->print("claim_par_id[%d]: sz = %d, claimed = %d\n", tslf, _sz, _claimed); +#endif + MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); + while (!_safepoint && _hd == end_of_list) { + _waiters++; +#if FID_STATS + if (_waiters > 5) { + tty->print("claim_par_id waiting[%d]: %d waiters, %d claimed.\n", + tslf, _waiters, _claimed); + } +#endif + _mon->wait(Mutex::_no_safepoint_check_flag); + _waiters--; + } + if (_hd == end_of_list) { +#if FID_STATS + tty->print("claim_par_id[%d]: returning EOL.\n", tslf); +#endif + return -1; + } else { + int res = _hd; + _hd = _ids[res]; + _ids[res] = claimed; // For debugging. + _claimed++; +#if FID_STATS + tty->print("claim_par_id[%d]: returning %d, claimed = %d.\n", + tslf, res, _claimed); +#endif + return res; + } +} + +bool FreeIdSet::claim_perm_id(int i) { + assert(0 <= i && i < _sz, "Out of range."); + MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); + int prev = end_of_list; + int cur = _hd; + while (cur != end_of_list) { + if (cur == i) { + if (prev == end_of_list) { + _hd = _ids[cur]; + } else { + _ids[prev] = _ids[cur]; + } + _ids[cur] = claimed; + _claimed++; + return true; + } else { + prev = cur; + cur = _ids[cur]; + } + } + return false; + +} + +void FreeIdSet::release_par_id(int id) { + MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); + assert(_ids[id] == claimed, "Precondition."); + _ids[id] = _hd; + _hd = id; + _claimed--; +#if FID_STATS + tty->print("[%d] release_par_id(%d), waiters =%d, claimed = %d.\n", + thr_self(), id, _waiters, _claimed); +#endif + if (_waiters > 0) + // Notify all would be safer, but this is OK, right? + _mon->notify_all(); +}