--- a/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp Thu Jul 25 07:02:45 2013 -0700
+++ b/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp Thu Jul 25 11:07:23 2013 -0700
@@ -733,7 +733,7 @@
assert(_eden_chunk_array != NULL || _eden_chunk_capacity == 0, "Error");
// Support for parallelizing survivor space rescan
- if (CMSParallelRemarkEnabled && CMSParallelSurvivorRemarkEnabled) {
+ if ((CMSParallelRemarkEnabled && CMSParallelSurvivorRemarkEnabled) || CMSParallelInitialMarkEnabled) {
const size_t max_plab_samples =
((DefNewGeneration*)_young_gen)->max_survivor_size()/MinTLABSize;
@@ -3583,6 +3583,31 @@
// CMS work
+// The common parts of CMSParInitialMarkTask and CMSParRemarkTask.
+class CMSParMarkTask : public AbstractGangTask {
+ protected:
+ CMSCollector* _collector;
+ int _n_workers;
+ CMSParMarkTask(const char* name, CMSCollector* collector, int n_workers) :
+ AbstractGangTask(name),
+ _collector(collector),
+ _n_workers(n_workers) {}
+ // Work method in support of parallel rescan ... of young gen spaces
+ void do_young_space_rescan(uint worker_id, OopsInGenClosure* cl,
+ ContiguousSpace* space,
+ HeapWord** chunk_array, size_t chunk_top);
+ void work_on_young_gen_roots(uint worker_id, OopsInGenClosure* cl);
+};
+
+// Parallel initial mark task
+class CMSParInitialMarkTask: public CMSParMarkTask {
+ public:
+ CMSParInitialMarkTask(CMSCollector* collector, int n_workers) :
+ CMSParMarkTask("Scan roots and young gen for initial mark in parallel",
+ collector, n_workers) {}
+ void work(uint worker_id);
+};
+
// Checkpoint the roots into this generation from outside
// this generation. [Note this initial checkpoint need only
// be approximate -- we'll do a catch up phase subsequently.]
@@ -3684,19 +3709,38 @@
print_eden_and_survivor_chunk_arrays();
}
- CMKlassClosure klass_closure(¬Older);
{
COMPILER2_PRESENT(DerivedPointerTableDeactivate dpt_deact;)
- gch->rem_set()->prepare_for_younger_refs_iterate(false); // Not parallel.
- gch->gen_process_strong_roots(_cmsGen->level(),
- true, // younger gens are roots
- true, // activate StrongRootsScope
- false, // not scavenging
- SharedHeap::ScanningOption(roots_scanning_options()),
- ¬Older,
- true, // walk all of code cache if (so & SO_CodeCache)
- NULL,
- &klass_closure);
+ if (CMSParallelInitialMarkEnabled && CollectedHeap::use_parallel_gc_threads()) {
+ // The parallel version.
+ FlexibleWorkGang* workers = gch->workers();
+ assert(workers != NULL, "Need parallel worker threads.");
+ int n_workers = workers->active_workers();
+ CMSParInitialMarkTask tsk(this, n_workers);
+ gch->set_par_threads(n_workers);
+ initialize_sequential_subtasks_for_young_gen_rescan(n_workers);
+ if (n_workers > 1) {
+ GenCollectedHeap::StrongRootsScope srs(gch);
+ workers->run_task(&tsk);
+ } else {
+ GenCollectedHeap::StrongRootsScope srs(gch);
+ tsk.work(0);
+ }
+ gch->set_par_threads(0);
+ } else {
+ // The serial version.
+ CMKlassClosure klass_closure(¬Older);
+ gch->rem_set()->prepare_for_younger_refs_iterate(false); // Not parallel.
+ gch->gen_process_strong_roots(_cmsGen->level(),
+ true, // younger gens are roots
+ true, // activate StrongRootsScope
+ false, // not scavenging
+ SharedHeap::ScanningOption(roots_scanning_options()),
+ ¬Older,
+ true, // walk all of code cache if (so & SO_CodeCache)
+ NULL,
+ &klass_closure);
+ }
}
// Clear mod-union table; it will be dirtied in the prologue of
@@ -5162,10 +5206,53 @@
}
}
+void CMSParInitialMarkTask::work(uint worker_id) {
+ elapsedTimer _timer;
+ ResourceMark rm;
+ HandleMark hm;
+
+ // ---------- scan from roots --------------
+ _timer.start();
+ GenCollectedHeap* gch = GenCollectedHeap::heap();
+ Par_MarkRefsIntoClosure par_mri_cl(_collector->_span, &(_collector->_markBitMap));
+ CMKlassClosure klass_closure(&par_mri_cl);
+
+ // ---------- young gen roots --------------
+ {
+ work_on_young_gen_roots(worker_id, &par_mri_cl);
+ _timer.stop();
+ if (PrintCMSStatistics != 0) {
+ gclog_or_tty->print_cr(
+ "Finished young gen initial mark scan work in %dth thread: %3.3f sec",
+ worker_id, _timer.seconds());
+ }
+ }
+
+ // ---------- remaining roots --------------
+ _timer.reset();
+ _timer.start();
+ gch->gen_process_strong_roots(_collector->_cmsGen->level(),
+ false, // yg was scanned above
+ false, // this is parallel code
+ false, // not scavenging
+ SharedHeap::ScanningOption(_collector->CMSCollector::roots_scanning_options()),
+ &par_mri_cl,
+ true, // walk all of code cache if (so & SO_CodeCache)
+ NULL,
+ &klass_closure);
+ assert(_collector->should_unload_classes()
+ || (_collector->CMSCollector::roots_scanning_options() & SharedHeap::SO_CodeCache),
+ "if we didn't scan the code cache, we have to be ready to drop nmethods with expired weak oops");
+ _timer.stop();
+ if (PrintCMSStatistics != 0) {
+ gclog_or_tty->print_cr(
+ "Finished remaining root initial mark scan work in %dth thread: %3.3f sec",
+ worker_id, _timer.seconds());
+ }
+}
+
// Parallel remark task
-class CMSParRemarkTask: public AbstractGangTask {
- CMSCollector* _collector;
- int _n_workers;
+class CMSParRemarkTask: public CMSParMarkTask {
CompactibleFreeListSpace* _cms_space;
// The per-thread work queues, available here for stealing.
@@ -5179,10 +5266,9 @@
CompactibleFreeListSpace* cms_space,
int n_workers, FlexibleWorkGang* workers,
OopTaskQueueSet* task_queues):
- AbstractGangTask("Rescan roots and grey objects in parallel"),
- _collector(collector),
+ CMSParMarkTask("Rescan roots and grey objects in parallel",
+ collector, n_workers),
_cms_space(cms_space),
- _n_workers(n_workers),
_task_queues(task_queues),
_term(n_workers, task_queues) { }
@@ -5196,11 +5282,6 @@
void work(uint worker_id);
private:
- // Work method in support of parallel rescan ... of young gen spaces
- void do_young_space_rescan(int i, Par_MarkRefsIntoAndScanClosure* cl,
- ContiguousSpace* space,
- HeapWord** chunk_array, size_t chunk_top);
-
// ... of dirty cards in old space
void do_dirty_card_rescan_tasks(CompactibleFreeListSpace* sp, int i,
Par_MarkRefsIntoAndScanClosure* cl);
@@ -5232,6 +5313,25 @@
}
};
+void CMSParMarkTask::work_on_young_gen_roots(uint worker_id, OopsInGenClosure* cl) {
+ DefNewGeneration* dng = _collector->_young_gen->as_DefNewGeneration();
+ EdenSpace* eden_space = dng->eden();
+ ContiguousSpace* from_space = dng->from();
+ ContiguousSpace* to_space = dng->to();
+
+ HeapWord** eca = _collector->_eden_chunk_array;
+ size_t ect = _collector->_eden_chunk_index;
+ HeapWord** sca = _collector->_survivor_chunk_array;
+ size_t sct = _collector->_survivor_chunk_index;
+
+ assert(ect <= _collector->_eden_chunk_capacity, "out of bounds");
+ assert(sct <= _collector->_survivor_chunk_capacity, "out of bounds");
+
+ do_young_space_rescan(worker_id, cl, to_space, NULL, 0);
+ do_young_space_rescan(worker_id, cl, from_space, sca, sct);
+ do_young_space_rescan(worker_id, cl, eden_space, eca, ect);
+}
+
// work_queue(i) is passed to the closure
// Par_MarkRefsIntoAndScanClosure. The "i" parameter
// also is passed to do_dirty_card_rescan_tasks() and to
@@ -5256,23 +5356,7 @@
// work first.
// ---------- young gen roots --------------
{
- DefNewGeneration* dng = _collector->_young_gen->as_DefNewGeneration();
- EdenSpace* eden_space = dng->eden();
- ContiguousSpace* from_space = dng->from();
- ContiguousSpace* to_space = dng->to();
-
- HeapWord** eca = _collector->_eden_chunk_array;
- size_t ect = _collector->_eden_chunk_index;
- HeapWord** sca = _collector->_survivor_chunk_array;
- size_t sct = _collector->_survivor_chunk_index;
-
- assert(ect <= _collector->_eden_chunk_capacity, "out of bounds");
- assert(sct <= _collector->_survivor_chunk_capacity, "out of bounds");
-
- do_young_space_rescan(worker_id, &par_mrias_cl, to_space, NULL, 0);
- do_young_space_rescan(worker_id, &par_mrias_cl, from_space, sca, sct);
- do_young_space_rescan(worker_id, &par_mrias_cl, eden_space, eca, ect);
-
+ work_on_young_gen_roots(worker_id, &par_mrias_cl);
_timer.stop();
if (PrintCMSStatistics != 0) {
gclog_or_tty->print_cr(
@@ -5380,8 +5464,8 @@
// Note that parameter "i" is not used.
void
-CMSParRemarkTask::do_young_space_rescan(int i,
- Par_MarkRefsIntoAndScanClosure* cl, ContiguousSpace* space,
+CMSParMarkTask::do_young_space_rescan(uint worker_id,
+ OopsInGenClosure* cl, ContiguousSpace* space,
HeapWord** chunk_array, size_t chunk_top) {
// Until all tasks completed:
// . claim an unclaimed task
@@ -5625,12 +5709,13 @@
// Merge the per-thread plab arrays into the global survivor chunk
// array which will provide the partitioning of the survivor space
-// for CMS rescan.
+// for CMS initial scan and rescan.
void CMSCollector::merge_survivor_plab_arrays(ContiguousSpace* surv,
int no_of_gc_threads) {
assert(_survivor_plab_array != NULL, "Error");
assert(_survivor_chunk_array != NULL, "Error");
- assert(_collectorState == FinalMarking, "Error");
+ assert(_collectorState == FinalMarking ||
+ (CMSParallelInitialMarkEnabled && _collectorState == InitialMarking), "Error");
for (int j = 0; j < no_of_gc_threads; j++) {
_cursor[j] = 0;
}
@@ -5693,7 +5778,7 @@
}
// Set up the space's par_seq_tasks structure for work claiming
-// for parallel rescan of young gen.
+// for parallel initial scan and rescan of young gen.
// See ParRescanTask where this is currently used.
void
CMSCollector::
@@ -6820,6 +6905,28 @@
void MarkRefsIntoClosure::do_oop(oop* p) { MarkRefsIntoClosure::do_oop_work(p); }
void MarkRefsIntoClosure::do_oop(narrowOop* p) { MarkRefsIntoClosure::do_oop_work(p); }
+Par_MarkRefsIntoClosure::Par_MarkRefsIntoClosure(
+ MemRegion span, CMSBitMap* bitMap):
+ _span(span),
+ _bitMap(bitMap)
+{
+ assert(_ref_processor == NULL, "deliberately left NULL");
+ assert(_bitMap->covers(_span), "_bitMap/_span mismatch");
+}
+
+void Par_MarkRefsIntoClosure::do_oop(oop obj) {
+ // if p points into _span, then mark corresponding bit in _markBitMap
+ assert(obj->is_oop(), "expected an oop");
+ HeapWord* addr = (HeapWord*)obj;
+ if (_span.contains(addr)) {
+ // this should be made more efficient
+ _bitMap->par_mark(addr);
+ }
+}
+
+void Par_MarkRefsIntoClosure::do_oop(oop* p) { Par_MarkRefsIntoClosure::do_oop_work(p); }
+void Par_MarkRefsIntoClosure::do_oop(narrowOop* p) { Par_MarkRefsIntoClosure::do_oop_work(p); }
+
// A variant of the above, used for CMS marking verification.
MarkRefsIntoVerifyClosure::MarkRefsIntoVerifyClosure(
MemRegion span, CMSBitMap* verification_bm, CMSBitMap* cms_bm):
@@ -9377,7 +9484,6 @@
return;
}
}
-
// Transfer some number of overflown objects to usual marking
// stack. Return true if some objects were transferred.
bool MarkRefsIntoAndScanClosure::take_from_overflow_list() {