1 /*
2 * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
429 // boundary is never crossed.)
430 virtual HeapWord* initialize_threshold() { return end(); }
431
432 // "q" is an object of the given "size" that should be forwarded;
433 // "cp" names the generation ("gen") and containing "this" (which must
434 // also equal "cp->space"). "compact_top" is where in "this" the
435 // next object should be forwarded to. If there is room in "this" for
436 // the object, insert an appropriate forwarding pointer in "q".
437 // If not, go to the next compaction space (there must
438 // be one, since compaction must succeed -- we go to the first space of
439 // the previous generation if necessary, updating "cp"), reset compact_top
440 // and then forward. In either case, returns the new value of "compact_top".
441 // If the forwarding crosses "cp->threshold", invokes the "cross_threshold"
442 // function of the then-current compaction space, and updates "cp->threshold
443 // accordingly".
444 virtual HeapWord* forward(oop q, size_t size, CompactPoint* cp,
445 HeapWord* compact_top);
446
447 // Return a size with adjustments as required of the space.
448 virtual size_t adjust_object_size_v(size_t size) const { return size; }
449
450 protected:
451 // Used during compaction.
452 HeapWord* _first_dead;
453 HeapWord* _end_of_live;
454
455 // Minimum size of a free block.
456 virtual size_t minimum_free_block_size() const { return 0; }
457
458 // This the function is invoked when an allocation of an object covering
459 // "start" to "end occurs crosses the threshold; returns the next
460 // threshold. (The default implementation does nothing.)
461 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* the_end) {
462 return end();
463 }
464
465 // Below are template functions for scan_and_* algorithms (avoiding virtual calls).
466 // The space argument should be a subclass of CompactibleSpace, implementing
467 // scan_limit(), scanned_block_is_obj(), and scanned_block_size(),
468 // and possibly also overriding obj_size(), and adjust_obj_size().
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1 /*
2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
429 // boundary is never crossed.)
430 virtual HeapWord* initialize_threshold() { return end(); }
431
432 // "q" is an object of the given "size" that should be forwarded;
433 // "cp" names the generation ("gen") and containing "this" (which must
434 // also equal "cp->space"). "compact_top" is where in "this" the
435 // next object should be forwarded to. If there is room in "this" for
436 // the object, insert an appropriate forwarding pointer in "q".
437 // If not, go to the next compaction space (there must
438 // be one, since compaction must succeed -- we go to the first space of
439 // the previous generation if necessary, updating "cp"), reset compact_top
440 // and then forward. In either case, returns the new value of "compact_top".
441 // If the forwarding crosses "cp->threshold", invokes the "cross_threshold"
442 // function of the then-current compaction space, and updates "cp->threshold
443 // accordingly".
444 virtual HeapWord* forward(oop q, size_t size, CompactPoint* cp,
445 HeapWord* compact_top);
446
447 // Return a size with adjustments as required of the space.
448 virtual size_t adjust_object_size_v(size_t size) const { return size; }
449
450 void set_first_dead(HeapWord* value) { _first_dead = value; }
451 void set_end_of_live(HeapWord* value) { _end_of_live = value; }
452
453 protected:
454 // Used during compaction.
455 HeapWord* _first_dead;
456 HeapWord* _end_of_live;
457
458 // Minimum size of a free block.
459 virtual size_t minimum_free_block_size() const { return 0; }
460
461 // This the function is invoked when an allocation of an object covering
462 // "start" to "end occurs crosses the threshold; returns the next
463 // threshold. (The default implementation does nothing.)
464 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* the_end) {
465 return end();
466 }
467
468 // Below are template functions for scan_and_* algorithms (avoiding virtual calls).
469 // The space argument should be a subclass of CompactibleSpace, implementing
470 // scan_limit(), scanned_block_is_obj(), and scanned_block_size(),
471 // and possibly also overriding obj_size(), and adjust_obj_size().
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