| /* |
| * Copyright (c) 2000, 2012, 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_MEMORY_SPACE_INLINE_HPP |
| #define SHARE_VM_MEMORY_SPACE_INLINE_HPP |
| |
| #include "gc_interface/collectedHeap.hpp" |
| #include "memory/space.hpp" |
| #include "memory/universe.hpp" |
| #include "runtime/prefetch.inline.hpp" |
| #include "runtime/safepoint.hpp" |
| |
| inline HeapWord* Space::block_start(const void* p) { |
| return block_start_const(p); |
| } |
| |
| #define SCAN_AND_FORWARD(cp,scan_limit,block_is_obj,block_size) { \ |
| /* Compute the new addresses for the live objects and store it in the mark \ |
| * Used by universe::mark_sweep_phase2() \ |
| */ \ |
| HeapWord* compact_top; /* This is where we are currently compacting to. */ \ |
| \ |
| /* We're sure to be here before any objects are compacted into this \ |
| * space, so this is a good time to initialize this: \ |
| */ \ |
| set_compaction_top(bottom()); \ |
| \ |
| if (cp->space == NULL) { \ |
| assert(cp->gen != NULL, "need a generation"); \ |
| assert(cp->threshold == NULL, "just checking"); \ |
| assert(cp->gen->first_compaction_space() == this, "just checking"); \ |
| cp->space = cp->gen->first_compaction_space(); \ |
| compact_top = cp->space->bottom(); \ |
| cp->space->set_compaction_top(compact_top); \ |
| cp->threshold = cp->space->initialize_threshold(); \ |
| } else { \ |
| compact_top = cp->space->compaction_top(); \ |
| } \ |
| \ |
| /* We allow some amount of garbage towards the bottom of the space, so \ |
| * we don't start compacting before there is a significant gain to be made.\ |
| * Occasionally, we want to ensure a full compaction, which is determined \ |
| * by the MarkSweepAlwaysCompactCount parameter. \ |
| */ \ |
| uint invocations = MarkSweep::total_invocations(); \ |
| bool skip_dead = ((invocations % MarkSweepAlwaysCompactCount) != 0); \ |
| \ |
| size_t allowed_deadspace = 0; \ |
| if (skip_dead) { \ |
| const size_t ratio = allowed_dead_ratio(); \ |
| allowed_deadspace = (capacity() * ratio / 100) / HeapWordSize; \ |
| } \ |
| \ |
| HeapWord* q = bottom(); \ |
| HeapWord* t = scan_limit(); \ |
| \ |
| HeapWord* end_of_live= q; /* One byte beyond the last byte of the last \ |
| live object. */ \ |
| HeapWord* first_dead = end();/* The first dead object. */ \ |
| LiveRange* liveRange = NULL; /* The current live range, recorded in the \ |
| first header of preceding free area. */ \ |
| _first_dead = first_dead; \ |
| \ |
| const intx interval = PrefetchScanIntervalInBytes; \ |
| \ |
| while (q < t) { \ |
| assert(!block_is_obj(q) || \ |
| oop(q)->mark()->is_marked() || oop(q)->mark()->is_unlocked() || \ |
| oop(q)->mark()->has_bias_pattern(), \ |
| "these are the only valid states during a mark sweep"); \ |
| if (block_is_obj(q) && oop(q)->is_gc_marked()) { \ |
| /* prefetch beyond q */ \ |
| Prefetch::write(q, interval); \ |
| size_t size = block_size(q); \ |
| compact_top = cp->space->forward(oop(q), size, cp, compact_top); \ |
| q += size; \ |
| end_of_live = q; \ |
| } else { \ |
| /* run over all the contiguous dead objects */ \ |
| HeapWord* end = q; \ |
| do { \ |
| /* prefetch beyond end */ \ |
| Prefetch::write(end, interval); \ |
| end += block_size(end); \ |
| } while (end < t && (!block_is_obj(end) || !oop(end)->is_gc_marked()));\ |
| \ |
| /* see if we might want to pretend this object is alive so that \ |
| * we don't have to compact quite as often. \ |
| */ \ |
| if (allowed_deadspace > 0 && q == compact_top) { \ |
| size_t sz = pointer_delta(end, q); \ |
| if (insert_deadspace(allowed_deadspace, q, sz)) { \ |
| compact_top = cp->space->forward(oop(q), sz, cp, compact_top); \ |
| q = end; \ |
| end_of_live = end; \ |
| continue; \ |
| } \ |
| } \ |
| \ |
| /* otherwise, it really is a free region. */ \ |
| \ |
| /* for the previous LiveRange, record the end of the live objects. */ \ |
| if (liveRange) { \ |
| liveRange->set_end(q); \ |
| } \ |
| \ |
| /* record the current LiveRange object. \ |
| * liveRange->start() is overlaid on the mark word. \ |
| */ \ |
| liveRange = (LiveRange*)q; \ |
| liveRange->set_start(end); \ |
| liveRange->set_end(end); \ |
| \ |
| /* see if this is the first dead region. */ \ |
| if (q < first_dead) { \ |
| first_dead = q; \ |
| } \ |
| \ |
| /* move on to the next object */ \ |
| q = end; \ |
| } \ |
| } \ |
| \ |
| assert(q == t, "just checking"); \ |
| if (liveRange != NULL) { \ |
| liveRange->set_end(q); \ |
| } \ |
| _end_of_live = end_of_live; \ |
| if (end_of_live < first_dead) { \ |
| first_dead = end_of_live; \ |
| } \ |
| _first_dead = first_dead; \ |
| \ |
| /* save the compaction_top of the compaction space. */ \ |
| cp->space->set_compaction_top(compact_top); \ |
| } |
| |
| #define SCAN_AND_ADJUST_POINTERS(adjust_obj_size) { \ |
| /* adjust all the interior pointers to point at the new locations of objects \ |
| * Used by MarkSweep::mark_sweep_phase3() */ \ |
| \ |
| HeapWord* q = bottom(); \ |
| HeapWord* t = _end_of_live; /* Established by "prepare_for_compaction". */ \ |
| \ |
| assert(_first_dead <= _end_of_live, "Stands to reason, no?"); \ |
| \ |
| if (q < t && _first_dead > q && \ |
| !oop(q)->is_gc_marked()) { \ |
| /* we have a chunk of the space which hasn't moved and we've \ |
| * reinitialized the mark word during the previous pass, so we can't \ |
| * use is_gc_marked for the traversal. */ \ |
| HeapWord* end = _first_dead; \ |
| \ |
| while (q < end) { \ |
| /* I originally tried to conjoin "block_start(q) == q" to the \ |
| * assertion below, but that doesn't work, because you can't \ |
| * accurately traverse previous objects to get to the current one \ |
| * after their pointers have been \ |
| * updated, until the actual compaction is done. dld, 4/00 */ \ |
| assert(block_is_obj(q), \ |
| "should be at block boundaries, and should be looking at objs"); \ |
| \ |
| /* point all the oops to the new location */ \ |
| size_t size = oop(q)->adjust_pointers(); \ |
| size = adjust_obj_size(size); \ |
| \ |
| q += size; \ |
| } \ |
| \ |
| if (_first_dead == t) { \ |
| q = t; \ |
| } else { \ |
| /* $$$ This is funky. Using this to read the previously written \ |
| * LiveRange. See also use below. */ \ |
| q = (HeapWord*)oop(_first_dead)->mark()->decode_pointer(); \ |
| } \ |
| } \ |
| \ |
| const intx interval = PrefetchScanIntervalInBytes; \ |
| \ |
| debug_only(HeapWord* prev_q = NULL); \ |
| while (q < t) { \ |
| /* prefetch beyond q */ \ |
| Prefetch::write(q, interval); \ |
| if (oop(q)->is_gc_marked()) { \ |
| /* q is alive */ \ |
| /* point all the oops to the new location */ \ |
| size_t size = oop(q)->adjust_pointers(); \ |
| size = adjust_obj_size(size); \ |
| debug_only(prev_q = q); \ |
| q += size; \ |
| } else { \ |
| /* q is not a live object, so its mark should point at the next \ |
| * live object */ \ |
| debug_only(prev_q = q); \ |
| q = (HeapWord*) oop(q)->mark()->decode_pointer(); \ |
| assert(q > prev_q, "we should be moving forward through memory"); \ |
| } \ |
| } \ |
| \ |
| assert(q == t, "just checking"); \ |
| } |
| |
| #define SCAN_AND_COMPACT(obj_size) { \ |
| /* Copy all live objects to their new location \ |
| * Used by MarkSweep::mark_sweep_phase4() */ \ |
| \ |
| HeapWord* q = bottom(); \ |
| HeapWord* const t = _end_of_live; \ |
| debug_only(HeapWord* prev_q = NULL); \ |
| \ |
| if (q < t && _first_dead > q && \ |
| !oop(q)->is_gc_marked()) { \ |
| debug_only( \ |
| /* we have a chunk of the space which hasn't moved and we've reinitialized \ |
| * the mark word during the previous pass, so we can't use is_gc_marked for \ |
| * the traversal. */ \ |
| HeapWord* const end = _first_dead; \ |
| \ |
| while (q < end) { \ |
| size_t size = obj_size(q); \ |
| assert(!oop(q)->is_gc_marked(), \ |
| "should be unmarked (special dense prefix handling)"); \ |
| debug_only(prev_q = q); \ |
| q += size; \ |
| } \ |
| ) /* debug_only */ \ |
| \ |
| if (_first_dead == t) { \ |
| q = t; \ |
| } else { \ |
| /* $$$ Funky */ \ |
| q = (HeapWord*) oop(_first_dead)->mark()->decode_pointer(); \ |
| } \ |
| } \ |
| \ |
| const intx scan_interval = PrefetchScanIntervalInBytes; \ |
| const intx copy_interval = PrefetchCopyIntervalInBytes; \ |
| while (q < t) { \ |
| if (!oop(q)->is_gc_marked()) { \ |
| /* mark is pointer to next marked oop */ \ |
| debug_only(prev_q = q); \ |
| q = (HeapWord*) oop(q)->mark()->decode_pointer(); \ |
| assert(q > prev_q, "we should be moving forward through memory"); \ |
| } else { \ |
| /* prefetch beyond q */ \ |
| Prefetch::read(q, scan_interval); \ |
| \ |
| /* size and destination */ \ |
| size_t size = obj_size(q); \ |
| HeapWord* compaction_top = (HeapWord*)oop(q)->forwardee(); \ |
| \ |
| /* prefetch beyond compaction_top */ \ |
| Prefetch::write(compaction_top, copy_interval); \ |
| \ |
| /* copy object and reinit its mark */ \ |
| assert(q != compaction_top, "everything in this pass should be moving"); \ |
| Copy::aligned_conjoint_words(q, compaction_top, size); \ |
| oop(compaction_top)->init_mark(); \ |
| assert(oop(compaction_top)->klass() != NULL, "should have a class"); \ |
| \ |
| debug_only(prev_q = q); \ |
| q += size; \ |
| } \ |
| } \ |
| \ |
| /* Let's remember if we were empty before we did the compaction. */ \ |
| bool was_empty = used_region().is_empty(); \ |
| /* Reset space after compaction is complete */ \ |
| reset_after_compaction(); \ |
| /* We do this clear, below, since it has overloaded meanings for some */ \ |
| /* space subtypes. For example, OffsetTableContigSpace's that were */ \ |
| /* compacted into will have had their offset table thresholds updated */ \ |
| /* continuously, but those that weren't need to have their thresholds */ \ |
| /* re-initialized. Also mangles unused area for debugging. */ \ |
| if (used_region().is_empty()) { \ |
| if (!was_empty) clear(SpaceDecorator::Mangle); \ |
| } else { \ |
| if (ZapUnusedHeapArea) mangle_unused_area(); \ |
| } \ |
| } |
| |
| inline HeapWord* OffsetTableContigSpace::allocate(size_t size) { |
| HeapWord* res = ContiguousSpace::allocate(size); |
| if (res != NULL) { |
| _offsets.alloc_block(res, size); |
| } |
| return res; |
| } |
| |
| // Because of the requirement of keeping "_offsets" up to date with the |
| // allocations, we sequentialize these with a lock. Therefore, best if |
| // this is used for larger LAB allocations only. |
| inline HeapWord* OffsetTableContigSpace::par_allocate(size_t size) { |
| MutexLocker x(&_par_alloc_lock); |
| // This ought to be just "allocate", because of the lock above, but that |
| // ContiguousSpace::allocate asserts that either the allocating thread |
| // holds the heap lock or it is the VM thread and we're at a safepoint. |
| // The best I (dld) could figure was to put a field in ContiguousSpace |
| // meaning "locking at safepoint taken care of", and set/reset that |
| // here. But this will do for now, especially in light of the comment |
| // above. Perhaps in the future some lock-free manner of keeping the |
| // coordination. |
| HeapWord* res = ContiguousSpace::par_allocate(size); |
| if (res != NULL) { |
| _offsets.alloc_block(res, size); |
| } |
| return res; |
| } |
| |
| inline HeapWord* |
| OffsetTableContigSpace::block_start_const(const void* p) const { |
| return _offsets.block_start(p); |
| } |
| |
| #endif // SHARE_VM_MEMORY_SPACE_INLINE_HPP |
