jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/concurrentMark.inline.hpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/concurrentMark.inline.hpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/concurrentMark.inline.hpp

Fri, 10 Oct 2014 15:51:58 +0200

author: tschatzl
date: Fri, 10 Oct 2014 15:51:58 +0200
changeset 7257: e7d0505c8a30
parent 7094: 9337d0e7ea4f
child 7535: 7ae4e26cb1e0
child 7829: 24c446b2460d
permissions: -rw-r--r--

8059758: Footprint regressions with JDK-8038423
Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything.
Reviewed-by: jwilhelm, brutisso

 /*
  * Copyright (c) 2001, 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.
  *
  */
 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP
 #include "gc_implementation/g1/concurrentMark.hpp"
 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
 // Utility routine to set an exclusive range of cards on the given
 // card liveness bitmap
 inline void ConcurrentMark::set_card_bitmap_range(BitMap* card_bm,
                                                   BitMap::idx_t start_idx,
                                                   BitMap::idx_t end_idx,
                                                   bool is_par) {
   // Set the exclusive bit range [start_idx, end_idx).
   assert((end_idx - start_idx) > 0, "at least one card");
   assert(end_idx <= card_bm->size(), "sanity");
   // Silently clip the end index
   end_idx = MIN2(end_idx, card_bm->size());
   // For small ranges use a simple loop; otherwise use set_range or
   // use par_at_put_range (if parallel). The range is made up of the
   // cards that are spanned by an object/mem region so 8 cards will
   // allow up to object sizes up to 4K to be handled using the loop.
   if ((end_idx - start_idx) <= 8) {
     for (BitMap::idx_t i = start_idx; i < end_idx; i += 1) {
       if (is_par) {
         card_bm->par_set_bit(i);
       } else {
         card_bm->set_bit(i);
       }
     }
   } else {
     // Note BitMap::par_at_put_range() and BitMap::set_range() are exclusive.
     if (is_par) {
       card_bm->par_at_put_range(start_idx, end_idx, true);
     } else {
       card_bm->set_range(start_idx, end_idx);
     }
   }
 }
 // Returns the index in the liveness accounting card bitmap
 // for the given address
 inline BitMap::idx_t ConcurrentMark::card_bitmap_index_for(HeapWord* addr) {
   // Below, the term "card num" means the result of shifting an address
   // by the card shift -- address 0 corresponds to card number 0.  One
   // must subtract the card num of the bottom of the heap to obtain a
   // card table index.
   intptr_t card_num = intptr_t(uintptr_t(addr) >> CardTableModRefBS::card_shift);
   return card_num - heap_bottom_card_num();
 }
 // Counts the given memory region in the given task/worker
 // counting data structures.
 inline void ConcurrentMark::count_region(MemRegion mr, HeapRegion* hr,
                                          size_t* marked_bytes_array,
                                          BitMap* task_card_bm) {
   G1CollectedHeap* g1h = _g1h;
   CardTableModRefBS* ct_bs = g1h->g1_barrier_set();
   HeapWord* start = mr.start();
   HeapWord* end = mr.end();
   size_t region_size_bytes = mr.byte_size();
   uint index = hr->hrm_index();
   assert(!hr->continuesHumongous(), "should not be HC region");
   assert(hr == g1h->heap_region_containing(start), "sanity");
   assert(hr == g1h->heap_region_containing(mr.last()), "sanity");
   assert(marked_bytes_array != NULL, "pre-condition");
   assert(task_card_bm != NULL, "pre-condition");
   // Add to the task local marked bytes for this region.
   marked_bytes_array[index] += region_size_bytes;
   BitMap::idx_t start_idx = card_bitmap_index_for(start);
   BitMap::idx_t end_idx = card_bitmap_index_for(end);
   // Note: if we're looking at the last region in heap - end
   // could be actually just beyond the end of the heap; end_idx
   // will then correspond to a (non-existent) card that is also
   // just beyond the heap.
   if (g1h->is_in_g1_reserved(end) && !ct_bs->is_card_aligned(end)) {
     // end of region is not card aligned - incremement to cover
     // all the cards spanned by the region.
     end_idx += 1;
   }
   // The card bitmap is task/worker specific => no need to use
   // the 'par' BitMap routines.
   // Set bits in the exclusive bit range [start_idx, end_idx).
   set_card_bitmap_range(task_card_bm, start_idx, end_idx, false /* is_par */);
 }
 // Counts the given memory region in the task/worker counting
 // data structures for the given worker id.
 inline void ConcurrentMark::count_region(MemRegion mr,
                                          HeapRegion* hr,
                                          uint worker_id) {
   size_t* marked_bytes_array = count_marked_bytes_array_for(worker_id);
   BitMap* task_card_bm = count_card_bitmap_for(worker_id);
   count_region(mr, hr, marked_bytes_array, task_card_bm);
 }
 // Counts the given object in the given task/worker counting data structures.
 inline void ConcurrentMark::count_object(oop obj,
                                          HeapRegion* hr,
                                          size_t* marked_bytes_array,
                                          BitMap* task_card_bm) {
   MemRegion mr((HeapWord*)obj, obj->size());
   count_region(mr, hr, marked_bytes_array, task_card_bm);
 }
 // Attempts to mark the given object and, if successful, counts
 // the object in the given task/worker counting structures.
 inline bool ConcurrentMark::par_mark_and_count(oop obj,
                                                HeapRegion* hr,
                                                size_t* marked_bytes_array,
                                                BitMap* task_card_bm) {
   HeapWord* addr = (HeapWord*)obj;
   if (_nextMarkBitMap->parMark(addr)) {
     // Update the task specific count data for the object.
     count_object(obj, hr, marked_bytes_array, task_card_bm);
     return true;
   }
   return false;
 }
 // Attempts to mark the given object and, if successful, counts
 // the object in the task/worker counting structures for the
 // given worker id.
 inline bool ConcurrentMark::par_mark_and_count(oop obj,
                                                size_t word_size,
                                                HeapRegion* hr,
                                                uint worker_id) {
   HeapWord* addr = (HeapWord*)obj;
   if (_nextMarkBitMap->parMark(addr)) {
     MemRegion mr(addr, word_size);
     count_region(mr, hr, worker_id);
     return true;
   }
   return false;
 }
 inline bool CMBitMapRO::iterate(BitMapClosure* cl, MemRegion mr) {
   HeapWord* start_addr = MAX2(startWord(), mr.start());
   HeapWord* end_addr = MIN2(endWord(), mr.end());
   if (end_addr > start_addr) {
     // Right-open interval [start-offset, end-offset).
     BitMap::idx_t start_offset = heapWordToOffset(start_addr);
     BitMap::idx_t end_offset = heapWordToOffset(end_addr);
     start_offset = _bm.get_next_one_offset(start_offset, end_offset);
     while (start_offset < end_offset) {
       if (!cl->do_bit(start_offset)) {
         return false;
       }
       HeapWord* next_addr = MIN2(nextObject(offsetToHeapWord(start_offset)), end_addr);
       BitMap::idx_t next_offset = heapWordToOffset(next_addr);
       start_offset = _bm.get_next_one_offset(next_offset, end_offset);
     }
   }
   return true;
 }
 inline bool CMBitMapRO::iterate(BitMapClosure* cl) {
   MemRegion mr(startWord(), sizeInWords());
   return iterate(cl, mr);
 }
 #define check_mark(addr)                                                       \
   assert(_bmStartWord <= (addr) && (addr) < (_bmStartWord + _bmWordSize),      \
          "outside underlying space?");                                         \
   assert(G1CollectedHeap::heap()->is_in_exact(addr),                           \
          err_msg("Trying to access not available bitmap "PTR_FORMAT            \
                  " corresponding to "PTR_FORMAT" (%u)",                        \
                  p2i(this), p2i(addr), G1CollectedHeap::heap()->addr_to_region(addr)));
 inline void CMBitMap::mark(HeapWord* addr) {
   check_mark(addr);
   _bm.set_bit(heapWordToOffset(addr));
 }
 inline void CMBitMap::clear(HeapWord* addr) {
   check_mark(addr);
   _bm.clear_bit(heapWordToOffset(addr));
 }
 inline bool CMBitMap::parMark(HeapWord* addr) {
   check_mark(addr);
   return _bm.par_set_bit(heapWordToOffset(addr));
 }
 inline bool CMBitMap::parClear(HeapWord* addr) {
   check_mark(addr);
   return _bm.par_clear_bit(heapWordToOffset(addr));
 }
 #undef check_mark
 inline void CMTask::push(oop obj) {
   HeapWord* objAddr = (HeapWord*) obj;
   assert(_g1h->is_in_g1_reserved(objAddr), "invariant");
   assert(!_g1h->is_on_master_free_list(
               _g1h->heap_region_containing((HeapWord*) objAddr)), "invariant");
   assert(!_g1h->is_obj_ill(obj), "invariant");
   assert(_nextMarkBitMap->isMarked(objAddr), "invariant");
   if (_cm->verbose_high()) {
     gclog_or_tty->print_cr("[%u] pushing " PTR_FORMAT, _worker_id, p2i((void*) obj));
   }
   if (!_task_queue->push(obj)) {
     // The local task queue looks full. We need to push some entries
     // to the global stack.
     if (_cm->verbose_medium()) {
       gclog_or_tty->print_cr("[%u] task queue overflow, "
                              "moving entries to the global stack",
                              _worker_id);
     }
     move_entries_to_global_stack();
     // this should succeed since, even if we overflow the global
     // stack, we should have definitely removed some entries from the
     // local queue. So, there must be space on it.
     bool success = _task_queue->push(obj);
     assert(success, "invariant");
   }
   statsOnly( int tmp_size = _task_queue->size();
              if (tmp_size > _local_max_size) {
                _local_max_size = tmp_size;
              }
              ++_local_pushes );
 }
 // This determines whether the method below will check both the local
 // and global fingers when determining whether to push on the stack a
 // gray object (value 1) or whether it will only check the global one
 // (value 0). The tradeoffs are that the former will be a bit more
 // accurate and possibly push less on the stack, but it might also be
 // a little bit slower.
 #define _CHECK_BOTH_FINGERS_      1
 inline void CMTask::deal_with_reference(oop obj) {
   if (_cm->verbose_high()) {
     gclog_or_tty->print_cr("[%u] we're dealing with reference = "PTR_FORMAT,
                            _worker_id, p2i((void*) obj));
   }
   ++_refs_reached;
   HeapWord* objAddr = (HeapWord*) obj;
   assert(obj->is_oop_or_null(true /* ignore mark word */), "Error");
   if (_g1h->is_in_g1_reserved(objAddr)) {
     assert(obj != NULL, "null check is implicit");
     if (!_nextMarkBitMap->isMarked(objAddr)) {
       // Only get the containing region if the object is not marked on the
       // bitmap (otherwise, it's a waste of time since we won't do
       // anything with it).
       HeapRegion* hr = _g1h->heap_region_containing_raw(obj);
       if (!hr->obj_allocated_since_next_marking(obj)) {
         if (_cm->verbose_high()) {
           gclog_or_tty->print_cr("[%u] "PTR_FORMAT" is not considered marked",
                                  _worker_id, p2i((void*) obj));
         }
         // we need to mark it first
         if (_cm->par_mark_and_count(obj, hr, _marked_bytes_array, _card_bm)) {
           // No OrderAccess:store_load() is needed. It is implicit in the
           // CAS done in CMBitMap::parMark() call in the routine above.
           HeapWord* global_finger = _cm->finger();
 #if _CHECK_BOTH_FINGERS_
           // we will check both the local and global fingers
           if (_finger != NULL && objAddr < _finger) {
             if (_cm->verbose_high()) {
               gclog_or_tty->print_cr("[%u] below the local finger ("PTR_FORMAT"), "
                                      "pushing it", _worker_id, p2i(_finger));
             }
             push(obj);
           } else if (_curr_region != NULL && objAddr < _region_limit) {
             // do nothing
           } else if (objAddr < global_finger) {
             // Notice that the global finger might be moving forward
             // concurrently. This is not a problem. In the worst case, we
             // mark the object while it is above the global finger and, by
             // the time we read the global finger, it has moved forward
             // passed this object. In this case, the object will probably
             // be visited when a task is scanning the region and will also
             // be pushed on the stack. So, some duplicate work, but no
             // correctness problems.
             if (_cm->verbose_high()) {
               gclog_or_tty->print_cr("[%u] below the global finger "
                                      "("PTR_FORMAT"), pushing it",
                                      _worker_id, p2i(global_finger));
             }
             push(obj);
           } else {
             // do nothing
           }
 #else // _CHECK_BOTH_FINGERS_
           // we will only check the global finger
           if (objAddr < global_finger) {
             // see long comment above
             if (_cm->verbose_high()) {
               gclog_or_tty->print_cr("[%u] below the global finger "
                                      "("PTR_FORMAT"), pushing it",
                                      _worker_id, p2i(global_finger));
             }
             push(obj);
           }
 #endif // _CHECK_BOTH_FINGERS_
         }
       }
     }
   }
 }
 inline void ConcurrentMark::markPrev(oop p) {
   assert(!_prevMarkBitMap->isMarked((HeapWord*) p), "sanity");
   // Note we are overriding the read-only view of the prev map here, via
   // the cast.
   ((CMBitMap*)_prevMarkBitMap)->mark((HeapWord*) p);
 }
 inline void ConcurrentMark::grayRoot(oop obj, size_t word_size,
                                      uint worker_id, HeapRegion* hr) {
   assert(obj != NULL, "pre-condition");
   HeapWord* addr = (HeapWord*) obj;
   if (hr == NULL) {
     hr = _g1h->heap_region_containing_raw(addr);
   } else {
     assert(hr->is_in(addr), "pre-condition");
   }
   assert(hr != NULL, "sanity");
   // Given that we're looking for a region that contains an object
   // header it's impossible to get back a HC region.
   assert(!hr->continuesHumongous(), "sanity");
   // We cannot assert that word_size == obj->size() given that obj
   // might not be in a consistent state (another thread might be in
   // the process of copying it). So the best thing we can do is to
   // assert that word_size is under an upper bound which is its
   // containing region's capacity.
   assert(word_size * HeapWordSize <= hr->capacity(),
          err_msg("size: "SIZE_FORMAT" capacity: "SIZE_FORMAT" "HR_FORMAT,
                  word_size * HeapWordSize, hr->capacity(),
                  HR_FORMAT_PARAMS(hr)));
   if (addr < hr->next_top_at_mark_start()) {
     if (!_nextMarkBitMap->isMarked(addr)) {
       par_mark_and_count(obj, word_size, hr, worker_id);
     }
   }
 }
 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/concurrentMark.inline.hpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/concurrentMark.inline.hpp