/*

 * 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/_psYoungGen.cpp.incl"

PSYoungGen::PSYoungGen(size_t        initial_size,

                       size_t        min_size,

                       size_t        max_size) :

  _init_gen_size(initial_size),

  _min_gen_size(min_size),

  _max_gen_size(max_size)

{}

void PSYoungGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {

  assert(_init_gen_size != 0, "Should have a finite size");

  _virtual_space = new PSVirtualSpace(rs, alignment);

  if (!_virtual_space->expand_by(_init_gen_size)) {

    vm_exit_during_initialization("Could not reserve enough space for "

                                  "object heap");

  }

}

void PSYoungGen::initialize(ReservedSpace rs, size_t alignment) {

  initialize_virtual_space(rs, alignment);

  initialize_work();

}

void PSYoungGen::initialize_work() {

  _reserved = MemRegion((HeapWord*)_virtual_space->low_boundary(),

                        (HeapWord*)_virtual_space->high_boundary());

  MemRegion cmr((HeapWord*)_virtual_space->low(),

                (HeapWord*)_virtual_space->high());

  Universe::heap()->barrier_set()->resize_covered_region(cmr);

  if (UseNUMA) {

    _eden_space = new MutableNUMASpace();

  } else {

    _eden_space = new MutableSpace();

  }

  _from_space = new MutableSpace();

  _to_space   = new MutableSpace();

  if (_eden_space == NULL || _from_space == NULL || _to_space == NULL) {

    vm_exit_during_initialization("Could not allocate a young gen space");

  }

  // Allocate the mark sweep views of spaces

  _eden_mark_sweep =

      new PSMarkSweepDecorator(_eden_space, NULL, MarkSweepDeadRatio);

  _from_mark_sweep =

      new PSMarkSweepDecorator(_from_space, NULL, MarkSweepDeadRatio);

  _to_mark_sweep =

      new PSMarkSweepDecorator(_to_space, NULL, MarkSweepDeadRatio);

  if (_eden_mark_sweep == NULL ||

      _from_mark_sweep == NULL ||

      _to_mark_sweep == NULL) {

    vm_exit_during_initialization("Could not complete allocation"

                                  " of the young generation");

  }

  // Generation Counters - generation 0, 3 subspaces

  _gen_counters = new PSGenerationCounters("new", 0, 3, _virtual_space);

  // Compute maximum space sizes for performance counters

  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();

  size_t alignment = heap->intra_generation_alignment();

  size_t size = _virtual_space->reserved_size();

  size_t max_survivor_size;

  size_t max_eden_size;

  if (UseAdaptiveSizePolicy) {

    max_survivor_size = size / MinSurvivorRatio;

    // round the survivor space size down to the nearest alignment

    // and make sure its size is greater than 0.

    max_survivor_size = align_size_down(max_survivor_size, alignment);

    max_survivor_size = MAX2(max_survivor_size, alignment);

    // set the maximum size of eden to be the size of the young gen

    // less two times the minimum survivor size. The minimum survivor

    // size for UseAdaptiveSizePolicy is one alignment.

    max_eden_size = size - 2 * alignment;

  } else {

    max_survivor_size = size / InitialSurvivorRatio;

    // round the survivor space size down to the nearest alignment

    // and make sure its size is greater than 0.

    max_survivor_size = align_size_down(max_survivor_size, alignment);

    max_survivor_size = MAX2(max_survivor_size, alignment);

    // set the maximum size of eden to be the size of the young gen

    // less two times the survivor size when the generation is 100%

    // committed. The minimum survivor size for -UseAdaptiveSizePolicy

    // is dependent on the committed portion (current capacity) of the

    // generation - the less space committed, the smaller the survivor

    // space, possibly as small as an alignment. However, we are interested

    // in the case where the young generation is 100% committed, as this

    // is the point where eden reachs its maximum size. At this point,

    // the size of a survivor space is max_survivor_size.

    max_eden_size = size - 2 * max_survivor_size;

  }

  _eden_counters = new SpaceCounters("eden", 0, max_eden_size, _eden_space,

                                     _gen_counters);

  _from_counters = new SpaceCounters("s0", 1, max_survivor_size, _from_space,

                                     _gen_counters);

  _to_counters = new SpaceCounters("s1", 2, max_survivor_size, _to_space,

                                   _gen_counters);

  compute_initial_space_boundaries();

}

void PSYoungGen::compute_initial_space_boundaries() {

  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();

  assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

  // Compute sizes

  size_t alignment = heap->intra_generation_alignment();

  size_t size = _virtual_space->committed_size();

  size_t survivor_size = size / InitialSurvivorRatio;

  survivor_size = align_size_down(survivor_size, alignment);

  // ... but never less than an alignment

  survivor_size = MAX2(survivor_size, alignment);

  // Young generation is eden + 2 survivor spaces

  size_t eden_size = size - (2 * survivor_size);

  // Now go ahead and set 'em.

  set_space_boundaries(eden_size, survivor_size);

  space_invariants();

  if (UsePerfData) {

    _eden_counters->update_capacity();

    _from_counters->update_capacity();

    _to_counters->update_capacity();

  }

}

void PSYoungGen::set_space_boundaries(size_t eden_size, size_t survivor_size) {

  assert(eden_size < _virtual_space->committed_size(), "just checking");

  assert(eden_size > 0  && survivor_size > 0, "just checking");

  // Initial layout is Eden, to, from. After swapping survivor spaces,

  // that leaves us with Eden, from, to, which is step one in our two

  // step resize-with-live-data procedure.

  char *eden_start = _virtual_space->low();

  char *to_start   = eden_start + eden_size;

  char *from_start = to_start   + survivor_size;

  char *from_end   = from_start + survivor_size;

  assert(from_end == _virtual_space->high(), "just checking");

  assert(is_object_aligned((intptr_t)eden_start), "checking alignment");

  assert(is_object_aligned((intptr_t)to_start),   "checking alignment");

  assert(is_object_aligned((intptr_t)from_start), "checking alignment");

  MemRegion eden_mr((HeapWord*)eden_start, (HeapWord*)to_start);

  MemRegion to_mr  ((HeapWord*)to_start, (HeapWord*)from_start);

  MemRegion from_mr((HeapWord*)from_start, (HeapWord*)from_end);

  eden_space()->initialize(eden_mr, true);

    to_space()->initialize(to_mr  , true);

  from_space()->initialize(from_mr, true);

}

#ifndef PRODUCT

void PSYoungGen::space_invariants() {

  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();

  const size_t alignment = heap->intra_generation_alignment();

  // Currently, our eden size cannot shrink to zero

  guarantee(eden_space()->capacity_in_bytes() >= alignment, "eden too small");

  guarantee(from_space()->capacity_in_bytes() >= alignment, "from too small");

  guarantee(to_space()->capacity_in_bytes() >= alignment, "to too small");

  // Relationship of spaces to each other

  char* eden_start = (char*)eden_space()->bottom();

  char* eden_end   = (char*)eden_space()->end();

  char* from_start = (char*)from_space()->bottom();

  char* from_end   = (char*)from_space()->end();

  char* to_start   = (char*)to_space()->bottom();

  char* to_end     = (char*)to_space()->end();

  guarantee(eden_start >= _virtual_space->low(), "eden bottom");

  guarantee(eden_start < eden_end, "eden space consistency");

  guarantee(from_start < from_end, "from space consistency");

  guarantee(to_start < to_end, "to space consistency");

  // Check whether from space is below to space

  if (from_start < to_start) {

    // Eden, from, to

    guarantee(eden_end <= from_start, "eden/from boundary");

    guarantee(from_end <= to_start,   "from/to boundary");

    guarantee(to_end <= _virtual_space->high(), "to end");

  } else {

    // Eden, to, from

    guarantee(eden_end <= to_start, "eden/to boundary");

    guarantee(to_end <= from_start, "to/from boundary");

    guarantee(from_end <= _virtual_space->high(), "from end");

  }

  // More checks that the virtual space is consistent with the spaces

  assert(_virtual_space->committed_size() >=

    (eden_space()->capacity_in_bytes() +

     to_space()->capacity_in_bytes() +

     from_space()->capacity_in_bytes()), "Committed size is inconsistent");

  assert(_virtual_space->committed_size() <= _virtual_space->reserved_size(),

    "Space invariant");

  char* eden_top = (char*)eden_space()->top();

  char* from_top = (char*)from_space()->top();

  char* to_top = (char*)to_space()->top();

  assert(eden_top <= _virtual_space->high(), "eden top");

  assert(from_top <= _virtual_space->high(), "from top");

  assert(to_top <= _virtual_space->high(), "to top");

  _virtual_space->verify();

}

#endif

void PSYoungGen::resize(size_t eden_size, size_t survivor_size) {

  // Resize the generation if needed. If the generation resize

  // reports false, do not attempt to resize the spaces.

  if (resize_generation(eden_size, survivor_size)) {

    // Then we lay out the spaces inside the generation

    resize_spaces(eden_size, survivor_size);

    space_invariants();

    if (PrintAdaptiveSizePolicy && Verbose) {

      gclog_or_tty->print_cr("Young generation size: "

        "desired eden: " SIZE_FORMAT " survivor: " SIZE_FORMAT

        " used: " SIZE_FORMAT " capacity: " SIZE_FORMAT

        " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,

        eden_size, survivor_size, used_in_bytes(), capacity_in_bytes(),

        _max_gen_size, min_gen_size());

    }

  }

}

bool PSYoungGen::resize_generation(size_t eden_size, size_t survivor_size) {

  const size_t alignment = _virtual_space->alignment();

  size_t orig_size = _virtual_space->committed_size();

  bool size_changed = false;

  // There used to be this guarantee there.

  // guarantee ((eden_size + 2*survivor_size)  <= _max_gen_size, "incorrect input arguments");

  // Code below forces this requirement.  In addition the desired eden

  // size and disired survivor sizes are desired goals and may

  // exceed the total generation size.

  assert(min_gen_size() <= orig_size && orig_size <= max_size(), "just checking");

  // Adjust new generation size

  const size_t eden_plus_survivors =

          align_size_up(eden_size + 2 * survivor_size, alignment);

  size_t desired_size = MAX2(MIN2(eden_plus_survivors, max_size()),

                             min_gen_size());

  assert(desired_size <= max_size(), "just checking");

  if (desired_size > orig_size) {

    // Grow the generation

    size_t change = desired_size - orig_size;

    assert(change % alignment == 0, "just checking");

    if (!_virtual_space->expand_by(change)) {

      return false; // Error if we fail to resize!

    }

    size_changed = true;

  } else if (desired_size < orig_size) {

    size_t desired_change = orig_size - desired_size;

    assert(desired_change % alignment == 0, "just checking");

    desired_change = limit_gen_shrink(desired_change);

    if (desired_change > 0) {

      virtual_space()->shrink_by(desired_change);

      reset_survivors_after_shrink();

      size_changed = true;

    }

  } else {

    if (Verbose && PrintGC) {

      if (orig_size == gen_size_limit()) {

        gclog_or_tty->print_cr("PSYoung generation size at maximum: "

          SIZE_FORMAT "K", orig_size/K);

      } else if (orig_size == min_gen_size()) {

        gclog_or_tty->print_cr("PSYoung generation size at minium: "

          SIZE_FORMAT "K", orig_size/K);

      }

    }

  }

  if (size_changed) {

    post_resize();

    if (Verbose && PrintGC) {

      size_t current_size  = _virtual_space->committed_size();

      gclog_or_tty->print_cr("PSYoung generation size changed: "

                             SIZE_FORMAT "K->" SIZE_FORMAT "K",

                             orig_size/K, current_size/K);

    }

  }

  guarantee(eden_plus_survivors <= _virtual_space->committed_size() ||

            _virtual_space->committed_size() == max_size(), "Sanity");

  return true;

}

void PSYoungGen::resize_spaces(size_t requested_eden_size,

                               size_t requested_survivor_size) {

  assert(UseAdaptiveSizePolicy, "sanity check");

  assert(requested_eden_size > 0  && requested_survivor_size > 0,

         "just checking");

  // We require eden and to space to be empty

  if ((!eden_space()->is_empty()) || (!to_space()->is_empty())) {

    return;

  }

  if (PrintAdaptiveSizePolicy && Verbose) {

    gclog_or_tty->print_cr("PSYoungGen::resize_spaces(requested_eden_size: "

                  SIZE_FORMAT

                  ", requested_survivor_size: " SIZE_FORMAT ")",

                  requested_eden_size, requested_survivor_size);

    gclog_or_tty->print_cr("    eden: [" PTR_FORMAT ".." PTR_FORMAT ") "

                  SIZE_FORMAT,

                  eden_space()->bottom(),

                  eden_space()->end(),

                  pointer_delta(eden_space()->end(),

                                eden_space()->bottom(),

                                sizeof(char)));

    gclog_or_tty->print_cr("    from: [" PTR_FORMAT ".." PTR_FORMAT ") "

                  SIZE_FORMAT,

                  from_space()->bottom(),

                  from_space()->end(),

                  pointer_delta(from_space()->end(),

                                from_space()->bottom(),

                                sizeof(char)));

    gclog_or_tty->print_cr("      to: [" PTR_FORMAT ".." PTR_FORMAT ") "

                  SIZE_FORMAT,

                  to_space()->bottom(),

                  to_space()->end(),

                  pointer_delta(  to_space()->end(),

                                  to_space()->bottom(),

                                  sizeof(char)));

  }

  // There's nothing to do if the new sizes are the same as the current

  if (requested_survivor_size == to_space()->capacity_in_bytes() &&

      requested_survivor_size == from_space()->capacity_in_bytes() &&

      requested_eden_size == eden_space()->capacity_in_bytes()) {

    if (PrintAdaptiveSizePolicy && Verbose) {

      gclog_or_tty->print_cr("    capacities are the right sizes, returning");

    }

    return;

  }

  char* eden_start = (char*)eden_space()->bottom();

  char* eden_end   = (char*)eden_space()->end();

  char* from_start = (char*)from_space()->bottom();

  char* from_end   = (char*)from_space()->end();

  char* to_start   = (char*)to_space()->bottom();

  char* to_end     = (char*)to_space()->end();

  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();

  const size_t alignment = heap->intra_generation_alignment();

  const bool maintain_minimum =

    (requested_eden_size + 2 * requested_survivor_size) <= min_gen_size();

  // Check whether from space is below to space

  if (from_start < to_start) {

    // Eden, from, to

    if (PrintAdaptiveSizePolicy && Verbose) {

      gclog_or_tty->print_cr("  Eden, from, to:");

    }

    // Set eden

    // "requested_eden_size" is a goal for the size of eden

    // and may not be attainable.  "eden_size" below is

    // calculated based on the location of from-space and

    // the goal for the size of eden.  from-space is

    // fixed in place because it contains live data.

    // The calculation is done this way to avoid 32bit

    // overflow (i.e., eden_start + requested_eden_size

    // may too large for representation in 32bits).

    size_t eden_size;

    if (maintain_minimum) {

      // Only make eden larger than the requested size if

      // the minimum size of the generation has to be maintained.

      // This could be done in general but policy at a higher

      // level is determining a requested size for eden and that

      // should be honored unless there is a fundamental reason.

      eden_size = pointer_delta(from_start,

                                eden_start,

                                sizeof(char));

    } else {

      eden_size = MIN2(requested_eden_size,

                       pointer_delta(from_start, eden_start, sizeof(char)));

    }

    eden_end = eden_start + eden_size;

    assert(eden_end >= eden_start, "addition overflowed")

    // To may resize into from space as long as it is clear of live data.

    // From space must remain page aligned, though, so we need to do some

    // extra calculations.

    // First calculate an optimal to-space

    to_end   = (char*)_virtual_space->high();

    to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size,

                                    sizeof(char));

    // Does the optimal to-space overlap from-space?

    if (to_start < (char*)from_space()->end()) {

      assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

      // Calculate the minimum offset possible for from_end

      size_t from_size = pointer_delta(from_space()->top(), from_start, sizeof(char));

      // Should we be in this method if from_space is empty? Why not the set_space method? FIX ME!

      if (from_size == 0) {

        from_size = alignment;

      } else {

        from_size = align_size_up(from_size, alignment);

      }

      from_end = from_start + from_size;

      assert(from_end > from_start, "addition overflow or from_size problem");

      guarantee(from_end <= (char*)from_space()->end(), "from_end moved to the right");

      // Now update to_start with the new from_end

      to_start = MAX2(from_end, to_start);

    }

    guarantee(to_start != to_end, "to space is zero sized");

    if (PrintAdaptiveSizePolicy && Verbose) {

      gclog_or_tty->print_cr("    [eden_start .. eden_end): "

                    "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,

                    eden_start,

                    eden_end,

                    pointer_delta(eden_end, eden_start, sizeof(char)));

      gclog_or_tty->print_cr("    [from_start .. from_end): "

                    "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,

                    from_start,

                    from_end,

                    pointer_delta(from_end, from_start, sizeof(char)));

      gclog_or_tty->print_cr("    [  to_start ..   to_end): "

                    "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,

                    to_start,

                    to_end,

                    pointer_delta(  to_end,   to_start, sizeof(char)));

    }

  } else {

    // Eden, to, from

    if (PrintAdaptiveSizePolicy && Verbose) {

      gclog_or_tty->print_cr("  Eden, to, from:");

    }

    // To space gets priority over eden resizing. Note that we position

    // to space as if we were able to resize from space, even though from

    // space is not modified.

    // Giving eden priority was tried and gave poorer performance.

    to_end   = (char*)pointer_delta(_virtual_space->high(),

                                    (char*)requested_survivor_size,

                                    sizeof(char));

    to_end   = MIN2(to_end, from_start);

    to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size,

                                    sizeof(char));

    // if the space sizes are to be increased by several times then

    // 'to_start' will point beyond the young generation. In this case

    // 'to_start' should be adjusted.

    to_start = MAX2(to_start, eden_start + alignment);

    // Compute how big eden can be, then adjust end.

    // See  comments above on calculating eden_end.

    size_t eden_size;

    if (maintain_minimum) {

      eden_size = pointer_delta(to_start, eden_start, sizeof(char));

    } else {

      eden_size = MIN2(requested_eden_size,

                       pointer_delta(to_start, eden_start, sizeof(char)));

    }

    eden_end = eden_start + eden_size;

    assert(eden_end >= eden_start, "addition overflowed")

    // Could choose to not let eden shrink

    // to_start = MAX2(to_start, eden_end);

    // Don't let eden shrink down to 0 or less.

    eden_end = MAX2(eden_end, eden_start + alignment);

    to_start = MAX2(to_start, eden_end);

    if (PrintAdaptiveSizePolicy && Verbose) {

      gclog_or_tty->print_cr("    [eden_start .. eden_end): "

                    "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,

                    eden_start,

                    eden_end,

                    pointer_delta(eden_end, eden_start, sizeof(char)));