g1RemSet.hpp revision 342
/*
* Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*
*/
// A G1RemSet provides ways of iterating over pointers into a selected
// collection set.
class G1CollectedHeap;
class CardTableModRefBarrierSet;
class HRInto_G1RemSet;
class ConcurrentG1Refine;
class G1RemSet {
protected:
unsigned _conc_refine_traversals;
unsigned _conc_refine_cards;
public:
{}
// Invoke "blk->do_oop" on all pointers into the CS in object 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) = 0;
// 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.)
virtual void prepare_for_oops_into_collection_set_do() = 0;
virtual void cleanup_after_oops_into_collection_set_do() = 0;
// If "this" is of the given subtype, return "this", else "NULL".
// Record, if necessary, the fact that *p (where "p" is in region "from")
// has changed to its new 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) = 0;
// Do any "refinement" activity that might be appropriate to the given
// G1RemSet. If "refinement" has iterateive "passes", do one pass.
// If "t" is non-NULL, it is the thread performing the refinement.
// Default implementation does nothing.
// 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.)
unsigned conc_refine_cards() { return _conc_refine_cards; }
// Print any relevant summary info.
virtual void print_summary_info() {}
// Prepare remebered set for verification.
virtual void prepare_for_verify() {};
};
// The simplest possible G1RemSet: iterates over all objects in non-CS
// regions, searching for pointers into the CS.
class StupidG1RemSet: public G1RemSet {
public:
int worker_i);
void prepare_for_oops_into_collection_set_do() {}
// Nothing is necessary in the version below.
int worker_num, int claim_val) {}
};
// 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 HRInto_G1RemSet: public G1RemSet {
protected:
enum SomePrivateConstants {
UpdateRStoMergeSync = 0,
MergeRStoDoDirtySync = 1,
DoDirtySync = 2,
LastSync = 3,
SeqTask = 0,
NumSeqTasks = 1
};
// _par_traversal_in_progress is "true" iff a parallel traversal is in
// progress. If so, then cards added to remembered sets should also have
// their references into the collection summarized in "_new_refs".
void set_par_traversal(bool b);
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();
~HRInto_G1RemSet();
int worker_i);
HeapRegion* calculateStartRegion(int i);
HRInto_G1RemSet* as_HRInto_G1RemSet() { return this; }
// 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.
// The "_nv" version is the same; it exists just so that it is not virtual.
int worker_num, int claim_val);
virtual void concurrentRefinementPass(ConcurrentG1Refine* t);
virtual void print_summary_info();
virtual void prepare_for_verify();
};
#define G1_REM_SET_LOGGING 0
class CountNonCleanMemRegionClosure: public MemRegionClosure {
int _n;
public:
{}
int n() { return _n; };
};