jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/collectionSetChooser.cpp@2ace1c4ee8da (annotated)

src/share/vm/gc_implementation/g1/collectionSetChooser.cpp@2ace1c4ee8da (annotated)

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

Tue, 10 Jan 2012 18:58:13 -0500

author: tonyp
date: Tue, 10 Jan 2012 18:58:13 -0500
changeset 3416: 2ace1c4ee8da
parent 3357: 441e946dc1af
child 3539: a9647476d1a4
permissions: -rw-r--r--

6888336: G1: avoid explicitly marking and pushing objects in survivor spaces
Summary: This change simplifies the interaction between GC and concurrent marking. By disabling survivor spaces during the initial-mark pause we don't need to propagate marks of objects we copy during each GC (since we never need to copy an explicitly marked object).
Reviewed-by: johnc, brutisso

 /*
  * 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;
   }
 }
 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++);
     guarantee(curr != NULL, "Regions in _markedRegions array cannot be 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
 void
 CollectionSetChooser::fillCache() {
   while (!_cache.is_full() && (_curMarkedIndex < _numMarkedRegions)) {
     HeapRegion* hr = _markedRegions.at(_curMarkedIndex);
     assert(hr != NULL,
            err_msg("Unexpected NULL hr in _markedRegions at index %d",
                    _curMarkedIndex));
     _curMarkedIndex += 1;
     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");
 }
 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;
   int n_threads = ParallelGCThreads;
   if (UseDynamicNumberOfGCThreads) {
     assert(G1CollectedHeap::heap()->workers()->active_workers() > 0,
       "Should have been set earlier");
     // This is defensive code. As the assertion above says, the number
     // of active threads should be > 0, but in case there is some path
     // or some improperly initialized variable with leads to no
     // active threads, protect against that in a product build.
     n_threads = MAX2(G1CollectedHeap::heap()->workers()->active_workers(),
 U);
   }
   size_t max_waste = n_threads * 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) {
   // Don't do this assert because this can be called at a point
   // where the loop up stream will not execute again but might
   // try to claim more chunks (loop test has not been done yet).
   // assert(_markedRegions.length() > _first_par_unreserved_idx,
   //  "Striding beyond the marked 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();
 }
 // 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@2ace1c4ee8da (annotated)

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