/*

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

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 * 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.

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#include "precompiled.hpp"

#include "gc/g1/g1Analytics.hpp"

#include "gc/g1/g1CollectorPolicy.hpp"

#include "gc/g1/g1YoungGenSizer.hpp"

#include "gc/g1/heapRegion.hpp"

#include "gc/g1/heapRegionRemSet.hpp"

#include "gc/shared/gcPolicyCounters.hpp"

#include "runtime/globals.hpp"

#include "utilities/debug.hpp"

G1CollectorPolicy::G1CollectorPolicy() {

  // Set up the region size and associated fields. Given that the

  // policy is created before the heap, we have to set this up here,

  // so it's done as soon as possible.

  // It would have been natural to pass initial_heap_byte_size() and

  // max_heap_byte_size() to setup_heap_region_size() but those have

  // not been set up at this point since they should be aligned with

  // the region size. So, there is a circular dependency here. We base

  // the region size on the heap size, but the heap size should be

  // aligned with the region size. To get around this we use the

  // unaligned values for the heap.

  HeapRegion::setup_heap_region_size(InitialHeapSize, MaxHeapSize);

  HeapRegionRemSet::setup_remset_size();

  // Below, we might need to calculate the pause time target based on

  // the pause interval. When we do so we are going to give G1 maximum

  // flexibility and allow it to do pauses when it needs to. So, we'll

  // arrange that the pause interval to be pause time target + 1 to

  // ensure that a) the pause time target is maximized with respect to

  // the pause interval and b) we maintain the invariant that pause

  // time target < pause interval. If the user does not want this

  // maximum flexibility, they will have to set the pause interval

  // explicitly.

  // First make sure that, if either parameter is set, its value is

  // reasonable.

  guarantee(MaxGCPauseMillis >= 1, "Range checking for MaxGCPauseMillis should guarantee that value is >= 1");

  // Then, if the pause time target parameter was not set, set it to

  // the default value.

  if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {

    if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {

      // The default pause time target in G1 is 200ms

      FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);

    } else {

      // We do not allow the pause interval to be set without the

      // pause time target

      vm_exit_during_initialization("GCPauseIntervalMillis cannot be set "

                                    "without setting MaxGCPauseMillis");

    }

  }

  // Then, if the interval parameter was not set, set it according to

  // the pause time target (this will also deal with the case when the

  // pause time target is the default value).

  if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {

    FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);

  }

  guarantee(GCPauseIntervalMillis >= 1, "Constraint for GCPauseIntervalMillis should guarantee that value is >= 1");

  guarantee(GCPauseIntervalMillis > MaxGCPauseMillis, "Constraint for GCPauseIntervalMillis should guarantee that GCPauseIntervalMillis > MaxGCPauseMillis");

}

void G1CollectorPolicy::initialize_alignments() {

  _space_alignment = HeapRegion::GrainBytes;

  size_t card_table_alignment = CardTableRS::ct_max_alignment_constraint();

  size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();

  _heap_alignment = MAX3(card_table_alignment, _space_alignment, page_size);

}

void G1CollectorPolicy::initialize_flags() {

  if (G1HeapRegionSize != HeapRegion::GrainBytes) {

    FLAG_SET_ERGO(size_t, G1HeapRegionSize, HeapRegion::GrainBytes);

  }

  guarantee(SurvivorRatio >= 1, "Range checking for SurvivorRatio should guarantee that value is >= 1");

  CollectorPolicy::initialize_flags();

}

// Create the jstat counters for the policy.

void G1CollectorPolicy::initialize_gc_policy_counters() {

  _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 3);

}