jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/collectionSetChooser.cpp@4dfb2df418f2 (annotated)

src/share/vm/gc_implementation/g1/collectionSetChooser.cpp@4dfb2df418f2 (annotated)

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

Thu, 22 Sep 2011 10:57:37 -0700

author: johnc
date: Thu, 22 Sep 2011 10:57:37 -0700
changeset 3175: 4dfb2df418f2
parent 3114: 20213c8a3c40
child 3185: b9390528617c
permissions: -rw-r--r--

6484982: G1: process references during evacuation pauses
Summary: G1 now uses two reference processors - one is used by concurrent marking and the other is used by STW GCs (both full and incremental evacuation pauses). In an evacuation pause, the reference processor is embedded into the closures used to scan objects. Doing so causes causes reference objects to be 'discovered' by the reference processor. At the end of the evacuation pause, these discovered reference objects are processed - preserving (and copying) referent objects (and their reachable graphs) as appropriate.
Reviewed-by: ysr, jwilhelm, brutisso, stefank, tonyp

 /*
  * Copyright (c) 2001, 2011, 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 "gc_implementation/g1/collectionSetChooser.hpp"
 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
 #include "gc_implementation/g1/g1ErgoVerbose.hpp"
 #include "memory/space.inline.hpp"
 CSetChooserCache::CSetChooserCache() {
   for (int i = 0; i < CacheLength; ++i)
     _cache[i] = NULL;
   clear();
 }
 void CSetChooserCache::clear() {
   _occupancy = 0;
   _first = 0;
   for (int i = 0; i < CacheLength; ++i) {
     HeapRegion *hr = _cache[i];
     if (hr != NULL)
       hr->set_sort_index(-1);
     _cache[i] = NULL;
   }
 }
 #ifndef PRODUCT
 bool CSetChooserCache::verify() {
   int index = _first;
   HeapRegion *prev = NULL;
   for (int i = 0; i < _occupancy; ++i) {
     guarantee(_cache[index] != NULL, "cache entry should not be empty");
     HeapRegion *hr = _cache[index];
     guarantee(!hr->is_young(), "should not be young!");
     if (prev != NULL) {
       guarantee(prev->gc_efficiency() >= hr->gc_efficiency(),
                 "cache should be correctly ordered");
     }
     guarantee(hr->sort_index() == get_sort_index(index),
               "sort index should be correct");
     index = trim_index(index + 1);
     prev = hr;
   }
   for (int i = 0; i < (CacheLength - _occupancy); ++i) {
     guarantee(_cache[index] == NULL, "cache entry should be empty");
     index = trim_index(index + 1);
   }
   guarantee(index == _first, "we should have reached where we started from");
   return true;
 }
 #endif // PRODUCT
 void CSetChooserCache::insert(HeapRegion *hr) {
   assert(!is_full(), "cache should not be empty");
   hr->calc_gc_efficiency();
   int empty_index;
   if (_occupancy == 0) {
     empty_index = _first;
   } else {
     empty_index = trim_index(_first + _occupancy);
     assert(_cache[empty_index] == NULL, "last slot should be empty");
     int last_index = trim_index(empty_index - 1);
     HeapRegion *last = _cache[last_index];
     assert(last != NULL,"as the cache is not empty, last should not be empty");
     while (empty_index != _first &&
            last->gc_efficiency() < hr->gc_efficiency()) {
       _cache[empty_index] = last;
       last->set_sort_index(get_sort_index(empty_index));
       empty_index = last_index;
       last_index = trim_index(last_index - 1);
       last = _cache[last_index];
     }
   }
   _cache[empty_index] = hr;
   hr->set_sort_index(get_sort_index(empty_index));
   ++_occupancy;
   assert(verify(), "cache should be consistent");
 }
 HeapRegion *CSetChooserCache::remove_first() {
   if (_occupancy > 0) {
     assert(_cache[_first] != NULL, "cache should have at least one region");
     HeapRegion *ret = _cache[_first];
     _cache[_first] = NULL;
     ret->set_sort_index(-1);
     --_occupancy;
     _first = trim_index(_first + 1);
     assert(verify(), "cache should be consistent");
     return ret;
   } else {
     return NULL;
   }
 }
 // this is a bit expensive... but we expect that it should not be called
 // to often.
 void CSetChooserCache::remove(HeapRegion *hr) {
   assert(_occupancy > 0, "cache should not be empty");
   assert(hr->sort_index() < -1, "should already be in the cache");
   int index = get_index(hr->sort_index());
   assert(_cache[index] == hr, "index should be correct");
   int next_index = trim_index(index + 1);
   int last_index = trim_index(_first + _occupancy - 1);
   while (index != last_index) {
     assert(_cache[next_index] != NULL, "should not be null");
     _cache[index] = _cache[next_index];
     _cache[index]->set_sort_index(get_sort_index(index));
     index = next_index;
     next_index = trim_index(next_index+1);
   }
   assert(index == last_index, "should have reached the last one");
   _cache[index] = NULL;
   hr->set_sort_index(-1);
   --_occupancy;
   assert(verify(), "cache should be consistent");
 }
 static inline int orderRegions(HeapRegion* hr1, HeapRegion* hr2) {
   if (hr1 == NULL) {
     if (hr2 == NULL) return 0;
     else return 1;
   } else if (hr2 == NULL) {
     return -1;
   }
   if (hr2->gc_efficiency() < hr1->gc_efficiency()) return -1;
   else if (hr1->gc_efficiency() < hr2->gc_efficiency()) return 1;
   else return 0;
 }
 static int orderRegions(HeapRegion** hr1p, HeapRegion** hr2p) {
   return orderRegions(*hr1p, *hr2p);
 }
 CollectionSetChooser::CollectionSetChooser() :
   // The line below is the worst bit of C++ hackery I've ever written
   // (Detlefs, 11/23).  You should think of it as equivalent to
   // "_regions(100, true)": initialize the growable array and inform it
   // that it should allocate its elem array(s) on the C heap.
   //
   // The first argument, however, is actually a comma expression
   // (set_allocation_type(this, C_HEAP), 100). The purpose of the
   // set_allocation_type() call is to replace the default allocation
   // type for embedded objects STACK_OR_EMBEDDED with C_HEAP. It will
   // allow to pass the assert in GenericGrowableArray() which checks
   // that a growable array object must be on C heap if elements are.
   //
   // Note: containing object is allocated on C heap since it is CHeapObj.
   //
   _markedRegions((ResourceObj::set_allocation_type((address)&_markedRegions,
                                              ResourceObj::C_HEAP),
 ),
                  true),
   _curMarkedIndex(0),
   _numMarkedRegions(0),
   _unmarked_age_1_returned_as_new(false),
   _first_par_unreserved_idx(0)
 {}
 #ifndef PRODUCT
 bool CollectionSetChooser::verify() {
   int index = 0;
   guarantee(_curMarkedIndex <= _numMarkedRegions,
             "_curMarkedIndex should be within bounds");
   while (index < _curMarkedIndex) {
     guarantee(_markedRegions.at(index++) == NULL,
               "all entries before _curMarkedIndex should be NULL");
   }
   HeapRegion *prev = NULL;
   while (index < _numMarkedRegions) {
     HeapRegion *curr = _markedRegions.at(index++);
     if (curr != NULL) {
       int si = curr->sort_index();
       guarantee(!curr->is_young(), "should not be young!");
       guarantee(si > -1 && si == (index-1), "sort index invariant");
       if (prev != NULL) {
         guarantee(orderRegions(prev, curr) != 1, "regions should be sorted");
       }
       prev = curr;
     }
   }
   return _cache.verify();
 }
 #endif
 bool
 CollectionSetChooser::addRegionToCache() {
   assert(!_cache.is_full(), "cache should not be full");
   HeapRegion *hr = NULL;
   while (hr == NULL && _curMarkedIndex < _numMarkedRegions) {
     hr = _markedRegions.at(_curMarkedIndex++);
   }
   if (hr == NULL)
     return false;
   assert(!hr->is_young(), "should not be young!");
   assert(hr->sort_index() == _curMarkedIndex-1, "sort_index invariant");
   _markedRegions.at_put(hr->sort_index(), NULL);
   _cache.insert(hr);
   assert(!_cache.is_empty(), "cache should not be empty");
   assert(verify(), "cache should be consistent");
   return false;
 }
 void
 CollectionSetChooser::fillCache() {
   while (!_cache.is_full() && addRegionToCache()) {
   }
 }
 void
 CollectionSetChooser::sortMarkedHeapRegions() {
   guarantee(_cache.is_empty(), "cache should be empty");
   // First trim any unused portion of the top in the parallel case.
   if (_first_par_unreserved_idx > 0) {
     if (G1PrintParCleanupStats) {
       gclog_or_tty->print("     Truncating _markedRegions from %d to %d.\n",
                           _markedRegions.length(), _first_par_unreserved_idx);
     }
     assert(_first_par_unreserved_idx <= _markedRegions.length(),
            "Or we didn't reserved enough length");
     _markedRegions.trunc_to(_first_par_unreserved_idx);
   }
   _markedRegions.sort(orderRegions);
   assert(_numMarkedRegions <= _markedRegions.length(), "Requirement");
   assert(_numMarkedRegions == 0
          || _markedRegions.at(_numMarkedRegions-1) != NULL,
          "Testing _numMarkedRegions");
   assert(_numMarkedRegions == _markedRegions.length()
          || _markedRegions.at(_numMarkedRegions) == NULL,
          "Testing _numMarkedRegions");
   if (G1PrintParCleanupStats) {
     gclog_or_tty->print_cr("     Sorted %d marked regions.", _numMarkedRegions);
   }
   for (int i = 0; i < _numMarkedRegions; i++) {
     assert(_markedRegions.at(i) != NULL, "Should be true by sorting!");
     _markedRegions.at(i)->set_sort_index(i);
   }
   if (G1PrintRegionLivenessInfo) {
     G1PrintRegionLivenessInfoClosure cl(gclog_or_tty, "Post-Sorting");
     for (int i = 0; i < _numMarkedRegions; ++i) {
       HeapRegion* r = _markedRegions.at(i);
       cl.doHeapRegion(r);
     }
   }
   assert(verify(), "should now be sorted");
 }
 void
 CollectionSetChooser::addMarkedHeapRegion(HeapRegion* hr) {
   assert(!hr->isHumongous(),
          "Humongous regions shouldn't be added to the collection set");
   assert(!hr->is_young(), "should not be young!");
   _markedRegions.append(hr);
   _numMarkedRegions++;
   hr->calc_gc_efficiency();
 }
 void
 CollectionSetChooser::
 prepareForAddMarkedHeapRegionsPar(size_t n_regions, size_t chunkSize) {
   _first_par_unreserved_idx = 0;
   size_t max_waste = ParallelGCThreads * chunkSize;
   // it should be aligned with respect to chunkSize
   size_t aligned_n_regions =
                      (n_regions + (chunkSize - 1)) / chunkSize * chunkSize;
   assert( aligned_n_regions % chunkSize == 0, "should be aligned" );
   _markedRegions.at_put_grow((int)(aligned_n_regions + max_waste - 1), NULL);
 }
 jint
 CollectionSetChooser::getParMarkedHeapRegionChunk(jint n_regions) {
   jint res = Atomic::add(n_regions, &_first_par_unreserved_idx);
   assert(_markedRegions.length() > res + n_regions - 1,
          "Should already have been expanded");
   return res - n_regions;
 }
 void
 CollectionSetChooser::setMarkedHeapRegion(jint index, HeapRegion* hr) {
   assert(_markedRegions.at(index) == NULL, "precondition");
   assert(!hr->is_young(), "should not be young!");
   _markedRegions.at_put(index, hr);
   hr->calc_gc_efficiency();
 }
 void
 CollectionSetChooser::incNumMarkedHeapRegions(jint inc_by) {
   (void)Atomic::add(inc_by, &_numMarkedRegions);
 }
 void
 CollectionSetChooser::clearMarkedHeapRegions(){
   for (int i = 0; i < _markedRegions.length(); i++) {
     HeapRegion* r =   _markedRegions.at(i);
     if (r != NULL) r->set_sort_index(-1);
   }
   _markedRegions.clear();
   _curMarkedIndex = 0;
   _numMarkedRegions = 0;
   _cache.clear();
 };
 void
 CollectionSetChooser::updateAfterFullCollection() {
   clearMarkedHeapRegions();
 }
 void CollectionSetChooser::removeRegion(HeapRegion *hr) {
   int si = hr->sort_index();
   assert(si == -1 || hr->is_marked(), "Sort index not valid.");
   if (si > -1) {
     assert(_markedRegions.at(si) == hr, "Sort index not valid." );
     _markedRegions.at_put(si, NULL);
   } else if (si < -1) {
     assert(_cache.region_in_cache(hr), "should be in the cache");
     _cache.remove(hr);
     assert(hr->sort_index() == -1, "sort index invariant");
   }
   hr->set_sort_index(-1);
 }
 // if time_remaining < 0.0, then this method should try to return
 // a region, whether it fits within the remaining time or not
 HeapRegion*
 CollectionSetChooser::getNextMarkedRegion(double time_remaining,
                                           double avg_prediction) {
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   G1CollectorPolicy* g1p = g1h->g1_policy();
   fillCache();
   if (_cache.is_empty()) {
     assert(_curMarkedIndex == _numMarkedRegions,
            "if cache is empty, list should also be empty");
     ergo_verbose0(ErgoCSetConstruction,
                   "stop adding old regions to CSet",
                   ergo_format_reason("cache is empty"));
     return NULL;
   }
   HeapRegion *hr = _cache.get_first();
   assert(hr != NULL, "if cache not empty, first entry should be non-null");
   double predicted_time = g1h->predict_region_elapsed_time_ms(hr, false);
   if (g1p->adaptive_young_list_length()) {
     if (time_remaining - predicted_time < 0.0) {
       g1h->check_if_region_is_too_expensive(predicted_time);
       ergo_verbose2(ErgoCSetConstruction,
                     "stop adding old regions to CSet",
                     ergo_format_reason("predicted old region time higher than remaining time")
                     ergo_format_ms("predicted old region time")
                     ergo_format_ms("remaining time"),
                     predicted_time, time_remaining);
       return NULL;
     }
   } else {
     double threshold = 2.0 * avg_prediction;
     if (predicted_time > threshold) {
       ergo_verbose2(ErgoCSetConstruction,
                     "stop adding old regions to CSet",
                     ergo_format_reason("predicted old region time higher than threshold")
                     ergo_format_ms("predicted old region time")
                     ergo_format_ms("threshold"),
                     predicted_time, threshold);
       return NULL;
     }
   }
   HeapRegion *hr2 = _cache.remove_first();
   assert(hr == hr2, "cache contents should not have changed");
   return hr;
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/collectionSetChooser.cpp@4dfb2df418f2 (annotated)

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