/*

 * Copyright (c) 2001, 2019, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

#include "precompiled.hpp"

#include "gc/parallel/mutableNUMASpace.hpp"

#include "gc/parallel/parallelScavengeHeap.hpp"

#include "gc/parallel/psMarkSweepDecorator.hpp"

#include "gc/parallel/psScavenge.hpp"

#include "gc/parallel/psYoungGen.hpp"

#include "gc/shared/gcUtil.hpp"

#include "gc/shared/genArguments.hpp"

#include "gc/shared/spaceDecorator.inline.hpp"

#include "logging/log.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/java.hpp"

#include "utilities/align.hpp"

PSYoungGen::PSYoungGen(size_t initial_size, size_t min_size, size_t max_size) :

  _reserved(),

  _virtual_space(NULL),

  _eden_space(NULL),

  _from_space(NULL),

  _to_space(NULL),

  _eden_mark_sweep(NULL),

  _from_mark_sweep(NULL),

  _to_mark_sweep(NULL),

  _init_gen_size(initial_size),

  _min_gen_size(min_size),

  _max_gen_size(max_size),

  _gen_counters(NULL),

  _eden_counters(NULL),

  _from_counters(NULL),

  _to_counters(NULL)

{}

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());

  ParallelScavengeHeap::heap()->card_table()->resize_covered_region(cmr);

  if (ZapUnusedHeapArea) {

    // Mangle newly committed space immediately because it

    // can be done here more simply that after the new

    // spaces have been computed.

    SpaceMangler::mangle_region(cmr);

  }

  if (UseNUMA) {

    _eden_space = new MutableNUMASpace(virtual_space()->alignment());

  } else {

    _eden_space = new MutableSpace(virtual_space()->alignment());

  }

  _from_space = new MutableSpace(virtual_space()->alignment());

  _to_space   = new MutableSpace(virtual_space()->alignment());

  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, _min_gen_size,

                                           _max_gen_size, _virtual_space);

  // Compute maximum space sizes for performance counters

  size_t alignment = SpaceAlignment;

  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_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_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 reaches 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() {

  // Compute sizes

  size_t size = virtual_space()->committed_size();

  assert(size >= 3 * SpaceAlignment, "Young space is not large enough for eden + 2 survivors");

  size_t survivor_size = size / InitialSurvivorRatio;

  survivor_size = align_down(survivor_size, SpaceAlignment);

  // ... but never less than an alignment

  survivor_size = MAX2(survivor_size, SpaceAlignment);

  // 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(eden_start), "checking alignment");

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

  assert(is_object_aligned(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, ZapUnusedHeapArea);

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

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

}

#ifndef PRODUCT

void PSYoungGen::space_invariants() {

  // Currently, our eden size cannot shrink to zero

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

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

  guarantee(to_space()->capacity_in_bytes() >= SpaceAlignment, "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();

    log_trace(gc, ergo)("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 desired 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_up(eden_size + 2 * survivor_size, alignment);

  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");

    HeapWord* prev_high = (HeapWord*) virtual_space()->high();

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

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

    }

    if (ZapUnusedHeapArea) {

      // Mangle newly committed space immediately because it

      // can be done here more simply that after the new

      // spaces have been computed.

      HeapWord* new_high = (HeapWord*) virtual_space()->high();

      MemRegion mangle_region(prev_high, new_high);

      SpaceMangler::mangle_region(mangle_region);

    }

    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 (orig_size == gen_size_limit()) {

      log_trace(gc)("PSYoung generation size at maximum: " SIZE_FORMAT "K", orig_size/K);

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

      log_trace(gc)("PSYoung generation size at minium: " SIZE_FORMAT "K", orig_size/K);

    }

  }

  if (size_changed) {

    post_resize();

    log_trace(gc)("PSYoung generation size changed: " SIZE_FORMAT "K->" SIZE_FORMAT "K",

                  orig_size/K, virtual_space()->committed_size()/K);

  }

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

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

  return true;

}

#ifndef PRODUCT

// In the numa case eden is not mangled so a survivor space

// moving into a region previously occupied by a survivor

// may find an unmangled region.  Also in the PS case eden

// to-space and from-space may not touch (i.e., there may be

// gaps between them due to movement while resizing the

// spaces).  Those gaps must be mangled.

void PSYoungGen::mangle_survivors(MutableSpace* s1,

                                  MemRegion s1MR,

                                  MutableSpace* s2,

                                  MemRegion s2MR) {

  // Check eden and gap between eden and from-space, in deciding

  // what to mangle in from-space.  Check the gap between from-space

  // and to-space when deciding what to mangle.

  //

  //      +--------+   +----+    +---+

  //      | eden   |   |s1  |    |s2 |

  //      +--------+   +----+    +---+

  //                 +-------+ +-----+

  //                 |s1MR   | |s2MR |

  //                 +-------+ +-----+

  // All of survivor-space is properly mangled so find the

  // upper bound on the mangling for any portion above current s1.

  HeapWord* delta_end = MIN2(s1->bottom(), s1MR.end());

  MemRegion delta1_left;

  if (s1MR.start() < delta_end) {

    delta1_left = MemRegion(s1MR.start(), delta_end);

    s1->mangle_region(delta1_left);

  }

  // Find any portion to the right of the current s1.

  HeapWord* delta_start = MAX2(s1->end(), s1MR.start());

  MemRegion delta1_right;

  if (delta_start < s1MR.end()) {

    delta1_right = MemRegion(delta_start, s1MR.end());

    s1->mangle_region(delta1_right);

  }

  // Similarly for the second survivor space except that

  // any of the new region that overlaps with the current

  // region of the first survivor space has already been

  // mangled.

  delta_end = MIN2(s2->bottom(), s2MR.end());

  delta_start = MAX2(s2MR.start(), s1->end());

  MemRegion delta2_left;

  if (s2MR.start() < delta_end) {

    delta2_left = MemRegion(s2MR.start(), delta_end);

    s2->mangle_region(delta2_left);

  }

  delta_start = MAX2(s2->end(), s2MR.start());

  MemRegion delta2_right;

  if (delta_start < s2MR.end()) {

    s2->mangle_region(delta2_right);

  }

  // s1

  log_develop_trace(gc)("Current region: [" PTR_FORMAT ", " PTR_FORMAT ") "

    "New region: [" PTR_FORMAT ", " PTR_FORMAT ")",

    p2i(s1->bottom()), p2i(s1->end()),

    p2i(s1MR.start()), p2i(s1MR.end()));

  log_develop_trace(gc)("    Mangle before: [" PTR_FORMAT ", "

    PTR_FORMAT ")  Mangle after: [" PTR_FORMAT ", " PTR_FORMAT ")",

    p2i(delta1_left.start()), p2i(delta1_left.end()),

    p2i(delta1_right.start()), p2i(delta1_right.end()));

  // s2

  log_develop_trace(gc)("Current region: [" PTR_FORMAT ", " PTR_FORMAT ") "

    "New region: [" PTR_FORMAT ", " PTR_FORMAT ")",

    p2i(s2->bottom()), p2i(s2->end()),

    p2i(s2MR.start()), p2i(s2MR.end()));

  log_develop_trace(gc)("    Mangle before: [" PTR_FORMAT ", "

    PTR_FORMAT ")  Mangle after: [" PTR_FORMAT ", " PTR_FORMAT ")",

    p2i(delta2_left.start()), p2i(delta2_left.end()),

    p2i(delta2_right.start()), p2i(delta2_right.end()));

}

#endif // NOT PRODUCT

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;

  }

  log_trace(gc, ergo)("PSYoungGen::resize_spaces(requested_eden_size: " SIZE_FORMAT ", requested_survivor_size: " SIZE_FORMAT ")",

                      requested_eden_size, requested_survivor_size);

  log_trace(gc, ergo)("    eden: [" PTR_FORMAT ".." PTR_FORMAT ") " SIZE_FORMAT,

                      p2i(eden_space()->bottom()),

                      p2i(eden_space()->end()),

                      pointer_delta(eden_space()->end(),

                                    eden_space()->bottom(),

                                    sizeof(char)));

  log_trace(gc, ergo)("    from: [" PTR_FORMAT ".." PTR_FORMAT ") " SIZE_FORMAT,

                      p2i(from_space()->bottom()),

                      p2i(from_space()->end()),

                      pointer_delta(from_space()->end(),

                                    from_space()->bottom(),

                                    sizeof(char)));

  log_trace(gc, ergo)("      to: [" PTR_FORMAT ".." PTR_FORMAT ") " SIZE_FORMAT,

                      p2i(to_space()->bottom()),

                      p2i(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()) {

    log_trace(gc, ergo)("    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();

  const bool maintain_minimum =

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

  bool eden_from_to_order = from_start < to_start;

  // Check whether from space is below to space

  if (eden_from_to_order) {

    // Eden, from, to

    eden_from_to_order = true;

    log_trace(gc, ergo)("  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,