/*

 * Copyright (c) 2019, SAP SE. All rights reserved.

 * Copyright (c) 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

#include "precompiled.hpp"

//#define LOG_PLEASE

#include "metaspaceTestsCommon.hpp"

class LeftOverBinsTest {

  // A simple preallocated buffer used to "feed" the allocator.

  // Mimicks chunk retirement leftover blocks.

  class FeederBuffer {

    static const size_t buf_word_size = 512 * K;

    MetaWord* _buf;

    size_t _used;

  public:

    FeederBuffer() : _used(0) {

      _buf = NEW_C_HEAP_ARRAY(MetaWord, buf_word_size, mtInternal);

    }

    ~FeederBuffer() {

      FREE_C_HEAP_ARRAY(MetaWord, _buf);

    }

    MetaWord* get(size_t word_size) {

      if (_used > (buf_word_size - word_size)) {

        return NULL;

      }

      MetaWord* p = _buf + _used;

      _used += word_size;

      return p;

    }

  };

  FeederBuffer _fb;

  LeftOverManager _lom;

  // random generator for block feeding

  RandSizeGenerator _rgen_feeding;

  // random generator for allocations (and, hence, deallocations)

  RandSizeGenerator _rgen_allocations;

  SizeCounter _allocated_words;

  struct allocation_t {

    allocation_t* next;

    size_t word_size;

    MetaWord* p;

  };

  // Array of the same size as the pool max capacity; holds the allocated elements.

  allocation_t* _allocations;

  int _num_allocs;

  int _num_deallocs;

  int _num_feeds;

  bool feed_some() {

    size_t word_size = _rgen_feeding.get();

    MetaWord* p = _fb.get(word_size);

    if (p != NULL) {

      _lom.add_block(p, word_size);

      return true;

    }

    return false;

  }

  void deallocate_top() {

    allocation_t* a = _allocations;

    if (a != NULL) {

      _allocations = a->next;

      check_marked_range(a->p, a->word_size);

      _lom.add_block(a->p, a->word_size);

      delete a;

      DEBUG_ONLY(_lom.verify();)

    }

  }

  bool allocate() {

    size_t word_size = MAX2(_rgen_allocations.get(), _lom.minimal_word_size());

    MetaWord* p = _lom.get_block(word_size);

    if (p != NULL) {

      _allocated_words.increment_by(word_size);

      allocation_t* a = new allocation_t;

      a->p = p; a->word_size = word_size;

      a->next = _allocations;

      _allocations = a;

      DEBUG_ONLY(_lom.verify();)

      mark_range(p, word_size);

      return true;

    }

    return false;

  }

  void test_all_marked_ranges() {

    for (allocation_t* a = _allocations; a != NULL; a = a->next) {

      check_marked_range(a->p, a->word_size);

    }

  }

  void test_loop() {

    // We loop and in each iteration execute one of three operations:

    // - allocation from lom

    // - deallocation to lom of a previously allocated block

    // - feeding a new larger block into the lom (mimicks chunk retiring)

    // When we have fed all large blocks into the lom (feedbuffer empty), we

    //  switch to draining the lom completely (only allocs)

    bool forcefeed = false;

    bool draining = false;

    bool stop = false;

    int iter = 100000; // safety stop

    while (!stop && iter > 0) {

      iter --;

      int surprise = (int)os::random() % 10;

      if (!draining && (surprise >= 7 || forcefeed)) {

        forcefeed = false;

        if (feed_some()) {

          _num_feeds ++;

        } else {

          // We fed all input memory into the LOM. Now lets proceed until the lom is drained.

          draining = true;

        }

      } else if (!draining && surprise < 1) {

        deallocate_top();

        _num_deallocs ++;

      } else {

        if (allocate()) {

          _num_allocs ++;

        } else {

          if (draining) {

            stop = _lom.total_word_size() < 512;

          } else {

            forcefeed = true;

          }

        }

      }

      if ((iter % 1000) == 0) {

        DEBUG_ONLY(_lom.verify();)

        test_all_marked_ranges();

        LOG("a %d (" SIZE_FORMAT "), d %d, f %d", _num_allocs, _allocated_words.get(), _num_deallocs, _num_feeds);

#ifdef LOG_PLEASE

        _lom.print(tty, true);

        tty->cr();

#endif

      }

    }

    // Drain

  }

public:

  LeftOverBinsTest(size_t avg_alloc_size) :

    _fb(), _lom(),

    _rgen_feeding(128, 4096),

    _rgen_allocations(avg_alloc_size / 4, avg_alloc_size * 2, 0.01f, avg_alloc_size / 3, avg_alloc_size * 30),

    _allocations(NULL),

    _num_allocs(0), _num_deallocs(0), _num_feeds(0)

  {

    // some initial feeding

    _lom.add_block(_fb.get(1024), 1024);

  }

  static void test_small_allocations() {

    LeftOverBinsTest test(10);

    test.test_loop();

  }

  static void test_medium_allocations() {

    LeftOverBinsTest test(30);

    test.test_loop();

  }

  static void test_large_allocations() {

    LeftOverBinsTest test(150);

    test.test_loop();

  }

};

TEST_VM(metaspace, leftoverbins_mask_basic) {

  // Basic tests

  metaspace::BinMap map;

  EXPECT_TRUE(map.all_zero());

  for (int i = 0; i < map.size(); i ++) {

    map.set_bit(i);

    EXPECT_TRUE(map.get_bit(i));

    map.clr_bit(i);

    EXPECT_FALSE(map.get_bit(i));

    EXPECT_TRUE(map.all_zero());

  }

}

TEST_VM(metaspace, leftoverbins_mask_find_next_set_bit) {

  metaspace::BinMap map;

  EXPECT_TRUE(map.all_zero());

  for (int i = 0; i < map.size(); i ++) {

    map.set_bit(i);

    for (int j = 0; j < i; j ++) {

      int n = map.find_next_set_bit(j);

      if (j <= i) {

        EXPECT_EQ(n, i);

      } else {

        EXPECT_EQ(n, -1);

      }

    }

    map.clr_bit(i);

  }

}

TEST_VM(metaspace, leftoverbins_basics) {

  LeftOverManager lom;

  MetaWord tmp[1024];

  metaspace::block_stats_t stats;

  lom.add_block(tmp, 1024);

  DEBUG_ONLY(lom.verify();)

  lom.statistics(&stats);

  EXPECT_EQ(stats.num_blocks, 1);

  EXPECT_EQ(stats.word_size, (size_t)1024);

  MetaWord* p = lom.get_block(1024);

  EXPECT_EQ(p, tmp);

  DEBUG_ONLY(lom.verify();)

  lom.statistics(&stats);

  EXPECT_EQ(stats.num_blocks, 0);

  EXPECT_EQ(stats.word_size, (size_t)0);

}

TEST_VM(metaspace, leftoverbins_small) {

  LeftOverBinsTest::test_small_allocations();

}

TEST_VM(metaspace, leftoverbins_medium) {

  LeftOverBinsTest::test_medium_allocations();

}

TEST_VM(metaspace, leftoverbins_large) {

  LeftOverBinsTest::test_large_allocations();

}