graal-jvmci-8: src/share/vm/gc_implementation/parallelScavenge/cardTableExtension.cpp comparison

comparison src/share/vm/gc_implementation/parallelScavenge/cardTableExtension.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 2001-2006 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/_cardTableExtension.cpp.incl"
+// Checks an individual oop for missing precise marks. Mark
+// may be either dirty or newgen.
+class CheckForUnmarkedOops : public OopClosure {
+PSYoungGen* _young_gen;
+CardTableExtension* _card_table;
+HeapWord* _unmarked_addr;
+jbyte* _unmarked_card;
+public:
+CheckForUnmarkedOops( PSYoungGen* young_gen, CardTableExtension* card_table ) :
+_young_gen(young_gen), _card_table(card_table), _unmarked_addr(NULL) { }
+virtual void do_oop(oop* p) {
+if (_young_gen->is_in_reserved(*p) &&
+!_card_table->addr_is_marked_imprecise(p)) {
+// Don't overwrite the first missing card mark
+if (_unmarked_addr == NULL) {
+_unmarked_addr = (HeapWord*)p;
+_unmarked_card = _card_table->byte_for(p);
+}
+}
+}
+bool has_unmarked_oop() {
+return _unmarked_addr != NULL;
+}
+};
+// Checks all objects for the existance of some type of mark,
+// precise or imprecise, dirty or newgen.
+class CheckForUnmarkedObjects : public ObjectClosure {
+PSYoungGen* _young_gen;
+CardTableExtension* _card_table;
+public:
+CheckForUnmarkedObjects() {
+ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
+_young_gen = heap->young_gen();
+_card_table = (CardTableExtension*)heap->barrier_set();
+// No point in asserting barrier set type here. Need to make CardTableExtension
+// a unique barrier set type.
+}
+// Card marks are not precise. The current system can leave us with
+// a mismash of precise marks and begining of object marks. This means
+// we test for missing precise marks first. If any are found, we don't
+// fail unless the object head is also unmarked.
+virtual void do_object(oop obj) {
+CheckForUnmarkedOops object_check( _young_gen, _card_table );
+obj->oop_iterate(&object_check);
+if (object_check.has_unmarked_oop()) {
+assert(_card_table->addr_is_marked_imprecise(obj), "Found unmarked young_gen object");
+}
+}
+};
+// Checks for precise marking of oops as newgen.
+class CheckForPreciseMarks : public OopClosure {
+PSYoungGen* _young_gen;
+CardTableExtension* _card_table;
+public:
+CheckForPreciseMarks( PSYoungGen* young_gen, CardTableExtension* card_table ) :
+_young_gen(young_gen), _card_table(card_table) { }
+virtual void do_oop(oop* p) {
+if (_young_gen->is_in_reserved(*p)) {
+assert(_card_table->addr_is_marked_precise(p), "Found unmarked precise oop");
+_card_table->set_card_newgen(p);
+}
+}
+};
+// We get passed the space_top value to prevent us from traversing into
+// the old_gen promotion labs, which cannot be safely parsed.
+void CardTableExtension::scavenge_contents(ObjectStartArray* start_array,
+MutableSpace* sp,
+HeapWord* space_top,
+PSPromotionManager* pm)
+{
+assert(start_array != NULL && sp != NULL && pm != NULL, "Sanity");
+assert(start_array->covered_region().contains(sp->used_region()),
+"ObjectStartArray does not cover space");
+bool depth_first = pm->depth_first();
+if (sp->not_empty()) {
+oop* sp_top = (oop*)space_top;
+oop* prev_top = NULL;
+jbyte* current_card = byte_for(sp->bottom());
+jbyte* end_card     = byte_for(sp_top - 1);    // sp_top is exclusive
+// scan card marking array
+while (current_card <= end_card) {
+jbyte value = *current_card;
+// skip clean cards
+if (card_is_clean(value)) {
+current_card++;
+} else {
+// we found a non-clean card
+jbyte* first_nonclean_card = current_card++;
+oop* bottom = (oop*)addr_for(first_nonclean_card);
+// find object starting on card
+oop* bottom_obj = (oop*)start_array->object_start((HeapWord*)bottom);
+// bottom_obj = (oop*)start_array->object_start((HeapWord*)bottom);
+assert(bottom_obj <= bottom, "just checking");
+// make sure we don't scan oops we already looked at
+if (bottom < prev_top) bottom = prev_top;
+// figure out when to stop scanning
+jbyte* first_clean_card;
+oop* top;
+bool restart_scanning;
+do {
+restart_scanning = false;
+// find a clean card
+while (current_card <= end_card) {
+value = *current_card;
+if (card_is_clean(value)) break;
+current_card++;
+}
+// check if we reached the end, if so we are done
+if (current_card >= end_card) {
+first_clean_card = end_card + 1;
+current_card++;
+top = sp_top;
+} else {
+// we have a clean card, find object starting on that card
+first_clean_card = current_card++;
+top = (oop*)addr_for(first_clean_card);
+oop* top_obj = (oop*)start_array->object_start((HeapWord*)top);
+// top_obj = (oop*)start_array->object_start((HeapWord*)top);
+assert(top_obj <= top, "just checking");
+if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) {
+// an arrayOop is starting on the clean card - since we do exact store
+// checks for objArrays we are done
+} else {
+// otherwise, it is possible that the object starting on the clean card
+// spans the entire card, and that the store happened on a later card.
+// figure out where the object ends
+top = top_obj + oop(top_obj)->size();
+jbyte* top_card = CardTableModRefBS::byte_for(top - 1);   // top is exclusive
+if (top_card > first_clean_card) {
+// object ends a different card
+current_card = top_card + 1;
+if (card_is_clean(*top_card)) {
+// the ending card is clean, we are done
+first_clean_card = top_card;
+} else {
+// the ending card is not clean, continue scanning at start of do-while
+restart_scanning = true;
+}
+} else {
+// object ends on the clean card, we are done.
+assert(first_clean_card == top_card, "just checking");
+}
+}
+}
+} while (restart_scanning);
+// we know which cards to scan, now clear them
+while (first_nonclean_card < first_clean_card) {
+*first_nonclean_card++ = clean_card;
+}
+// scan oops in objects
+// hoisted the if (depth_first) check out of the loop
+if (depth_first){
+do {
+oop(bottom_obj)->push_contents(pm);
+bottom_obj += oop(bottom_obj)->size();
+assert(bottom_obj <= sp_top, "just checking");
+} while (bottom_obj < top);
+pm->drain_stacks_cond_depth();
+} else {
+do {
+oop(bottom_obj)->copy_contents(pm);
+bottom_obj += oop(bottom_obj)->size();
+assert(bottom_obj <= sp_top, "just checking");
+} while (bottom_obj < top);
+}
+// remember top oop* scanned
+prev_top = top;
+}
+}
+}
+}
+void CardTableExtension::scavenge_contents_parallel(ObjectStartArray* start_array,
+MutableSpace* sp,
+HeapWord* space_top,
+PSPromotionManager* pm,
+uint stripe_number) {
+int ssize = 128; // Naked constant!  Work unit = 64k.
+int dirty_card_count = 0;
+bool depth_first = pm->depth_first();
+oop* sp_top = (oop*)space_top;
+jbyte* start_card = byte_for(sp->bottom());
+jbyte* end_card   = byte_for(sp_top - 1) + 1;
+oop* last_scanned = NULL; // Prevent scanning objects more than once
+for (jbyte* slice = start_card; slice < end_card; slice += ssize*ParallelGCThreads) {
+jbyte* worker_start_card = slice + stripe_number * ssize;
+if (worker_start_card >= end_card)
+return; // We're done.
+jbyte* worker_end_card = worker_start_card + ssize;
+if (worker_end_card > end_card)
+worker_end_card = end_card;
+// We do not want to scan objects more than once. In order to accomplish
+// this, we assert that any object with an object head inside our 'slice'
+// belongs to us. We may need to extend the range of scanned cards if the
+// last object continues into the next 'slice'.
+//
+// Note! ending cards are exclusive!
+HeapWord* slice_start = addr_for(worker_start_card);
+HeapWord* slice_end = MIN2((HeapWord*) sp_top, addr_for(worker_end_card));
+// If there are not objects starting within the chunk, skip it.
+if (!start_array->object_starts_in_range(slice_start, slice_end)) {
+continue;
+}
+// Update our begining addr
+HeapWord* first_object = start_array->object_start(slice_start);
+debug_only(oop* first_object_within_slice = (oop*) first_object;)
+if (first_object < slice_start) {
+last_scanned = (oop*)(first_object + oop(first_object)->size());
+debug_only(first_object_within_slice = last_scanned;)
+worker_start_card = byte_for(last_scanned);
+}
+// Update the ending addr
+if (slice_end < (HeapWord*)sp_top) {
+// The subtraction is important! An object may start precisely at slice_end.
+HeapWord* last_object = start_array->object_start(slice_end - 1);
+slice_end = last_object + oop(last_object)->size();
+// worker_end_card is exclusive, so bump it one past the end of last_object's
+// covered span.
+worker_end_card = byte_for(slice_end) + 1;
+if (worker_end_card > end_card)
+worker_end_card = end_card;
+}
+assert(slice_end <= (HeapWord*)sp_top, "Last object in slice crosses space boundary");
+assert(is_valid_card_address(worker_start_card), "Invalid worker start card");
+assert(is_valid_card_address(worker_end_card), "Invalid worker end card");
+// Note that worker_start_card >= worker_end_card is legal, and happens when
+// an object spans an entire slice.
+assert(worker_start_card <= end_card, "worker start card beyond end card");
+assert(worker_end_card <= end_card, "worker end card beyond end card");
+jbyte* current_card = worker_start_card;
+while (current_card < worker_end_card) {
+// Find an unclean card.
+while (current_card < worker_end_card && card_is_clean(*current_card)) {
+current_card++;
+}
+jbyte* first_unclean_card = current_card;
+// Find the end of a run of contiguous unclean cards
+while (current_card < worker_end_card && !card_is_clean(*current_card)) {
+while (current_card < worker_end_card && !card_is_clean(*current_card)) {
+current_card++;
+}
+if (current_card < worker_end_card) {
+// Some objects may be large enough to span several cards. If such
+// an object has more than one dirty card, separated by a clean card,
+// we will attempt to scan it twice. The test against "last_scanned"
+// prevents the redundant object scan, but it does not prevent newly
+// marked cards from being cleaned.
+HeapWord* last_object_in_dirty_region = start_array->object_start(addr_for(current_card)-1);
+size_t size_of_last_object = oop(last_object_in_dirty_region)->size();
+HeapWord* end_of_last_object = last_object_in_dirty_region + size_of_last_object;
+jbyte* ending_card_of_last_object = byte_for(end_of_last_object);
+assert(ending_card_of_last_object <= worker_end_card, "ending_card_of_last_object is greater than worker_end_card");
+if (ending_card_of_last_object > current_card) {
+// This means the object spans the next complete card.
+// We need to bump the current_card to ending_card_of_last_object
+current_card = ending_card_of_last_object;
+}
+}
+}
+jbyte* following_clean_card = current_card;
+if (first_unclean_card < worker_end_card) {
+oop* p = (oop*) start_array->object_start(addr_for(first_unclean_card));
+assert((HeapWord*)p <= addr_for(first_unclean_card), "checking");
+// "p" should always be >= "last_scanned" because newly GC dirtied
+// cards are no longer scanned again (see comment at end
+// of loop on the increment of "current_card").  Test that
+// hypothesis before removing this code.
+// If this code is removed, deal with the first time through
+// the loop when the last_scanned is the object starting in
+// the previous slice.
+assert((p >= last_scanned) ||
+(last_scanned == first_object_within_slice),
+"Should no longer be possible");
+if (p < last_scanned) {
+// Avoid scanning more than once; this can happen because
+// newgen cards set by GC may a different set than the
+// originally dirty set
+p = last_scanned;
+}
+oop* to = (oop*)addr_for(following_clean_card);
+// Test slice_end first!
+if ((HeapWord*)to > slice_end) {
+to = (oop*)slice_end;
+} else if (to > sp_top) {
+to = sp_top;
+}
+// we know which cards to scan, now clear them
+if (first_unclean_card <= worker_start_card+1)
+first_unclean_card = worker_start_card+1;
+if (following_clean_card >= worker_end_card-1)
+following_clean_card = worker_end_card-1;
+while (first_unclean_card < following_clean_card) {
+*first_unclean_card++ = clean_card;
+}
+const int interval = PrefetchScanIntervalInBytes;
+// scan all objects in the range
+if (interval != 0) {
+// hoisted the if (depth_first) check out of the loop
+if (depth_first) {
+while (p < to) {
+Prefetch::write(p, interval);
+oop m = oop(p);
+assert(m->is_oop_or_null(), "check for header");
+m->push_contents(pm);
+p += m->size();
+}
+pm->drain_stacks_cond_depth();
+} else {
+while (p < to) {
+Prefetch::write(p, interval);
+oop m = oop(p);
+assert(m->is_oop_or_null(), "check for header");
+m->copy_contents(pm);
+p += m->size();
+}
+}
+} else {
+// hoisted the if (depth_first) check out of the loop
+if (depth_first) {
+while (p < to) {
+oop m = oop(p);
+assert(m->is_oop_or_null(), "check for header");
+m->push_contents(pm);
+p += m->size();
+}
+pm->drain_stacks_cond_depth();
+} else {
+while (p < to) {
+oop m = oop(p);
+assert(m->is_oop_or_null(), "check for header");
+m->copy_contents(pm);
+p += m->size();
+}
+}
+}
+last_scanned = p;
+}
+// "current_card" is still the "following_clean_card" or
+// the current_card is >= the worker_end_card so the
+// loop will not execute again.
+assert((current_card == following_clean_card) ||
+(current_card >= worker_end_card),
+"current_card should only be incremented if it still equals "
+"following_clean_card");
+// Increment current_card so that it is not processed again.
+// It may now be dirty because a old-to-young pointer was
+// found on it an updated.  If it is now dirty, it cannot be
+// be safely cleaned in the next iteration.
+current_card++;
+}
+}
+}
+// This should be called before a scavenge.
+void CardTableExtension::verify_all_young_refs_imprecise() {
+CheckForUnmarkedObjects check;
+ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
+PSOldGen* old_gen = heap->old_gen();
+PSPermGen* perm_gen = heap->perm_gen();
+old_gen->object_iterate(&check);
+perm_gen->object_iterate(&check);
+}
+// This should be called immediately after a scavenge, before mutators resume.
+void CardTableExtension::verify_all_young_refs_precise() {
+ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
+PSOldGen* old_gen = heap->old_gen();
+PSPermGen* perm_gen = heap->perm_gen();
+CheckForPreciseMarks check(heap->young_gen(), (CardTableExtension*)heap->barrier_set());
+old_gen->oop_iterate(&check);
+perm_gen->oop_iterate(&check);
+verify_all_young_refs_precise_helper(old_gen->object_space()->used_region());
+verify_all_young_refs_precise_helper(perm_gen->object_space()->used_region());
+}
+void CardTableExtension::verify_all_young_refs_precise_helper(MemRegion mr) {
+CardTableExtension* card_table = (CardTableExtension*)Universe::heap()->barrier_set();
+// FIX ME ASSERT HERE
+jbyte* bot = card_table->byte_for(mr.start());
+jbyte* top = card_table->byte_for(mr.end());
+while(bot <= top) {
+assert(*bot == clean_card || *bot == verify_card, "Found unwanted or unknown card mark");
+if (*bot == verify_card)
+*bot = youngergen_card;
+bot++;
+}
+}
+bool CardTableExtension::addr_is_marked_imprecise(void *addr) {
+jbyte* p = byte_for(addr);
+jbyte val = *p;
+if (card_is_dirty(val))
+return true;
+if (card_is_newgen(val))
+return true;
+if (card_is_clean(val))
+return false;
+assert(false, "Found unhandled card mark type");
+return false;
+}
+// Also includes verify_card
+bool CardTableExtension::addr_is_marked_precise(void *addr) {
+jbyte* p = byte_for(addr);
+jbyte val = *p;
+if (card_is_newgen(val))
+return true;
+if (card_is_verify(val))
+return true;
+if (card_is_clean(val))
+return false;
+if (card_is_dirty(val))
+return false;
+assert(false, "Found unhandled card mark type");
+return false;
+}
+// Assumes that only the base or the end changes.  This allows indentification
+// of the region that is being resized.  The
+// CardTableModRefBS::resize_covered_region() is used for the normal case
+// where the covered regions are growing or shrinking at the high end.
+// The method resize_covered_region_by_end() is analogous to
+// CardTableModRefBS::resize_covered_region() but
+// for regions that grow or shrink at the low end.
+void CardTableExtension::resize_covered_region(MemRegion new_region) {
+for (int i = 0; i < _cur_covered_regions; i++) {
+if (_covered[i].start() == new_region.start()) {
+// Found a covered region with the same start as the
+// new region.  The region is growing or shrinking
+// from the start of the region.
+resize_covered_region_by_start(new_region);
+return;
+}
+if (_covered[i].start() > new_region.start()) {
+break;
+}
+}
+int changed_region = -1;
+for (int j = 0; j < _cur_covered_regions; j++) {
+if (_covered[j].end() == new_region.end()) {
+changed_region = j;
+// This is a case where the covered region is growing or shrinking
+// at the start of the region.
+assert(changed_region != -1, "Don't expect to add a covered region");
+assert(_covered[changed_region].byte_size() != new_region.byte_size(),
+"The sizes should be different here");
+resize_covered_region_by_end(changed_region, new_region);
+return;
+}
+}
+// This should only be a new covered region (where no existing
+// covered region matches at the start or the end).
+assert(_cur_covered_regions < _max_covered_regions,
+"An existing region should have been found");
+resize_covered_region_by_start(new_region);
+}
+void CardTableExtension::resize_covered_region_by_start(MemRegion new_region) {
+CardTableModRefBS::resize_covered_region(new_region);
+debug_only(verify_guard();)
+}
+void CardTableExtension::resize_covered_region_by_end(int changed_region,
+MemRegion new_region) {
+assert(SafepointSynchronize::is_at_safepoint(),
+"Only expect an expansion at the low end at a GC");
+debug_only(verify_guard();)
+#ifdef ASSERT
+for (int k = 0; k < _cur_covered_regions; k++) {
+if (_covered[k].end() == new_region.end()) {
+assert(changed_region == k, "Changed region is incorrect");
+break;
+}
+}
+#endif
+// Commit new or uncommit old pages, if necessary.
+resize_commit_uncommit(changed_region, new_region);
+// Update card table entries
+resize_update_card_table_entries(changed_region, new_region);
+// Set the new start of the committed region
+resize_update_committed_table(changed_region, new_region);
+// Update the covered region
+resize_update_covered_table(changed_region, new_region);
+if (TraceCardTableModRefBS) {
+int ind = changed_region;
+gclog_or_tty->print_cr("CardTableModRefBS::resize_covered_region: ");
+gclog_or_tty->print_cr("  "
+"  _covered[%d].start(): " INTPTR_FORMAT
+"  _covered[%d].last(): " INTPTR_FORMAT,
+ind, _covered[ind].start(),
+ind, _covered[ind].last());
+gclog_or_tty->print_cr("  "
+"  _committed[%d].start(): " INTPTR_FORMAT
+"  _committed[%d].last(): " INTPTR_FORMAT,
+ind, _committed[ind].start(),
+ind, _committed[ind].last());
+gclog_or_tty->print_cr("  "
+"  byte_for(start): " INTPTR_FORMAT
+"  byte_for(last): " INTPTR_FORMAT,
+byte_for(_covered[ind].start()),
+byte_for(_covered[ind].last()));
+gclog_or_tty->print_cr("  "
+"  addr_for(start): " INTPTR_FORMAT
+"  addr_for(last): " INTPTR_FORMAT,
+addr_for((jbyte*) _committed[ind].start()),
+addr_for((jbyte*) _committed[ind].last()));
+}
+debug_only(verify_guard();)
+}
+void CardTableExtension::resize_commit_uncommit(int changed_region,
+MemRegion new_region) {
+// Commit new or uncommit old pages, if necessary.
+MemRegion cur_committed = _committed[changed_region];
+assert(_covered[changed_region].end() == new_region.end(),
+"The ends of the regions are expected to match");
+// Extend the start of this _committed region to
+// to cover the start of any previous _committed region.
+// This forms overlapping regions, but never interior regions.
+HeapWord* min_prev_start = lowest_prev_committed_start(changed_region);
+if (min_prev_start < cur_committed.start()) {
+// Only really need to set start of "cur_committed" to
+// the new start (min_prev_start) but assertion checking code
+// below use cur_committed.end() so make it correct.
+MemRegion new_committed =
+MemRegion(min_prev_start, cur_committed.end());
+cur_committed = new_committed;
+}
+#ifdef ASSERT
+ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+assert(cur_committed.start() ==
+(HeapWord*) align_size_up((uintptr_t) cur_committed.start(),
+os::vm_page_size()),
+"Starts should have proper alignment");
+#endif
+jbyte* new_start = byte_for(new_region.start());
+// Round down because this is for the start address
+HeapWord* new_start_aligned =
+(HeapWord*)align_size_down((uintptr_t)new_start, os::vm_page_size());
+// The guard page is always committed and should not be committed over.
+// This method is used in cases where the generation is growing toward
+// lower addresses but the guard region is still at the end of the
+// card table.  That still makes sense when looking for writes
+// off the end of the card table.
+if (new_start_aligned < cur_committed.start()) {
+// Expand the committed region
+//
+// Case A
+//                                          |+ guard +|
+//                          |+ cur committed +++++++++|
+//                  |+ new committed +++++++++++++++++|
+//
+// Case B
+//                                          |+ guard +|
+//                        |+ cur committed +|
+//                  |+ new committed +++++++|
+//
+// These are not expected because the calculation of the
+// cur committed region and the new committed region
+// share the same end for the covered region.
+// Case C
+//                                          |+ guard +|
+//                        |+ cur committed +|
+//                  |+ new committed +++++++++++++++++|
+// Case D
+//                                          |+ guard +|
+//                        |+ cur committed +++++++++++|
+//                  |+ new committed +++++++|
+HeapWord* new_end_for_commit =
+MIN2(cur_committed.end(), _guard_region.start());
+MemRegion new_committed =
+MemRegion(new_start_aligned, new_end_for_commit);
+if(!new_committed.is_empty()) {
+if (!os::commit_memory((char*)new_committed.start(),
+new_committed.byte_size())) {
+vm_exit_out_of_memory(new_committed.byte_size(),
+"card table expansion");
+}
+}
+} else if (new_start_aligned > cur_committed.start()) {
+// Shrink the committed region
+MemRegion uncommit_region = committed_unique_to_self(changed_region,
+MemRegion(cur_committed.start(), new_start_aligned));
+if (!uncommit_region.is_empty()) {
+if (!os::uncommit_memory((char*)uncommit_region.start(),
+uncommit_region.byte_size())) {
+vm_exit_out_of_memory(uncommit_region.byte_size(),
+"card table contraction");
+}
+}
+}
+assert(_committed[changed_region].end() == cur_committed.end(),
+"end should not change");
+}
+void CardTableExtension::resize_update_committed_table(int changed_region,
+MemRegion new_region) {
+jbyte* new_start = byte_for(new_region.start());
+// Set the new start of the committed region
+HeapWord* new_start_aligned =
+(HeapWord*)align_size_down((uintptr_t)new_start,
+os::vm_page_size());
+MemRegion new_committed = MemRegion(new_start_aligned,
+_committed[changed_region].end());
+_committed[changed_region] = new_committed;
+_committed[changed_region].set_start(new_start_aligned);
+}
+void CardTableExtension::resize_update_card_table_entries(int changed_region,
+MemRegion new_region) {
+debug_only(verify_guard();)
+MemRegion original_covered = _covered[changed_region];
+// Initialize the card entries.  Only consider the
+// region covered by the card table (_whole_heap)
+jbyte* entry;
+if (new_region.start() < _whole_heap.start()) {
+entry = byte_for(_whole_heap.start());
+} else {
+entry = byte_for(new_region.start());
+}
+jbyte* end = byte_for(original_covered.start());
+// If _whole_heap starts at the original covered regions start,
+// this loop will not execute.
+while (entry < end) { *entry++ = clean_card; }
+}
+void CardTableExtension::resize_update_covered_table(int changed_region,
+MemRegion new_region) {
+// Update the covered region
+_covered[changed_region].set_start(new_region.start());
+_covered[changed_region].set_word_size(new_region.word_size());
+// reorder regions.  There should only be at most 1 out
+// of order.
+for (int i = _cur_covered_regions-1 ; i > 0; i--) {
+if (_covered[i].start() < _covered[i-1].start()) {
+MemRegion covered_mr = _covered[i-1];
+_covered[i-1] = _covered[i];
+_covered[i] = covered_mr;
+MemRegion committed_mr = _committed[i-1];
+_committed[i-1] = _committed[i];
+_committed[i] = committed_mr;
+break;
+}
+}
+#ifdef ASSERT
+for (int m = 0; m < _cur_covered_regions-1; m++) {
+assert(_covered[m].start() <= _covered[m+1].start(),
+"Covered regions out of order");
+assert(_committed[m].start() <= _committed[m+1].start(),
+"Committed regions out of order");
+}
+#endif
+}
+// Returns the start of any committed region that is lower than
+// the target committed region (index ind) and that intersects the
+// target region.  If none, return start of target region.
+//
+//      -------------
+//      |           |
+//      -------------
+//              ------------
+//              | target   |
+//              ------------
+//                               -------------
+//                               |           |
+//                               -------------
+//      ^ returns this
+//
+//      -------------
+//      |           |
+//      -------------
+//                      ------------
+//                      | target   |
+//                      ------------
+//                               -------------
+//                               |           |
+//                               -------------
+//                      ^ returns this
+HeapWord* CardTableExtension::lowest_prev_committed_start(int ind) const {
+assert(_cur_covered_regions >= 0, "Expecting at least on region");
+HeapWord* min_start = _committed[ind].start();
+for (int j = 0; j < ind; j++) {
+HeapWord* this_start = _committed[j].start();
+if ((this_start < min_start) &&
+!(_committed[j].intersection(_committed[ind])).is_empty()) {
+min_start = this_start;
+}
+}
+return min_start;
+}

Mercurial > hg > graal-jvmci-8

comparison src/share/vm/gc_implementation/parallelScavenge/cardTableExtension.cpp @ 0:a61af66fc99e jdk7-b24