stan/jdk-24
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

6412968: CMS Long initial mark pauses

Browse Source 
Reviewed-by: rasbold, tschatzl, jmasa
This commit is contained in:
Hiroshi Yamauchi 2013-07-25 11:07:23 -07:00 committed by Jon Masamitsu
parent 7d582a33d1
commit 6060a2999c
5 changed files with 175 additions and 47 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/cmsOopClosures.hpp
View File

@ -122,6 +122,22 @@ class MarkRefsIntoClosure: public CMSOopsInGenClosure {
}
};
class Par_MarkRefsIntoClosure: public CMSOopsInGenClosure {
private:
const MemRegion _span;
CMSBitMap* _bitMap;
protected:
DO_OOP_WORK_DEFN
public:
Par_MarkRefsIntoClosure(MemRegion span, CMSBitMap* bitMap);
virtual void do_oop(oop* p);
virtual void do_oop(narrowOop* p);
Prefetch::style prefetch_style() {
return Prefetch::do_read;
}
};
// A variant of the above used in certain kinds of CMS
// marking verification.
class MarkRefsIntoVerifyClosure: public CMSOopsInGenClosure {

198
hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp
View File

@ -733,7 +733,7 @@ CMSCollector::CMSCollector(ConcurrentMarkSweepGeneration* cmsGen,
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 @@ CMSPhaseAccounting::~CMSPhaseAccounting() {
// 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 @@ void CMSCollector::checkpointRootsInitialWork(bool asynch) {
print_eden_and_survivor_chunk_arrays();
}
CMKlassClosure klass_closure(&notOlder);
{
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()),
&notOlder,
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(&notOlder);
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()),
&notOlder,
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 CMSCollector::checkpointRootsFinalWork(bool asynch,
}
}
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 @@ class CMSParRemarkTask: public AbstractGangTask {
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 @@ class CMSParRemarkTask: public AbstractGangTask {
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 @@ class RemarkKlassClosure : public KlassClosure {
}
};
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 @@ void CMSParRemarkTask::work(uint worker_id) {
// 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 @@ void CMSParRemarkTask::work(uint worker_id) {
// 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 @@ void CMSCollector::reset_survivor_plab_arrays() {
// 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 @@ void CMSCollector::merge_survivor_plab_arrays(ContiguousSpace* surv,
}
// 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 obj) {
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 @@ void ASConcurrentMarkSweepGeneration::shrink_by(size_t desired_bytes) {
return;
}
}
// Transfer some number of overflown objects to usual marking
// stack. Return true if some objects were transferred.
bool MarkRefsIntoAndScanClosure::take_from_overflow_list() {

2
hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.hpp
View File

@ -515,6 +515,8 @@ class CMSCollector: public CHeapObj<mtGC> {
friend class ConcurrentMarkSweepThread;
friend class ConcurrentMarkSweepGeneration;
friend class CompactibleFreeListSpace;
friend class CMSParMarkTask;
friend class CMSParInitialMarkTask;
friend class CMSParRemarkTask;
friend class CMSConcMarkingTask;
friend class CMSRefProcTaskProxy;

3
hotspot/src/share/vm/memory/sharedHeap.cpp
View File

@ -65,7 +65,8 @@ SharedHeap::SharedHeap(CollectorPolicy* policy_) :
}
_sh = this; // ch is static, should be set only once.
if ((UseParNewGC ||
(UseConcMarkSweepGC && CMSParallelRemarkEnabled) ||
(UseConcMarkSweepGC && (CMSParallelInitialMarkEnabled ||
CMSParallelRemarkEnabled)) ||
UseG1GC) &&
ParallelGCThreads > 0) {
_workers = new FlexibleWorkGang("Parallel GC Threads", ParallelGCThreads,

3
hotspot/src/share/vm/runtime/globals.hpp
View File

@ -1689,6 +1689,9 @@ class CommandLineFlags {
product(bool, CMSAbortSemantics, false, \
"Whether abort-on-overflow semantics is implemented") \
\
product(bool, CMSParallelInitialMarkEnabled, true, \
"Use the parallel initial mark.") \
\
product(bool, CMSParallelRemarkEnabled, true, \
"Whether parallel remark enabled (only if ParNewGC)") \
\