/*

 * Copyright 2001-2008 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/_collectedHeap.cpp.incl"

#ifdef ASSERT

int CollectedHeap::_fire_out_of_memory_count = 0;

#endif

// Memory state functions.

CollectedHeap::CollectedHeap() :

  _reserved(), _barrier_set(NULL), _is_gc_active(false),

  _total_collections(0), _total_full_collections(0),

  _gc_cause(GCCause::_no_gc), _gc_lastcause(GCCause::_no_gc) {

  NOT_PRODUCT(_promotion_failure_alot_count = 0;)

  NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)

  if (UsePerfData) {

    EXCEPTION_MARK;

    // create the gc cause jvmstat counters

    _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",

                             80, GCCause::to_string(_gc_cause), CHECK);

    _perf_gc_lastcause =

                PerfDataManager::create_string_variable(SUN_GC, "lastCause",

                             80, GCCause::to_string(_gc_lastcause), CHECK);

  }

}

#ifndef PRODUCT

void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {

  if (CheckMemoryInitialization && ZapUnusedHeapArea) {

    for (size_t slot = 0; slot < size; slot += 1) {

      assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),

             "Found badHeapWordValue in post-allocation check");

    }

  }

}

void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size)

 {

  if (CheckMemoryInitialization && ZapUnusedHeapArea) {

    for (size_t slot = 0; slot < size; slot += 1) {

      assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),

             "Found non badHeapWordValue in pre-allocation check");

    }

  }

}

#endif // PRODUCT

#ifdef ASSERT

void CollectedHeap::check_for_valid_allocation_state() {

  Thread *thread = Thread::current();

  // How to choose between a pending exception and a potential

  // OutOfMemoryError?  Don't allow pending exceptions.

  // This is a VM policy failure, so how do we exhaustively test it?

  assert(!thread->has_pending_exception(),

         "shouldn't be allocating with pending exception");

  if (StrictSafepointChecks) {

    assert(thread->allow_allocation(),

           "Allocation done by thread for which allocation is blocked "

           "by No_Allocation_Verifier!");

    // Allocation of an oop can always invoke a safepoint,

    // hence, the true argument

    thread->check_for_valid_safepoint_state(true);

  }

}

#endif

HeapWord* CollectedHeap::allocate_from_tlab_slow(Thread* thread, size_t size) {

  // Retain tlab and allocate object in shared space if

  // the amount free in the tlab is too large to discard.

  if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {

    thread->tlab().record_slow_allocation(size);

    return NULL;

  }

  // Discard tlab and allocate a new one.

  // To minimize fragmentation, the last TLAB may be smaller than the rest.

  size_t new_tlab_size = thread->tlab().compute_size(size);

  thread->tlab().clear_before_allocation();

  if (new_tlab_size == 0) {

    return NULL;

  }

  // Allocate a new TLAB...

  HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);

  if (obj == NULL) {

    return NULL;

  }

  if (ZeroTLAB) {

    // ..and clear it.

    Copy::zero_to_words(obj, new_tlab_size);

  } else {

    // ...and clear just the allocated object.

    Copy::zero_to_words(obj, size);

  }

  thread->tlab().fill(obj, obj + size, new_tlab_size);

  return obj;

}

oop CollectedHeap::new_store_barrier(oop new_obj) {

  // %%% This needs refactoring.  (It was imported from the server compiler.)

  guarantee(can_elide_tlab_store_barriers(), "store barrier elision not supported");

  BarrierSet* bs = this->barrier_set();

  assert(bs->has_write_region_opt(), "Barrier set does not have write_region");

  int new_size = new_obj->size();

  bs->write_region(MemRegion((HeapWord*)new_obj, new_size));

  return new_obj;

}

HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {

  guarantee(false, "thread-local allocation buffers not supported");

  return NULL;

}

void CollectedHeap::fill_all_tlabs(bool retire) {

  assert(UseTLAB, "should not reach here");

  // See note in ensure_parsability() below.

  assert(SafepointSynchronize::is_at_safepoint() ||

         !is_init_completed(),

         "should only fill tlabs at safepoint");

  // The main thread starts allocating via a TLAB even before it

  // has added itself to the threads list at vm boot-up.

  assert(Threads::first() != NULL,

         "Attempt to fill tlabs before main thread has been added"

         " to threads list is doomed to failure!");

  for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {

     thread->tlab().make_parsable(retire);

  }

}

void CollectedHeap::ensure_parsability(bool retire_tlabs) {

  // The second disjunct in the assertion below makes a concession

  // for the start-up verification done while the VM is being

  // created. Callers be careful that you know that mutators

  // aren't going to interfere -- for instance, this is permissible

  // if we are still single-threaded and have either not yet

  // started allocating (nothing much to verify) or we have

  // started allocating but are now a full-fledged JavaThread

  // (and have thus made our TLAB's) available for filling.

  assert(SafepointSynchronize::is_at_safepoint() ||

         !is_init_completed(),

         "Should only be called at a safepoint or at start-up"

         " otherwise concurrent mutator activity may make heap "

         " unparsable again");

  if (UseTLAB) {

    fill_all_tlabs(retire_tlabs);

  }

}

void CollectedHeap::accumulate_statistics_all_tlabs() {

  if (UseTLAB) {

    assert(SafepointSynchronize::is_at_safepoint() ||

         !is_init_completed(),

         "should only accumulate statistics on tlabs at safepoint");

    ThreadLocalAllocBuffer::accumulate_statistics_before_gc();

  }

}

void CollectedHeap::resize_all_tlabs() {

  if (UseTLAB) {

    assert(SafepointSynchronize::is_at_safepoint() ||

         !is_init_completed(),

         "should only resize tlabs at safepoint");

    ThreadLocalAllocBuffer::resize_all_tlabs();

  }

}