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/*
* Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* 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
* questions.
*
*/
#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1REMSET_HPP
#define SHARE_VM_GC_IMPLEMENTATION_G1_G1REMSET_HPP
#include "gc_implementation/g1/g1RemSetSummary.hpp"
// A G1RemSet provides ways of iterating over pointers into a selected
// collection set.
class G1CollectedHeap;
class CardTableModRefBarrierSet;
class ConcurrentG1Refine;
class G1ParPushHeapRSClosure;
// 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.
class G1RemSet: public CHeapObj<mtGC> {
private:
G1RemSetSummary _prev_period_summary;
protected:
G1CollectedHeap* _g1;
size_t _conc_refine_cards;
uint n_workers();
protected:
enum SomePrivateConstants {
UpdateRStoMergeSync = 0,
MergeRStoDoDirtySync = 1,
DoDirtySync = 2,
LastSync = 3,
SeqTask = 0,
NumSeqTasks = 1
};
CardTableModRefBS* _ct_bs;
G1CollectorPolicy* _g1p;
ConcurrentG1Refine* _cg1r;
size_t* _cards_scanned;
size_t _total_cards_scanned;
// Used for caching the closure that is responsible for scanning
// references into the collection set.
G1ParPushHeapRSClosure** _cset_rs_update_cl;
// Print the given summary info
virtual void print_summary_info(G1RemSetSummary * summary, const char * header = NULL);
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(G1CollectedHeap* g1, CardTableModRefBS* ct_bs);
~G1RemSet();
// Invoke "blk->do_oop" on all pointers into the collection set
// from objects in regions outside the collection set (having
// invoked "blk->set_region" to set the "from" region correctly
// beforehand.)
//
// Invoke code_root_cl->do_code_blob on the unmarked nmethods
// on the strong code roots list for each region in the
// collection set.
//
// The "worker_i" param is for the parallel case where the id
// 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 ignored.
void oops_into_collection_set_do(G1ParPushHeapRSClosure* blk,
CodeBlobClosure* code_root_cl,
uint 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.)
void prepare_for_oops_into_collection_set_do();
void cleanup_after_oops_into_collection_set_do();
void scanRS(G1ParPushHeapRSClosure* oc,
CodeBlobClosure* code_root_cl,
uint worker_i);
void updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i);
CardTableModRefBS* ct_bs() { return _ct_bs; }
size_t cardsScanned() { return _total_cards_scanned; }
// 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.
template <class T> void write_ref(HeapRegion* from, T* p);
template <class T> void par_write_ref(HeapRegion* from, T* p, int tid);
// 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.
void scrub(BitMap* region_bm, BitMap* card_bm);
// 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.
void scrub_par(BitMap* region_bm, BitMap* card_bm,
uint worker_num, int claim_val);
// Refine the card corresponding to "card_ptr".
// 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.
virtual bool refine_card(jbyte* card_ptr,
uint worker_i,
bool check_for_refs_into_cset);
// Print accumulated summary info from the start of the VM.
virtual void print_summary_info();
// Print accumulated summary info from the last time called.
virtual void print_periodic_summary_info(const char* header);
// Prepare remembered set for verification.
virtual void prepare_for_verify();
size_t conc_refine_cards() const {
return _conc_refine_cards;
}
};
class CountNonCleanMemRegionClosure: public MemRegionClosure {
G1CollectedHeap* _g1;
int _n;
HeapWord* _start_first;
public:
CountNonCleanMemRegionClosure(G1CollectedHeap* g1) :
_g1(g1), _n(0), _start_first(NULL)
{}
void do_MemRegion(MemRegion mr);
int n() { return _n; };
HeapWord* start_first() { return _start_first; }
};
class UpdateRSOopClosure: public ExtendedOopClosure {
HeapRegion* _from;
G1RemSet* _rs;
uint _worker_i;
template <class T> void do_oop_work(T* p);
public:
UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) :
_from(NULL), _rs(rs), _worker_i(worker_i)
{}
void set_from(HeapRegion* from) {
assert(from != NULL, "from region must be non-NULL");
_from = from;
}
virtual void do_oop(narrowOop* p) { do_oop_work(p); }
virtual void do_oop(oop* p) { do_oop_work(p); }
// Override: this closure is idempotent.
// bool idempotent() { return true; }
bool apply_to_weak_ref_discovered_field() { return true; }
};
#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1REMSET_HPP
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