--- old/src/share/vm/memory/space.cpp 2015-05-13 13:58:50.297077180 +0200 +++ /dev/null 2015-03-18 17:10:38.111854831 +0100 @@ -1,787 +0,0 @@ -/* - * Copyright (c) 1997, 2015, 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. - * - */ - -#include "precompiled.hpp" -#include "classfile/systemDictionary.hpp" -#include "classfile/vmSymbols.hpp" -#include "gc_implementation/shared/liveRange.hpp" -#include "gc_implementation/shared/spaceDecorator.hpp" -#include "gc_interface/collectedHeap.inline.hpp" -#include "memory/blockOffsetTable.inline.hpp" -#include "memory/defNewGeneration.hpp" -#include "memory/genCollectedHeap.hpp" -#include "memory/genOopClosures.inline.hpp" -#include "memory/space.hpp" -#include "memory/space.inline.hpp" -#include "memory/universe.inline.hpp" -#include "oops/oop.inline.hpp" -#include "runtime/java.hpp" -#include "runtime/atomic.inline.hpp" -#include "runtime/prefetch.inline.hpp" -#include "runtime/orderAccess.inline.hpp" -#include "runtime/safepoint.hpp" -#include "utilities/copy.hpp" -#include "utilities/globalDefinitions.hpp" -#include "utilities/macros.hpp" - -HeapWord* DirtyCardToOopClosure::get_actual_top(HeapWord* top, - HeapWord* top_obj) { - if (top_obj != NULL) { - if (_sp->block_is_obj(top_obj)) { - if (_precision == CardTableModRefBS::ObjHeadPreciseArray) { - if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) { - // An arrayOop is starting on the dirty card - since we do exact - // store checks for objArrays we are done. - } else { - // Otherwise, it is possible that the object starting on the dirty - // card spans the entire card, and that the store happened on a - // later card. Figure out where the object ends. - // Use the block_size() method of the space over which - // the iteration is being done. That space (e.g. CMS) may have - // specific requirements on object sizes which will - // be reflected in the block_size() method. - top = top_obj + oop(top_obj)->size(); - } - } - } else { - top = top_obj; - } - } else { - assert(top == _sp->end(), "only case where top_obj == NULL"); - } - return top; -} - -void DirtyCardToOopClosure::walk_mem_region(MemRegion mr, - HeapWord* bottom, - HeapWord* top) { - // 1. Blocks may or may not be objects. - // 2. Even when a block_is_obj(), it may not entirely - // occupy the block if the block quantum is larger than - // the object size. - // We can and should try to optimize by calling the non-MemRegion - // version of oop_iterate() for all but the extremal objects - // (for which we need to call the MemRegion version of - // oop_iterate()) To be done post-beta XXX - for (; bottom < top; bottom += _sp->block_size(bottom)) { - // As in the case of contiguous space above, we'd like to - // just use the value returned by oop_iterate to increment the - // current pointer; unfortunately, that won't work in CMS because - // we'd need an interface change (it seems) to have the space - // "adjust the object size" (for instance pad it up to its - // block alignment or minimum block size restrictions. XXX - if (_sp->block_is_obj(bottom) && - !_sp->obj_allocated_since_save_marks(oop(bottom))) { - oop(bottom)->oop_iterate(_cl, mr); - } - } -} - -// We get called with "mr" representing the dirty region -// that we want to process. Because of imprecise marking, -// we may need to extend the incoming "mr" to the right, -// and scan more. However, because we may already have -// scanned some of that extended region, we may need to -// trim its right-end back some so we do not scan what -// we (or another worker thread) may already have scanned -// or planning to scan. -void DirtyCardToOopClosure::do_MemRegion(MemRegion mr) { - - // Some collectors need to do special things whenever their dirty - // cards are processed. For instance, CMS must remember mutator updates - // (i.e. dirty cards) so as to re-scan mutated objects. - // Such work can be piggy-backed here on dirty card scanning, so as to make - // it slightly more efficient than doing a complete non-destructive pre-scan - // of the card table. - MemRegionClosure* pCl = _sp->preconsumptionDirtyCardClosure(); - if (pCl != NULL) { - pCl->do_MemRegion(mr); - } - - HeapWord* bottom = mr.start(); - HeapWord* last = mr.last(); - HeapWord* top = mr.end(); - HeapWord* bottom_obj; - HeapWord* top_obj; - - assert(_precision == CardTableModRefBS::ObjHeadPreciseArray || - _precision == CardTableModRefBS::Precise, - "Only ones we deal with for now."); - - assert(_precision != CardTableModRefBS::ObjHeadPreciseArray || - _cl->idempotent() || _last_bottom == NULL || - top <= _last_bottom, - "Not decreasing"); - NOT_PRODUCT(_last_bottom = mr.start()); - - bottom_obj = _sp->block_start(bottom); - top_obj = _sp->block_start(last); - - assert(bottom_obj <= bottom, "just checking"); - assert(top_obj <= top, "just checking"); - - // Given what we think is the top of the memory region and - // the start of the object at the top, get the actual - // value of the top. - top = get_actual_top(top, top_obj); - - // If the previous call did some part of this region, don't redo. - if (_precision == CardTableModRefBS::ObjHeadPreciseArray && - _min_done != NULL && - _min_done < top) { - top = _min_done; - } - - // Top may have been reset, and in fact may be below bottom, - // e.g. the dirty card region is entirely in a now free object - // -- something that could happen with a concurrent sweeper. - bottom = MIN2(bottom, top); - MemRegion extended_mr = MemRegion(bottom, top); - assert(bottom <= top && - (_precision != CardTableModRefBS::ObjHeadPreciseArray || - _min_done == NULL || - top <= _min_done), - "overlap!"); - - // Walk the region if it is not empty; otherwise there is nothing to do. - if (!extended_mr.is_empty()) { - walk_mem_region(extended_mr, bottom_obj, top); - } - - // An idempotent closure might be applied in any order, so we don't - // record a _min_done for it. - if (!_cl->idempotent()) { - _min_done = bottom; - } else { - assert(_min_done == _last_explicit_min_done, - "Don't update _min_done for idempotent cl"); - } -} - -DirtyCardToOopClosure* Space::new_dcto_cl(ExtendedOopClosure* cl, - CardTableModRefBS::PrecisionStyle precision, - HeapWord* boundary) { - return new DirtyCardToOopClosure(this, cl, precision, boundary); -} - -HeapWord* ContiguousSpaceDCTOC::get_actual_top(HeapWord* top, - HeapWord* top_obj) { - if (top_obj != NULL && top_obj < (_sp->toContiguousSpace())->top()) { - if (_precision == CardTableModRefBS::ObjHeadPreciseArray) { - if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) { - // An arrayOop is starting on the dirty card - since we do exact - // store checks for objArrays we are done. - } else { - // Otherwise, it is possible that the object starting on the dirty - // card spans the entire card, and that the store happened on a - // later card. Figure out where the object ends. - assert(_sp->block_size(top_obj) == (size_t) oop(top_obj)->size(), - "Block size and object size mismatch"); - top = top_obj + oop(top_obj)->size(); - } - } - } else { - top = (_sp->toContiguousSpace())->top(); - } - return top; -} - -void Filtering_DCTOC::walk_mem_region(MemRegion mr, - HeapWord* bottom, - HeapWord* top) { - // Note that this assumption won't hold if we have a concurrent - // collector in this space, which may have freed up objects after - // they were dirtied and before the stop-the-world GC that is - // examining cards here. - assert(bottom < top, "ought to be at least one obj on a dirty card."); - - if (_boundary != NULL) { - // We have a boundary outside of which we don't want to look - // at objects, so create a filtering closure around the - // oop closure before walking the region. - FilteringClosure filter(_boundary, _cl); - walk_mem_region_with_cl(mr, bottom, top, &filter); - } else { - // No boundary, simply walk the heap with the oop closure. - walk_mem_region_with_cl(mr, bottom, top, _cl); - } - -} - -// We must replicate this so that the static type of "FilteringClosure" -// (see above) is apparent at the oop_iterate calls. -#define ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(ClosureType) \ -void ContiguousSpaceDCTOC::walk_mem_region_with_cl(MemRegion mr, \ - HeapWord* bottom, \ - HeapWord* top, \ - ClosureType* cl) { \ - bottom += oop(bottom)->oop_iterate(cl, mr); \ - if (bottom < top) { \ - HeapWord* next_obj = bottom + oop(bottom)->size(); \ - while (next_obj < top) { \ - /* Bottom lies entirely below top, so we can call the */ \ - /* non-memRegion version of oop_iterate below. */ \ - oop(bottom)->oop_iterate(cl); \ - bottom = next_obj; \ - next_obj = bottom + oop(bottom)->size(); \ - } \ - /* Last object. */ \ - oop(bottom)->oop_iterate(cl, mr); \ - } \ -} - -// (There are only two of these, rather than N, because the split is due -// only to the introduction of the FilteringClosure, a local part of the -// impl of this abstraction.) -ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(ExtendedOopClosure) -ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(FilteringClosure) - -DirtyCardToOopClosure* -ContiguousSpace::new_dcto_cl(ExtendedOopClosure* cl, - CardTableModRefBS::PrecisionStyle precision, - HeapWord* boundary) { - return new ContiguousSpaceDCTOC(this, cl, precision, boundary); -} - -void Space::initialize(MemRegion mr, - bool clear_space, - bool mangle_space) { - HeapWord* bottom = mr.start(); - HeapWord* end = mr.end(); - assert(Universe::on_page_boundary(bottom) && Universe::on_page_boundary(end), - "invalid space boundaries"); - set_bottom(bottom); - set_end(end); - if (clear_space) clear(mangle_space); -} - -void Space::clear(bool mangle_space) { - if (ZapUnusedHeapArea && mangle_space) { - mangle_unused_area(); - } -} - -ContiguousSpace::ContiguousSpace(): CompactibleSpace(), _top(NULL), - _concurrent_iteration_safe_limit(NULL) { - _mangler = new GenSpaceMangler(this); -} - -ContiguousSpace::~ContiguousSpace() { - delete _mangler; -} - -void ContiguousSpace::initialize(MemRegion mr, - bool clear_space, - bool mangle_space) -{ - CompactibleSpace::initialize(mr, clear_space, mangle_space); - set_concurrent_iteration_safe_limit(top()); -} - -void ContiguousSpace::clear(bool mangle_space) { - set_top(bottom()); - set_saved_mark(); - CompactibleSpace::clear(mangle_space); -} - -bool ContiguousSpace::is_free_block(const HeapWord* p) const { - return p >= _top; -} - -void OffsetTableContigSpace::clear(bool mangle_space) { - ContiguousSpace::clear(mangle_space); - _offsets.initialize_threshold(); -} - -void OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) { - Space::set_bottom(new_bottom); - _offsets.set_bottom(new_bottom); -} - -void OffsetTableContigSpace::set_end(HeapWord* new_end) { - // Space should not advertise an increase in size - // until after the underlying offset table has been enlarged. - _offsets.resize(pointer_delta(new_end, bottom())); - Space::set_end(new_end); -} - -#ifndef PRODUCT - -void ContiguousSpace::set_top_for_allocations(HeapWord* v) { - mangler()->set_top_for_allocations(v); -} -void ContiguousSpace::set_top_for_allocations() { - mangler()->set_top_for_allocations(top()); -} -void ContiguousSpace::check_mangled_unused_area(HeapWord* limit) { - mangler()->check_mangled_unused_area(limit); -} - -void ContiguousSpace::check_mangled_unused_area_complete() { - mangler()->check_mangled_unused_area_complete(); -} - -// Mangled only the unused space that has not previously -// been mangled and that has not been allocated since being -// mangled. -void ContiguousSpace::mangle_unused_area() { - mangler()->mangle_unused_area(); -} -void ContiguousSpace::mangle_unused_area_complete() { - mangler()->mangle_unused_area_complete(); -} -#endif // NOT_PRODUCT - -void CompactibleSpace::initialize(MemRegion mr, - bool clear_space, - bool mangle_space) { - Space::initialize(mr, clear_space, mangle_space); - set_compaction_top(bottom()); - _next_compaction_space = NULL; -} - -void CompactibleSpace::clear(bool mangle_space) { - Space::clear(mangle_space); - _compaction_top = bottom(); -} - -HeapWord* CompactibleSpace::forward(oop q, size_t size, - CompactPoint* cp, HeapWord* compact_top) { - // q is alive - // First check if we should switch compaction space - assert(this == cp->space, "'this' should be current compaction space."); - size_t compaction_max_size = pointer_delta(end(), compact_top); - while (size > compaction_max_size) { - // switch to next compaction space - cp->space->set_compaction_top(compact_top); - cp->space = cp->space->next_compaction_space(); - if (cp->space == NULL) { - cp->gen = GenCollectedHeap::heap()->young_gen(); - assert(cp->gen != NULL, "compaction must succeed"); - cp->space = cp->gen->first_compaction_space(); - assert(cp->space != NULL, "generation must have a first compaction space"); - } - compact_top = cp->space->bottom(); - cp->space->set_compaction_top(compact_top); - cp->threshold = cp->space->initialize_threshold(); - compaction_max_size = pointer_delta(cp->space->end(), compact_top); - } - - // store the forwarding pointer into the mark word - if ((HeapWord*)q != compact_top) { - q->forward_to(oop(compact_top)); - assert(q->is_gc_marked(), "encoding the pointer should preserve the mark"); - } else { - // if the object isn't moving we can just set the mark to the default - // mark and handle it specially later on. - q->init_mark(); - assert(q->forwardee() == NULL, "should be forwarded to NULL"); - } - - compact_top += size; - - // we need to update the offset table so that the beginnings of objects can be - // found during scavenge. Note that we are updating the offset table based on - // where the object will be once the compaction phase finishes. - if (compact_top > cp->threshold) - cp->threshold = - cp->space->cross_threshold(compact_top - size, compact_top); - return compact_top; -} - - -bool CompactibleSpace::insert_deadspace(size_t& allowed_deadspace_words, - HeapWord* q, size_t deadlength) { - if (allowed_deadspace_words >= deadlength) { - allowed_deadspace_words -= deadlength; - CollectedHeap::fill_with_object(q, deadlength); - oop(q)->set_mark(oop(q)->mark()->set_marked()); - assert((int) deadlength == oop(q)->size(), "bad filler object size"); - // Recall that we required "q == compaction_top". - return true; - } else { - allowed_deadspace_words = 0; - return false; - } -} - -void ContiguousSpace::prepare_for_compaction(CompactPoint* cp) { - scan_and_forward(this, cp); -} - -void CompactibleSpace::adjust_pointers() { - // Check first is there is any work to do. - if (used() == 0) { - return; // Nothing to do. - } - - scan_and_adjust_pointers(this); -} - -void CompactibleSpace::compact() { - scan_and_compact(this); -} - -void Space::print_short() const { print_short_on(tty); } - -void Space::print_short_on(outputStream* st) const { - st->print(" space " SIZE_FORMAT "K, %3d%% used", capacity() / K, - (int) ((double) used() * 100 / capacity())); -} - -void Space::print() const { print_on(tty); } - -void Space::print_on(outputStream* st) const { - print_short_on(st); - st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ")", - p2i(bottom()), p2i(end())); -} - -void ContiguousSpace::print_on(outputStream* st) const { - print_short_on(st); - st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")", - p2i(bottom()), p2i(top()), p2i(end())); -} - -void OffsetTableContigSpace::print_on(outputStream* st) const { - print_short_on(st); - st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " - INTPTR_FORMAT ", " INTPTR_FORMAT ")", - p2i(bottom()), p2i(top()), p2i(_offsets.threshold()), p2i(end())); -} - -void ContiguousSpace::verify() const { - HeapWord* p = bottom(); - HeapWord* t = top(); - HeapWord* prev_p = NULL; - while (p < t) { - oop(p)->verify(); - prev_p = p; - p += oop(p)->size(); - } - guarantee(p == top(), "end of last object must match end of space"); - if (top() != end()) { - guarantee(top() == block_start_const(end()-1) && - top() == block_start_const(top()), - "top should be start of unallocated block, if it exists"); - } -} - -void Space::oop_iterate(ExtendedOopClosure* blk) { - ObjectToOopClosure blk2(blk); - object_iterate(&blk2); -} - -bool Space::obj_is_alive(const HeapWord* p) const { - assert (block_is_obj(p), "The address should point to an object"); - return true; -} - -#if INCLUDE_ALL_GCS -#define ContigSpace_PAR_OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \ - \ - void ContiguousSpace::par_oop_iterate(MemRegion mr, OopClosureType* blk) {\ - HeapWord* obj_addr = mr.start(); \ - HeapWord* t = mr.end(); \ - while (obj_addr < t) { \ - assert(oop(obj_addr)->is_oop(), "Should be an oop"); \ - obj_addr += oop(obj_addr)->oop_iterate(blk); \ - } \ - } - - ALL_PAR_OOP_ITERATE_CLOSURES(ContigSpace_PAR_OOP_ITERATE_DEFN) - -#undef ContigSpace_PAR_OOP_ITERATE_DEFN -#endif // INCLUDE_ALL_GCS - -void ContiguousSpace::oop_iterate(ExtendedOopClosure* blk) { - if (is_empty()) return; - HeapWord* obj_addr = bottom(); - HeapWord* t = top(); - // Could call objects iterate, but this is easier. - while (obj_addr < t) { - obj_addr += oop(obj_addr)->oop_iterate(blk); - } -} - -void ContiguousSpace::object_iterate(ObjectClosure* blk) { - if (is_empty()) return; - WaterMark bm = bottom_mark(); - object_iterate_from(bm, blk); -} - -// For a ContiguousSpace object_iterate() and safe_object_iterate() -// are the same. -void ContiguousSpace::safe_object_iterate(ObjectClosure* blk) { - object_iterate(blk); -} - -void ContiguousSpace::object_iterate_from(WaterMark mark, ObjectClosure* blk) { - assert(mark.space() == this, "Mark does not match space"); - HeapWord* p = mark.point(); - while (p < top()) { - blk->do_object(oop(p)); - p += oop(p)->size(); - } -} - -HeapWord* -ContiguousSpace::object_iterate_careful(ObjectClosureCareful* blk) { - HeapWord * limit = concurrent_iteration_safe_limit(); - assert(limit <= top(), "sanity check"); - for (HeapWord* p = bottom(); p < limit;) { - size_t size = blk->do_object_careful(oop(p)); - if (size == 0) { - return p; // failed at p - } else { - p += size; - } - } - return NULL; // all done -} - -#define ContigSpace_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \ - \ -void ContiguousSpace:: \ -oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk) { \ - HeapWord* t; \ - HeapWord* p = saved_mark_word(); \ - assert(p != NULL, "expected saved mark"); \ - \ - const intx interval = PrefetchScanIntervalInBytes; \ - do { \ - t = top(); \ - while (p < t) { \ - Prefetch::write(p, interval); \ - debug_only(HeapWord* prev = p); \ - oop m = oop(p); \ - p += m->oop_iterate(blk); \ - } \ - } while (t < top()); \ - \ - set_saved_mark_word(p); \ -} - -ALL_SINCE_SAVE_MARKS_CLOSURES(ContigSpace_OOP_SINCE_SAVE_MARKS_DEFN) - -#undef ContigSpace_OOP_SINCE_SAVE_MARKS_DEFN - -// Very general, slow implementation. -HeapWord* ContiguousSpace::block_start_const(const void* p) const { - assert(MemRegion(bottom(), end()).contains(p), - err_msg("p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")", - p2i(p), p2i(bottom()), p2i(end()))); - if (p >= top()) { - return top(); - } else { - HeapWord* last = bottom(); - HeapWord* cur = last; - while (cur <= p) { - last = cur; - cur += oop(cur)->size(); - } - assert(oop(last)->is_oop(), - err_msg(PTR_FORMAT " should be an object start", p2i(last))); - return last; - } -} - -size_t ContiguousSpace::block_size(const HeapWord* p) const { - assert(MemRegion(bottom(), end()).contains(p), - err_msg("p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")", - p2i(p), p2i(bottom()), p2i(end()))); - HeapWord* current_top = top(); - assert(p <= current_top, - err_msg("p > current top - p: " PTR_FORMAT ", current top: " PTR_FORMAT, - p2i(p), p2i(current_top))); - assert(p == current_top || oop(p)->is_oop(), - err_msg("p (" PTR_FORMAT ") is not a block start - " - "current_top: " PTR_FORMAT ", is_oop: %s", - p2i(p), p2i(current_top), BOOL_TO_STR(oop(p)->is_oop()))); - if (p < current_top) { - return oop(p)->size(); - } else { - assert(p == current_top, "just checking"); - return pointer_delta(end(), (HeapWord*) p); - } -} - -// This version requires locking. -inline HeapWord* ContiguousSpace::allocate_impl(size_t size) { - assert(Heap_lock->owned_by_self() || - (SafepointSynchronize::is_at_safepoint() && Thread::current()->is_VM_thread()), - "not locked"); - HeapWord* obj = top(); - if (pointer_delta(end(), obj) >= size) { - HeapWord* new_top = obj + size; - set_top(new_top); - assert(is_aligned(obj) && is_aligned(new_top), "checking alignment"); - return obj; - } else { - return NULL; - } -} - -// This version is lock-free. -inline HeapWord* ContiguousSpace::par_allocate_impl(size_t size) { - do { - HeapWord* obj = top(); - if (pointer_delta(end(), obj) >= size) { - HeapWord* new_top = obj + size; - HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj); - // result can be one of two: - // the old top value: the exchange succeeded - // otherwise: the new value of the top is returned. - if (result == obj) { - assert(is_aligned(obj) && is_aligned(new_top), "checking alignment"); - return obj; - } - } else { - return NULL; - } - } while (true); -} - -HeapWord* ContiguousSpace::allocate_aligned(size_t size) { - assert(Heap_lock->owned_by_self() || (SafepointSynchronize::is_at_safepoint() && Thread::current()->is_VM_thread()), "not locked"); - HeapWord* end_value = end(); - - HeapWord* obj = CollectedHeap::align_allocation_or_fail(top(), end_value, SurvivorAlignmentInBytes); - if (obj == NULL) { - return NULL; - } - - if (pointer_delta(end_value, obj) >= size) { - HeapWord* new_top = obj + size; - set_top(new_top); - assert(is_ptr_aligned(obj, SurvivorAlignmentInBytes) && is_aligned(new_top), - "checking alignment"); - return obj; - } else { - set_top(obj); - return NULL; - } -} - -// Requires locking. -HeapWord* ContiguousSpace::allocate(size_t size) { - return allocate_impl(size); -} - -// Lock-free. -HeapWord* ContiguousSpace::par_allocate(size_t size) { - return par_allocate_impl(size); -} - -void ContiguousSpace::allocate_temporary_filler(int factor) { - // allocate temporary type array decreasing free size with factor 'factor' - assert(factor >= 0, "just checking"); - size_t size = pointer_delta(end(), top()); - - // if space is full, return - if (size == 0) return; - - if (factor > 0) { - size -= size/factor; - } - size = align_object_size(size); - - const size_t array_header_size = typeArrayOopDesc::header_size(T_INT); - if (size >= (size_t)align_object_size(array_header_size)) { - size_t length = (size - array_header_size) * (HeapWordSize / sizeof(jint)); - // allocate uninitialized int array - typeArrayOop t = (typeArrayOop) allocate(size); - assert(t != NULL, "allocation should succeed"); - t->set_mark(markOopDesc::prototype()); - t->set_klass(Universe::intArrayKlassObj()); - t->set_length((int)length); - } else { - assert(size == CollectedHeap::min_fill_size(), - "size for smallest fake object doesn't match"); - instanceOop obj = (instanceOop) allocate(size); - obj->set_mark(markOopDesc::prototype()); - obj->set_klass_gap(0); - obj->set_klass(SystemDictionary::Object_klass()); - } -} - -HeapWord* OffsetTableContigSpace::initialize_threshold() { - return _offsets.initialize_threshold(); -} - -HeapWord* OffsetTableContigSpace::cross_threshold(HeapWord* start, HeapWord* end) { - _offsets.alloc_block(start, end); - return _offsets.threshold(); -} - -OffsetTableContigSpace::OffsetTableContigSpace(BlockOffsetSharedArray* sharedOffsetArray, - MemRegion mr) : - _offsets(sharedOffsetArray, mr), - _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true) -{ - _offsets.set_contig_space(this); - initialize(mr, SpaceDecorator::Clear, SpaceDecorator::Mangle); -} - -#define OBJ_SAMPLE_INTERVAL 0 -#define BLOCK_SAMPLE_INTERVAL 100 - -void OffsetTableContigSpace::verify() const { - HeapWord* p = bottom(); - HeapWord* prev_p = NULL; - int objs = 0; - int blocks = 0; - - if (VerifyObjectStartArray) { - _offsets.verify(); - } - - while (p < top()) { - size_t size = oop(p)->size(); - // For a sampling of objects in the space, find it using the - // block offset table. - if (blocks == BLOCK_SAMPLE_INTERVAL) { - guarantee(p == block_start_const(p + (size/2)), - "check offset computation"); - blocks = 0; - } else { - blocks++; - } - - if (objs == OBJ_SAMPLE_INTERVAL) { - oop(p)->verify(); - objs = 0; - } else { - objs++; - } - prev_p = p; - p += size; - } - guarantee(p == top(), "end of last object must match end of space"); -} - - -size_t TenuredSpace::allowed_dead_ratio() const { - return MarkSweepDeadRatio; -} --- /dev/null 2015-03-18 17:10:38.111854831 +0100 +++ new/src/share/vm/gc/shared/space.cpp 2015-05-13 13:58:50.117069701 +0200 @@ -0,0 +1,787 @@ +/* + * Copyright (c) 1997, 2015, 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. + * + */ + +#include "precompiled.hpp" +#include "classfile/systemDictionary.hpp" +#include "classfile/vmSymbols.hpp" +#include "gc/serial/defNewGeneration.hpp" +#include "gc/shared/blockOffsetTable.inline.hpp" +#include "gc/shared/collectedHeap.inline.hpp" +#include "gc/shared/genCollectedHeap.hpp" +#include "gc/shared/genOopClosures.inline.hpp" +#include "gc/shared/liveRange.hpp" +#include "gc/shared/space.hpp" +#include "gc/shared/space.inline.hpp" +#include "gc/shared/spaceDecorator.hpp" +#include "memory/universe.inline.hpp" +#include "oops/oop.inline.hpp" +#include "runtime/atomic.inline.hpp" +#include "runtime/java.hpp" +#include "runtime/orderAccess.inline.hpp" +#include "runtime/prefetch.inline.hpp" +#include "runtime/safepoint.hpp" +#include "utilities/copy.hpp" +#include "utilities/globalDefinitions.hpp" +#include "utilities/macros.hpp" + +HeapWord* DirtyCardToOopClosure::get_actual_top(HeapWord* top, + HeapWord* top_obj) { + if (top_obj != NULL) { + if (_sp->block_is_obj(top_obj)) { + if (_precision == CardTableModRefBS::ObjHeadPreciseArray) { + if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) { + // An arrayOop is starting on the dirty card - since we do exact + // store checks for objArrays we are done. + } else { + // Otherwise, it is possible that the object starting on the dirty + // card spans the entire card, and that the store happened on a + // later card. Figure out where the object ends. + // Use the block_size() method of the space over which + // the iteration is being done. That space (e.g. CMS) may have + // specific requirements on object sizes which will + // be reflected in the block_size() method. + top = top_obj + oop(top_obj)->size(); + } + } + } else { + top = top_obj; + } + } else { + assert(top == _sp->end(), "only case where top_obj == NULL"); + } + return top; +} + +void DirtyCardToOopClosure::walk_mem_region(MemRegion mr, + HeapWord* bottom, + HeapWord* top) { + // 1. Blocks may or may not be objects. + // 2. Even when a block_is_obj(), it may not entirely + // occupy the block if the block quantum is larger than + // the object size. + // We can and should try to optimize by calling the non-MemRegion + // version of oop_iterate() for all but the extremal objects + // (for which we need to call the MemRegion version of + // oop_iterate()) To be done post-beta XXX + for (; bottom < top; bottom += _sp->block_size(bottom)) { + // As in the case of contiguous space above, we'd like to + // just use the value returned by oop_iterate to increment the + // current pointer; unfortunately, that won't work in CMS because + // we'd need an interface change (it seems) to have the space + // "adjust the object size" (for instance pad it up to its + // block alignment or minimum block size restrictions. XXX + if (_sp->block_is_obj(bottom) && + !_sp->obj_allocated_since_save_marks(oop(bottom))) { + oop(bottom)->oop_iterate(_cl, mr); + } + } +} + +// We get called with "mr" representing the dirty region +// that we want to process. Because of imprecise marking, +// we may need to extend the incoming "mr" to the right, +// and scan more. However, because we may already have +// scanned some of that extended region, we may need to +// trim its right-end back some so we do not scan what +// we (or another worker thread) may already have scanned +// or planning to scan. +void DirtyCardToOopClosure::do_MemRegion(MemRegion mr) { + + // Some collectors need to do special things whenever their dirty + // cards are processed. For instance, CMS must remember mutator updates + // (i.e. dirty cards) so as to re-scan mutated objects. + // Such work can be piggy-backed here on dirty card scanning, so as to make + // it slightly more efficient than doing a complete non-destructive pre-scan + // of the card table. + MemRegionClosure* pCl = _sp->preconsumptionDirtyCardClosure(); + if (pCl != NULL) { + pCl->do_MemRegion(mr); + } + + HeapWord* bottom = mr.start(); + HeapWord* last = mr.last(); + HeapWord* top = mr.end(); + HeapWord* bottom_obj; + HeapWord* top_obj; + + assert(_precision == CardTableModRefBS::ObjHeadPreciseArray || + _precision == CardTableModRefBS::Precise, + "Only ones we deal with for now."); + + assert(_precision != CardTableModRefBS::ObjHeadPreciseArray || + _cl->idempotent() || _last_bottom == NULL || + top <= _last_bottom, + "Not decreasing"); + NOT_PRODUCT(_last_bottom = mr.start()); + + bottom_obj = _sp->block_start(bottom); + top_obj = _sp->block_start(last); + + assert(bottom_obj <= bottom, "just checking"); + assert(top_obj <= top, "just checking"); + + // Given what we think is the top of the memory region and + // the start of the object at the top, get the actual + // value of the top. + top = get_actual_top(top, top_obj); + + // If the previous call did some part of this region, don't redo. + if (_precision == CardTableModRefBS::ObjHeadPreciseArray && + _min_done != NULL && + _min_done < top) { + top = _min_done; + } + + // Top may have been reset, and in fact may be below bottom, + // e.g. the dirty card region is entirely in a now free object + // -- something that could happen with a concurrent sweeper. + bottom = MIN2(bottom, top); + MemRegion extended_mr = MemRegion(bottom, top); + assert(bottom <= top && + (_precision != CardTableModRefBS::ObjHeadPreciseArray || + _min_done == NULL || + top <= _min_done), + "overlap!"); + + // Walk the region if it is not empty; otherwise there is nothing to do. + if (!extended_mr.is_empty()) { + walk_mem_region(extended_mr, bottom_obj, top); + } + + // An idempotent closure might be applied in any order, so we don't + // record a _min_done for it. + if (!_cl->idempotent()) { + _min_done = bottom; + } else { + assert(_min_done == _last_explicit_min_done, + "Don't update _min_done for idempotent cl"); + } +} + +DirtyCardToOopClosure* Space::new_dcto_cl(ExtendedOopClosure* cl, + CardTableModRefBS::PrecisionStyle precision, + HeapWord* boundary) { + return new DirtyCardToOopClosure(this, cl, precision, boundary); +} + +HeapWord* ContiguousSpaceDCTOC::get_actual_top(HeapWord* top, + HeapWord* top_obj) { + if (top_obj != NULL && top_obj < (_sp->toContiguousSpace())->top()) { + if (_precision == CardTableModRefBS::ObjHeadPreciseArray) { + if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) { + // An arrayOop is starting on the dirty card - since we do exact + // store checks for objArrays we are done. + } else { + // Otherwise, it is possible that the object starting on the dirty + // card spans the entire card, and that the store happened on a + // later card. Figure out where the object ends. + assert(_sp->block_size(top_obj) == (size_t) oop(top_obj)->size(), + "Block size and object size mismatch"); + top = top_obj + oop(top_obj)->size(); + } + } + } else { + top = (_sp->toContiguousSpace())->top(); + } + return top; +} + +void Filtering_DCTOC::walk_mem_region(MemRegion mr, + HeapWord* bottom, + HeapWord* top) { + // Note that this assumption won't hold if we have a concurrent + // collector in this space, which may have freed up objects after + // they were dirtied and before the stop-the-world GC that is + // examining cards here. + assert(bottom < top, "ought to be at least one obj on a dirty card."); + + if (_boundary != NULL) { + // We have a boundary outside of which we don't want to look + // at objects, so create a filtering closure around the + // oop closure before walking the region. + FilteringClosure filter(_boundary, _cl); + walk_mem_region_with_cl(mr, bottom, top, &filter); + } else { + // No boundary, simply walk the heap with the oop closure. + walk_mem_region_with_cl(mr, bottom, top, _cl); + } + +} + +// We must replicate this so that the static type of "FilteringClosure" +// (see above) is apparent at the oop_iterate calls. +#define ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(ClosureType) \ +void ContiguousSpaceDCTOC::walk_mem_region_with_cl(MemRegion mr, \ + HeapWord* bottom, \ + HeapWord* top, \ + ClosureType* cl) { \ + bottom += oop(bottom)->oop_iterate(cl, mr); \ + if (bottom < top) { \ + HeapWord* next_obj = bottom + oop(bottom)->size(); \ + while (next_obj < top) { \ + /* Bottom lies entirely below top, so we can call the */ \ + /* non-memRegion version of oop_iterate below. */ \ + oop(bottom)->oop_iterate(cl); \ + bottom = next_obj; \ + next_obj = bottom + oop(bottom)->size(); \ + } \ + /* Last object. */ \ + oop(bottom)->oop_iterate(cl, mr); \ + } \ +} + +// (There are only two of these, rather than N, because the split is due +// only to the introduction of the FilteringClosure, a local part of the +// impl of this abstraction.) +ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(ExtendedOopClosure) +ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(FilteringClosure) + +DirtyCardToOopClosure* +ContiguousSpace::new_dcto_cl(ExtendedOopClosure* cl, + CardTableModRefBS::PrecisionStyle precision, + HeapWord* boundary) { + return new ContiguousSpaceDCTOC(this, cl, precision, boundary); +} + +void Space::initialize(MemRegion mr, + bool clear_space, + bool mangle_space) { + HeapWord* bottom = mr.start(); + HeapWord* end = mr.end(); + assert(Universe::on_page_boundary(bottom) && Universe::on_page_boundary(end), + "invalid space boundaries"); + set_bottom(bottom); + set_end(end); + if (clear_space) clear(mangle_space); +} + +void Space::clear(bool mangle_space) { + if (ZapUnusedHeapArea && mangle_space) { + mangle_unused_area(); + } +} + +ContiguousSpace::ContiguousSpace(): CompactibleSpace(), _top(NULL), + _concurrent_iteration_safe_limit(NULL) { + _mangler = new GenSpaceMangler(this); +} + +ContiguousSpace::~ContiguousSpace() { + delete _mangler; +} + +void ContiguousSpace::initialize(MemRegion mr, + bool clear_space, + bool mangle_space) +{ + CompactibleSpace::initialize(mr, clear_space, mangle_space); + set_concurrent_iteration_safe_limit(top()); +} + +void ContiguousSpace::clear(bool mangle_space) { + set_top(bottom()); + set_saved_mark(); + CompactibleSpace::clear(mangle_space); +} + +bool ContiguousSpace::is_free_block(const HeapWord* p) const { + return p >= _top; +} + +void OffsetTableContigSpace::clear(bool mangle_space) { + ContiguousSpace::clear(mangle_space); + _offsets.initialize_threshold(); +} + +void OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) { + Space::set_bottom(new_bottom); + _offsets.set_bottom(new_bottom); +} + +void OffsetTableContigSpace::set_end(HeapWord* new_end) { + // Space should not advertise an increase in size + // until after the underlying offset table has been enlarged. + _offsets.resize(pointer_delta(new_end, bottom())); + Space::set_end(new_end); +} + +#ifndef PRODUCT + +void ContiguousSpace::set_top_for_allocations(HeapWord* v) { + mangler()->set_top_for_allocations(v); +} +void ContiguousSpace::set_top_for_allocations() { + mangler()->set_top_for_allocations(top()); +} +void ContiguousSpace::check_mangled_unused_area(HeapWord* limit) { + mangler()->check_mangled_unused_area(limit); +} + +void ContiguousSpace::check_mangled_unused_area_complete() { + mangler()->check_mangled_unused_area_complete(); +} + +// Mangled only the unused space that has not previously +// been mangled and that has not been allocated since being +// mangled. +void ContiguousSpace::mangle_unused_area() { + mangler()->mangle_unused_area(); +} +void ContiguousSpace::mangle_unused_area_complete() { + mangler()->mangle_unused_area_complete(); +} +#endif // NOT_PRODUCT + +void CompactibleSpace::initialize(MemRegion mr, + bool clear_space, + bool mangle_space) { + Space::initialize(mr, clear_space, mangle_space); + set_compaction_top(bottom()); + _next_compaction_space = NULL; +} + +void CompactibleSpace::clear(bool mangle_space) { + Space::clear(mangle_space); + _compaction_top = bottom(); +} + +HeapWord* CompactibleSpace::forward(oop q, size_t size, + CompactPoint* cp, HeapWord* compact_top) { + // q is alive + // First check if we should switch compaction space + assert(this == cp->space, "'this' should be current compaction space."); + size_t compaction_max_size = pointer_delta(end(), compact_top); + while (size > compaction_max_size) { + // switch to next compaction space + cp->space->set_compaction_top(compact_top); + cp->space = cp->space->next_compaction_space(); + if (cp->space == NULL) { + cp->gen = GenCollectedHeap::heap()->young_gen(); + assert(cp->gen != NULL, "compaction must succeed"); + cp->space = cp->gen->first_compaction_space(); + assert(cp->space != NULL, "generation must have a first compaction space"); + } + compact_top = cp->space->bottom(); + cp->space->set_compaction_top(compact_top); + cp->threshold = cp->space->initialize_threshold(); + compaction_max_size = pointer_delta(cp->space->end(), compact_top); + } + + // store the forwarding pointer into the mark word + if ((HeapWord*)q != compact_top) { + q->forward_to(oop(compact_top)); + assert(q->is_gc_marked(), "encoding the pointer should preserve the mark"); + } else { + // if the object isn't moving we can just set the mark to the default + // mark and handle it specially later on. + q->init_mark(); + assert(q->forwardee() == NULL, "should be forwarded to NULL"); + } + + compact_top += size; + + // we need to update the offset table so that the beginnings of objects can be + // found during scavenge. Note that we are updating the offset table based on + // where the object will be once the compaction phase finishes. + if (compact_top > cp->threshold) + cp->threshold = + cp->space->cross_threshold(compact_top - size, compact_top); + return compact_top; +} + + +bool CompactibleSpace::insert_deadspace(size_t& allowed_deadspace_words, + HeapWord* q, size_t deadlength) { + if (allowed_deadspace_words >= deadlength) { + allowed_deadspace_words -= deadlength; + CollectedHeap::fill_with_object(q, deadlength); + oop(q)->set_mark(oop(q)->mark()->set_marked()); + assert((int) deadlength == oop(q)->size(), "bad filler object size"); + // Recall that we required "q == compaction_top". + return true; + } else { + allowed_deadspace_words = 0; + return false; + } +} + +void ContiguousSpace::prepare_for_compaction(CompactPoint* cp) { + scan_and_forward(this, cp); +} + +void CompactibleSpace::adjust_pointers() { + // Check first is there is any work to do. + if (used() == 0) { + return; // Nothing to do. + } + + scan_and_adjust_pointers(this); +} + +void CompactibleSpace::compact() { + scan_and_compact(this); +} + +void Space::print_short() const { print_short_on(tty); } + +void Space::print_short_on(outputStream* st) const { + st->print(" space " SIZE_FORMAT "K, %3d%% used", capacity() / K, + (int) ((double) used() * 100 / capacity())); +} + +void Space::print() const { print_on(tty); } + +void Space::print_on(outputStream* st) const { + print_short_on(st); + st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ")", + p2i(bottom()), p2i(end())); +} + +void ContiguousSpace::print_on(outputStream* st) const { + print_short_on(st); + st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")", + p2i(bottom()), p2i(top()), p2i(end())); +} + +void OffsetTableContigSpace::print_on(outputStream* st) const { + print_short_on(st); + st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " + INTPTR_FORMAT ", " INTPTR_FORMAT ")", + p2i(bottom()), p2i(top()), p2i(_offsets.threshold()), p2i(end())); +} + +void ContiguousSpace::verify() const { + HeapWord* p = bottom(); + HeapWord* t = top(); + HeapWord* prev_p = NULL; + while (p < t) { + oop(p)->verify(); + prev_p = p; + p += oop(p)->size(); + } + guarantee(p == top(), "end of last object must match end of space"); + if (top() != end()) { + guarantee(top() == block_start_const(end()-1) && + top() == block_start_const(top()), + "top should be start of unallocated block, if it exists"); + } +} + +void Space::oop_iterate(ExtendedOopClosure* blk) { + ObjectToOopClosure blk2(blk); + object_iterate(&blk2); +} + +bool Space::obj_is_alive(const HeapWord* p) const { + assert (block_is_obj(p), "The address should point to an object"); + return true; +} + +#if INCLUDE_ALL_GCS +#define ContigSpace_PAR_OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \ + \ + void ContiguousSpace::par_oop_iterate(MemRegion mr, OopClosureType* blk) {\ + HeapWord* obj_addr = mr.start(); \ + HeapWord* t = mr.end(); \ + while (obj_addr < t) { \ + assert(oop(obj_addr)->is_oop(), "Should be an oop"); \ + obj_addr += oop(obj_addr)->oop_iterate(blk); \ + } \ + } + + ALL_PAR_OOP_ITERATE_CLOSURES(ContigSpace_PAR_OOP_ITERATE_DEFN) + +#undef ContigSpace_PAR_OOP_ITERATE_DEFN +#endif // INCLUDE_ALL_GCS + +void ContiguousSpace::oop_iterate(ExtendedOopClosure* blk) { + if (is_empty()) return; + HeapWord* obj_addr = bottom(); + HeapWord* t = top(); + // Could call objects iterate, but this is easier. + while (obj_addr < t) { + obj_addr += oop(obj_addr)->oop_iterate(blk); + } +} + +void ContiguousSpace::object_iterate(ObjectClosure* blk) { + if (is_empty()) return; + WaterMark bm = bottom_mark(); + object_iterate_from(bm, blk); +} + +// For a ContiguousSpace object_iterate() and safe_object_iterate() +// are the same. +void ContiguousSpace::safe_object_iterate(ObjectClosure* blk) { + object_iterate(blk); +} + +void ContiguousSpace::object_iterate_from(WaterMark mark, ObjectClosure* blk) { + assert(mark.space() == this, "Mark does not match space"); + HeapWord* p = mark.point(); + while (p < top()) { + blk->do_object(oop(p)); + p += oop(p)->size(); + } +} + +HeapWord* +ContiguousSpace::object_iterate_careful(ObjectClosureCareful* blk) { + HeapWord * limit = concurrent_iteration_safe_limit(); + assert(limit <= top(), "sanity check"); + for (HeapWord* p = bottom(); p < limit;) { + size_t size = blk->do_object_careful(oop(p)); + if (size == 0) { + return p; // failed at p + } else { + p += size; + } + } + return NULL; // all done +} + +#define ContigSpace_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \ + \ +void ContiguousSpace:: \ +oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk) { \ + HeapWord* t; \ + HeapWord* p = saved_mark_word(); \ + assert(p != NULL, "expected saved mark"); \ + \ + const intx interval = PrefetchScanIntervalInBytes; \ + do { \ + t = top(); \ + while (p < t) { \ + Prefetch::write(p, interval); \ + debug_only(HeapWord* prev = p); \ + oop m = oop(p); \ + p += m->oop_iterate(blk); \ + } \ + } while (t < top()); \ + \ + set_saved_mark_word(p); \ +} + +ALL_SINCE_SAVE_MARKS_CLOSURES(ContigSpace_OOP_SINCE_SAVE_MARKS_DEFN) + +#undef ContigSpace_OOP_SINCE_SAVE_MARKS_DEFN + +// Very general, slow implementation. +HeapWord* ContiguousSpace::block_start_const(const void* p) const { + assert(MemRegion(bottom(), end()).contains(p), + err_msg("p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")", + p2i(p), p2i(bottom()), p2i(end()))); + if (p >= top()) { + return top(); + } else { + HeapWord* last = bottom(); + HeapWord* cur = last; + while (cur <= p) { + last = cur; + cur += oop(cur)->size(); + } + assert(oop(last)->is_oop(), + err_msg(PTR_FORMAT " should be an object start", p2i(last))); + return last; + } +} + +size_t ContiguousSpace::block_size(const HeapWord* p) const { + assert(MemRegion(bottom(), end()).contains(p), + err_msg("p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")", + p2i(p), p2i(bottom()), p2i(end()))); + HeapWord* current_top = top(); + assert(p <= current_top, + err_msg("p > current top - p: " PTR_FORMAT ", current top: " PTR_FORMAT, + p2i(p), p2i(current_top))); + assert(p == current_top || oop(p)->is_oop(), + err_msg("p (" PTR_FORMAT ") is not a block start - " + "current_top: " PTR_FORMAT ", is_oop: %s", + p2i(p), p2i(current_top), BOOL_TO_STR(oop(p)->is_oop()))); + if (p < current_top) { + return oop(p)->size(); + } else { + assert(p == current_top, "just checking"); + return pointer_delta(end(), (HeapWord*) p); + } +} + +// This version requires locking. +inline HeapWord* ContiguousSpace::allocate_impl(size_t size) { + assert(Heap_lock->owned_by_self() || + (SafepointSynchronize::is_at_safepoint() && Thread::current()->is_VM_thread()), + "not locked"); + HeapWord* obj = top(); + if (pointer_delta(end(), obj) >= size) { + HeapWord* new_top = obj + size; + set_top(new_top); + assert(is_aligned(obj) && is_aligned(new_top), "checking alignment"); + return obj; + } else { + return NULL; + } +} + +// This version is lock-free. +inline HeapWord* ContiguousSpace::par_allocate_impl(size_t size) { + do { + HeapWord* obj = top(); + if (pointer_delta(end(), obj) >= size) { + HeapWord* new_top = obj + size; + HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj); + // result can be one of two: + // the old top value: the exchange succeeded + // otherwise: the new value of the top is returned. + if (result == obj) { + assert(is_aligned(obj) && is_aligned(new_top), "checking alignment"); + return obj; + } + } else { + return NULL; + } + } while (true); +} + +HeapWord* ContiguousSpace::allocate_aligned(size_t size) { + assert(Heap_lock->owned_by_self() || (SafepointSynchronize::is_at_safepoint() && Thread::current()->is_VM_thread()), "not locked"); + HeapWord* end_value = end(); + + HeapWord* obj = CollectedHeap::align_allocation_or_fail(top(), end_value, SurvivorAlignmentInBytes); + if (obj == NULL) { + return NULL; + } + + if (pointer_delta(end_value, obj) >= size) { + HeapWord* new_top = obj + size; + set_top(new_top); + assert(is_ptr_aligned(obj, SurvivorAlignmentInBytes) && is_aligned(new_top), + "checking alignment"); + return obj; + } else { + set_top(obj); + return NULL; + } +} + +// Requires locking. +HeapWord* ContiguousSpace::allocate(size_t size) { + return allocate_impl(size); +} + +// Lock-free. +HeapWord* ContiguousSpace::par_allocate(size_t size) { + return par_allocate_impl(size); +} + +void ContiguousSpace::allocate_temporary_filler(int factor) { + // allocate temporary type array decreasing free size with factor 'factor' + assert(factor >= 0, "just checking"); + size_t size = pointer_delta(end(), top()); + + // if space is full, return + if (size == 0) return; + + if (factor > 0) { + size -= size/factor; + } + size = align_object_size(size); + + const size_t array_header_size = typeArrayOopDesc::header_size(T_INT); + if (size >= (size_t)align_object_size(array_header_size)) { + size_t length = (size - array_header_size) * (HeapWordSize / sizeof(jint)); + // allocate uninitialized int array + typeArrayOop t = (typeArrayOop) allocate(size); + assert(t != NULL, "allocation should succeed"); + t->set_mark(markOopDesc::prototype()); + t->set_klass(Universe::intArrayKlassObj()); + t->set_length((int)length); + } else { + assert(size == CollectedHeap::min_fill_size(), + "size for smallest fake object doesn't match"); + instanceOop obj = (instanceOop) allocate(size); + obj->set_mark(markOopDesc::prototype()); + obj->set_klass_gap(0); + obj->set_klass(SystemDictionary::Object_klass()); + } +} + +HeapWord* OffsetTableContigSpace::initialize_threshold() { + return _offsets.initialize_threshold(); +} + +HeapWord* OffsetTableContigSpace::cross_threshold(HeapWord* start, HeapWord* end) { + _offsets.alloc_block(start, end); + return _offsets.threshold(); +} + +OffsetTableContigSpace::OffsetTableContigSpace(BlockOffsetSharedArray* sharedOffsetArray, + MemRegion mr) : + _offsets(sharedOffsetArray, mr), + _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true) +{ + _offsets.set_contig_space(this); + initialize(mr, SpaceDecorator::Clear, SpaceDecorator::Mangle); +} + +#define OBJ_SAMPLE_INTERVAL 0 +#define BLOCK_SAMPLE_INTERVAL 100 + +void OffsetTableContigSpace::verify() const { + HeapWord* p = bottom(); + HeapWord* prev_p = NULL; + int objs = 0; + int blocks = 0; + + if (VerifyObjectStartArray) { + _offsets.verify(); + } + + while (p < top()) { + size_t size = oop(p)->size(); + // For a sampling of objects in the space, find it using the + // block offset table. + if (blocks == BLOCK_SAMPLE_INTERVAL) { + guarantee(p == block_start_const(p + (size/2)), + "check offset computation"); + blocks = 0; + } else { + blocks++; + } + + if (objs == OBJ_SAMPLE_INTERVAL) { + oop(p)->verify(); + objs = 0; + } else { + objs++; + } + prev_p = p; + p += size; + } + guarantee(p == top(), "end of last object must match end of space"); +} + + +size_t TenuredSpace::allowed_dead_ratio() const { + return MarkSweepDeadRatio; +}