truffle: src/share/vm/memory/space.cpp comparison

comparison src/share/vm/memory/space.cpp @ 0:a61af66fc99e jdk7-b24

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author	duke
date	Sat, 01 Dec 2007 00:00:00 +0000
parents
children	ba764ed4b6f2

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--1:000000000000
+:a61af66fc99e
+/*
+* Copyright 1997-2006 Sun Microsystems, Inc.  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 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.
+*
+*/
+# include "incls/_precompiled.incl"
+# include "incls/_space.cpp.incl"
+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);
+}
+}
+}
+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-detructive 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 ||
+_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);
+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 (!mr.is_empty()) {
+walk_mem_region(mr, bottom_obj, top);
+}
+_min_done = bottom;
+}
+DirtyCardToOopClosure* Space::new_dcto_cl(OopClosure* cl,
+CardTableModRefBS::PrecisionStyle precision,
+HeapWord* boundary) {
+return new DirtyCardToOopClosure(this, cl, precision, boundary);
+}
+void FilteringClosure::do_oop(oop* p) {
+do_oop_nv(p);
+}
+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(OopClosure)
+ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(FilteringClosure)
+DirtyCardToOopClosure*
+ContiguousSpace::new_dcto_cl(OopClosure* cl,
+CardTableModRefBS::PrecisionStyle precision,
+HeapWord* boundary) {
+return new ContiguousSpaceDCTOC(this, cl, precision, boundary);
+}
+void Space::initialize(MemRegion mr, bool clear_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();
+}
+void Space::clear() {
+if (ZapUnusedHeapArea) mangle_unused_area();
+}
+void ContiguousSpace::initialize(MemRegion mr, bool clear_space)
+{
+CompactibleSpace::initialize(mr, clear_space);
+_concurrent_iteration_safe_limit = top();
+}
+void ContiguousSpace::clear() {
+set_top(bottom());
+set_saved_mark();
+Space::clear();
+}
+bool Space::is_in(const void* p) const {
+HeapWord* b = block_start(p);
+return b != NULL && block_is_obj(b);
+}
+bool ContiguousSpace::is_in(const void* p) const {
+return _bottom <= p && p < _top;
+}
+bool ContiguousSpace::is_free_block(const HeapWord* p) const {
+return p >= _top;
+}
+void OffsetTableContigSpace::clear() {
+ContiguousSpace::clear();
+_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 advertize an increase in size
+// until after the underlying offest table has been enlarged.
+_offsets.resize(pointer_delta(new_end, bottom()));
+Space::set_end(new_end);
+}
+void ContiguousSpace::mangle_unused_area() {
+// to-space is used for storing marks during mark-sweep
+mangle_region(MemRegion(top(), end()));
+}
+void ContiguousSpace::mangle_region(MemRegion mr) {
+debug_only(Copy::fill_to_words(mr.start(), mr.word_size(), badHeapWord));
+}
+void CompactibleSpace::initialize(MemRegion mr, bool clear_space) {
+Space::initialize(mr, clear_space);
+_compaction_top = bottom();
+_next_compaction_space = NULL;
+}
+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()->prev_gen(cp->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");
+}
+debug_only(MarkSweep::register_live_oop(q, size));
+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;
+oop(q)->set_mark(markOopDesc::prototype()->set_marked());
+const size_t min_int_array_size = typeArrayOopDesc::header_size(T_INT);
+if (deadlength >= min_int_array_size) {
+oop(q)->set_klass(Universe::intArrayKlassObj());
+typeArrayOop(q)->set_length((int)((deadlength - min_int_array_size)
+* (HeapWordSize/sizeof(jint))));
+} else {
+assert((int) deadlength == instanceOopDesc::header_size(),
+"size for smallest fake dead object doesn't match");
+oop(q)->set_klass(SystemDictionary::object_klass());
+}
+assert((int) deadlength == oop(q)->size(),
+"make sure size for fake dead object match");
+// Recall that we required "q == compaction_top".
+return true;
+} else {
+allowed_deadspace_words = 0;
+return false;
+}
+}
+#define block_is_always_obj(q) true
+#define obj_size(q) oop(q)->size()
+#define adjust_obj_size(s) s
+void CompactibleSpace::prepare_for_compaction(CompactPoint* cp) {
+SCAN_AND_FORWARD(cp, end, block_is_obj, block_size);
+}
+// Faster object search.
+void ContiguousSpace::prepare_for_compaction(CompactPoint* cp) {
+SCAN_AND_FORWARD(cp, top, block_is_always_obj, obj_size);
+}
+void Space::adjust_pointers() {
+// adjust all the interior pointers to point at the new locations of objects
+// Used by MarkSweep::mark_sweep_phase3()
+// First check to see if there is any work to be done.
+if (used() == 0) {
+return;  // Nothing to do.
+}
+// Otherwise...
+HeapWord* q = bottom();
+HeapWord* t = end();
+debug_only(HeapWord* prev_q = NULL);
+while (q < t) {
+if (oop(q)->is_gc_marked()) {
+// q is alive
+debug_only(MarkSweep::track_interior_pointers(oop(q)));
+// point all the oops to the new location
+size_t size = oop(q)->adjust_pointers();
+debug_only(MarkSweep::check_interior_pointers());
+debug_only(prev_q = q);
+debug_only(MarkSweep::validate_live_oop(oop(q), size));
+q += size;
+} else {
+// q is not a live object.  But we're not in a compactible space,
+// So we don't have live ranges.
+debug_only(prev_q = q);
+q += block_size(q);
+assert(q > prev_q, "we should be moving forward through memory");
+}
+}
+assert(q == t, "just checking");
+}
+void CompactibleSpace::adjust_pointers() {
+// Check first is there is any work to do.
+if (used() == 0) {
+return;   // Nothing to do.
+}
+SCAN_AND_ADJUST_POINTERS(adjust_obj_size);
+}
+void CompactibleSpace::compact() {
+SCAN_AND_COMPACT(obj_size);
+}
+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 ")",
+bottom(), end());
+}
+void ContiguousSpace::print_on(outputStream* st) const {
+print_short_on(st);
+st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
+bottom(), top(), end());
+}
+void OffsetTableContigSpace::print_on(outputStream* st) const {
+print_short_on(st);
+st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
+INTPTR_FORMAT ", " INTPTR_FORMAT ")",
+bottom(), top(), _offsets.threshold(), end());
+}
+void ContiguousSpace::verify(bool allow_dirty) 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(end()-1) &&
+top() == block_start(top()),
+"top should be start of unallocated block, if it exists");
+}
+}
+void Space::oop_iterate(OopClosure* blk) {
+ObjectToOopClosure blk2(blk);
+object_iterate(&blk2);
+}
+HeapWord* Space::object_iterate_careful(ObjectClosureCareful* cl) {
+guarantee(false, "NYI");
+return bottom();
+}
+HeapWord* Space::object_iterate_careful_m(MemRegion mr,
+ObjectClosureCareful* cl) {
+guarantee(false, "NYI");
+return bottom();
+}
+void Space::object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl) {
+assert(!mr.is_empty(), "Should be non-empty");
+// We use MemRegion(bottom(), end()) rather than used_region() below
+// because the two are not necessarily equal for some kinds of
+// spaces, in particular, certain kinds of free list spaces.
+// We could use the more complicated but more precise:
+// MemRegion(used_region().start(), round_to(used_region().end(), CardSize))
+// but the slight imprecision seems acceptable in the assertion check.
+assert(MemRegion(bottom(), end()).contains(mr),
+"Should be within used space");
+HeapWord* prev = cl->previous();   // max address from last time
+if (prev >= mr.end()) { // nothing to do
+return;
+}
+// This assert will not work when we go from cms space to perm
+// space, and use same closure. Easy fix deferred for later. XXX YSR
+// assert(prev == NULL || contains(prev), "Should be within space");
+bool last_was_obj_array = false;
+HeapWord *blk_start_addr, *region_start_addr;
+if (prev > mr.start()) {
+region_start_addr = prev;
+blk_start_addr    = prev;
+assert(blk_start_addr == block_start(region_start_addr), "invariant");
+} else {
+region_start_addr = mr.start();
+blk_start_addr    = block_start(region_start_addr);
+}
+HeapWord* region_end_addr = mr.end();
+MemRegion derived_mr(region_start_addr, region_end_addr);
+while (blk_start_addr < region_end_addr) {
+const size_t size = block_size(blk_start_addr);
+if (block_is_obj(blk_start_addr)) {
+last_was_obj_array = cl->do_object_bm(oop(blk_start_addr), derived_mr);
+} else {
+last_was_obj_array = false;
+}
+blk_start_addr += size;
+}
+if (!last_was_obj_array) {
+assert((bottom() <= blk_start_addr) && (blk_start_addr <= end()),
+"Should be within (closed) used space");
+assert(blk_start_addr > prev, "Invariant");
+cl->set_previous(blk_start_addr); // min address for next time
+}
+}
+bool Space::obj_is_alive(const HeapWord* p) const {
+assert (block_is_obj(p), "The address should point to an object");
+return true;
+}
+void ContiguousSpace::object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl) {
+assert(!mr.is_empty(), "Should be non-empty");
+assert(used_region().contains(mr), "Should be within used space");
+HeapWord* prev = cl->previous();   // max address from last time
+if (prev >= mr.end()) { // nothing to do
+return;
+}
+// See comment above (in more general method above) in case you
+// happen to use this method.
+assert(prev == NULL || is_in_reserved(prev), "Should be within space");
+bool last_was_obj_array = false;
+HeapWord *obj_start_addr, *region_start_addr;
+if (prev > mr.start()) {
+region_start_addr = prev;
+obj_start_addr    = prev;
+assert(obj_start_addr == block_start(region_start_addr), "invariant");
+} else {
+region_start_addr = mr.start();
+obj_start_addr    = block_start(region_start_addr);
+}
+HeapWord* region_end_addr = mr.end();
+MemRegion derived_mr(region_start_addr, region_end_addr);
+while (obj_start_addr < region_end_addr) {
+oop obj = oop(obj_start_addr);
+const size_t size = obj->size();
+last_was_obj_array = cl->do_object_bm(obj, derived_mr);
+obj_start_addr += size;
+}
+if (!last_was_obj_array) {
+assert((bottom() <= obj_start_addr)  && (obj_start_addr <= end()),
+"Should be within (closed) used space");
+assert(obj_start_addr > prev, "Invariant");
+cl->set_previous(obj_start_addr); // min address for next time
+}
+}
+#ifndef SERIALGC
+#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 // SERIALGC
+void ContiguousSpace::oop_iterate(OopClosure* 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::oop_iterate(MemRegion mr, OopClosure* blk) {
+if (is_empty()) {
+return;
+}
+MemRegion cur = MemRegion(bottom(), top());
+mr = mr.intersection(cur);
+if (mr.is_empty()) {
+return;
+}
+if (mr.equals(cur)) {
+oop_iterate(blk);
+return;
+}
+assert(mr.end() <= top(), "just took an intersection above");
+HeapWord* obj_addr = block_start(mr.start());
+HeapWord* t = mr.end();
+// Handle first object specially.
+oop obj = oop(obj_addr);
+SpaceMemRegionOopsIterClosure smr_blk(blk, mr);
+obj_addr += obj->oop_iterate(&smr_blk);
+while (obj_addr < t) {
+oop obj = oop(obj_addr);
+assert(obj->is_oop(), "expected an oop");
+obj_addr += obj->size();
+// If "obj_addr" is not greater than top, then the
+// entire object "obj" is within the region.
+if (obj_addr <= t) {
+obj->oop_iterate(blk);
+} else {
+// "obj" extends beyond end of region
+obj->oop_iterate(&smr_blk);
+break;
+}
+};
+}
+void ContiguousSpace::object_iterate(ObjectClosure* blk) {
+if (is_empty()) return;
+WaterMark bm = bottom_mark();
+object_iterate_from(bm, 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 void* p) const {
+assert(MemRegion(bottom(), end()).contains(p), "p not in space");
+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(), "Should be an object start");
+return last;
+}
+}
+size_t ContiguousSpace::block_size(const HeapWord* p) const {
+assert(MemRegion(bottom(), end()).contains(p), "p not in space");
+HeapWord* current_top = top();
+assert(p <= current_top, "p is not a block start");
+assert(p == current_top || oop(p)->is_oop(), "p is not a block start");
+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,
+HeapWord* const end_value) {
+assert(Heap_lock->owned_by_self() ||
+(SafepointSynchronize::is_at_safepoint() &&
+Thread::current()->is_VM_thread()),
+"not locked");
+HeapWord* obj = top();
+if (pointer_delta(end_value, 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,
+HeapWord* const end_value) {
+do {
+HeapWord* obj = top();
+if (pointer_delta(end_value, 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);
+}
+// Requires locking.
+HeapWord* ContiguousSpace::allocate(size_t size) {
+return allocate_impl(size, end());
+}
+// Lock-free.
+HeapWord* ContiguousSpace::par_allocate(size_t size) {
+return par_allocate_impl(size, end());
+}
+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 min_int_array_size = typeArrayOopDesc::header_size(T_INT);
+if (size >= min_int_array_size) {
+size_t length = (size - min_int_array_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((int) size == instanceOopDesc::header_size(),
+"size for smallest fake object doesn't match");
+instanceOop obj = (instanceOop) allocate(size);
+obj->set_mark(markOopDesc::prototype());
+obj->set_klass(SystemDictionary::object_klass());
+}
+}
+void EdenSpace::clear() {
+ContiguousSpace::clear();
+set_soft_end(end());
+}
+// Requires locking.
+HeapWord* EdenSpace::allocate(size_t size) {
+return allocate_impl(size, soft_end());
+}
+// Lock-free.
+HeapWord* EdenSpace::par_allocate(size_t size) {
+return par_allocate_impl(size, soft_end());
+}
+HeapWord* ConcEdenSpace::par_allocate(size_t size)
+{
+do {
+// The invariant is top() should be read before end() because
+// top() can't be greater than end(), so if an update of _soft_end
+// occurs between 'end_val = end();' and 'top_val = top();' top()
+// also can grow up to the new end() and the condition
+// 'top_val > end_val' is true. To ensure the loading order
+// OrderAccess::loadload() is required after top() read.
+HeapWord* obj = top();
+OrderAccess::loadload();
+if (pointer_delta(*soft_end_addr(), 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* 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, true);
+}
+class VerifyOldOopClosure : public OopClosure {
+public:
+oop the_obj;
+bool allow_dirty;
+void do_oop(oop* p) {
+the_obj->verify_old_oop(p, allow_dirty);
+}
+};
+#define OBJ_SAMPLE_INTERVAL 0
+#define BLOCK_SAMPLE_INTERVAL 100
+void OffsetTableContigSpace::verify(bool allow_dirty) const {
+HeapWord* p = bottom();
+HeapWord* prev_p = NULL;
+VerifyOldOopClosure blk;      // Does this do anything?
+blk.allow_dirty = allow_dirty;
+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(p + (size/2)), "check offset computation");
+blocks = 0;
+} else {
+blocks++;
+}
+if (objs == OBJ_SAMPLE_INTERVAL) {
+oop(p)->verify();
+blk.the_obj = oop(p);
+oop(p)->oop_iterate(&blk);
+objs = 0;
+} else {
+objs++;
+}
+prev_p = p;
+p += size;
+}
+guarantee(p == top(), "end of last object must match end of space");
+}
+void OffsetTableContigSpace::serialize_block_offset_array_offsets(
+SerializeOopClosure* soc) {
+_offsets.serialize(soc);
+}
+int TenuredSpace::allowed_dead_ratio() const {
+return MarkSweepDeadRatio;
+}
+int ContigPermSpace::allowed_dead_ratio() const {
+return PermMarkSweepDeadRatio;
+}

Mercurial > hg > truffle

comparison src/share/vm/memory/space.cpp @ 0:a61af66fc99e jdk7-b24