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6711316: Open source the Garbage-First garbage collector
First mercurial integration of the code for the Garbage-First garbage collector. Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr
This commit is contained in:
Y. Srinivas Ramakrishna
parent
39463bb3fc
commit
18f3386a98
215 changed files with 36088 additions and 1249 deletions
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@ -22,25 +22,19 @@
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*
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*/
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// Closure for iterating over BitMaps
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// Forward decl;
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class BitMapClosure;
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class BitMapClosure VALUE_OBJ_CLASS_SPEC {
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public:
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// Callback when bit in map is set
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virtual void do_bit(size_t offset) = 0;
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};
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// Operations for bitmaps represented as arrays of unsigned 32- or 64-bit
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// integers (uintptr_t).
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//
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// Bit offsets are numbered from 0 to size-1
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// Operations for bitmaps represented as arrays of unsigned integers.
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// Bit offsets are numbered from 0 to size-1.
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class BitMap VALUE_OBJ_CLASS_SPEC {
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friend class BitMap2D;
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public:
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typedef size_t idx_t; // Type used for bit and word indices.
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typedef uintptr_t bm_word_t; // Element type of array that represents
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// the bitmap.
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// Hints for range sizes.
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typedef enum {
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@ -48,8 +42,8 @@ class BitMap VALUE_OBJ_CLASS_SPEC {
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} RangeSizeHint;
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private:
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idx_t* _map; // First word in bitmap
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idx_t _size; // Size of bitmap (in bits)
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bm_word_t* _map; // First word in bitmap
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idx_t _size; // Size of bitmap (in bits)
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// Puts the given value at the given offset, using resize() to size
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// the bitmap appropriately if needed using factor-of-two expansion.
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@ -62,7 +56,7 @@ class BitMap VALUE_OBJ_CLASS_SPEC {
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// Return a mask that will select the specified bit, when applied to the word
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// containing the bit.
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static idx_t bit_mask(idx_t bit) { return (idx_t)1 << bit_in_word(bit); }
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static bm_word_t bit_mask(idx_t bit) { return (bm_word_t)1 << bit_in_word(bit); }
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// Return the index of the word containing the specified bit.
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static idx_t word_index(idx_t bit) { return bit >> LogBitsPerWord; }
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@ -71,66 +65,68 @@ class BitMap VALUE_OBJ_CLASS_SPEC {
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static idx_t bit_index(idx_t word) { return word << LogBitsPerWord; }
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// Return the array of bitmap words, or a specific word from it.
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idx_t* map() const { return _map; }
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idx_t map(idx_t word) const { return _map[word]; }
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bm_word_t* map() const { return _map; }
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bm_word_t map(idx_t word) const { return _map[word]; }
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// Return a pointer to the word containing the specified bit.
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idx_t* word_addr(idx_t bit) const { return map() + word_index(bit); }
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bm_word_t* word_addr(idx_t bit) const { return map() + word_index(bit); }
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// Set a word to a specified value or to all ones; clear a word.
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void set_word (idx_t word, idx_t val) { _map[word] = val; }
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void set_word (idx_t word, bm_word_t val) { _map[word] = val; }
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void set_word (idx_t word) { set_word(word, ~(uintptr_t)0); }
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void clear_word(idx_t word) { _map[word] = 0; }
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// Utilities for ranges of bits. Ranges are half-open [beg, end).
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// Ranges within a single word.
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inline idx_t inverted_bit_mask_for_range(idx_t beg, idx_t end) const;
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inline void set_range_within_word (idx_t beg, idx_t end);
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inline void clear_range_within_word (idx_t beg, idx_t end);
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inline void par_put_range_within_word (idx_t beg, idx_t end, bool value);
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bm_word_t inverted_bit_mask_for_range(idx_t beg, idx_t end) const;
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void set_range_within_word (idx_t beg, idx_t end);
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void clear_range_within_word (idx_t beg, idx_t end);
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void par_put_range_within_word (idx_t beg, idx_t end, bool value);
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// Ranges spanning entire words.
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inline void set_range_of_words (idx_t beg, idx_t end);
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inline void clear_range_of_words (idx_t beg, idx_t end);
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inline void set_large_range_of_words (idx_t beg, idx_t end);
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inline void clear_large_range_of_words (idx_t beg, idx_t end);
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void set_range_of_words (idx_t beg, idx_t end);
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void clear_range_of_words (idx_t beg, idx_t end);
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void set_large_range_of_words (idx_t beg, idx_t end);
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void clear_large_range_of_words (idx_t beg, idx_t end);
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// The index of the first full word in a range.
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inline idx_t word_index_round_up(idx_t bit) const;
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idx_t word_index_round_up(idx_t bit) const;
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// Verification, statistics.
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void verify_index(idx_t index) const {
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assert(index < _size, "BitMap index out of bounds");
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}
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void verify_index(idx_t index) const;
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void verify_range(idx_t beg_index, idx_t end_index) const;
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void verify_range(idx_t beg_index, idx_t end_index) const {
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#ifdef ASSERT
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assert(beg_index <= end_index, "BitMap range error");
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// Note that [0,0) and [size,size) are both valid ranges.
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if (end_index != _size) verify_index(end_index);
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#endif
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}
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static idx_t* _pop_count_table;
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static void init_pop_count_table();
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static idx_t num_set_bits(bm_word_t w);
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static idx_t num_set_bits_from_table(unsigned char c);
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public:
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// Constructs a bitmap with no map, and size 0.
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BitMap() : _map(NULL), _size(0) {}
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// Construction
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BitMap(idx_t* map, idx_t size_in_bits);
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// Constructs a bitmap with the given map and size.
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BitMap(bm_word_t* map, idx_t size_in_bits);
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// Allocates necessary data structure in resource area
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BitMap(idx_t size_in_bits);
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// Constructs an empty bitmap of the given size (that is, this clears the
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// new bitmap). Allocates the map array in resource area if
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// "in_resource_area" is true, else in the C heap.
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BitMap(idx_t size_in_bits, bool in_resource_area = true);
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void set_map(idx_t* map) { _map = map; }
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// Set the map and size.
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void set_map(bm_word_t* map) { _map = map; }
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void set_size(idx_t size_in_bits) { _size = size_in_bits; }
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// Allocates necessary data structure in resource area.
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// Allocates necessary data structure, either in the resource area
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// or in the C heap, as indicated by "in_resource_area."
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// Preserves state currently in bit map by copying data.
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// Zeros any newly-addressable bits.
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// Does not perform any frees (i.e., of current _map).
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void resize(idx_t size_in_bits);
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// If "in_resource_area" is false, frees the current map.
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// (Note that this assumes that all calls to "resize" on the same BitMap
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// use the same value for "in_resource_area".)
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void resize(idx_t size_in_bits, bool in_resource_area = true);
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// Accessing
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idx_t size() const { return _size; }
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@ -157,11 +153,11 @@ class BitMap VALUE_OBJ_CLASS_SPEC {
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// Set or clear the specified bit.
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inline void set_bit(idx_t bit);
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inline void clear_bit(idx_t bit);
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void clear_bit(idx_t bit);
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// Atomically set or clear the specified bit.
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inline bool par_set_bit(idx_t bit);
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inline bool par_clear_bit(idx_t bit);
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bool par_set_bit(idx_t bit);
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bool par_clear_bit(idx_t bit);
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// Put the given value at the given offset. The parallel version
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// will CAS the value into the bitmap and is quite a bit slower.
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@ -183,23 +179,61 @@ class BitMap VALUE_OBJ_CLASS_SPEC {
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// Update a range of bits, using a hint about the size. Currently only
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// inlines the predominant case of a 1-bit range. Works best when hint is a
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// compile-time constant.
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inline void set_range(idx_t beg, idx_t end, RangeSizeHint hint);
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inline void clear_range(idx_t beg, idx_t end, RangeSizeHint hint);
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inline void par_set_range(idx_t beg, idx_t end, RangeSizeHint hint);
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inline void par_clear_range (idx_t beg, idx_t end, RangeSizeHint hint);
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void set_range(idx_t beg, idx_t end, RangeSizeHint hint);
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void clear_range(idx_t beg, idx_t end, RangeSizeHint hint);
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void par_set_range(idx_t beg, idx_t end, RangeSizeHint hint);
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void par_clear_range (idx_t beg, idx_t end, RangeSizeHint hint);
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// It performs the union operation between subsets of equal length
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// of two bitmaps (the target bitmap of the method and the
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// from_bitmap) and stores the result to the target bitmap. The
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// from_start_index represents the first bit index of the subrange
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// of the from_bitmap. The to_start_index is the equivalent of the
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// target bitmap. Both indexes should be word-aligned, i.e. they
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// should correspond to the first bit on a bitmap word (it's up to
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// the caller to ensure this; the method does check it). The length
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// of the subset is specified with word_num and it is in number of
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// bitmap words. The caller should ensure that this is at least 2
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// (smaller ranges are not support to save extra checks). Again,
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// this is checked in the method.
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//
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// Atomicity concerns: it is assumed that any contention on the
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// target bitmap with other threads will happen on the first and
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// last words; the ones in between will be "owned" exclusively by
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// the calling thread and, in fact, they will already be 0. So, the
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// method performs a CAS on the first word, copies the next
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// word_num-2 words, and finally performs a CAS on the last word.
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void mostly_disjoint_range_union(BitMap* from_bitmap,
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idx_t from_start_index,
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idx_t to_start_index,
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size_t word_num);
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// Clearing
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void clear();
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void clear_large();
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inline void clear();
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// Iteration support
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void iterate(BitMapClosure* blk, idx_t leftIndex, idx_t rightIndex);
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inline void iterate(BitMapClosure* blk) {
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// Iteration support. Returns "true" if the iteration completed, false
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// if the iteration terminated early (because the closure "blk" returned
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// false).
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bool iterate(BitMapClosure* blk, idx_t leftIndex, idx_t rightIndex);
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bool iterate(BitMapClosure* blk) {
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// call the version that takes an interval
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iterate(blk, 0, size());
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return iterate(blk, 0, size());
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}
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// Looking for 1's and 0's to the "right"
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// Looking for 1's and 0's at indices equal to or greater than "l_index",
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// stopping if none has been found before "r_index", and returning
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// "r_index" (which must be at most "size") in that case.
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idx_t get_next_one_offset_inline (idx_t l_index, idx_t r_index) const;
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idx_t get_next_zero_offset_inline(idx_t l_index, idx_t r_index) const;
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// Like "get_next_one_offset_inline", except requires that "r_index" is
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// aligned to bitsizeof(bm_word_t).
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idx_t get_next_one_offset_inline_aligned_right(idx_t l_index,
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idx_t r_index) const;
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// Non-inline versionsof the above.
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idx_t get_next_one_offset (idx_t l_index, idx_t r_index) const;
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idx_t get_next_zero_offset(idx_t l_index, idx_t r_index) const;
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@ -210,12 +244,8 @@ class BitMap VALUE_OBJ_CLASS_SPEC {
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return get_next_zero_offset(offset, size());
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}
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// Find the next one bit in the range [beg_bit, end_bit), or return end_bit if
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// no one bit is found. Equivalent to get_next_one_offset(), but inline for
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// use in performance-critical code.
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inline idx_t find_next_one_bit(idx_t beg_bit, idx_t end_bit) const;
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// Returns the number of bits set in the bitmap.
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idx_t count_one_bits() const;
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// Set operations.
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void set_union(BitMap bits);
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@ -232,6 +262,15 @@ class BitMap VALUE_OBJ_CLASS_SPEC {
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bool set_difference_with_result(BitMap bits);
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bool set_intersection_with_result(BitMap bits);
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// Requires the submap of "bits" starting at offset to be at least as
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// large as "this". Modifies "this" to be the intersection of its
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// current contents and the submap of "bits" starting at "offset" of the
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// same length as "this."
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// (For expedience, currently requires the offset to be aligned to the
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// bitsize of a uintptr_t. This should go away in the future though it
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// will probably remain a good case to optimize.)
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void set_intersection_at_offset(BitMap bits, idx_t offset);
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void set_from(BitMap bits);
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bool is_same(BitMap bits);
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@ -248,58 +287,13 @@ class BitMap VALUE_OBJ_CLASS_SPEC {
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#endif
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};
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inline void BitMap::set_bit(idx_t bit) {
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verify_index(bit);
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*word_addr(bit) |= bit_mask(bit);
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}
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inline void BitMap::clear_bit(idx_t bit) {
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verify_index(bit);
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*word_addr(bit) &= ~bit_mask(bit);
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}
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inline void BitMap::set_range(idx_t beg, idx_t end, RangeSizeHint hint) {
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if (hint == small_range && end - beg == 1) {
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set_bit(beg);
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} else {
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if (hint == large_range) {
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set_large_range(beg, end);
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} else {
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set_range(beg, end);
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}
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}
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}
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inline void BitMap::clear_range(idx_t beg, idx_t end, RangeSizeHint hint) {
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if (hint == small_range && end - beg == 1) {
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clear_bit(beg);
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} else {
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if (hint == large_range) {
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clear_large_range(beg, end);
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} else {
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clear_range(beg, end);
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}
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}
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}
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inline void BitMap::par_set_range(idx_t beg, idx_t end, RangeSizeHint hint) {
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if (hint == small_range && end - beg == 1) {
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par_at_put(beg, true);
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} else {
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if (hint == large_range) {
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par_at_put_large_range(beg, end, true);
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} else {
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par_at_put_range(beg, end, true);
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}
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}
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}
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// Convenience class wrapping BitMap which provides multiple bits per slot.
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class BitMap2D VALUE_OBJ_CLASS_SPEC {
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public:
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typedef size_t idx_t; // Type used for bit and word indices.
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typedef BitMap::idx_t idx_t; // Type used for bit and word indices.
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typedef BitMap::bm_word_t bm_word_t; // Element type of array that
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// represents the bitmap.
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private:
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BitMap _map;
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idx_t _bits_per_slot;
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@ -314,7 +308,7 @@ class BitMap2D VALUE_OBJ_CLASS_SPEC {
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public:
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// Construction. bits_per_slot must be greater than 0.
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BitMap2D(uintptr_t* map, idx_t size_in_slots, idx_t bits_per_slot);
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BitMap2D(bm_word_t* map, idx_t size_in_slots, idx_t bits_per_slot);
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// Allocates necessary data structure in resource area. bits_per_slot must be greater than 0.
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BitMap2D(idx_t size_in_slots, idx_t bits_per_slot);
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@ -359,38 +353,14 @@ class BitMap2D VALUE_OBJ_CLASS_SPEC {
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_map.at_put_grow(bit_index(slot_index, bit_within_slot_index), value);
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}
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void clear() {
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_map.clear();
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}
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void clear();
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};
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// Closure for iterating over BitMaps
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inline void BitMap::set_range_of_words(idx_t beg, idx_t end) {
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uintptr_t* map = _map;
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for (idx_t i = beg; i < end; ++i) map[i] = ~(uintptr_t)0;
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}
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inline void BitMap::clear_range_of_words(idx_t beg, idx_t end) {
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uintptr_t* map = _map;
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for (idx_t i = beg; i < end; ++i) map[i] = 0;
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}
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inline void BitMap::clear() {
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clear_range_of_words(0, size_in_words());
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}
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inline void BitMap::par_clear_range(idx_t beg, idx_t end, RangeSizeHint hint) {
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if (hint == small_range && end - beg == 1) {
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par_at_put(beg, false);
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} else {
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if (hint == large_range) {
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par_at_put_large_range(beg, end, false);
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} else {
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par_at_put_range(beg, end, false);
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}
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}
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}
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class BitMapClosure VALUE_OBJ_CLASS_SPEC {
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public:
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// Callback when bit in map is set. Should normally return "true";
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// return of false indicates that the bitmap iteration should terminate.
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virtual bool do_bit(BitMap::idx_t offset) = 0;
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};
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