jdk8-mips64-public/hotspot: src/share/vm/memory/cardTableModRefBS.cpp@2c6ef90f030a (annotated)

src/share/vm/memory/cardTableModRefBS.cpp@2c6ef90f030a (annotated)

src/share/vm/memory/cardTableModRefBS.cpp

Mon, 07 Jul 2014 10:12:40 +0200

author: stefank
date: Mon, 07 Jul 2014 10:12:40 +0200
changeset 6992: 2c6ef90f030a
parent 6680: 78bbf4d43a14
child 7051: 1f1d373cd044
permissions: -rw-r--r--

8049421: G1 Class Unloading after completing a concurrent mark cycle
Reviewed-by: tschatzl, ehelin, brutisso, coleenp, roland, iveresov
Contributed-by: stefan.karlsson@oracle.com, mikael.gerdin@oracle.com

 /*
  * Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #include "precompiled.hpp"
 #include "memory/allocation.inline.hpp"
 #include "memory/cardTableModRefBS.hpp"
 #include "memory/cardTableRS.hpp"
 #include "memory/sharedHeap.hpp"
 #include "memory/space.hpp"
 #include "memory/space.inline.hpp"
 #include "memory/universe.hpp"
 #include "runtime/java.hpp"
 #include "runtime/mutexLocker.hpp"
 #include "runtime/virtualspace.hpp"
 #include "services/memTracker.hpp"
 #include "utilities/macros.hpp"
 #ifdef COMPILER1
 #include "c1/c1_LIR.hpp"
 #include "c1/c1_LIRGenerator.hpp"
 #endif
 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and
 // enumerate ref fields that have been modified (since the last
 // enumeration.)
 size_t CardTableModRefBS::cards_required(size_t covered_words)
 {
   // Add one for a guard card, used to detect errors.
   const size_t words = align_size_up(covered_words, card_size_in_words);
   return words / card_size_in_words + 1;
 }
 size_t CardTableModRefBS::compute_byte_map_size()
 {
   assert(_guard_index == cards_required(_whole_heap.word_size()) - 1,
                                         "unitialized, check declaration order");
   assert(_page_size != 0, "unitialized, check declaration order");
   const size_t granularity = os::vm_allocation_granularity();
   return align_size_up(_guard_index + 1, MAX2(_page_size, granularity));
 }
 CardTableModRefBS::CardTableModRefBS(MemRegion whole_heap,
                                      int max_covered_regions):
   ModRefBarrierSet(max_covered_regions),
   _whole_heap(whole_heap),
   _guard_index(cards_required(whole_heap.word_size()) - 1),
   _last_valid_index(_guard_index - 1),
   _page_size(os::vm_page_size()),
   _byte_map_size(compute_byte_map_size())
 {
   _kind = BarrierSet::CardTableModRef;
   HeapWord* low_bound  = _whole_heap.start();
   HeapWord* high_bound = _whole_heap.end();
   assert((uintptr_t(low_bound)  & (card_size - 1))  == 0, "heap must start at card boundary");
   assert((uintptr_t(high_bound) & (card_size - 1))  == 0, "heap must end at card boundary");
   assert(card_size <= 512, "card_size must be less than 512"); // why?
   _covered   = new MemRegion[max_covered_regions];
   _committed = new MemRegion[max_covered_regions];
   if (_covered == NULL || _committed == NULL) {
     vm_exit_during_initialization("couldn't alloc card table covered region set.");
   }
   _cur_covered_regions = 0;
   const size_t rs_align = _page_size == (size_t) os::vm_page_size() ? 0 :
     MAX2(_page_size, (size_t) os::vm_allocation_granularity());
   ReservedSpace heap_rs(_byte_map_size, rs_align, false);
   MemTracker::record_virtual_memory_type((address)heap_rs.base(), mtGC);
   os::trace_page_sizes("card table", _guard_index + 1, _guard_index + 1,
                        _page_size, heap_rs.base(), heap_rs.size());
   if (!heap_rs.is_reserved()) {
     vm_exit_during_initialization("Could not reserve enough space for the "
                                   "card marking array");
   }
   // The assember store_check code will do an unsigned shift of the oop,
   // then add it to byte_map_base, i.e.
   //
   //   _byte_map = byte_map_base + (uintptr_t(low_bound) >> card_shift)
   _byte_map = (jbyte*) heap_rs.base();
   byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
   assert(byte_for(low_bound) == &_byte_map[0], "Checking start of map");
   assert(byte_for(high_bound-1) <= &_byte_map[_last_valid_index], "Checking end of map");
   jbyte* guard_card = &_byte_map[_guard_index];
   uintptr_t guard_page = align_size_down((uintptr_t)guard_card, _page_size);
   _guard_region = MemRegion((HeapWord*)guard_page, _page_size);
   os::commit_memory_or_exit((char*)guard_page, _page_size, _page_size,
                             !ExecMem, "card table last card");
   *guard_card = last_card;
    _lowest_non_clean =
     NEW_C_HEAP_ARRAY(CardArr, max_covered_regions, mtGC);
   _lowest_non_clean_chunk_size =
     NEW_C_HEAP_ARRAY(size_t, max_covered_regions, mtGC);
   _lowest_non_clean_base_chunk_index =
     NEW_C_HEAP_ARRAY(uintptr_t, max_covered_regions, mtGC);
   _last_LNC_resizing_collection =
     NEW_C_HEAP_ARRAY(int, max_covered_regions, mtGC);
   if (_lowest_non_clean == NULL
       || _lowest_non_clean_chunk_size == NULL
       || _lowest_non_clean_base_chunk_index == NULL
       || _last_LNC_resizing_collection == NULL)
     vm_exit_during_initialization("couldn't allocate an LNC array.");
   for (int i = 0; i < max_covered_regions; i++) {
     _lowest_non_clean[i] = NULL;
     _lowest_non_clean_chunk_size[i] = 0;
     _last_LNC_resizing_collection[i] = -1;
   }
   if (TraceCardTableModRefBS) {
     gclog_or_tty->print_cr("CardTableModRefBS::CardTableModRefBS: ");
     gclog_or_tty->print_cr("  "
                   "  &_byte_map[0]: " INTPTR_FORMAT
                   "  &_byte_map[_last_valid_index]: " INTPTR_FORMAT,
                   p2i(&_byte_map[0]),
                   p2i(&_byte_map[_last_valid_index]));
     gclog_or_tty->print_cr("  "
                   "  byte_map_base: " INTPTR_FORMAT,
                   p2i(byte_map_base));
   }
 }
 CardTableModRefBS::~CardTableModRefBS() {
   if (_covered) {
     delete[] _covered;
     _covered = NULL;
   }
   if (_committed) {
     delete[] _committed;
     _committed = NULL;
   }
   if (_lowest_non_clean) {
     FREE_C_HEAP_ARRAY(CardArr, _lowest_non_clean, mtGC);
     _lowest_non_clean = NULL;
   }
   if (_lowest_non_clean_chunk_size) {
     FREE_C_HEAP_ARRAY(size_t, _lowest_non_clean_chunk_size, mtGC);
     _lowest_non_clean_chunk_size = NULL;
   }
   if (_lowest_non_clean_base_chunk_index) {
     FREE_C_HEAP_ARRAY(uintptr_t, _lowest_non_clean_base_chunk_index, mtGC);
     _lowest_non_clean_base_chunk_index = NULL;
   }
   if (_last_LNC_resizing_collection) {
     FREE_C_HEAP_ARRAY(int, _last_LNC_resizing_collection, mtGC);
     _last_LNC_resizing_collection = NULL;
   }
 }
 int CardTableModRefBS::find_covering_region_by_base(HeapWord* base) {
   int i;
   for (i = 0; i < _cur_covered_regions; i++) {
     if (_covered[i].start() == base) return i;
     if (_covered[i].start() > base) break;
   }
   // If we didn't find it, create a new one.
   assert(_cur_covered_regions < _max_covered_regions,
          "too many covered regions");
   // Move the ones above up, to maintain sorted order.
   for (int j = _cur_covered_regions; j > i; j--) {
     _covered[j] = _covered[j-1];
     _committed[j] = _committed[j-1];
   }
   int res = i;
   _cur_covered_regions++;
   _covered[res].set_start(base);
   _covered[res].set_word_size(0);
   jbyte* ct_start = byte_for(base);
   uintptr_t ct_start_aligned = align_size_down((uintptr_t)ct_start, _page_size);
   _committed[res].set_start((HeapWord*)ct_start_aligned);
   _committed[res].set_word_size(0);
   return res;
 }
 int CardTableModRefBS::find_covering_region_containing(HeapWord* addr) {
   for (int i = 0; i < _cur_covered_regions; i++) {
     if (_covered[i].contains(addr)) {
       return i;
     }
   }
   assert(0, "address outside of heap?");
   return -1;
 }
 HeapWord* CardTableModRefBS::largest_prev_committed_end(int ind) const {
   HeapWord* max_end = NULL;
   for (int j = 0; j < ind; j++) {
     HeapWord* this_end = _committed[j].end();
     if (this_end > max_end) max_end = this_end;
   }
   return max_end;
 }
 MemRegion CardTableModRefBS::committed_unique_to_self(int self,
                                                       MemRegion mr) const {
   MemRegion result = mr;
   for (int r = 0; r < _cur_covered_regions; r += 1) {
     if (r != self) {
       result = result.minus(_committed[r]);
     }
   }
   // Never include the guard page.
   result = result.minus(_guard_region);
   return result;
 }
 void CardTableModRefBS::resize_covered_region(MemRegion new_region) {
   // We don't change the start of a region, only the end.
   assert(_whole_heap.contains(new_region),
            "attempt to cover area not in reserved area");
   debug_only(verify_guard();)
   // collided is true if the expansion would push into another committed region
   debug_only(bool collided = false;)
   int const ind = find_covering_region_by_base(new_region.start());
   MemRegion const old_region = _covered[ind];
   assert(old_region.start() == new_region.start(), "just checking");
   if (new_region.word_size() != old_region.word_size()) {
     // Commit new or uncommit old pages, if necessary.
     MemRegion cur_committed = _committed[ind];
     // Extend the end of this _commited region
     // to cover the end of any lower _committed regions.
     // This forms overlapping regions, but never interior regions.
     HeapWord* const max_prev_end = largest_prev_committed_end(ind);
     if (max_prev_end > cur_committed.end()) {
       cur_committed.set_end(max_prev_end);
     }
     // Align the end up to a page size (starts are already aligned).
     jbyte* const new_end = byte_after(new_region.last());
     HeapWord* new_end_aligned =
       (HeapWord*) align_size_up((uintptr_t)new_end, _page_size);
     assert(new_end_aligned >= (HeapWord*) new_end,
            "align up, but less");
     // Check the other regions (excludes "ind") to ensure that
     // the new_end_aligned does not intrude onto the committed
     // space of another region.
     int ri = 0;
     for (ri = 0; ri < _cur_covered_regions; ri++) {
       if (ri != ind) {
         if (_committed[ri].contains(new_end_aligned)) {
           // The prior check included in the assert
           // (new_end_aligned >= _committed[ri].start())
           // is redundant with the "contains" test.
           // Any region containing the new end
           // should start at or beyond the region found (ind)
           // for the new end (committed regions are not expected to
           // be proper subsets of other committed regions).
           assert(_committed[ri].start() >= _committed[ind].start(),
                  "New end of committed region is inconsistent");
           new_end_aligned = _committed[ri].start();
           // new_end_aligned can be equal to the start of its
           // committed region (i.e., of "ind") if a second
           // region following "ind" also start at the same location
           // as "ind".
           assert(new_end_aligned >= _committed[ind].start(),
             "New end of committed region is before start");
           debug_only(collided = true;)
           // Should only collide with 1 region
           break;
         }
       }
     }
 #ifdef ASSERT
     for (++ri; ri < _cur_covered_regions; ri++) {
       assert(!_committed[ri].contains(new_end_aligned),
         "New end of committed region is in a second committed region");
     }
 #endif
     // The guard page is always committed and should not be committed over.
     // "guarded" is used for assertion checking below and recalls the fact
     // that the would-be end of the new committed region would have
     // penetrated the guard page.
     HeapWord* new_end_for_commit = new_end_aligned;
     DEBUG_ONLY(bool guarded = false;)
     if (new_end_for_commit > _guard_region.start()) {
       new_end_for_commit = _guard_region.start();
       DEBUG_ONLY(guarded = true;)
     }
     if (new_end_for_commit > cur_committed.end()) {
       // Must commit new pages.
       MemRegion const new_committed =
         MemRegion(cur_committed.end(), new_end_for_commit);
       assert(!new_committed.is_empty(), "Region should not be empty here");
       os::commit_memory_or_exit((char*)new_committed.start(),
                                 new_committed.byte_size(), _page_size,
                                 !ExecMem, "card table expansion");
     // Use new_end_aligned (as opposed to new_end_for_commit) because
     // the cur_committed region may include the guard region.
     } else if (new_end_aligned < cur_committed.end()) {
       // Must uncommit pages.
       MemRegion const uncommit_region =
         committed_unique_to_self(ind, MemRegion(new_end_aligned,
                                                 cur_committed.end()));
       if (!uncommit_region.is_empty()) {
         // It is not safe to uncommit cards if the boundary between
         // the generations is moving.  A shrink can uncommit cards
         // owned by generation A but being used by generation B.
         if (!UseAdaptiveGCBoundary) {
           if (!os::uncommit_memory((char*)uncommit_region.start(),
                                    uncommit_region.byte_size())) {
             assert(false, "Card table contraction failed");
             // The call failed so don't change the end of the
             // committed region.  This is better than taking the
             // VM down.
             new_end_aligned = _committed[ind].end();
           }
         } else {
           new_end_aligned = _committed[ind].end();
         }
       }
     }
     // In any case, we can reset the end of the current committed entry.
     _committed[ind].set_end(new_end_aligned);
 #ifdef ASSERT
     // Check that the last card in the new region is committed according
     // to the tables.
     bool covered = false;
     for (int cr = 0; cr < _cur_covered_regions; cr++) {
       if (_committed[cr].contains(new_end - 1)) {
         covered = true;
         break;
       }
     }
     assert(covered, "Card for end of new region not committed");
 #endif
     // The default of 0 is not necessarily clean cards.
     jbyte* entry;
     if (old_region.last() < _whole_heap.start()) {
       entry = byte_for(_whole_heap.start());
     } else {
       entry = byte_after(old_region.last());
     }
     assert(index_for(new_region.last()) <  _guard_index,
       "The guard card will be overwritten");
     // This line commented out cleans the newly expanded region and
     // not the aligned up expanded region.
     // jbyte* const end = byte_after(new_region.last());
     jbyte* const end = (jbyte*) new_end_for_commit;
     assert((end >= byte_after(new_region.last())) || collided || guarded,
       "Expect to be beyond new region unless impacting another region");
     // do nothing if we resized downward.
 #ifdef ASSERT
     for (int ri = 0; ri < _cur_covered_regions; ri++) {
       if (ri != ind) {
         // The end of the new committed region should not
         // be in any existing region unless it matches
         // the start of the next region.
         assert(!_committed[ri].contains(end) ||
                (_committed[ri].start() == (HeapWord*) end),
                "Overlapping committed regions");
       }
     }
 #endif
     if (entry < end) {
       memset(entry, clean_card, pointer_delta(end, entry, sizeof(jbyte)));
     }
   }
   // In any case, the covered size changes.
   _covered[ind].set_word_size(new_region.word_size());
   if (TraceCardTableModRefBS) {
     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, p2i(_covered[ind].start()),
                   ind, p2i(_covered[ind].last()));
     gclog_or_tty->print_cr("  "
                   "  _committed[%d].start(): " INTPTR_FORMAT
                   "  _committed[%d].last(): " INTPTR_FORMAT,
                   ind, p2i(_committed[ind].start()),
                   ind, p2i(_committed[ind].last()));
     gclog_or_tty->print_cr("  "
                   "  byte_for(start): " INTPTR_FORMAT
                   "  byte_for(last): " INTPTR_FORMAT,
                   p2i(byte_for(_covered[ind].start())),
                   p2i(byte_for(_covered[ind].last())));
     gclog_or_tty->print_cr("  "
                   "  addr_for(start): " INTPTR_FORMAT
                   "  addr_for(last): " INTPTR_FORMAT,
                   p2i(addr_for((jbyte*) _committed[ind].start())),
                   p2i(addr_for((jbyte*) _committed[ind].last())));
   }
   // Touch the last card of the covered region to show that it
   // is committed (or SEGV).
   debug_only((void) (*byte_for(_covered[ind].last()));)
   debug_only(verify_guard();)
 }
 // Note that these versions are precise!  The scanning code has to handle the
 // fact that the write barrier may be either precise or imprecise.
 void CardTableModRefBS::write_ref_field_work(void* field, oop newVal, bool release) {
   inline_write_ref_field(field, newVal, release);
 }
 void CardTableModRefBS::non_clean_card_iterate_possibly_parallel(Space* sp,
                                                                  MemRegion mr,
                                                                  OopsInGenClosure* cl,
                                                                  CardTableRS* ct) {
   if (!mr.is_empty()) {
     // Caller (process_roots()) claims that all GC threads
     // execute this call.  With UseDynamicNumberOfGCThreads now all
     // active GC threads execute this call.  The number of active GC
     // threads needs to be passed to par_non_clean_card_iterate_work()
     // to get proper partitioning and termination.
     //
     // This is an example of where n_par_threads() is used instead
     // of workers()->active_workers().  n_par_threads can be set to 0 to
     // turn off parallelism.  For example when this code is called as
     // part of verification and SharedHeap::process_roots() is being
     // used, then n_par_threads() may have been set to 0.  active_workers
     // is not overloaded with the meaning that it is a switch to disable
     // parallelism and so keeps the meaning of the number of
     // active gc workers.  If parallelism has not been shut off by
     // setting n_par_threads to 0, then n_par_threads should be
     // equal to active_workers.  When a different mechanism for shutting
     // off parallelism is used, then active_workers can be used in
     // place of n_par_threads.
     //  This is an example of a path where n_par_threads is
     // set to 0 to turn off parallism.
     //  [7] CardTableModRefBS::non_clean_card_iterate()
     //  [8] CardTableRS::younger_refs_in_space_iterate()
     //  [9] Generation::younger_refs_in_space_iterate()
     //  [10] OneContigSpaceCardGeneration::younger_refs_iterate()
     //  [11] CompactingPermGenGen::younger_refs_iterate()
     //  [12] CardTableRS::younger_refs_iterate()
     //  [13] SharedHeap::process_strong_roots()
     //  [14] G1CollectedHeap::verify()
     //  [15] Universe::verify()
     //  [16] G1CollectedHeap::do_collection_pause_at_safepoint()
     //
     int n_threads =  SharedHeap::heap()->n_par_threads();
     bool is_par = n_threads > 0;
     if (is_par) {
 #if INCLUDE_ALL_GCS
       assert(SharedHeap::heap()->n_par_threads() ==
              SharedHeap::heap()->workers()->active_workers(), "Mismatch");
       non_clean_card_iterate_parallel_work(sp, mr, cl, ct, n_threads);
 #else  // INCLUDE_ALL_GCS
       fatal("Parallel gc not supported here.");
 #endif // INCLUDE_ALL_GCS
     } else {
       // We do not call the non_clean_card_iterate_serial() version below because
       // we want to clear the cards (which non_clean_card_iterate_serial() does not
       // do for us): clear_cl here does the work of finding contiguous dirty ranges
       // of cards to process and clear.
       DirtyCardToOopClosure* dcto_cl = sp->new_dcto_cl(cl, precision(),
                                                        cl->gen_boundary());
       ClearNoncleanCardWrapper clear_cl(dcto_cl, ct);
       clear_cl.do_MemRegion(mr);
     }
   }
 }
 // The iterator itself is not MT-aware, but
 // MT-aware callers and closures can use this to
 // accomplish dirty card iteration in parallel. The
 // iterator itself does not clear the dirty cards, or
 // change their values in any manner.
 void CardTableModRefBS::non_clean_card_iterate_serial(MemRegion mr,
                                                       MemRegionClosure* cl) {
   bool is_par = (SharedHeap::heap()->n_par_threads() > 0);
   assert(!is_par ||
           (SharedHeap::heap()->n_par_threads() ==
           SharedHeap::heap()->workers()->active_workers()), "Mismatch");
   for (int i = 0; i < _cur_covered_regions; i++) {
     MemRegion mri = mr.intersection(_covered[i]);
     if (mri.word_size() > 0) {
       jbyte* cur_entry = byte_for(mri.last());
       jbyte* limit = byte_for(mri.start());
       while (cur_entry >= limit) {
         jbyte* next_entry = cur_entry - 1;
         if (*cur_entry != clean_card) {
           size_t non_clean_cards = 1;
           // Should the next card be included in this range of dirty cards.
           while (next_entry >= limit && *next_entry != clean_card) {
             non_clean_cards++;
             cur_entry = next_entry;
             next_entry--;
           }
           // The memory region may not be on a card boundary.  So that
           // objects beyond the end of the region are not processed, make
           // cur_cards precise with regard to the end of the memory region.
           MemRegion cur_cards(addr_for(cur_entry),
                               non_clean_cards * card_size_in_words);
           MemRegion dirty_region = cur_cards.intersection(mri);
           cl->do_MemRegion(dirty_region);
         }
         cur_entry = next_entry;
       }
     }
   }
 }
 void CardTableModRefBS::dirty_MemRegion(MemRegion mr) {
   assert((HeapWord*)align_size_down((uintptr_t)mr.start(), HeapWordSize) == mr.start(), "Unaligned start");
   assert((HeapWord*)align_size_up  ((uintptr_t)mr.end(),   HeapWordSize) == mr.end(),   "Unaligned end"  );
   jbyte* cur  = byte_for(mr.start());
   jbyte* last = byte_after(mr.last());
   while (cur < last) {
     *cur = dirty_card;
     cur++;
   }
 }
 void CardTableModRefBS::invalidate(MemRegion mr, bool whole_heap) {
   assert((HeapWord*)align_size_down((uintptr_t)mr.start(), HeapWordSize) == mr.start(), "Unaligned start");
   assert((HeapWord*)align_size_up  ((uintptr_t)mr.end(),   HeapWordSize) == mr.end(),   "Unaligned end"  );
   for (int i = 0; i < _cur_covered_regions; i++) {
     MemRegion mri = mr.intersection(_covered[i]);
     if (!mri.is_empty()) dirty_MemRegion(mri);
   }
 }
 void CardTableModRefBS::clear_MemRegion(MemRegion mr) {
   // Be conservative: only clean cards entirely contained within the
   // region.
   jbyte* cur;
   if (mr.start() == _whole_heap.start()) {
     cur = byte_for(mr.start());
   } else {
     assert(mr.start() > _whole_heap.start(), "mr is not covered.");
     cur = byte_after(mr.start() - 1);
   }
   jbyte* last = byte_after(mr.last());
   memset(cur, clean_card, pointer_delta(last, cur, sizeof(jbyte)));
 }
 void CardTableModRefBS::clear(MemRegion mr) {
   for (int i = 0; i < _cur_covered_regions; i++) {
     MemRegion mri = mr.intersection(_covered[i]);
     if (!mri.is_empty()) clear_MemRegion(mri);
   }
 }
 void CardTableModRefBS::dirty(MemRegion mr) {
   jbyte* first = byte_for(mr.start());
   jbyte* last  = byte_after(mr.last());
   memset(first, dirty_card, last-first);
 }
 // Unlike several other card table methods, dirty_card_iterate()
 // iterates over dirty cards ranges in increasing address order.
 void CardTableModRefBS::dirty_card_iterate(MemRegion mr,
                                            MemRegionClosure* cl) {
   for (int i = 0; i < _cur_covered_regions; i++) {
     MemRegion mri = mr.intersection(_covered[i]);
     if (!mri.is_empty()) {
       jbyte *cur_entry, *next_entry, *limit;
       for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last());
            cur_entry <= limit;
            cur_entry  = next_entry) {
         next_entry = cur_entry + 1;
         if (*cur_entry == dirty_card) {
           size_t dirty_cards;
           // Accumulate maximal dirty card range, starting at cur_entry
           for (dirty_cards = 1;
                next_entry <= limit && *next_entry == dirty_card;
                dirty_cards++, next_entry++);
           MemRegion cur_cards(addr_for(cur_entry),
                               dirty_cards*card_size_in_words);
           cl->do_MemRegion(cur_cards);
         }
       }
     }
   }
 }
 MemRegion CardTableModRefBS::dirty_card_range_after_reset(MemRegion mr,
                                                           bool reset,
                                                           int reset_val) {
   for (int i = 0; i < _cur_covered_regions; i++) {
     MemRegion mri = mr.intersection(_covered[i]);
     if (!mri.is_empty()) {
       jbyte* cur_entry, *next_entry, *limit;
       for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last());
            cur_entry <= limit;
            cur_entry  = next_entry) {
         next_entry = cur_entry + 1;
         if (*cur_entry == dirty_card) {
           size_t dirty_cards;
           // Accumulate maximal dirty card range, starting at cur_entry
           for (dirty_cards = 1;
                next_entry <= limit && *next_entry == dirty_card;
                dirty_cards++, next_entry++);
           MemRegion cur_cards(addr_for(cur_entry),
                               dirty_cards*card_size_in_words);
           if (reset) {
             for (size_t i = 0; i < dirty_cards; i++) {
               cur_entry[i] = reset_val;
             }
           }
           return cur_cards;
         }
       }
     }
   }
   return MemRegion(mr.end(), mr.end());
 }
 uintx CardTableModRefBS::ct_max_alignment_constraint() {
   return card_size * os::vm_page_size();
 }
 void CardTableModRefBS::verify_guard() {
   // For product build verification
   guarantee(_byte_map[_guard_index] == last_card,
             "card table guard has been modified");
 }
 void CardTableModRefBS::verify() {
   verify_guard();
 }
 #ifndef PRODUCT
 void CardTableModRefBS::verify_region(MemRegion mr,
                                       jbyte val, bool val_equals) {
   jbyte* start    = byte_for(mr.start());
   jbyte* end      = byte_for(mr.last());
   bool   failures = false;
   for (jbyte* curr = start; curr <= end; ++curr) {
     jbyte curr_val = *curr;
     bool failed = (val_equals) ? (curr_val != val) : (curr_val == val);
     if (failed) {
       if (!failures) {
         tty->cr();
         tty->print_cr("== CT verification failed: [" INTPTR_FORMAT "," INTPTR_FORMAT "]", p2i(start), p2i(end));
         tty->print_cr("==   %sexpecting value: %d",
                       (val_equals) ? "" : "not ", val);
         failures = true;
       }
       tty->print_cr("==   card "PTR_FORMAT" ["PTR_FORMAT","PTR_FORMAT"], "
                     "val: %d", p2i(curr), p2i(addr_for(curr)),
                     p2i((HeapWord*) (((size_t) addr_for(curr)) + card_size)),
                     (int) curr_val);
     }
   }
   guarantee(!failures, "there should not have been any failures");
 }
 void CardTableModRefBS::verify_not_dirty_region(MemRegion mr) {
   verify_region(mr, dirty_card, false /* val_equals */);
 }
 void CardTableModRefBS::verify_dirty_region(MemRegion mr) {
   verify_region(mr, dirty_card, true /* val_equals */);
 }
 #endif
 void CardTableModRefBS::print_on(outputStream* st) const {
   st->print_cr("Card table byte_map: [" INTPTR_FORMAT "," INTPTR_FORMAT "] byte_map_base: " INTPTR_FORMAT,
                p2i(_byte_map), p2i(_byte_map + _byte_map_size), p2i(byte_map_base));
 }
 bool CardTableModRefBSForCTRS::card_will_be_scanned(jbyte cv) {
   return
     CardTableModRefBS::card_will_be_scanned(cv) ||
     _rs->is_prev_nonclean_card_val(cv);
 };
 bool CardTableModRefBSForCTRS::card_may_have_been_dirty(jbyte cv) {
   return
     cv != clean_card &&
     (CardTableModRefBS::card_may_have_been_dirty(cv) ||
      CardTableRS::youngergen_may_have_been_dirty(cv));
 };

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/memory/cardTableModRefBS.cpp@2c6ef90f030a (annotated)

src/share/vm/memory/cardTableModRefBS.cpp