duke@435: /*
trims@1907:  * Copyright (c) 2001, 2008, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: # include "incls/_precompiled.incl"
duke@435: # include "incls/_cardTableExtension.cpp.incl"
duke@435: 
duke@435: // Checks an individual oop for missing precise marks. Mark
duke@435: // may be either dirty or newgen.
duke@435: class CheckForUnmarkedOops : public OopClosure {
coleenp@548:  private:
coleenp@548:   PSYoungGen*         _young_gen;
duke@435:   CardTableExtension* _card_table;
coleenp@548:   HeapWord*           _unmarked_addr;
coleenp@548:   jbyte*              _unmarked_card;
duke@435: 
coleenp@548:  protected:
coleenp@548:   template <class T> void do_oop_work(T* p) {
coleenp@548:     oop obj = oopDesc::load_decode_heap_oop_not_null(p);
coleenp@548:     if (_young_gen->is_in_reserved(obj) &&
duke@435:         !_card_table->addr_is_marked_imprecise(p)) {
duke@435:       // Don't overwrite the first missing card mark
duke@435:       if (_unmarked_addr == NULL) {
duke@435:         _unmarked_addr = (HeapWord*)p;
duke@435:         _unmarked_card = _card_table->byte_for(p);
duke@435:       }
duke@435:     }
duke@435:   }
duke@435: 
coleenp@548:  public:
coleenp@548:   CheckForUnmarkedOops(PSYoungGen* young_gen, CardTableExtension* card_table) :
coleenp@548:     _young_gen(young_gen), _card_table(card_table), _unmarked_addr(NULL) { }
coleenp@548: 
coleenp@548:   virtual void do_oop(oop* p)       { CheckForUnmarkedOops::do_oop_work(p); }
coleenp@548:   virtual void do_oop(narrowOop* p) { CheckForUnmarkedOops::do_oop_work(p); }
coleenp@548: 
duke@435:   bool has_unmarked_oop() {
duke@435:     return _unmarked_addr != NULL;
duke@435:   }
duke@435: };
duke@435: 
duke@435: // Checks all objects for the existance of some type of mark,
duke@435: // precise or imprecise, dirty or newgen.
duke@435: class CheckForUnmarkedObjects : public ObjectClosure {
coleenp@548:  private:
coleenp@548:   PSYoungGen*         _young_gen;
duke@435:   CardTableExtension* _card_table;
duke@435: 
duke@435:  public:
duke@435:   CheckForUnmarkedObjects() {
duke@435:     ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
duke@435:     assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
duke@435: 
duke@435:     _young_gen = heap->young_gen();
duke@435:     _card_table = (CardTableExtension*)heap->barrier_set();
duke@435:     // No point in asserting barrier set type here. Need to make CardTableExtension
duke@435:     // a unique barrier set type.
duke@435:   }
duke@435: 
duke@435:   // Card marks are not precise. The current system can leave us with
twisti@1040:   // a mismash of precise marks and beginning of object marks. This means
duke@435:   // we test for missing precise marks first. If any are found, we don't
duke@435:   // fail unless the object head is also unmarked.
duke@435:   virtual void do_object(oop obj) {
coleenp@548:     CheckForUnmarkedOops object_check(_young_gen, _card_table);
duke@435:     obj->oop_iterate(&object_check);
duke@435:     if (object_check.has_unmarked_oop()) {
duke@435:       assert(_card_table->addr_is_marked_imprecise(obj), "Found unmarked young_gen object");
duke@435:     }
duke@435:   }
duke@435: };
duke@435: 
duke@435: // Checks for precise marking of oops as newgen.
duke@435: class CheckForPreciseMarks : public OopClosure {
coleenp@548:  private:
coleenp@548:   PSYoungGen*         _young_gen;
duke@435:   CardTableExtension* _card_table;
duke@435: 
coleenp@548:  protected:
coleenp@548:   template <class T> void do_oop_work(T* p) {
coleenp@548:     oop obj = oopDesc::load_decode_heap_oop_not_null(p);
coleenp@548:     if (_young_gen->is_in_reserved(obj)) {
coleenp@548:       assert(_card_table->addr_is_marked_precise(p), "Found unmarked precise oop");
coleenp@548:       _card_table->set_card_newgen(p);
coleenp@548:     }
coleenp@548:   }
coleenp@548: 
duke@435:  public:
duke@435:   CheckForPreciseMarks( PSYoungGen* young_gen, CardTableExtension* card_table ) :
duke@435:     _young_gen(young_gen), _card_table(card_table) { }
duke@435: 
coleenp@548:   virtual void do_oop(oop* p)       { CheckForPreciseMarks::do_oop_work(p); }
coleenp@548:   virtual void do_oop(narrowOop* p) { CheckForPreciseMarks::do_oop_work(p); }
duke@435: };
duke@435: 
duke@435: // We get passed the space_top value to prevent us from traversing into
duke@435: // the old_gen promotion labs, which cannot be safely parsed.
duke@435: void CardTableExtension::scavenge_contents(ObjectStartArray* start_array,
duke@435:                                            MutableSpace* sp,
duke@435:                                            HeapWord* space_top,
duke@435:                                            PSPromotionManager* pm)
duke@435: {
duke@435:   assert(start_array != NULL && sp != NULL && pm != NULL, "Sanity");
duke@435:   assert(start_array->covered_region().contains(sp->used_region()),
duke@435:          "ObjectStartArray does not cover space");
duke@435:   bool depth_first = pm->depth_first();
duke@435: 
duke@435:   if (sp->not_empty()) {
duke@435:     oop* sp_top = (oop*)space_top;
duke@435:     oop* prev_top = NULL;
duke@435:     jbyte* current_card = byte_for(sp->bottom());
duke@435:     jbyte* end_card     = byte_for(sp_top - 1);    // sp_top is exclusive
duke@435:     // scan card marking array
duke@435:     while (current_card <= end_card) {
duke@435:       jbyte value = *current_card;
duke@435:       // skip clean cards
duke@435:       if (card_is_clean(value)) {
duke@435:         current_card++;
duke@435:       } else {
duke@435:         // we found a non-clean card
duke@435:         jbyte* first_nonclean_card = current_card++;
duke@435:         oop* bottom = (oop*)addr_for(first_nonclean_card);
duke@435:         // find object starting on card
duke@435:         oop* bottom_obj = (oop*)start_array->object_start((HeapWord*)bottom);
duke@435:         // bottom_obj = (oop*)start_array->object_start((HeapWord*)bottom);
duke@435:         assert(bottom_obj <= bottom, "just checking");
duke@435:         // make sure we don't scan oops we already looked at
duke@435:         if (bottom < prev_top) bottom = prev_top;
duke@435:         // figure out when to stop scanning
duke@435:         jbyte* first_clean_card;
duke@435:         oop* top;
duke@435:         bool restart_scanning;
duke@435:         do {
duke@435:           restart_scanning = false;
duke@435:           // find a clean card
duke@435:           while (current_card <= end_card) {
duke@435:             value = *current_card;
duke@435:             if (card_is_clean(value)) break;
duke@435:             current_card++;
duke@435:           }
duke@435:           // check if we reached the end, if so we are done
duke@435:           if (current_card >= end_card) {
duke@435:             first_clean_card = end_card + 1;
duke@435:             current_card++;
duke@435:             top = sp_top;
duke@435:           } else {
duke@435:             // we have a clean card, find object starting on that card
duke@435:             first_clean_card = current_card++;
duke@435:             top = (oop*)addr_for(first_clean_card);
duke@435:             oop* top_obj = (oop*)start_array->object_start((HeapWord*)top);
duke@435:             // top_obj = (oop*)start_array->object_start((HeapWord*)top);
duke@435:             assert(top_obj <= top, "just checking");
duke@435:             if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) {
duke@435:               // an arrayOop is starting on the clean card - since we do exact store
duke@435:               // checks for objArrays we are done
duke@435:             } else {
duke@435:               // otherwise, it is possible that the object starting on the clean card
duke@435:               // spans the entire card, and that the store happened on a later card.
duke@435:               // figure out where the object ends
duke@435:               top = top_obj + oop(top_obj)->size();
duke@435:               jbyte* top_card = CardTableModRefBS::byte_for(top - 1);   // top is exclusive
duke@435:               if (top_card > first_clean_card) {
duke@435:                 // object ends a different card
duke@435:                 current_card = top_card + 1;
duke@435:                 if (card_is_clean(*top_card)) {
duke@435:                   // the ending card is clean, we are done
duke@435:                   first_clean_card = top_card;
duke@435:                 } else {
duke@435:                   // the ending card is not clean, continue scanning at start of do-while
duke@435:                   restart_scanning = true;
duke@435:                 }
duke@435:               } else {
duke@435:                 // object ends on the clean card, we are done.
duke@435:                 assert(first_clean_card == top_card, "just checking");
duke@435:               }
duke@435:             }
duke@435:           }
duke@435:         } while (restart_scanning);
duke@435:         // we know which cards to scan, now clear them
duke@435:         while (first_nonclean_card < first_clean_card) {
duke@435:           *first_nonclean_card++ = clean_card;
duke@435:         }
duke@435:         // scan oops in objects
duke@435:         // hoisted the if (depth_first) check out of the loop
duke@435:         if (depth_first){
duke@435:           do {
duke@435:             oop(bottom_obj)->push_contents(pm);
duke@435:             bottom_obj += oop(bottom_obj)->size();
duke@435:             assert(bottom_obj <= sp_top, "just checking");
duke@435:           } while (bottom_obj < top);
duke@435:           pm->drain_stacks_cond_depth();
duke@435:         } else {
duke@435:           do {
duke@435:             oop(bottom_obj)->copy_contents(pm);
duke@435:             bottom_obj += oop(bottom_obj)->size();
duke@435:             assert(bottom_obj <= sp_top, "just checking");
duke@435:           } while (bottom_obj < top);
duke@435:         }
duke@435:         // remember top oop* scanned
duke@435:         prev_top = top;
duke@435:       }
duke@435:     }
duke@435:   }
duke@435: }
duke@435: 
duke@435: void CardTableExtension::scavenge_contents_parallel(ObjectStartArray* start_array,
duke@435:                                                     MutableSpace* sp,
duke@435:                                                     HeapWord* space_top,
duke@435:                                                     PSPromotionManager* pm,
duke@435:                                                     uint stripe_number) {
duke@435:   int ssize = 128; // Naked constant!  Work unit = 64k.
duke@435:   int dirty_card_count = 0;
duke@435:   bool depth_first = pm->depth_first();
duke@435: 
duke@435:   oop* sp_top = (oop*)space_top;
duke@435:   jbyte* start_card = byte_for(sp->bottom());
duke@435:   jbyte* end_card   = byte_for(sp_top - 1) + 1;
duke@435:   oop* last_scanned = NULL; // Prevent scanning objects more than once
duke@435:   for (jbyte* slice = start_card; slice < end_card; slice += ssize*ParallelGCThreads) {
duke@435:     jbyte* worker_start_card = slice + stripe_number * ssize;
duke@435:     if (worker_start_card >= end_card)
duke@435:       return; // We're done.
duke@435: 
duke@435:     jbyte* worker_end_card = worker_start_card + ssize;
duke@435:     if (worker_end_card > end_card)
duke@435:       worker_end_card = end_card;
duke@435: 
duke@435:     // We do not want to scan objects more than once. In order to accomplish
duke@435:     // this, we assert that any object with an object head inside our 'slice'
duke@435:     // belongs to us. We may need to extend the range of scanned cards if the
duke@435:     // last object continues into the next 'slice'.
duke@435:     //
duke@435:     // Note! ending cards are exclusive!
duke@435:     HeapWord* slice_start = addr_for(worker_start_card);
duke@435:     HeapWord* slice_end = MIN2((HeapWord*) sp_top, addr_for(worker_end_card));
duke@435: 
duke@435:     // If there are not objects starting within the chunk, skip it.
duke@435:     if (!start_array->object_starts_in_range(slice_start, slice_end)) {
duke@435:       continue;
duke@435:     }
twisti@1040:     // Update our beginning addr
duke@435:     HeapWord* first_object = start_array->object_start(slice_start);
duke@435:     debug_only(oop* first_object_within_slice = (oop*) first_object;)
duke@435:     if (first_object < slice_start) {
duke@435:       last_scanned = (oop*)(first_object + oop(first_object)->size());
duke@435:       debug_only(first_object_within_slice = last_scanned;)
duke@435:       worker_start_card = byte_for(last_scanned);
duke@435:     }
duke@435: 
duke@435:     // Update the ending addr
duke@435:     if (slice_end < (HeapWord*)sp_top) {
duke@435:       // The subtraction is important! An object may start precisely at slice_end.
duke@435:       HeapWord* last_object = start_array->object_start(slice_end - 1);
duke@435:       slice_end = last_object + oop(last_object)->size();
duke@435:       // worker_end_card is exclusive, so bump it one past the end of last_object's
duke@435:       // covered span.
duke@435:       worker_end_card = byte_for(slice_end) + 1;
duke@435: 
duke@435:       if (worker_end_card > end_card)
duke@435:         worker_end_card = end_card;
duke@435:     }
duke@435: 
duke@435:     assert(slice_end <= (HeapWord*)sp_top, "Last object in slice crosses space boundary");
duke@435:     assert(is_valid_card_address(worker_start_card), "Invalid worker start card");
duke@435:     assert(is_valid_card_address(worker_end_card), "Invalid worker end card");
duke@435:     // Note that worker_start_card >= worker_end_card is legal, and happens when
duke@435:     // an object spans an entire slice.
duke@435:     assert(worker_start_card <= end_card, "worker start card beyond end card");
duke@435:     assert(worker_end_card <= end_card, "worker end card beyond end card");
duke@435: 
duke@435:     jbyte* current_card = worker_start_card;
duke@435:     while (current_card < worker_end_card) {
duke@435:       // Find an unclean card.
duke@435:       while (current_card < worker_end_card && card_is_clean(*current_card)) {
duke@435:         current_card++;
duke@435:       }
duke@435:       jbyte* first_unclean_card = current_card;
duke@435: 
duke@435:       // Find the end of a run of contiguous unclean cards
duke@435:       while (current_card < worker_end_card && !card_is_clean(*current_card)) {
duke@435:         while (current_card < worker_end_card && !card_is_clean(*current_card)) {
duke@435:           current_card++;
duke@435:         }
duke@435: 
duke@435:         if (current_card < worker_end_card) {
duke@435:           // Some objects may be large enough to span several cards. If such
duke@435:           // an object has more than one dirty card, separated by a clean card,
duke@435:           // we will attempt to scan it twice. The test against "last_scanned"
duke@435:           // prevents the redundant object scan, but it does not prevent newly
duke@435:           // marked cards from being cleaned.
duke@435:           HeapWord* last_object_in_dirty_region = start_array->object_start(addr_for(current_card)-1);
duke@435:           size_t size_of_last_object = oop(last_object_in_dirty_region)->size();
duke@435:           HeapWord* end_of_last_object = last_object_in_dirty_region + size_of_last_object;
duke@435:           jbyte* ending_card_of_last_object = byte_for(end_of_last_object);
duke@435:           assert(ending_card_of_last_object <= worker_end_card, "ending_card_of_last_object is greater than worker_end_card");
duke@435:           if (ending_card_of_last_object > current_card) {
duke@435:             // This means the object spans the next complete card.
duke@435:             // We need to bump the current_card to ending_card_of_last_object
duke@435:             current_card = ending_card_of_last_object;
duke@435:           }
duke@435:         }
duke@435:       }
duke@435:       jbyte* following_clean_card = current_card;
duke@435: 
duke@435:       if (first_unclean_card < worker_end_card) {
duke@435:         oop* p = (oop*) start_array->object_start(addr_for(first_unclean_card));
duke@435:         assert((HeapWord*)p <= addr_for(first_unclean_card), "checking");
duke@435:         // "p" should always be >= "last_scanned" because newly GC dirtied
duke@435:         // cards are no longer scanned again (see comment at end
duke@435:         // of loop on the increment of "current_card").  Test that
duke@435:         // hypothesis before removing this code.
duke@435:         // If this code is removed, deal with the first time through
duke@435:         // the loop when the last_scanned is the object starting in
duke@435:         // the previous slice.
duke@435:         assert((p >= last_scanned) ||
duke@435:                (last_scanned == first_object_within_slice),
duke@435:                "Should no longer be possible");
duke@435:         if (p < last_scanned) {
duke@435:           // Avoid scanning more than once; this can happen because
duke@435:           // newgen cards set by GC may a different set than the
duke@435:           // originally dirty set
duke@435:           p = last_scanned;
duke@435:         }
duke@435:         oop* to = (oop*)addr_for(following_clean_card);
duke@435: 
duke@435:         // Test slice_end first!
duke@435:         if ((HeapWord*)to > slice_end) {
duke@435:           to = (oop*)slice_end;
duke@435:         } else if (to > sp_top) {
duke@435:           to = sp_top;
duke@435:         }
duke@435: 
duke@435:         // we know which cards to scan, now clear them
duke@435:         if (first_unclean_card <= worker_start_card+1)
duke@435:           first_unclean_card = worker_start_card+1;
duke@435:         if (following_clean_card >= worker_end_card-1)
duke@435:           following_clean_card = worker_end_card-1;
duke@435: 
duke@435:         while (first_unclean_card < following_clean_card) {
duke@435:           *first_unclean_card++ = clean_card;
duke@435:         }
duke@435: 
duke@435:         const int interval = PrefetchScanIntervalInBytes;
duke@435:         // scan all objects in the range
duke@435:         if (interval != 0) {
duke@435:           // hoisted the if (depth_first) check out of the loop
duke@435:           if (depth_first) {
duke@435:             while (p < to) {
duke@435:               Prefetch::write(p, interval);
duke@435:               oop m = oop(p);
duke@435:               assert(m->is_oop_or_null(), "check for header");
duke@435:               m->push_contents(pm);
duke@435:               p += m->size();
duke@435:             }
duke@435:             pm->drain_stacks_cond_depth();
duke@435:           } else {
duke@435:             while (p < to) {
duke@435:               Prefetch::write(p, interval);
duke@435:               oop m = oop(p);
duke@435:               assert(m->is_oop_or_null(), "check for header");
duke@435:               m->copy_contents(pm);
duke@435:               p += m->size();
duke@435:             }
duke@435:           }
duke@435:         } else {
duke@435:           // hoisted the if (depth_first) check out of the loop
duke@435:           if (depth_first) {
duke@435:             while (p < to) {
duke@435:               oop m = oop(p);
duke@435:               assert(m->is_oop_or_null(), "check for header");
duke@435:               m->push_contents(pm);
duke@435:               p += m->size();
duke@435:             }
duke@435:             pm->drain_stacks_cond_depth();
duke@435:           } else {
duke@435:             while (p < to) {
duke@435:               oop m = oop(p);
duke@435:               assert(m->is_oop_or_null(), "check for header");
duke@435:               m->copy_contents(pm);
duke@435:               p += m->size();
duke@435:             }
duke@435:           }
duke@435:         }
duke@435:         last_scanned = p;
duke@435:       }
duke@435:       // "current_card" is still the "following_clean_card" or
duke@435:       // the current_card is >= the worker_end_card so the
duke@435:       // loop will not execute again.
duke@435:       assert((current_card == following_clean_card) ||
duke@435:              (current_card >= worker_end_card),
duke@435:         "current_card should only be incremented if it still equals "
duke@435:         "following_clean_card");
duke@435:       // Increment current_card so that it is not processed again.
duke@435:       // It may now be dirty because a old-to-young pointer was
duke@435:       // found on it an updated.  If it is now dirty, it cannot be
duke@435:       // be safely cleaned in the next iteration.
duke@435:       current_card++;
duke@435:     }
duke@435:   }
duke@435: }
duke@435: 
duke@435: // This should be called before a scavenge.
duke@435: void CardTableExtension::verify_all_young_refs_imprecise() {
duke@435:   CheckForUnmarkedObjects check;
duke@435: 
duke@435:   ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
duke@435:   assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
duke@435: 
duke@435:   PSOldGen* old_gen = heap->old_gen();
duke@435:   PSPermGen* perm_gen = heap->perm_gen();
duke@435: 
duke@435:   old_gen->object_iterate(&check);
duke@435:   perm_gen->object_iterate(&check);
duke@435: }
duke@435: 
duke@435: // This should be called immediately after a scavenge, before mutators resume.
duke@435: void CardTableExtension::verify_all_young_refs_precise() {
duke@435:   ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
duke@435:   assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
duke@435: 
duke@435:   PSOldGen* old_gen = heap->old_gen();
duke@435:   PSPermGen* perm_gen = heap->perm_gen();
duke@435: 
duke@435:   CheckForPreciseMarks check(heap->young_gen(), (CardTableExtension*)heap->barrier_set());
duke@435: 
duke@435:   old_gen->oop_iterate(&check);
duke@435:   perm_gen->oop_iterate(&check);
duke@435: 
duke@435:   verify_all_young_refs_precise_helper(old_gen->object_space()->used_region());
duke@435:   verify_all_young_refs_precise_helper(perm_gen->object_space()->used_region());
duke@435: }
duke@435: 
duke@435: void CardTableExtension::verify_all_young_refs_precise_helper(MemRegion mr) {
duke@435:   CardTableExtension* card_table = (CardTableExtension*)Universe::heap()->barrier_set();
duke@435:   // FIX ME ASSERT HERE
duke@435: 
duke@435:   jbyte* bot = card_table->byte_for(mr.start());
duke@435:   jbyte* top = card_table->byte_for(mr.end());
duke@435:   while(bot <= top) {
duke@435:     assert(*bot == clean_card || *bot == verify_card, "Found unwanted or unknown card mark");
duke@435:     if (*bot == verify_card)
duke@435:       *bot = youngergen_card;
duke@435:     bot++;
duke@435:   }
duke@435: }
duke@435: 
duke@435: bool CardTableExtension::addr_is_marked_imprecise(void *addr) {
duke@435:   jbyte* p = byte_for(addr);
duke@435:   jbyte val = *p;
duke@435: 
duke@435:   if (card_is_dirty(val))
duke@435:     return true;
duke@435: 
duke@435:   if (card_is_newgen(val))
duke@435:     return true;
duke@435: 
duke@435:   if (card_is_clean(val))
duke@435:     return false;
duke@435: 
duke@435:   assert(false, "Found unhandled card mark type");
duke@435: 
duke@435:   return false;
duke@435: }
duke@435: 
duke@435: // Also includes verify_card
duke@435: bool CardTableExtension::addr_is_marked_precise(void *addr) {
duke@435:   jbyte* p = byte_for(addr);
duke@435:   jbyte val = *p;
duke@435: 
duke@435:   if (card_is_newgen(val))
duke@435:     return true;
duke@435: 
duke@435:   if (card_is_verify(val))
duke@435:     return true;
duke@435: 
duke@435:   if (card_is_clean(val))
duke@435:     return false;
duke@435: 
duke@435:   if (card_is_dirty(val))
duke@435:     return false;
duke@435: 
duke@435:   assert(false, "Found unhandled card mark type");
duke@435: 
duke@435:   return false;
duke@435: }
duke@435: 
duke@435: // Assumes that only the base or the end changes.  This allows indentification
duke@435: // of the region that is being resized.  The
duke@435: // CardTableModRefBS::resize_covered_region() is used for the normal case
duke@435: // where the covered regions are growing or shrinking at the high end.
duke@435: // The method resize_covered_region_by_end() is analogous to
duke@435: // CardTableModRefBS::resize_covered_region() but
duke@435: // for regions that grow or shrink at the low end.
duke@435: void CardTableExtension::resize_covered_region(MemRegion new_region) {
duke@435: 
duke@435:   for (int i = 0; i < _cur_covered_regions; i++) {
duke@435:     if (_covered[i].start() == new_region.start()) {
duke@435:       // Found a covered region with the same start as the
duke@435:       // new region.  The region is growing or shrinking
duke@435:       // from the start of the region.
duke@435:       resize_covered_region_by_start(new_region);
duke@435:       return;
duke@435:     }
duke@435:     if (_covered[i].start() > new_region.start()) {
duke@435:       break;
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   int changed_region = -1;
duke@435:   for (int j = 0; j < _cur_covered_regions; j++) {
duke@435:     if (_covered[j].end() == new_region.end()) {
duke@435:       changed_region = j;
duke@435:       // This is a case where the covered region is growing or shrinking
duke@435:       // at the start of the region.
duke@435:       assert(changed_region != -1, "Don't expect to add a covered region");
duke@435:       assert(_covered[changed_region].byte_size() != new_region.byte_size(),
duke@435:         "The sizes should be different here");
duke@435:       resize_covered_region_by_end(changed_region, new_region);
duke@435:       return;
duke@435:     }
duke@435:   }
duke@435:   // This should only be a new covered region (where no existing
duke@435:   // covered region matches at the start or the end).
duke@435:   assert(_cur_covered_regions < _max_covered_regions,
duke@435:     "An existing region should have been found");
duke@435:   resize_covered_region_by_start(new_region);
duke@435: }
duke@435: 
duke@435: void CardTableExtension::resize_covered_region_by_start(MemRegion new_region) {
duke@435:   CardTableModRefBS::resize_covered_region(new_region);
duke@435:   debug_only(verify_guard();)
duke@435: }
duke@435: 
duke@435: void CardTableExtension::resize_covered_region_by_end(int changed_region,
duke@435:                                                       MemRegion new_region) {
duke@435:   assert(SafepointSynchronize::is_at_safepoint(),
duke@435:     "Only expect an expansion at the low end at a GC");
duke@435:   debug_only(verify_guard();)
duke@435: #ifdef ASSERT
duke@435:   for (int k = 0; k < _cur_covered_regions; k++) {
duke@435:     if (_covered[k].end() == new_region.end()) {
duke@435:       assert(changed_region == k, "Changed region is incorrect");
duke@435:       break;
duke@435:     }
duke@435:   }
duke@435: #endif
duke@435: 
duke@435:   // Commit new or uncommit old pages, if necessary.
duke@435:   resize_commit_uncommit(changed_region, new_region);
duke@435: 
duke@435:   // Update card table entries
duke@435:   resize_update_card_table_entries(changed_region, new_region);
duke@435: 
duke@435:   // Set the new start of the committed region
duke@435:   resize_update_committed_table(changed_region, new_region);
duke@435: 
duke@435:   // Update the covered region
duke@435:   resize_update_covered_table(changed_region, new_region);
duke@435: 
duke@435:   if (TraceCardTableModRefBS) {
duke@435:     int ind = changed_region;
duke@435:     gclog_or_tty->print_cr("CardTableModRefBS::resize_covered_region: ");
duke@435:     gclog_or_tty->print_cr("  "
duke@435:                   "  _covered[%d].start(): " INTPTR_FORMAT
duke@435:                   "  _covered[%d].last(): " INTPTR_FORMAT,
duke@435:                   ind, _covered[ind].start(),
duke@435:                   ind, _covered[ind].last());
duke@435:     gclog_or_tty->print_cr("  "
duke@435:                   "  _committed[%d].start(): " INTPTR_FORMAT
duke@435:                   "  _committed[%d].last(): " INTPTR_FORMAT,
duke@435:                   ind, _committed[ind].start(),
duke@435:                   ind, _committed[ind].last());
duke@435:     gclog_or_tty->print_cr("  "
duke@435:                   "  byte_for(start): " INTPTR_FORMAT
duke@435:                   "  byte_for(last): " INTPTR_FORMAT,
duke@435:                   byte_for(_covered[ind].start()),
duke@435:                   byte_for(_covered[ind].last()));
duke@435:     gclog_or_tty->print_cr("  "
duke@435:                   "  addr_for(start): " INTPTR_FORMAT
duke@435:                   "  addr_for(last): " INTPTR_FORMAT,
duke@435:                   addr_for((jbyte*) _committed[ind].start()),
duke@435:                   addr_for((jbyte*) _committed[ind].last()));
duke@435:   }
duke@435:   debug_only(verify_guard();)
duke@435: }
duke@435: 
duke@435: void CardTableExtension::resize_commit_uncommit(int changed_region,
duke@435:                                                 MemRegion new_region) {
duke@435:   // Commit new or uncommit old pages, if necessary.
duke@435:   MemRegion cur_committed = _committed[changed_region];
duke@435:   assert(_covered[changed_region].end() == new_region.end(),
duke@435:     "The ends of the regions are expected to match");
duke@435:   // Extend the start of this _committed region to
duke@435:   // to cover the start of any previous _committed region.
duke@435:   // This forms overlapping regions, but never interior regions.
duke@435:   HeapWord* min_prev_start = lowest_prev_committed_start(changed_region);
duke@435:   if (min_prev_start < cur_committed.start()) {
duke@435:     // Only really need to set start of "cur_committed" to
duke@435:     // the new start (min_prev_start) but assertion checking code
duke@435:     // below use cur_committed.end() so make it correct.
duke@435:     MemRegion new_committed =
duke@435:         MemRegion(min_prev_start, cur_committed.end());
duke@435:     cur_committed = new_committed;
duke@435:   }
duke@435: #ifdef ASSERT
duke@435:   ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
duke@435:   assert(cur_committed.start() ==
duke@435:     (HeapWord*) align_size_up((uintptr_t) cur_committed.start(),
duke@435:                               os::vm_page_size()),
duke@435:     "Starts should have proper alignment");
duke@435: #endif
duke@435: 
duke@435:   jbyte* new_start = byte_for(new_region.start());
duke@435:   // Round down because this is for the start address
duke@435:   HeapWord* new_start_aligned =
duke@435:     (HeapWord*)align_size_down((uintptr_t)new_start, os::vm_page_size());
duke@435:   // The guard page is always committed and should not be committed over.
duke@435:   // This method is used in cases where the generation is growing toward
duke@435:   // lower addresses but the guard region is still at the end of the
duke@435:   // card table.  That still makes sense when looking for writes
duke@435:   // off the end of the card table.
duke@435:   if (new_start_aligned < cur_committed.start()) {
duke@435:     // Expand the committed region
duke@435:     //
duke@435:     // Case A
duke@435:     //                                          |+ guard +|
duke@435:     //                          |+ cur committed +++++++++|
duke@435:     //                  |+ new committed +++++++++++++++++|
duke@435:     //
duke@435:     // Case B
duke@435:     //                                          |+ guard +|
duke@435:     //                        |+ cur committed +|
duke@435:     //                  |+ new committed +++++++|
duke@435:     //
duke@435:     // These are not expected because the calculation of the
duke@435:     // cur committed region and the new committed region
duke@435:     // share the same end for the covered region.
duke@435:     // Case C
duke@435:     //                                          |+ guard +|
duke@435:     //                        |+ cur committed +|
duke@435:     //                  |+ new committed +++++++++++++++++|
duke@435:     // Case D
duke@435:     //                                          |+ guard +|
duke@435:     //                        |+ cur committed +++++++++++|
duke@435:     //                  |+ new committed +++++++|
duke@435: 
duke@435:     HeapWord* new_end_for_commit =
duke@435:       MIN2(cur_committed.end(), _guard_region.start());
jmasa@698:     if(new_start_aligned < new_end_for_commit) {
jmasa@698:       MemRegion new_committed =
jmasa@698:         MemRegion(new_start_aligned, new_end_for_commit);
duke@435:       if (!os::commit_memory((char*)new_committed.start(),
duke@435:                              new_committed.byte_size())) {
duke@435:         vm_exit_out_of_memory(new_committed.byte_size(),
duke@435:                               "card table expansion");
duke@435:       }
duke@435:     }
duke@435:   } else if (new_start_aligned > cur_committed.start()) {
duke@435:     // Shrink the committed region
duke@435:     MemRegion uncommit_region = committed_unique_to_self(changed_region,
duke@435:       MemRegion(cur_committed.start(), new_start_aligned));
duke@435:     if (!uncommit_region.is_empty()) {
duke@435:       if (!os::uncommit_memory((char*)uncommit_region.start(),
duke@435:                                uncommit_region.byte_size())) {
duke@435:         vm_exit_out_of_memory(uncommit_region.byte_size(),
duke@435:           "card table contraction");
duke@435:       }
duke@435:     }
duke@435:   }
duke@435:   assert(_committed[changed_region].end() == cur_committed.end(),
duke@435:     "end should not change");
duke@435: }
duke@435: 
duke@435: void CardTableExtension::resize_update_committed_table(int changed_region,
duke@435:                                                        MemRegion new_region) {
duke@435: 
duke@435:   jbyte* new_start = byte_for(new_region.start());
duke@435:   // Set the new start of the committed region
duke@435:   HeapWord* new_start_aligned =
duke@435:     (HeapWord*)align_size_down((uintptr_t)new_start,
duke@435:                              os::vm_page_size());
duke@435:   MemRegion new_committed = MemRegion(new_start_aligned,
duke@435:     _committed[changed_region].end());
duke@435:   _committed[changed_region] = new_committed;
duke@435:   _committed[changed_region].set_start(new_start_aligned);
duke@435: }
duke@435: 
duke@435: void CardTableExtension::resize_update_card_table_entries(int changed_region,
duke@435:                                                           MemRegion new_region) {
duke@435:   debug_only(verify_guard();)
duke@435:   MemRegion original_covered = _covered[changed_region];
duke@435:   // Initialize the card entries.  Only consider the
duke@435:   // region covered by the card table (_whole_heap)
duke@435:   jbyte* entry;
duke@435:   if (new_region.start() < _whole_heap.start()) {
duke@435:     entry = byte_for(_whole_heap.start());
duke@435:   } else {
duke@435:     entry = byte_for(new_region.start());
duke@435:   }
duke@435:   jbyte* end = byte_for(original_covered.start());
duke@435:   // If _whole_heap starts at the original covered regions start,
duke@435:   // this loop will not execute.
duke@435:   while (entry < end) { *entry++ = clean_card; }
duke@435: }
duke@435: 
duke@435: void CardTableExtension::resize_update_covered_table(int changed_region,
duke@435:                                                      MemRegion new_region) {
duke@435:   // Update the covered region
duke@435:   _covered[changed_region].set_start(new_region.start());
duke@435:   _covered[changed_region].set_word_size(new_region.word_size());
duke@435: 
duke@435:   // reorder regions.  There should only be at most 1 out
duke@435:   // of order.
duke@435:   for (int i = _cur_covered_regions-1 ; i > 0; i--) {
duke@435:     if (_covered[i].start() < _covered[i-1].start()) {
duke@435:         MemRegion covered_mr = _covered[i-1];
duke@435:         _covered[i-1] = _covered[i];
duke@435:         _covered[i] = covered_mr;
duke@435:         MemRegion committed_mr = _committed[i-1];
duke@435:       _committed[i-1] = _committed[i];
duke@435:       _committed[i] = committed_mr;
duke@435:       break;
duke@435:     }
duke@435:   }
duke@435: #ifdef ASSERT
duke@435:   for (int m = 0; m < _cur_covered_regions-1; m++) {
duke@435:     assert(_covered[m].start() <= _covered[m+1].start(),
duke@435:       "Covered regions out of order");
duke@435:     assert(_committed[m].start() <= _committed[m+1].start(),
duke@435:       "Committed regions out of order");
duke@435:   }
duke@435: #endif
duke@435: }
duke@435: 
duke@435: // Returns the start of any committed region that is lower than
duke@435: // the target committed region (index ind) and that intersects the
duke@435: // target region.  If none, return start of target region.
duke@435: //
duke@435: //      -------------
duke@435: //      |           |
duke@435: //      -------------
duke@435: //              ------------
duke@435: //              | target   |
duke@435: //              ------------
duke@435: //                               -------------
duke@435: //                               |           |
duke@435: //                               -------------
duke@435: //      ^ returns this
duke@435: //
duke@435: //      -------------
duke@435: //      |           |
duke@435: //      -------------
duke@435: //                      ------------
duke@435: //                      | target   |
duke@435: //                      ------------
duke@435: //                               -------------
duke@435: //                               |           |
duke@435: //                               -------------
duke@435: //                      ^ returns this
duke@435: 
duke@435: HeapWord* CardTableExtension::lowest_prev_committed_start(int ind) const {
duke@435:   assert(_cur_covered_regions >= 0, "Expecting at least on region");
duke@435:   HeapWord* min_start = _committed[ind].start();
duke@435:   for (int j = 0; j < ind; j++) {
duke@435:     HeapWord* this_start = _committed[j].start();
duke@435:     if ((this_start < min_start) &&
duke@435:         !(_committed[j].intersection(_committed[ind])).is_empty()) {
duke@435:        min_start = this_start;
duke@435:     }
duke@435:   }
duke@435:   return min_start;
duke@435: }