1 /*

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

     3  * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.

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

     5  *

     6  * This code is free software; you can redistribute it and/or modify it

     7  * under the terms of the GNU General Public License version 2 only, as

     8  * published by the Free Software Foundation.

     9  *

    10  * This code is distributed in the hope that it will be useful, but WITHOUT

    11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    13  * version 2 for more details (a copy is included in the LICENSE file that

    14  * accompanied this code).

    15  *

    16  * You should have received a copy of the GNU General Public License version

    17  * 2 along with this work; if not, write to the Free Software Foundation,

    18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    19  *

    20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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

    22  * questions.

    23  *

    24  */

    25 

    26 #ifndef SHARE_MEMORY_METASPACE_COMMITMASK_HPP

    27 #define SHARE_MEMORY_METASPACE_COMMITMASK_HPP

    28 

    29 #include "utilities/debug.hpp"

    30 #include "utilities/bitMap.hpp"

    31 #include "utilities/globalDefinitions.hpp"

    32 

    33 class outputStream;

    34 

    35 namespace metaspace {

    36 

    37 // A bitmap covering a range of metaspace; each bit in this mask corresponds to

    38 //

    39 class CommitMask : public CHeapBitMap {

    40 

    41   const MetaWord* const _base;

    42   const size_t _word_size;

    43   const size_t _words_per_bit;

    44 

    45   // Given an offset, in words, into the area, return the number of the bit

    46   // covering it.

    47   static idx_t bitno_for_word_offset(size_t offset, size_t words_per_bit) {

    48     return offset / words_per_bit;

    49   }

    50 

    51   idx_t bitno_for_address(const MetaWord* p) const {

    52     // Note: we allow one-beyond since this is a typical need.

    53     assert(p >= _base && p <= _base + _word_size, "Invalid address");

    54     const size_t off = p - _base;

    55     return bitno_for_word_offset(off, _words_per_bit);

    56   }

    57 

    58   static idx_t mask_size(size_t word_size, size_t words_per_bit) {

    59     return bitno_for_word_offset(word_size, words_per_bit);

    60   }

    61 

    62   struct BitCounterClosure : public BitMapClosure {

    63     idx_t cnt;

    64     bool do_bit(BitMap::idx_t offset) { cnt ++; return true; }

    65   };

    66 

    67   // Missing from BitMap.

    68   // Count 1 bits in range [start, end).

    69   idx_t count_one_bits_in_range(idx_t start, idx_t end) const {

    70     assert(start < end, "Zero range");

    71     // TODO: This can be done more efficiently.

    72     BitCounterClosure bcc;

    73     bcc.cnt = 0;

    74     iterate(&bcc, start, end);

    75     return bcc.cnt;

    76   }

    77 

    78 #ifdef ASSERT

    79   // Given a pointer, check if it points into the range this bitmap covers.

    80   bool is_pointer_valid(const MetaWord* p) const {

    81     return p >= _base && p < _base + _word_size;

    82   }

    83 

    84   // Given a pointer, check if it points into the range this bitmap covers.

    85   void check_pointer(const MetaWord* p) const {

    86     assert(is_pointer_valid(p),

    87            "Pointer " PTR_FORMAT " not in range of this bitmap [" PTR_FORMAT ", " PTR_FORMAT ").",

    88            p2i(p), p2i(_base), p2i(_base + _word_size));

    89   }

    90   // Given a pointer, check if it points into the range this bitmap covers,

    91   // and if it is aligned to commit granule border.

    92   void check_pointer_aligned(const MetaWord* p) const {

    93     check_pointer(p);

    94     assert(is_aligned(p, _words_per_bit * BytesPerWord),

    95            "Pointer " PTR_FORMAT " should be aligned to commit granule size " SIZE_FORMAT ".",

    96            p2i(p), _words_per_bit * BytesPerWord);

    97   }

    98   // Given a range, check if it points into the range this bitmap covers,

    99   // and if its borders are aligned to commit granule border.

   100   void check_range(const MetaWord* start, size_t word_size) const {

   101     check_pointer_aligned(start);

   102     assert(is_aligned(word_size, _words_per_bit),

   103            "Range " SIZE_FORMAT " should be aligned to commit granule size " SIZE_FORMAT ".",

   104            word_size, _words_per_bit);

   105     check_pointer(start + word_size - 1);

   106   }

   107 #endif

   108 

   109   // Marks a single commit granule as committed (value == true)

   110   // or uncomitted (value == false) and returns

   111   // its prior state.

   112   bool mark_granule(idx_t bitno, bool value) {

   113     bool b = at(bitno);

   114     at_put(bitno, value);

   115     return b;

   116   }

   117 

   118 public:

   119 

   120   CommitMask(const MetaWord* start, size_t word_size);

   121 

   122   const MetaWord* base() const  { return _base; }

   123   size_t word_size() const      { return _word_size; }

   124   const MetaWord* end() const   { return _base + word_size(); }

   125 

   126   // Given an address, returns true if the address is committed, false if not.

   127   bool is_committed_address(const MetaWord* p) const {

   128     DEBUG_ONLY(check_pointer(p));

   129     const idx_t bitno = bitno_for_address(p);

   130     return at(bitno);

   131   }

   132 

   133   // Given an address range [start..end), returns true if area is fully committed through.

   134   bool is_fully_committed_range(const MetaWord* start, size_t word_size) const {

   135     DEBUG_ONLY(check_range(start, word_size));

   136     assert(word_size > 0, "zero range");

   137     const idx_t b1 = bitno_for_address(start);

   138     const idx_t b2 = bitno_for_address(start + word_size);

   139     return get_next_zero_offset(b1, b2) == b2;

   140   }

   141 

   142   // Given an address range, return size, in number of words, of committed area within that range.

   143   size_t get_committed_size_in_range(const MetaWord* start, size_t word_size) const {

   144     DEBUG_ONLY(check_range(start, word_size));

   145     assert(word_size > 0, "zero range");

   146     const idx_t b1 = bitno_for_address(start);

   147     const idx_t b2 = bitno_for_address(start + word_size);

   148     const idx_t num_bits = count_one_bits_in_range(b1, b2);

   149     return num_bits * _words_per_bit;

   150   }

   151 

   152   // Return total committed size, in number of words.

   153   size_t get_committed_size() const {

   154     return count_one_bits() * _words_per_bit;

   155   }

   156 

   157   // Mark a whole address range [start, end) as committed.

   158   // Return the number of words which had already been committed before this operation.

   159   size_t mark_range_as_committed(const MetaWord* start, size_t word_size) {

   160     DEBUG_ONLY(check_range(start, word_size));

   161     assert(word_size > 0, "zero range");

   162     const idx_t b1 = bitno_for_address(start);

   163     const idx_t b2 = bitno_for_address(start + word_size);

   164     if (b1 == b2) { // Simple case, 1 granule

   165       bool was_committed = mark_granule(b1, true);

   166       return was_committed ? _words_per_bit : 0;

   167     }

   168     const idx_t one_bits_in_range_before = count_one_bits_in_range(b1, b2);

   169     set_range(b1, b2);

   170     return one_bits_in_range_before * _words_per_bit;

   171   }

   172 

   173   // Mark a whole address range [start, end) as uncommitted.

   174   // Return the number of words which had already been uncommitted before this operation.

   175   size_t mark_range_as_uncommitted(const MetaWord* start, size_t word_size) {

   176     DEBUG_ONLY(check_range(start, word_size));

   177     assert(word_size > 0, "zero range");

   178     const idx_t b1 = bitno_for_address(start);

   179     const idx_t b2 = bitno_for_address(start + word_size);

   180     if (b1 == b2) { // Simple case, 1 granule

   181       bool was_committed = mark_granule(b1, false);

   182       return was_committed ? 0 : _words_per_bit;

   183     }

   184     const idx_t zero_bits_in_range_before =

   185         (b2 - b1) - count_one_bits_in_range(b1, b2);

   186     clear_range(b1, b2);

   187     return zero_bits_in_range_before * _words_per_bit;

   188   }

   189 

   190 

   191   //// Debug stuff ////

   192   DEBUG_ONLY(void verify(bool slow, bool do_touch_test = true) const;)

   193 

   194   void print_on(outputStream* st) const;

   195 

   196 };

   197 

   198 } // namespace metaspace

   199 

   200 #endif // SHARE_MEMORY_METASPACE_COMMITMASK_HPP