jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/concurrentG1Refine.cpp@6270f80a7331 (annotated)

src/share/vm/gc_implementation/g1/concurrentG1Refine.cpp@6270f80a7331 (annotated)

src/share/vm/gc_implementation/g1/concurrentG1Refine.cpp

Wed, 30 Sep 2009 14:50:51 -0400

author: tonyp
date: Wed, 30 Sep 2009 14:50:51 -0400
changeset 1479: 6270f80a7331
parent 1454: 035d2e036a9b
child 1546: 44f61c24ddab
permissions: -rw-r--r--

6890137: G1: revamp reachable object dump
Summary: Revamp the reachable object dump debugging facility.
Reviewed-by: jmasa, apetrusenko

 /*
  * Copyright 2001-2009 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/_concurrentG1Refine.cpp.incl"
 // Possible sizes for the card counts cache: odd primes that roughly double in size.
 // (See jvmtiTagMap.cpp).
 int ConcurrentG1Refine::_cc_cache_sizes[] = {
 ,    32771,    76831,    150001,   307261,
 ,  1228891,  2457733,   4915219,  9830479,
      19660831, 39321619, 78643219, 157286461,       -1
   };
 ConcurrentG1Refine::ConcurrentG1Refine() :
   _card_counts(NULL), _card_epochs(NULL),
   _n_card_counts(0), _max_n_card_counts(0),
   _cache_size_index(0), _expand_card_counts(false),
   _hot_cache(NULL),
   _def_use_cache(false), _use_cache(false),
   _n_periods(0),
   _threads(NULL), _n_threads(0)
 {
   if (G1ConcRefine) {
     _n_threads = (int)thread_num();
     if (_n_threads > 0) {
       _threads = NEW_C_HEAP_ARRAY(ConcurrentG1RefineThread*, _n_threads);
       int worker_id_offset = (int)DirtyCardQueueSet::num_par_ids();
       ConcurrentG1RefineThread *next = NULL;
       for (int i = _n_threads - 1; i >= 0; i--) {
         ConcurrentG1RefineThread* t = new ConcurrentG1RefineThread(this, next, worker_id_offset, i);
         assert(t != NULL, "Conc refine should have been created");
         assert(t->cg1r() == this, "Conc refine thread should refer to this");
         _threads[i] = t;
         next = t;
       }
     }
   }
 }
 size_t ConcurrentG1Refine::thread_num() {
   if (G1ConcRefine) {
     return (G1ParallelRSetThreads > 0) ? G1ParallelRSetThreads : ParallelGCThreads;
   }
   return 0;
 }
 void ConcurrentG1Refine::init() {
   if (G1ConcRSLogCacheSize > 0) {
     _g1h = G1CollectedHeap::heap();
     _max_n_card_counts =
       (unsigned) (_g1h->g1_reserved_obj_bytes() >> CardTableModRefBS::card_shift);
     size_t max_card_num = ((size_t)1 << (sizeof(unsigned)*BitsPerByte-1)) - 1;
     guarantee(_max_n_card_counts < max_card_num, "card_num representation");
     int desired = _max_n_card_counts / InitialCacheFraction;
     for (_cache_size_index = 0;
               _cc_cache_sizes[_cache_size_index] >= 0; _cache_size_index++) {
       if (_cc_cache_sizes[_cache_size_index] >= desired) break;
     }
     _cache_size_index = MAX2(0, (_cache_size_index - 1));
     int initial_size = _cc_cache_sizes[_cache_size_index];
     if (initial_size < 0) initial_size = _max_n_card_counts;
     // Make sure we don't go bigger than we will ever need
     _n_card_counts = MIN2((unsigned) initial_size, _max_n_card_counts);
     _card_counts = NEW_C_HEAP_ARRAY(CardCountCacheEntry, _n_card_counts);
     _card_epochs = NEW_C_HEAP_ARRAY(CardEpochCacheEntry, _n_card_counts);
     Copy::fill_to_bytes(&_card_counts[0],
                         _n_card_counts * sizeof(CardCountCacheEntry));
     Copy::fill_to_bytes(&_card_epochs[0], _n_card_counts * sizeof(CardEpochCacheEntry));
     ModRefBarrierSet* bs = _g1h->mr_bs();
     guarantee(bs->is_a(BarrierSet::CardTableModRef), "Precondition");
     _ct_bs = (CardTableModRefBS*)bs;
     _ct_bot = _ct_bs->byte_for_const(_g1h->reserved_region().start());
     _def_use_cache = true;
     _use_cache = true;
     _hot_cache_size = (1 << G1ConcRSLogCacheSize);
     _hot_cache = NEW_C_HEAP_ARRAY(jbyte*, _hot_cache_size);
     _n_hot = 0;
     _hot_cache_idx = 0;
     // For refining the cards in the hot cache in parallel
     int n_workers = (ParallelGCThreads > 0 ?
                         _g1h->workers()->total_workers() : 1);
     _hot_cache_par_chunk_size = MAX2(1, _hot_cache_size / n_workers);
     _hot_cache_par_claimed_idx = 0;
   }
 }
 void ConcurrentG1Refine::stop() {
   if (_threads != NULL) {
     for (int i = 0; i < _n_threads; i++) {
       _threads[i]->stop();
     }
   }
 }
 ConcurrentG1Refine::~ConcurrentG1Refine() {
   if (G1ConcRSLogCacheSize > 0) {
     assert(_card_counts != NULL, "Logic");
     FREE_C_HEAP_ARRAY(CardCountCacheEntry, _card_counts);
     assert(_card_epochs != NULL, "Logic");
     FREE_C_HEAP_ARRAY(CardEpochCacheEntry, _card_epochs);
     assert(_hot_cache != NULL, "Logic");
     FREE_C_HEAP_ARRAY(jbyte*, _hot_cache);
   }
   if (_threads != NULL) {
     for (int i = 0; i < _n_threads; i++) {
       delete _threads[i];
     }
     FREE_C_HEAP_ARRAY(ConcurrentG1RefineThread*, _threads);
   }
 }
 void ConcurrentG1Refine::threads_do(ThreadClosure *tc) {
   if (_threads != NULL) {
     for (int i = 0; i < _n_threads; i++) {
       tc->do_thread(_threads[i]);
     }
   }
 }
 bool ConcurrentG1Refine::is_young_card(jbyte* card_ptr) {
   HeapWord* start = _ct_bs->addr_for(card_ptr);
   HeapRegion* r = _g1h->heap_region_containing(start);
   if (r != NULL && r->is_young()) {
     return true;
   }
   // This card is not associated with a heap region
   // so can't be young.
   return false;
 }
 jbyte* ConcurrentG1Refine::add_card_count(jbyte* card_ptr, int* count, bool* defer) {
   unsigned new_card_num = ptr_2_card_num(card_ptr);
   unsigned bucket = hash(new_card_num);
   assert(0 <= bucket && bucket < _n_card_counts, "Bounds");
   CardCountCacheEntry* count_ptr = &_card_counts[bucket];
   CardEpochCacheEntry* epoch_ptr = &_card_epochs[bucket];
   // We have to construct a new entry if we haven't updated the counts
   // during the current period, or if the count was updated for a
   // different card number.
   unsigned int new_epoch = (unsigned int) _n_periods;
   julong new_epoch_entry = make_epoch_entry(new_card_num, new_epoch);
   while (true) {
     // Fetch the previous epoch value
     julong prev_epoch_entry = epoch_ptr->_value;
     julong cas_res;
     if (extract_epoch(prev_epoch_entry) != new_epoch) {
       // This entry has not yet been updated during this period.
       // Note: we update the epoch value atomically to ensure
       // that there is only one winner that updates the cached
       // card_ptr value even though all the refine threads share
       // the same epoch value.
       cas_res = (julong) Atomic::cmpxchg((jlong) new_epoch_entry,
                                          (volatile jlong*)&epoch_ptr->_value,
                                          (jlong) prev_epoch_entry);
       if (cas_res == prev_epoch_entry) {
         // We have successfully won the race to update the
         // epoch and card_num value. Make it look like the
         // count and eviction count were previously cleared.
         count_ptr->_count = 1;
         count_ptr->_evict_count = 0;
         *count = 0;
         // We can defer the processing of card_ptr
         *defer = true;
         return card_ptr;
       }
       // We did not win the race to update the epoch field, so some other
       // thread must have done it. The value that gets returned by CAS
       // should be the new epoch value.
       assert(extract_epoch(cas_res) == new_epoch, "unexpected epoch");
       // We could 'continue' here or just re-read the previous epoch value
       prev_epoch_entry = epoch_ptr->_value;
     }
     // The epoch entry for card_ptr has been updated during this period.
     unsigned old_card_num = extract_card_num(prev_epoch_entry);
     // The card count that will be returned to caller
     *count = count_ptr->_count;
     // Are we updating the count for the same card?
     if (new_card_num == old_card_num) {
       // Same card - just update the count. We could have more than one
       // thread racing to update count for the current card. It should be
       // OK not to use a CAS as the only penalty should be some missed
       // increments of the count which delays identifying the card as "hot".
       if (*count < max_jubyte) count_ptr->_count++;
       // We can defer the processing of card_ptr
       *defer = true;
       return card_ptr;
     }
     // Different card - evict old card info
     if (count_ptr->_evict_count < max_jubyte) count_ptr->_evict_count++;
     if (count_ptr->_evict_count > G1CardCountCacheExpandThreshold) {
       // Trigger a resize the next time we clear
       _expand_card_counts = true;
     }
     cas_res = (julong) Atomic::cmpxchg((jlong) new_epoch_entry,
                                        (volatile jlong*)&epoch_ptr->_value,
                                        (jlong) prev_epoch_entry);
     if (cas_res == prev_epoch_entry) {
       // We successfully updated the card num value in the epoch entry
       count_ptr->_count = 0; // initialize counter for new card num
       // Even though the region containg the card at old_card_num was not
       // in the young list when old_card_num was recorded in the epoch
       // cache it could have been added to the free list and subsequently
       // added to the young list in the intervening time. If the evicted
       // card is in a young region just return the card_ptr and the evicted
       // card will not be cleaned. See CR 6817995.
       jbyte* old_card_ptr = card_num_2_ptr(old_card_num);
       if (is_young_card(old_card_ptr)) {
         *count = 0;
         // We can defer the processing of card_ptr
         *defer = true;
         return card_ptr;
       }
       // We do not want to defer processing of card_ptr in this case
       // (we need to refine old_card_ptr and card_ptr)
       *defer = false;
       return old_card_ptr;
     }
     // Someone else beat us - try again.
   }
 }
 jbyte* ConcurrentG1Refine::cache_insert(jbyte* card_ptr, bool* defer) {
   int count;
   jbyte* cached_ptr = add_card_count(card_ptr, &count, defer);
   assert(cached_ptr != NULL, "bad cached card ptr");
   assert(!is_young_card(cached_ptr), "shouldn't get a card in young region");
   // The card pointer we obtained from card count cache is not hot
   // so do not store it in the cache; return it for immediate
   // refining.
   if (count < G1ConcRSHotCardLimit) {
     return cached_ptr;
   }
   // Otherwise, the pointer we got from the _card_counts is hot.
   jbyte* res = NULL;
   MutexLockerEx x(HotCardCache_lock, Mutex::_no_safepoint_check_flag);
   if (_n_hot == _hot_cache_size) {
     res = _hot_cache[_hot_cache_idx];
     _n_hot--;
   }
   // Now _n_hot < _hot_cache_size, and we can insert at _hot_cache_idx.
   _hot_cache[_hot_cache_idx] = cached_ptr;
   _hot_cache_idx++;
   if (_hot_cache_idx == _hot_cache_size) _hot_cache_idx = 0;
   _n_hot++;
   if (res != NULL) {
     // Even though the region containg res was not in the young list
     // when it was recorded in the hot cache it could have been added
     // to the free list and subsequently added to the young list in
     // the intervening time. If res is in a young region, return NULL
     // so that res is not cleaned. See CR 6817995.
     if (is_young_card(res)) {
       res = NULL;
     }
   }
   return res;
 }
 void ConcurrentG1Refine::clean_up_cache(int worker_i, G1RemSet* g1rs) {
   assert(!use_cache(), "cache should be disabled");
   int start_idx;
   while ((start_idx = _hot_cache_par_claimed_idx) < _n_hot) { // read once
     int end_idx = start_idx + _hot_cache_par_chunk_size;
     if (start_idx ==
         Atomic::cmpxchg(end_idx, &_hot_cache_par_claimed_idx, start_idx)) {
       // The current worker has successfully claimed the chunk [start_idx..end_idx)
       end_idx = MIN2(end_idx, _n_hot);
       for (int i = start_idx; i < end_idx; i++) {
         jbyte* entry = _hot_cache[i];
         if (entry != NULL) {
           g1rs->concurrentRefineOneCard(entry, worker_i);
         }
       }
     }
   }
 }
 void ConcurrentG1Refine::expand_card_count_cache() {
   if (_n_card_counts < _max_n_card_counts) {
     int new_idx = _cache_size_index+1;
     int new_size = _cc_cache_sizes[new_idx];
     if (new_size < 0) new_size = _max_n_card_counts;
     // Make sure we don't go bigger than we will ever need
     new_size = MIN2((unsigned) new_size, _max_n_card_counts);
     // Expand the card count and card epoch tables
     if (new_size > (int)_n_card_counts) {
       // We can just free and allocate a new array as we're
       // not interested in preserving the contents
       assert(_card_counts != NULL, "Logic!");
       assert(_card_epochs != NULL, "Logic!");
       FREE_C_HEAP_ARRAY(CardCountCacheEntry, _card_counts);
       FREE_C_HEAP_ARRAY(CardEpochCacheEntry, _card_epochs);
       _n_card_counts = new_size;
       _card_counts = NEW_C_HEAP_ARRAY(CardCountCacheEntry, _n_card_counts);
       _card_epochs = NEW_C_HEAP_ARRAY(CardEpochCacheEntry, _n_card_counts);
       _cache_size_index = new_idx;
     }
   }
 }
 void ConcurrentG1Refine::clear_and_record_card_counts() {
   if (G1ConcRSLogCacheSize == 0) return;
 #ifndef PRODUCT
   double start = os::elapsedTime();
 #endif
   if (_expand_card_counts) {
     expand_card_count_cache();
     _expand_card_counts = false;
     // Only need to clear the epochs.
     Copy::fill_to_bytes(&_card_epochs[0], _n_card_counts * sizeof(CardEpochCacheEntry));
   }
   int this_epoch = (int) _n_periods;
   assert((this_epoch+1) <= max_jint, "to many periods");
   // Update epoch
   _n_periods++;
 #ifndef PRODUCT
   double elapsed = os::elapsedTime() - start;
   _g1h->g1_policy()->record_cc_clear_time(elapsed * 1000.0);
 #endif
 }
 void ConcurrentG1Refine::print_worker_threads_on(outputStream* st) const {
   for (int i = 0; i < _n_threads; ++i) {
     _threads[i]->print_on(st);
     st->cr();
   }
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/concurrentG1Refine.cpp@6270f80a7331 (annotated)

src/share/vm/gc_implementation/g1/concurrentG1Refine.cpp