jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/collectionSetChooser.cpp@64bf7c8270cb (annotated)

src/share/vm/gc_implementation/g1/collectionSetChooser.cpp@64bf7c8270cb (annotated)

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

Mon, 12 Mar 2012 14:59:00 -0700

author: johnc
date: Mon, 12 Mar 2012 14:59:00 -0700
changeset 3666: 64bf7c8270cb
parent 3539: a9647476d1a4
child 3667: 21595f05bc93
permissions: -rw-r--r--

7147724: G1: hang in SurrogateLockerThread::manipulatePLL
Summary: Attempting to initiate a marking cycle when allocating a humongous object can, if a marking cycle is successfully initiated by another thread, result in the allocating thread spinning until the marking cycle is complete. Eliminate a deadlock between the main ConcurrentMarkThread, the SurrogateLocker thread, the VM thread, and a mutator thread waiting on the SecondaryFreeList_lock (while free regions are going to become available) by not manipulating the pending list lock during the prologue and epilogue of the cleanup pause.
Reviewed-by: brutisso, jcoomes, tonyp

 /*
  * Copyright (c) 2001, 2012, 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() {
   guarantee(false, "CSetChooserCache::verify(): don't call this any more");
   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) {
   guarantee(false, "CSetChooserCache::insert(): don't call this any more");
   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() {
   guarantee(false, "CSetChooserCache::remove_first(): "
                    "don't call this any more");
   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;
   }
 }
 // Even though we don't use the GC efficiency in our heuristics as
 // much as we used to, we still order according to GC efficiency. This
 // will cause regions with a lot of live objects and large RSets to
 // end up at the end of the array. Given that we might skip collecting
 // the last few old regions, if after a few mixed GCs the remaining
 // have reclaimable bytes under a certain threshold, the hope is that
 // the ones we'll skip are ones with both large RSets and a lot of
 // live objects, not the ones with just a lot of live objects if we
 // ordered according to the amount of reclaimable bytes per region.
 static int orderRegions(HeapRegion* hr1, HeapRegion* hr2) {
   if (hr1 == NULL) {
     if (hr2 == NULL) {
       return 0;
     } else {
       return 1;
     }
   } else if (hr2 == NULL) {
     return -1;
   }
   double gc_eff1 = hr1->gc_efficiency();
   double gc_eff2 = hr2->gc_efficiency();
   if (gc_eff1 > gc_eff2) {
     return -1;
   } if (gc_eff1 < gc_eff2) {
     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 /* C_Heap */),
     _curr_index(0), _length(0),
     _regionLiveThresholdBytes(0), _remainingReclaimableBytes(0),
     _first_par_unreserved_idx(0) {
   _regionLiveThresholdBytes =
     HeapRegion::GrainBytes * (size_t) G1OldCSetRegionLiveThresholdPercent / 100;
 }
 #ifndef PRODUCT
 bool CollectionSetChooser::verify() {
   guarantee(_length >= 0, err_msg("_length: %d", _length));
   guarantee(0 <= _curr_index && _curr_index <= _length,
             err_msg("_curr_index: %d _length: %d", _curr_index, _length));
   int index = 0;
   size_t sum_of_reclaimable_bytes = 0;
   while (index < _curr_index) {
     guarantee(_markedRegions.at(index) == NULL,
               "all entries before _curr_index should be NULL");
     index += 1;
   }
   HeapRegion *prev = NULL;
   while (index < _length) {
     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(!curr->isHumongous(), "should not be humongous!");
     guarantee(si > -1 && si == (index-1), "sort index invariant");
     if (prev != NULL) {
       guarantee(orderRegions(prev, curr) != 1,
                 err_msg("GC eff prev: %1.4f GC eff curr: %1.4f",
                         prev->gc_efficiency(), curr->gc_efficiency()));
     }
     sum_of_reclaimable_bytes += curr->reclaimable_bytes();
     prev = curr;
   }
   guarantee(sum_of_reclaimable_bytes == _remainingReclaimableBytes,
             err_msg("reclaimable bytes inconsistent, "
                     "remaining: "SIZE_FORMAT" sum: "SIZE_FORMAT,
                     _remainingReclaimableBytes, sum_of_reclaimable_bytes));
   return true;
 }
 #endif
 void CollectionSetChooser::fillCache() {
   guarantee(false, "fillCache: don't call this any more");
   while (!_cache.is_full() && (_curr_index < _length)) {
     HeapRegion* hr = _markedRegions.at(_curr_index);
     assert(hr != NULL,
            err_msg("Unexpected NULL hr in _markedRegions at index %d",
                    _curr_index));
     _curr_index += 1;
     assert(!hr->is_young(), "should not be young!");
     assert(hr->sort_index() == _curr_index-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() {
   // 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(_length <= _markedRegions.length(), "Requirement");
   assert(_length == 0 || _markedRegions.at(_length - 1) != NULL,
          "Testing _length");
   assert(_length == _markedRegions.length() ||
                         _markedRegions.at(_length) == NULL, "Testing _length");
   if (G1PrintParCleanupStats) {
     gclog_or_tty->print_cr("     Sorted %d marked regions.", _length);
   }
   for (int i = 0; i < _length; 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 < _length; ++i) {
       HeapRegion* r = _markedRegions.at(i);
       cl.doHeapRegion(r);
     }
   }
   assert(verify(), "CSet chooser verification");
 }
 size_t CollectionSetChooser::calcMinOldCSetLength() {
   // The min old CSet region bound is based on the maximum desired
   // number of mixed GCs after a cycle. I.e., even if some old regions
   // look expensive, we should add them to the CSet anyway to make
   // sure we go through the available old regions in no more than the
   // maximum desired number of mixed GCs.
   //
   // The calculation is based on the number of marked regions we added
   // to the CSet chooser in the first place, not how many remain, so
   // that the result is the same during all mixed GCs that follow a cycle.
   const size_t region_num = (size_t) _length;
   const size_t gc_num = (size_t) G1MaxMixedGCNum;
   size_t result = region_num / gc_num;
   // emulate ceiling
   if (result * gc_num < region_num) {
     result += 1;
   }
   return result;
 }
 size_t CollectionSetChooser::calcMaxOldCSetLength() {
   // The max old CSet region bound is based on the threshold expressed
   // as a percentage of the heap size. I.e., it should bound the
   // number of old regions added to the CSet irrespective of how many
   // of them are available.
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   const size_t region_num = g1h->n_regions();
   const size_t perc = (size_t) G1OldCSetRegionThresholdPercent;
   size_t result = region_num * perc / 100;
   // emulate ceiling
   if (100 * result < region_num * perc) {
     result += 1;
   }
   return result;
 }
 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);
   _length++;
   _remainingReclaimableBytes += hr->reclaimable_bytes();
   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::updateTotals(jint region_num,
                                         size_t reclaimable_bytes) {
   // Only take the lock if we actually need to update the totals.
   if (region_num > 0) {
     assert(reclaimable_bytes > 0, "invariant");
     // We could have just used atomics instead of taking the
     // lock. However, we currently don't have an atomic add for size_t.
     MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag);
     _length += (int) region_num;
     _remainingReclaimableBytes += reclaimable_bytes;
   } else {
     assert(reclaimable_bytes == 0, "invariant");
   }
 }
 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();
   _curr_index = 0;
   _length = 0;
   _remainingReclaimableBytes = 0;
 };

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/collectionSetChooser.cpp@64bf7c8270cb (annotated)

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