g1RemSet.hpp revision 1879
/*
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* published by the Free Software Foundation.
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
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// A G1RemSet provides ways of iterating over pointers into a selected
// collection set.
class G1CollectedHeap;
class CardTableModRefBarrierSet;
class ConcurrentG1Refine;
// A G1RemSet in which each heap region has a rem set that records the
// external heap references into it. Uses a mod ref bs to track updates,
// so that they can be used to update the individual region remsets.
protected:
unsigned _conc_refine_cards;
protected:
enum SomePrivateConstants {
UpdateRStoMergeSync = 0,
MergeRStoDoDirtySync = 1,
DoDirtySync = 2,
LastSync = 3,
SeqTask = 0,
NumSeqTasks = 1
};
// Used for caching the closure that is responsible for scanning
// references into the collection set.
// The routine that performs the actual work of refining a dirty
// card.
// If check_for_refs_into_refs is true then a true result is returned
// if the card contains oops that have references into the current
// collection set.
bool check_for_refs_into_cset);
public:
// This is called to reset dual hash tables after the gc pause
// is finished and the initial hash table is no longer being
// scanned.
void cleanupHRRS();
~G1RemSet();
// Invoke "blk->do_oop" on all pointers into the CS in objects in regions
// outside the CS (having invoked "blk->set_region" to set the "from"
// region correctly beforehand.) The "worker_i" param is for the
// parallel case where the number of the worker thread calling this
// function can be helpful in partitioning the work to be done. It
// should be the same as the "i" passed to the calling thread's
// work(i) function. In the sequential case this param will be ingored.
int worker_i);
// Prepare for and cleanup after an oops_into_collection_set_do
// call. Must call each of these once before and after (in sequential
// code) any threads call oops_into_collection_set_do. (This offers an
// opportunity to sequential setup and teardown of structures needed by a
// parallel iteration over the CS's RS.)
HeapRegion* calculateStartRegion(int i);
// Record, if necessary, the fact that *p (where "p" is in region "from",
// which is required to be non-NULL) has changed to a new non-NULL value.
// Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region
// or card, respectively, such that a region or card with a corresponding
// 0 bit contains no part of any live object. Eliminates any remembered
// set entries that correspond to dead heap ranges.
// Like the above, but assumes is called in parallel: "worker_num" is the
// parallel thread id of the current thread, and "claim_val" is the
// value that should be used to claim heap regions.
int worker_num, int claim_val);
// Refine the card corresponding to "card_ptr". If "sts" is non-NULL,
// join and leave around parts that must be atomic wrt GC. (NULL means
// being done at a safepoint.)
// If check_for_refs_into_cset is true, a true result is returned
// if the given card contains oops that have references into the
// current collection set.
bool check_for_refs_into_cset);
// Print any relevant summary info.
virtual void print_summary_info();
// Prepare remembered set for verification.
virtual void prepare_for_verify();
};
#define G1_REM_SET_LOGGING 0
class CountNonCleanMemRegionClosure: public MemRegionClosure {
int _n;
public:
{}
int n() { return _n; };
};
class UpdateRSOopClosure: public OopClosure {
int _worker_i;
template <class T> void do_oop_work(T* p);
public:
{}
}
// Override: this closure is idempotent.
// bool idempotent() { return true; }
bool apply_to_weak_ref_discovered_field() { return true; }
};
class UpdateRSetImmediate: public OopsInHeapRegionClosure {
private:
template <class T> void do_oop_work(T* p);
public:
_g1_rem_set(rs) {}
};
class UpdateRSOrPushRefOopClosure: public OopClosure {
bool _record_refs_into_cset;
int _worker_i;
template <class T> void do_oop_work(T* p);
public:
bool record_refs_into_cset,
int worker_i = 0) :
}
return result;
}
bool apply_to_weak_ref_discovered_field() { return true; }
};
#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1REMSET_HPP