/*

 * Copyright 2001-2007 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/_collectorPolicy.cpp.incl"

// CollectorPolicy methods.

void CollectorPolicy::initialize_flags() {

  if (PermSize > MaxPermSize) {

    MaxPermSize = PermSize;

  }

  PermSize = align_size_down(PermSize, min_alignment());

  MaxPermSize = align_size_up(MaxPermSize, max_alignment());

  MinPermHeapExpansion = align_size_down(MinPermHeapExpansion, min_alignment());

  MaxPermHeapExpansion = align_size_down(MaxPermHeapExpansion, min_alignment());

  MinHeapDeltaBytes = align_size_up(MinHeapDeltaBytes, min_alignment());

  SharedReadOnlySize = align_size_up(SharedReadOnlySize, max_alignment());

  SharedReadWriteSize = align_size_up(SharedReadWriteSize, max_alignment());

  SharedMiscDataSize = align_size_up(SharedMiscDataSize, max_alignment());

  assert(PermSize    % min_alignment() == 0, "permanent space alignment");

  assert(MaxPermSize % max_alignment() == 0, "maximum permanent space alignment");

  assert(SharedReadOnlySize % max_alignment() == 0, "read-only space alignment");

  assert(SharedReadWriteSize % max_alignment() == 0, "read-write space alignment");

  assert(SharedMiscDataSize % max_alignment() == 0, "misc-data space alignment");

  if (PermSize < M) {

    vm_exit_during_initialization("Too small initial permanent heap");

  }

}

void CollectorPolicy::initialize_size_info() {

  // User inputs from -mx and ms are aligned

  _initial_heap_byte_size = align_size_up(Arguments::initial_heap_size(),

                                          min_alignment());

  _min_heap_byte_size = align_size_up(Arguments::min_heap_size(),

                                          min_alignment());

  _max_heap_byte_size = align_size_up(MaxHeapSize, max_alignment());

  // Check validity of heap parameters from launcher

  if (_initial_heap_byte_size == 0) {

    _initial_heap_byte_size = NewSize + OldSize;

  } else {

    Universe::check_alignment(_initial_heap_byte_size, min_alignment(),

                            "initial heap");

  }

  if (_min_heap_byte_size == 0) {

    _min_heap_byte_size = NewSize + OldSize;

  } else {

    Universe::check_alignment(_min_heap_byte_size, min_alignment(),

                            "initial heap");

  }

  // Check heap parameter properties

  if (_initial_heap_byte_size < M) {

    vm_exit_during_initialization("Too small initial heap");

  }

  // Check heap parameter properties

  if (_min_heap_byte_size < M) {

    vm_exit_during_initialization("Too small minimum heap");

  }

  if (_initial_heap_byte_size <= NewSize) {

     // make sure there is at least some room in old space

    vm_exit_during_initialization("Too small initial heap for new size specified");

  }

  if (_max_heap_byte_size < _min_heap_byte_size) {

    vm_exit_during_initialization("Incompatible minimum and maximum heap sizes specified");

  }

  if (_initial_heap_byte_size < _min_heap_byte_size) {

    vm_exit_during_initialization("Incompatible minimum and initial heap sizes specified");

  }

  if (_max_heap_byte_size < _initial_heap_byte_size) {

    vm_exit_during_initialization("Incompatible initial and maximum heap sizes specified");

  }

}

void CollectorPolicy::initialize_perm_generation(PermGen::Name pgnm) {

  _permanent_generation =

    new PermanentGenerationSpec(pgnm, PermSize, MaxPermSize,

                                SharedReadOnlySize,

                                SharedReadWriteSize,

                                SharedMiscDataSize,

                                SharedMiscCodeSize);

  if (_permanent_generation == NULL) {

    vm_exit_during_initialization("Unable to allocate gen spec");

  }

}

GenRemSet* CollectorPolicy::create_rem_set(MemRegion whole_heap,

                                           int max_covered_regions) {

  switch (rem_set_name()) {

  case GenRemSet::CardTable: {

    if (barrier_set_name() != BarrierSet::CardTableModRef)

      vm_exit_during_initialization("Mismatch between RS and BS.");

    CardTableRS* res = new CardTableRS(whole_heap, max_covered_regions);

    return res;

  }

  default:

    guarantee(false, "unrecognized GenRemSet::Name");

    return NULL;

  }

}

// GenCollectorPolicy methods.

void GenCollectorPolicy::initialize_size_policy(size_t init_eden_size,

                                                size_t init_promo_size,

                                                size_t init_survivor_size) {

  double max_gc_minor_pause_sec = ((double) MaxGCMinorPauseMillis)/1000.0;

  _size_policy = new AdaptiveSizePolicy(init_eden_size,

                                        init_promo_size,

                                        init_survivor_size,

                                        max_gc_minor_pause_sec,

                                        GCTimeRatio);

}

size_t GenCollectorPolicy::compute_max_alignment() {

  // The card marking array and the offset arrays for old generations are

  // committed in os pages as well. Make sure they are entirely full (to

  // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1

  // byte entry and the os page size is 4096, the maximum heap size should

  // be 512*4096 = 2MB aligned.

  size_t alignment = GenRemSet::max_alignment_constraint(rem_set_name());

  // Parallel GC does its own alignment of the generations to avoid requiring a

  // large page (256M on some platforms) for the permanent generation.  The

  // other collectors should also be updated to do their own alignment and then

  // this use of lcm() should be removed.

  if (UseLargePages && !UseParallelGC) {

      // in presence of large pages we have to make sure that our

      // alignment is large page aware

      alignment = lcm(os::large_page_size(), alignment);

  }

  return alignment;

}

void GenCollectorPolicy::initialize_flags() {

  // All sizes must be multiples of the generation granularity.

  set_min_alignment((uintx) Generation::GenGrain);

  set_max_alignment(compute_max_alignment());

  assert(max_alignment() >= min_alignment() &&

         max_alignment() % min_alignment() == 0,

         "invalid alignment constraints");

  CollectorPolicy::initialize_flags();

  // All generational heaps have a youngest gen; handle those flags here.

  // Adjust max size parameters

  if (NewSize > MaxNewSize) {

    MaxNewSize = NewSize;

  }

  NewSize = align_size_down(NewSize, min_alignment());

  MaxNewSize = align_size_down(MaxNewSize, min_alignment());

  // Check validity of heap flags

  assert(NewSize     % min_alignment() == 0, "eden space alignment");

  assert(MaxNewSize  % min_alignment() == 0, "survivor space alignment");

  if (NewSize < 3*min_alignment()) {

     // make sure there room for eden and two survivor spaces

    vm_exit_during_initialization("Too small new size specified");

  }

  if (SurvivorRatio < 1 || NewRatio < 1) {

    vm_exit_during_initialization("Invalid heap ratio specified");

  }

}

void TwoGenerationCollectorPolicy::initialize_flags() {

  GenCollectorPolicy::initialize_flags();

  OldSize = align_size_down(OldSize, min_alignment());

  if (NewSize + OldSize > MaxHeapSize) {

    MaxHeapSize = NewSize + OldSize;

  }

  MaxHeapSize = align_size_up(MaxHeapSize, max_alignment());

  always_do_update_barrier = UseConcMarkSweepGC;

  BlockOffsetArrayUseUnallocatedBlock =

      BlockOffsetArrayUseUnallocatedBlock || ParallelGCThreads > 0;

  // Check validity of heap flags

  assert(OldSize     % min_alignment() == 0, "old space alignment");

  assert(MaxHeapSize % max_alignment() == 0, "maximum heap alignment");

}

void GenCollectorPolicy::initialize_size_info() {

  CollectorPolicy::initialize_size_info();

  // Minimum sizes of the generations may be different than

  // the initial sizes.

  if (!FLAG_IS_DEFAULT(NewSize)) {

    _min_gen0_size = NewSize;

  } else {

    _min_gen0_size = align_size_down(_min_heap_byte_size / (NewRatio+1),

                                     min_alignment());

    // We bound the minimum size by NewSize below (since it historically

    // would have been NewSize and because the NewRatio calculation could

    // yield a size that is too small) and bound it by MaxNewSize above.

    // This is not always best.  The NewSize calculated by CMS (which has

    // a fixed minimum of 16m) can sometimes be "too" large.  Consider

    // the case where -Xmx32m.  The CMS calculated NewSize would be about

    // half the entire heap which seems too large.  But the counter

    // example is seen when the client defaults for NewRatio are used.

    // An initial young generation size of 640k was observed

    // with -Xmx128m -XX:MaxNewSize=32m when NewSize was not used

    // as a lower bound as with

    // _min_gen0_size = MIN2(_min_gen0_size, MaxNewSize);

    // and 640k seemed too small a young generation.

    _min_gen0_size = MIN2(MAX2(_min_gen0_size, NewSize), MaxNewSize);

  }

  // Parameters are valid, compute area sizes.

  size_t max_new_size = align_size_down(_max_heap_byte_size / (NewRatio+1),

                                        min_alignment());

  max_new_size = MIN2(MAX2(max_new_size, _min_gen0_size), MaxNewSize);

  // desired_new_size is used to set the initial size.  The

  // initial size must be greater than the minimum size.

  size_t desired_new_size =

    align_size_down(_initial_heap_byte_size / (NewRatio+1),

                  min_alignment());

  size_t new_size = MIN2(MAX2(desired_new_size, _min_gen0_size), max_new_size);

  _initial_gen0_size = new_size;

  _max_gen0_size = max_new_size;

}

void TwoGenerationCollectorPolicy::initialize_size_info() {

  GenCollectorPolicy::initialize_size_info();

  // Minimum sizes of the generations may be different than

  // the initial sizes.  An inconsistently is permitted here

  // in the total size that can be specified explicitly by

  // command line specification of OldSize and NewSize and

  // also a command line specification of -Xms.  Issue a warning

  // but allow the values to pass.

  if (!FLAG_IS_DEFAULT(OldSize)) {

    _min_gen1_size = OldSize;

    // The generation minimums and the overall heap mimimum should

    // be within one heap alignment.

    if ((_min_gen1_size + _min_gen0_size + max_alignment()) <

         _min_heap_byte_size) {

      warning("Inconsistency between minimum heap size and minimum "

        "generation sizes: using min heap = " SIZE_FORMAT,

        _min_heap_byte_size);

    }

  } else {

    _min_gen1_size = _min_heap_byte_size - _min_gen0_size;

  }

  _initial_gen1_size = _initial_heap_byte_size - _initial_gen0_size;

  _max_gen1_size = _max_heap_byte_size - _max_gen0_size;

}

HeapWord* GenCollectorPolicy::mem_allocate_work(size_t size,

                                        bool is_tlab,

                                        bool* gc_overhead_limit_was_exceeded) {

  GenCollectedHeap *gch = GenCollectedHeap::heap();

  debug_only(gch->check_for_valid_allocation_state());

  assert(gch->no_gc_in_progress(), "Allocation during gc not allowed");

  HeapWord* result = NULL;

  // Loop until the allocation is satisified,

  // or unsatisfied after GC.

  for (int try_count = 1; /* return or throw */; try_count += 1) {

    HandleMark hm; // discard any handles allocated in each iteration

    // First allocation attempt is lock-free.

    Generation *gen0 = gch->get_gen(0);

    assert(gen0->supports_inline_contig_alloc(),

      "Otherwise, must do alloc within heap lock");

    if (gen0->should_allocate(size, is_tlab)) {

      result = gen0->par_allocate(size, is_tlab);

      if (result != NULL) {

        assert(gch->is_in_reserved(result), "result not in heap");

        return result;

      }

    }

    unsigned int gc_count_before;  // read inside the Heap_lock locked region

    {

      MutexLocker ml(Heap_lock);

      if (PrintGC && Verbose) {

        gclog_or_tty->print_cr("TwoGenerationCollectorPolicy::mem_allocate_work:"

                      " attempting locked slow path allocation");

      }

      // Note that only large objects get a shot at being

      // allocated in later generations.

      bool first_only = ! should_try_older_generation_allocation(size);

      result = gch->attempt_allocation(size, is_tlab, first_only);

      if (result != NULL) {

        assert(gch->is_in_reserved(result), "result not in heap");

        return result;

      }

      // There are NULL's returned for different circumstances below.

      // In general gc_overhead_limit_was_exceeded should be false so

      // set it so here and reset it to true only if the gc time

      // limit is being exceeded as checked below.

      *gc_overhead_limit_was_exceeded = false;

      if (GC_locker::is_active_and_needs_gc()) {

        if (is_tlab) {

          return NULL;  // Caller will retry allocating individual object

        }

        if (!gch->is_maximal_no_gc()) {

          // Try and expand heap to satisfy request

          result = expand_heap_and_allocate(size, is_tlab);

          // result could be null if we are out of space

          if (result != NULL) {

            return result;

          }

        }

        // If this thread is not in a jni critical section, we stall

        // the requestor until the critical section has cleared and

        // GC allowed. When the critical section clears, a GC is

        // initiated by the last thread exiting the critical section; so

        // we retry the allocation sequence from the beginning of the loop,

        // rather than causing more, now probably unnecessary, GC attempts.

        JavaThread* jthr = JavaThread::current();

        if (!jthr->in_critical()) {

          MutexUnlocker mul(Heap_lock);

          // Wait for JNI critical section to be exited

          GC_locker::stall_until_clear();

          continue;

        } else {

          if (CheckJNICalls) {

            fatal("Possible deadlock due to allocating while"

                  " in jni critical section");

          }

          return NULL;

        }

      }

      // Read the gc count while the heap lock is held.

      gc_count_before = Universe::heap()->total_collections();

    }

    // Allocation has failed and a collection is about

    // to be done.  If the gc time limit was exceeded the

    // last time a collection was done, return NULL so

    // that an out-of-memory will be thrown.  Clear

    // gc_time_limit_exceeded so that subsequent attempts

    // at a collection will be made.

    if (size_policy()->gc_time_limit_exceeded()) {

      *gc_overhead_limit_was_exceeded = true;

      size_policy()->set_gc_time_limit_exceeded(false);

      return NULL;

    }

    VM_GenCollectForAllocation op(size,

                                  is_tlab,

                                  gc_count_before);

    VMThread::execute(&op);

    if (op.prologue_succeeded()) {

      result = op.result();

      if (op.gc_locked()) {

         assert(result == NULL, "must be NULL if gc_locked() is true");

         continue;  // retry and/or stall as necessary

      }

      assert(result == NULL || gch->is_in_reserved(result),

             "result not in heap");

      return result;

    }

    // Give a warning if we seem to be looping forever.

    if ((QueuedAllocationWarningCount > 0) &&

        (try_count % QueuedAllocationWarningCount == 0)) {

          warning("TwoGenerationCollectorPolicy::mem_allocate_work retries %d times \n\t"

                  " size=%d %s", try_count, size, is_tlab ? "(TLAB)" : "");

    }

  }

}

HeapWord* GenCollectorPolicy::expand_heap_and_allocate(size_t size,

                                                       bool   is_tlab) {

  GenCollectedHeap *gch = GenCollectedHeap::heap();

  HeapWord* result = NULL;

  for (int i = number_of_generations() - 1; i >= 0 && result == NULL; i--) {

    Generation *gen = gch->get_gen(i);

    if (gen->should_allocate(size, is_tlab)) {

      result = gen->expand_and_allocate(size, is_tlab);

    }

  }

  assert(result == NULL || gch->is_in_reserved(result), "result not in heap");

  return result;

}

HeapWord* GenCollectorPolicy::satisfy_failed_allocation(size_t size,

                                                        bool   is_tlab) {

  GenCollectedHeap *gch = GenCollectedHeap::heap();

  GCCauseSetter x(gch, GCCause::_allocation_failure);

  HeapWord* result = NULL;

  assert(size != 0, "Precondition violated");

  if (GC_locker::is_active_and_needs_gc()) {

    // GC locker is active; instead of a collection we will attempt

    // to expand the heap, if there's room for expansion.

    if (!gch->is_maximal_no_gc()) {

      result = expand_heap_and_allocate(size, is_tlab);

    }

    return result;   // could be null if we are out of space

  } else if (!gch->incremental_collection_will_fail()) {

    // The gc_prologues have not executed yet.  The value

    // for incremental_collection_will_fail() is the remanent

    // of the last collection.

    // Do an incremental collection.

    gch->do_collection(false            /* full */,

                       false            /* clear_all_soft_refs */,

                       size             /* size */,

                       is_tlab          /* is_tlab */,

                       number_of_generations() - 1 /* max_level */);

  } else {

    // Try a full collection; see delta for bug id 6266275

    // for the original code and why this has been simplified

    // with from-space allocation criteria modified and

    // such allocation moved out of the safepoint path.

    gch->do_collection(true             /* full */,

                       false            /* clear_all_soft_refs */,

                       size             /* size */,

                       is_tlab          /* is_tlab */,

                       number_of_generations() - 1 /* max_level */);

  }

  result = gch->attempt_allocation(size, is_tlab, false /*first_only*/);

  if (result != NULL) {

    assert(gch->is_in_reserved(result), "result not in heap");

    return result;

  }

  // OK, collection failed, try expansion.

  result = expand_heap_and_allocate(size, is_tlab);

  if (result != NULL) {

    return result;

  }

  // If we reach this point, we're really out of memory. Try every trick

  // we can to reclaim memory. Force collection of soft references. Force

  // a complete compaction of the heap. Any additional methods for finding

  // free memory should be here, especially if they are expensive. If this

  // attempt fails, an OOM exception will be thrown.

  {

    IntFlagSetting flag_change(MarkSweepAlwaysCompactCount, 1); // Make sure the heap is fully compacted

    gch->do_collection(true             /* full */,

                       true             /* clear_all_soft_refs */,

                       size             /* size */,

                       is_tlab          /* is_tlab */,

                       number_of_generations() - 1 /* max_level */);

  }

  result = gch->attempt_allocation(size, is_tlab, false /* first_only */);

  if (result != NULL) {

    assert(gch->is_in_reserved(result), "result not in heap");

    return result;

  }

  // What else?  We might try synchronous finalization later.  If the total

  // space available is large enough for the allocation, then a more

  // complete compaction phase than we've tried so far might be

  // appropriate.

  return NULL;

}

size_t GenCollectorPolicy::large_typearray_limit() {

  return FastAllocateSizeLimit;

}

// Return true if any of the following is true:

// . the allocation won't fit into the current young gen heap

// . gc locker is occupied (jni critical section)

// . heap memory is tight -- the most recent previous collection

//   was a full collection because a partial collection (would

//   have) failed and is likely to fail again

bool GenCollectorPolicy::should_try_older_generation_allocation(

        size_t word_size) const {

  GenCollectedHeap* gch = GenCollectedHeap::heap();

  size_t gen0_capacity = gch->get_gen(0)->capacity_before_gc();

  return    (word_size > heap_word_size(gen0_capacity))

         || (GC_locker::is_active_and_needs_gc())

         || (   gch->last_incremental_collection_failed()

             && gch->incremental_collection_will_fail());

}

//

// MarkSweepPolicy methods

//

MarkSweepPolicy::MarkSweepPolicy() {

  initialize_all();

}

void MarkSweepPolicy::initialize_generations() {

  initialize_perm_generation(PermGen::MarkSweepCompact);

  _generations = new GenerationSpecPtr[number_of_generations()];

  if (_generations == NULL)

    vm_exit_during_initialization("Unable to allocate gen spec");