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

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 *

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 * 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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#ifndef SHARE_VM_GC_G1_HEAPREGION_INLINE_HPP

#define SHARE_VM_GC_G1_HEAPREGION_INLINE_HPP

#include "gc/g1/g1BlockOffsetTable.inline.hpp"

#include "gc/g1/g1CollectedHeap.inline.hpp"

#include "gc/g1/g1ConcurrentMarkBitMap.inline.hpp"

#include "gc/g1/heapRegion.hpp"

#include "gc/shared/space.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/atomic.hpp"

#include "runtime/prefetch.inline.hpp"

#include "utilities/align.hpp"

inline HeapWord* G1ContiguousSpace::allocate_impl(size_t min_word_size,

                                                  size_t desired_word_size,

                                                  size_t* actual_size) {

  HeapWord* obj = top();

  size_t available = pointer_delta(end(), obj);

  size_t want_to_allocate = MIN2(available, desired_word_size);

  if (want_to_allocate >= min_word_size) {

    HeapWord* new_top = obj + want_to_allocate;

    set_top(new_top);

    assert(is_aligned(obj) && is_aligned(new_top), "checking alignment");

    *actual_size = want_to_allocate;

    return obj;

  } else {

    return NULL;

  }

}

inline HeapWord* G1ContiguousSpace::par_allocate_impl(size_t min_word_size,

                                                      size_t desired_word_size,

                                                      size_t* actual_size) {

  do {

    HeapWord* obj = top();

    size_t available = pointer_delta(end(), obj);

    size_t want_to_allocate = MIN2(available, desired_word_size);

    if (want_to_allocate >= min_word_size) {

      HeapWord* new_top = obj + want_to_allocate;

      HeapWord* result = Atomic::cmpxchg(new_top, top_addr(), obj);

      // result can be one of two:

      //  the old top value: the exchange succeeded

      //  otherwise: the new value of the top is returned.

      if (result == obj) {

        assert(is_aligned(obj) && is_aligned(new_top), "checking alignment");

        *actual_size = want_to_allocate;

        return obj;

      }

    } else {

      return NULL;

    }

  } while (true);

}

inline HeapWord* G1ContiguousSpace::allocate(size_t min_word_size,

                                             size_t desired_word_size,

                                             size_t* actual_size) {

  HeapWord* res = allocate_impl(min_word_size, desired_word_size, actual_size);

  if (res != NULL) {

    _bot_part.alloc_block(res, *actual_size);

  }

  return res;

}

inline HeapWord* G1ContiguousSpace::allocate(size_t word_size) {

  size_t temp;

  return allocate(word_size, word_size, &temp);

}

inline HeapWord* G1ContiguousSpace::par_allocate(size_t word_size) {

  size_t temp;

  return par_allocate(word_size, word_size, &temp);

}

// Because of the requirement of keeping "_offsets" up to date with the

// allocations, we sequentialize these with a lock.  Therefore, best if

// this is used for larger LAB allocations only.

inline HeapWord* G1ContiguousSpace::par_allocate(size_t min_word_size,

                                                 size_t desired_word_size,

                                                 size_t* actual_size) {

  MutexLocker x(&_par_alloc_lock);

  return allocate(min_word_size, desired_word_size, actual_size);

}

inline HeapWord* G1ContiguousSpace::block_start(const void* p) {

  return _bot_part.block_start(p);

}

inline HeapWord*

G1ContiguousSpace::block_start_const(const void* p) const {

  return _bot_part.block_start_const(p);

}

inline bool HeapRegion::is_obj_dead_with_size(const oop obj, const G1CMBitMap* const prev_bitmap, size_t* size) const {

  HeapWord* addr = (HeapWord*) obj;

  assert(addr < top(), "must be");

  assert(!is_closed_archive(),

         "Closed archive regions should not have references into other regions");

  assert(!is_humongous(), "Humongous objects not handled here");

  bool obj_is_dead = is_obj_dead(obj, prev_bitmap);

  if (ClassUnloadingWithConcurrentMark && obj_is_dead) {

    assert(!block_is_obj(addr), "must be");

    *size = block_size_using_bitmap(addr, prev_bitmap);

  } else {

    assert(block_is_obj(addr), "must be");

    *size = obj->size();

  }

  return obj_is_dead;

}

inline bool

HeapRegion::block_is_obj(const HeapWord* p) const {

  G1CollectedHeap* g1h = G1CollectedHeap::heap();

  if (!this->is_in(p)) {

    assert(is_continues_humongous(), "This case can only happen for humongous regions");

    return (p == humongous_start_region()->bottom());

  }

  if (ClassUnloadingWithConcurrentMark) {

    return !g1h->is_obj_dead(oop(p), this);

  }

  return p < top();

}

inline size_t HeapRegion::block_size_using_bitmap(const HeapWord* addr, const G1CMBitMap* const prev_bitmap) const {

  assert(ClassUnloadingWithConcurrentMark,

         "All blocks should be objects if class unloading isn't used, so this method should not be called. "

         "HR: [" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT ") "

         "addr: " PTR_FORMAT,

         p2i(bottom()), p2i(top()), p2i(end()), p2i(addr));

  // Old regions' dead objects may have dead classes

  // We need to find the next live object using the bitmap

  HeapWord* next = prev_bitmap->get_next_marked_addr(addr, prev_top_at_mark_start());

  assert(next > addr, "must get the next live object");

  return pointer_delta(next, addr);

}

inline bool HeapRegion::is_obj_dead(const oop obj, const G1CMBitMap* const prev_bitmap) const {

  assert(is_in_reserved(obj), "Object " PTR_FORMAT " must be in region", p2i(obj));

  return !obj_allocated_since_prev_marking(obj) &&

         !prev_bitmap->is_marked((HeapWord*)obj) &&

         !is_open_archive();

}

inline size_t HeapRegion::block_size(const HeapWord *addr) const {

  if (addr == top()) {

    return pointer_delta(end(), addr);

  }

  if (block_is_obj(addr)) {

    return oop(addr)->size();

  }

  return block_size_using_bitmap(addr, G1CollectedHeap::heap()->concurrent_mark()->prev_mark_bitmap());

}

inline void HeapRegion::complete_compaction() {

  // Reset space and bot after compaction is complete if needed.

  reset_after_compaction();

  if (used_region().is_empty()) {

    reset_bot();

  }

  // After a compaction the mark bitmap is invalid, so we must

  // treat all objects as being inside the unmarked area.

  zero_marked_bytes();

  init_top_at_mark_start();

  // Clear unused heap memory in debug builds.

  if (ZapUnusedHeapArea) {

    mangle_unused_area();

  }

}

template<typename ApplyToMarkedClosure>

inline void HeapRegion::apply_to_marked_objects(G1CMBitMap* bitmap, ApplyToMarkedClosure* closure) {

  HeapWord* limit = scan_limit();

  HeapWord* next_addr = bottom();

  while (next_addr < limit) {

    Prefetch::write(next_addr, PrefetchScanIntervalInBytes);

    // This explicit is_marked check is a way to avoid

    // some extra work done by get_next_marked_addr for

    // the case where next_addr is marked.

    if (bitmap->is_marked(next_addr)) {

      oop current = oop(next_addr);

      next_addr += closure->apply(current);

    } else {

      next_addr = bitmap->get_next_marked_addr(next_addr, limit);

    }

  }

  assert(next_addr == limit, "Should stop the scan at the limit.");

}

inline HeapWord* HeapRegion::par_allocate_no_bot_updates(size_t min_word_size,

                                                         size_t desired_word_size,

                                                         size_t* actual_word_size) {

  assert(is_young(), "we can only skip BOT updates on young regions");

  return par_allocate_impl(min_word_size, desired_word_size, actual_word_size);

}

inline HeapWord* HeapRegion::allocate_no_bot_updates(size_t word_size) {

  size_t temp;

  return allocate_no_bot_updates(word_size, word_size, &temp);

}

inline HeapWord* HeapRegion::allocate_no_bot_updates(size_t min_word_size,

                                                     size_t desired_word_size,

                                                     size_t* actual_word_size) {

  assert(is_young(), "we can only skip BOT updates on young regions");

  return allocate_impl(min_word_size, desired_word_size, actual_word_size);

}

inline void HeapRegion::note_start_of_marking() {

  _next_marked_bytes = 0;

  _next_top_at_mark_start = top();

}

inline void HeapRegion::note_end_of_marking() {

  _prev_top_at_mark_start = _next_top_at_mark_start;

  _next_top_at_mark_start = bottom();

  _prev_marked_bytes = _next_marked_bytes;

  _next_marked_bytes = 0;

}

inline void HeapRegion::note_start_of_copying(bool during_initial_mark) {

  if (is_survivor()) {

    // This is how we always allocate survivors.

    assert(_next_top_at_mark_start == bottom(), "invariant");

  } else {

    if (during_initial_mark) {

      // During initial-mark we'll explicitly mark any objects on old

      // regions that are pointed to by roots. Given that explicit

      // marks only make sense under NTAMS it'd be nice if we could

      // check that condition if we wanted to. Given that we don't

      // know where the top of this region will end up, we simply set

      // NTAMS to the end of the region so all marks will be below

      // NTAMS. We'll set it to the actual top when we retire this region.

      _next_top_at_mark_start = end();

    } else {

      // We could have re-used this old region as to-space over a

      // couple of GCs since the start of the concurrent marking

      // cycle. This means that [bottom,NTAMS) will contain objects

      // copied up to and including initial-mark and [NTAMS, top)

      // will contain objects copied during the concurrent marking cycle.

      assert(top() >= _next_top_at_mark_start, "invariant");

    }

  }

}

inline void HeapRegion::note_end_of_copying(bool during_initial_mark) {

  if (is_survivor()) {

    // This is how we always allocate survivors.

    assert(_next_top_at_mark_start == bottom(), "invariant");

  } else {

    if (during_initial_mark) {

      // See the comment for note_start_of_copying() for the details

      // on this.

      assert(_next_top_at_mark_start == end(), "pre-condition");

      _next_top_at_mark_start = top();

    } else {

      // See the comment for note_start_of_copying() for the details

      // on this.

      assert(top() >= _next_top_at_mark_start, "invariant");

    }

  }

}

inline bool HeapRegion::in_collection_set() const {

  return G1CollectedHeap::heap()->is_in_cset(this);

}

template <class Closure, bool is_gc_active>

bool HeapRegion::do_oops_on_card_in_humongous(MemRegion mr,

                                              Closure* cl,

                                              G1CollectedHeap* g1h) {

  assert(is_humongous(), "precondition");

  HeapRegion* sr = humongous_start_region();

  oop obj = oop(sr->bottom());

  // If concurrent and klass_or_null is NULL, then space has been

  // allocated but the object has not yet been published by setting

  // the klass.  That can only happen if the card is stale.  However,

  // we've already set the card clean, so we must return failure,

  // since the allocating thread could have performed a write to the

  // card that might be missed otherwise.

  if (!is_gc_active && (obj->klass_or_null_acquire() == NULL)) {

    return false;

  }

  // We have a well-formed humongous object at the start of sr.

  // Only filler objects follow a humongous object in the containing

  // regions, and we can ignore those.  So only process the one

  // humongous object.

  if (!g1h->is_obj_dead(obj, sr)) {

    if (obj->is_objArray() || (sr->bottom() < mr.start())) {

      // objArrays are always marked precisely, so limit processing

      // with mr.  Non-objArrays might be precisely marked, and since

      // it's humongous it's worthwhile avoiding full processing.

      // However, the card could be stale and only cover filler

      // objects.  That should be rare, so not worth checking for;

      // instead let it fall out from the bounded iteration.

      obj->oop_iterate(cl, mr);

    } else {

      // If obj is not an objArray and mr contains the start of the

      // obj, then this could be an imprecise mark, and we need to

      // process the entire object.

      obj->oop_iterate(cl);

    }

  }

  return true;

}

template <bool is_gc_active, class Closure>

bool HeapRegion::oops_on_card_seq_iterate_careful(MemRegion mr,

                                                  Closure* cl) {

  assert(MemRegion(bottom(), end()).contains(mr), "Card region not in heap region");

  G1CollectedHeap* g1h = G1CollectedHeap::heap();

  // Special handling for humongous regions.

  if (is_humongous()) {

    return do_oops_on_card_in_humongous<Closure, is_gc_active>(mr, cl, g1h);

  }

  assert(is_old(), "precondition");

  // Because mr has been trimmed to what's been allocated in this

  // region, the parts of the heap that are examined here are always

  // parsable; there's no need to use klass_or_null to detect

  // in-progress allocation.

  // Cache the boundaries of the memory region in some const locals

  HeapWord* const start = mr.start();

  HeapWord* const end = mr.end();

  // Find the obj that extends onto mr.start().

  // Update BOT as needed while finding start of (possibly dead)

  // object containing the start of the region.

  HeapWord* cur = block_start(start);

#ifdef ASSERT

  {

    assert(cur <= start,

           "cur: " PTR_FORMAT ", start: " PTR_FORMAT, p2i(cur), p2i(start));

    HeapWord* next = cur + block_size(cur);

    assert(start < next,

           "start: " PTR_FORMAT ", next: " PTR_FORMAT, p2i(start), p2i(next));

  }

#endif

  const G1CMBitMap* const bitmap = g1h->concurrent_mark()->prev_mark_bitmap();

  do {

    oop obj = oop(cur);

    assert(oopDesc::is_oop(obj, true), "Not an oop at " PTR_FORMAT, p2i(cur));

    assert(obj->klass_or_null() != NULL,

           "Unparsable heap at " PTR_FORMAT, p2i(cur));

    size_t size;

    bool is_dead = is_obj_dead_with_size(obj, bitmap, &size);

    cur += size;

    if (!is_dead) {

      // Process live object's references.

      // Non-objArrays are usually marked imprecise at the object

      // start, in which case we need to iterate over them in full.

      // objArrays are precisely marked, but can still be iterated

      // over in full if completely covered.

      if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) {

        obj->oop_iterate(cl);

      } else {

        obj->oop_iterate(cl, mr);

      }

    }

  } while (cur < end);

  return true;

}

#endif // SHARE_VM_GC_G1_HEAPREGION_INLINE_HPP