< prev index next >
src/share/vm/memory/sharedHeap.cpp
Print this page
rev 7992 : G1RootProcessor
rev 7993 : Convert G1 to G1RootProcessor
rev 7994 : Move remaining root processing to GenCollectedHeap
@@ -30,44 +30,23 @@
#include "memory/sharedHeap.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/atomic.inline.hpp"
#include "runtime/fprofiler.hpp"
#include "runtime/java.hpp"
-#include "services/management.hpp"
#include "utilities/copy.hpp"
#include "utilities/workgroup.hpp"
PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
SharedHeap* SharedHeap::_sh;
-// The set of potentially parallel tasks in root scanning.
-enum SH_process_roots_tasks {
- SH_PS_Universe_oops_do,
- SH_PS_JNIHandles_oops_do,
- SH_PS_ObjectSynchronizer_oops_do,
- SH_PS_FlatProfiler_oops_do,
- SH_PS_Management_oops_do,
- SH_PS_SystemDictionary_oops_do,
- SH_PS_ClassLoaderDataGraph_oops_do,
- SH_PS_jvmti_oops_do,
- SH_PS_CodeCache_oops_do,
- // Leave this one last.
- SH_PS_NumElements
-};
-
SharedHeap::SharedHeap(CollectorPolicy* policy_) :
CollectedHeap(),
_collector_policy(policy_),
- _strong_roots_scope(NULL),
_strong_roots_parity(0),
- _process_strong_tasks(new SubTasksDone(SH_PS_NumElements)),
_workers(NULL)
{
- if (_process_strong_tasks == NULL || !_process_strong_tasks->valid()) {
- vm_exit_during_initialization("Failed necessary allocation.");
- }
_sh = this; // ch is static, should be set only once.
if (UseConcMarkSweepGC || UseG1GC) {
_workers = new FlexibleWorkGang("GC Thread", ParallelGCThreads,
/* are_GC_task_threads */true,
/* are_ConcurrentGC_threads */false);
@@ -77,53 +56,20 @@
_workers->initialize_workers();
}
}
}
-int SharedHeap::n_termination() {
- return _process_strong_tasks->n_threads();
-}
-
-void SharedHeap::set_n_termination(int t) {
- _process_strong_tasks->set_n_threads(t);
-}
-
bool SharedHeap::heap_lock_held_for_gc() {
Thread* t = Thread::current();
return Heap_lock->owned_by_self()
|| ( (t->is_GC_task_thread() || t->is_VM_thread())
&& _thread_holds_heap_lock_for_gc);
}
void SharedHeap::set_par_threads(uint t) {
assert(t == 0 || !UseSerialGC, "Cannot have parallel threads");
_n_par_threads = t;
- _process_strong_tasks->set_n_threads(t);
-}
-
-#ifdef ASSERT
-class AssertNonScavengableClosure: public OopClosure {
-public:
- virtual void do_oop(oop* p) {
- assert(!Universe::heap()->is_in_partial_collection(*p),
- "Referent should not be scavengable."); }
- virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
-};
-static AssertNonScavengableClosure assert_is_non_scavengable_closure;
-#endif
-
-SharedHeap::StrongRootsScope* SharedHeap::active_strong_roots_scope() const {
- return _strong_roots_scope;
-}
-void SharedHeap::register_strong_roots_scope(SharedHeap::StrongRootsScope* scope) {
- assert(_strong_roots_scope == NULL, "Should only have one StrongRootsScope active");
- assert(scope != NULL, "Illegal argument");
- _strong_roots_scope = scope;
-}
-void SharedHeap::unregister_strong_roots_scope(SharedHeap::StrongRootsScope* scope) {
- assert(_strong_roots_scope == scope, "Wrong scope unregistered");
- _strong_roots_scope = NULL;
}
void SharedHeap::change_strong_roots_parity() {
// Also set the new collection parity.
assert(_strong_roots_parity >= 0 && _strong_roots_parity <= 2,
@@ -133,178 +79,19 @@
assert(_strong_roots_parity >= 1 && _strong_roots_parity <= 2,
"Not in range.");
}
SharedHeap::StrongRootsScope::StrongRootsScope(SharedHeap* heap, bool activate)
- : MarkScope(activate), _sh(heap), _n_workers_done_with_threads(0)
+ : MarkScope(activate), _sh(heap)
{
if (_active) {
- _sh->register_strong_roots_scope(this);
_sh->change_strong_roots_parity();
// Zero the claimed high water mark in the StringTable
StringTable::clear_parallel_claimed_index();
}
}
-SharedHeap::StrongRootsScope::~StrongRootsScope() {
- if (_active) {
- _sh->unregister_strong_roots_scope(this);
- }
-}
-
-Monitor* SharedHeap::StrongRootsScope::_lock = new Monitor(Mutex::leaf, "StrongRootsScope lock", false, Monitor::_safepoint_check_never);
-
-void SharedHeap::StrongRootsScope::mark_worker_done_with_threads(uint n_workers) {
- // The Thread work barrier is only needed by G1 Class Unloading.
- // No need to use the barrier if this is single-threaded code.
- if (UseG1GC && ClassUnloadingWithConcurrentMark && n_workers > 0) {
- uint new_value = (uint)Atomic::add(1, &_n_workers_done_with_threads);
- if (new_value == n_workers) {
- // This thread is last. Notify the others.
- MonitorLockerEx ml(_lock, Mutex::_no_safepoint_check_flag);
- _lock->notify_all();
- }
- }
-}
-
-void SharedHeap::StrongRootsScope::wait_until_all_workers_done_with_threads(uint n_workers) {
- assert(UseG1GC, "Currently only used by G1");
- assert(ClassUnloadingWithConcurrentMark, "Currently only needed when doing G1 Class Unloading");
-
- // No need to use the barrier if this is single-threaded code.
- if (n_workers > 0 && (uint)_n_workers_done_with_threads != n_workers) {
- MonitorLockerEx ml(_lock, Mutex::_no_safepoint_check_flag);
- while ((uint)_n_workers_done_with_threads != n_workers) {
- _lock->wait(Mutex::_no_safepoint_check_flag, 0, false);
- }
- }
-}
-
-void SharedHeap::process_roots(bool activate_scope,
- ScanningOption so,
- OopClosure* strong_roots,
- OopClosure* weak_roots,
- CLDClosure* strong_cld_closure,
- CLDClosure* weak_cld_closure,
- CodeBlobClosure* code_roots) {
- StrongRootsScope srs(this, activate_scope);
-
- // General roots.
- assert(_strong_roots_parity != 0, "must have called prologue code");
- assert(code_roots != NULL, "code root closure should always be set");
- // _n_termination for _process_strong_tasks should be set up stream
- // in a method not running in a GC worker. Otherwise the GC worker
- // could be trying to change the termination condition while the task
- // is executing in another GC worker.
-
- // Iterating over the CLDG and the Threads are done early to allow G1 to
- // first process the strong CLDs and nmethods and then, after a barrier,
- // let the thread process the weak CLDs and nmethods.
-
- if (!_process_strong_tasks->is_task_claimed(SH_PS_ClassLoaderDataGraph_oops_do)) {
- ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure);
- }
-
- // Some CLDs contained in the thread frames should be considered strong.
- // Don't process them if they will be processed during the ClassLoaderDataGraph phase.
- CLDClosure* roots_from_clds_p = (strong_cld_closure != weak_cld_closure) ? strong_cld_closure : NULL;
- // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway
- CodeBlobClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots;
-
- Threads::possibly_parallel_oops_do(strong_roots, roots_from_clds_p, roots_from_code_p);
-
- // This is the point where this worker thread will not find more strong CLDs/nmethods.
- // Report this so G1 can synchronize the strong and weak CLDs/nmethods processing.
- active_strong_roots_scope()->mark_worker_done_with_threads(n_par_threads());
-
- if (!_process_strong_tasks->is_task_claimed(SH_PS_Universe_oops_do)) {
- Universe::oops_do(strong_roots);
- }
- // Global (strong) JNI handles
- if (!_process_strong_tasks->is_task_claimed(SH_PS_JNIHandles_oops_do))
- JNIHandles::oops_do(strong_roots);
-
- if (!_process_strong_tasks-> is_task_claimed(SH_PS_ObjectSynchronizer_oops_do))
- ObjectSynchronizer::oops_do(strong_roots);
- if (!_process_strong_tasks->is_task_claimed(SH_PS_FlatProfiler_oops_do))
- FlatProfiler::oops_do(strong_roots);
- if (!_process_strong_tasks->is_task_claimed(SH_PS_Management_oops_do))
- Management::oops_do(strong_roots);
- if (!_process_strong_tasks->is_task_claimed(SH_PS_jvmti_oops_do))
- JvmtiExport::oops_do(strong_roots);
-
- if (!_process_strong_tasks->is_task_claimed(SH_PS_SystemDictionary_oops_do)) {
- SystemDictionary::roots_oops_do(strong_roots, weak_roots);
- }
-
- // All threads execute the following. A specific chunk of buckets
- // from the StringTable are the individual tasks.
- if (weak_roots != NULL) {
- if (CollectedHeap::use_parallel_gc_threads()) {
- StringTable::possibly_parallel_oops_do(weak_roots);
- } else {
- StringTable::oops_do(weak_roots);
- }
- }
-
- if (!_process_strong_tasks->is_task_claimed(SH_PS_CodeCache_oops_do)) {
- if (so & SO_ScavengeCodeCache) {
- assert(code_roots != NULL, "must supply closure for code cache");
-
- // We only visit parts of the CodeCache when scavenging.
- CodeCache::scavenge_root_nmethods_do(code_roots);
- }
- if (so & SO_AllCodeCache) {
- assert(code_roots != NULL, "must supply closure for code cache");
-
- // CMSCollector uses this to do intermediate-strength collections.
- // We scan the entire code cache, since CodeCache::do_unloading is not called.
- CodeCache::blobs_do(code_roots);
- }
- // Verify that the code cache contents are not subject to
- // movement by a scavenging collection.
- DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations));
- DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
- }
-
- _process_strong_tasks->all_tasks_completed();
-}
-
-void SharedHeap::process_all_roots(bool activate_scope,
- ScanningOption so,
- OopClosure* roots,
- CLDClosure* cld_closure,
- CodeBlobClosure* code_closure) {
- process_roots(activate_scope, so,
- roots, roots,
- cld_closure, cld_closure,
- code_closure);
-}
-
-void SharedHeap::process_strong_roots(bool activate_scope,
- ScanningOption so,
- OopClosure* roots,
- CLDClosure* cld_closure,
- CodeBlobClosure* code_closure) {
- process_roots(activate_scope, so,
- roots, NULL,
- cld_closure, NULL,
- code_closure);
-}
-
-
-class AlwaysTrueClosure: public BoolObjectClosure {
-public:
- bool do_object_b(oop p) { return true; }
-};
-static AlwaysTrueClosure always_true;
-
-void SharedHeap::process_weak_roots(OopClosure* root_closure) {
- // Global (weak) JNI handles
- JNIHandles::weak_oops_do(&always_true, root_closure);
-}
-
void SharedHeap::set_barrier_set(BarrierSet* bs) {
_barrier_set = bs;
// Cached barrier set for fast access in oops
oopDesc::set_bs(bs);
}
< prev index next >