1 #ifndef JEMALLOC_INTERNAL_EXTENT_STRUCTS_H 2 #define JEMALLOC_INTERNAL_EXTENT_STRUCTS_H 3 4 #include "jemalloc/internal/atomic.h" 5 #include "jemalloc/internal/bitmap.h" 6 #include "jemalloc/internal/mutex.h" 7 #include "jemalloc/internal/ql.h" 8 #include "jemalloc/internal/rb.h" 9 #include "jemalloc/internal/ph.h" 10 #include "jemalloc/internal/size_classes.h" 11 12 typedef enum { 13 extent_state_active = 0, 14 extent_state_dirty = 1, 15 extent_state_muzzy = 2, 16 extent_state_retained = 3 17 } extent_state_t; 18 19 /* Extent (span of pages). Use accessor functions for e_* fields. */ 20 struct extent_s { 21 /* 22 * Bitfield containing several fields: 23 * 24 * a: arena_ind 25 * b: slab 26 * c: committed 27 * z: zeroed 28 * t: state 29 * i: szind 30 * f: nfree 31 * n: sn 32 * 33 * nnnnnnnn ... nnnnnfff fffffffi iiiiiiit tzcbaaaa aaaaaaaa 34 * 35 * arena_ind: Arena from which this extent came, or all 1 bits if 36 * unassociated. 37 * 38 * slab: The slab flag indicates whether the extent is used for a slab 39 * of small regions. This helps differentiate small size classes, 40 * and it indicates whether interior pointers can be looked up via 41 * iealloc(). 42 * 43 * committed: The committed flag indicates whether physical memory is 44 * committed to the extent, whether explicitly or implicitly 45 * as on a system that overcommits and satisfies physical 46 * memory needs on demand via soft page faults. 47 * 48 * zeroed: The zeroed flag is used by extent recycling code to track 49 * whether memory is zero-filled. 50 * 51 * state: The state flag is an extent_state_t. 52 * 53 * szind: The szind flag indicates usable size class index for 54 * allocations residing in this extent, regardless of whether the 55 * extent is a slab. Extent size and usable size often differ 56 * even for non-slabs, either due to sz_large_pad or promotion of 57 * sampled small regions. 58 * 59 * nfree: Number of free regions in slab. 60 * 61 * sn: Serial number (potentially non-unique). 62 * 63 * Serial numbers may wrap around if !opt_retain, but as long as 64 * comparison functions fall back on address comparison for equal 65 * serial numbers, stable (if imperfect) ordering is maintained. 66 * 67 * Serial numbers may not be unique even in the absence of 68 * wrap-around, e.g. when splitting an extent and assigning the same 69 * serial number to both resulting adjacent extents. 70 */ 71 uint64_t e_bits; 72 #define EXTENT_BITS_ARENA_SHIFT 0 73 #define EXTENT_BITS_ARENA_MASK \ 74 (((uint64_t)(1U << MALLOCX_ARENA_BITS) - 1) << EXTENT_BITS_ARENA_SHIFT) 75 76 #define EXTENT_BITS_SLAB_SHIFT MALLOCX_ARENA_BITS 77 #define EXTENT_BITS_SLAB_MASK \ 78 ((uint64_t)0x1U << EXTENT_BITS_SLAB_SHIFT) 79 80 #define EXTENT_BITS_COMMITTED_SHIFT (MALLOCX_ARENA_BITS + 1) 81 #define EXTENT_BITS_COMMITTED_MASK \ 82 ((uint64_t)0x1U << EXTENT_BITS_COMMITTED_SHIFT) 83 84 #define EXTENT_BITS_ZEROED_SHIFT (MALLOCX_ARENA_BITS + 2) 85 #define EXTENT_BITS_ZEROED_MASK \ 86 ((uint64_t)0x1U << EXTENT_BITS_ZEROED_SHIFT) 87 88 #define EXTENT_BITS_STATE_SHIFT (MALLOCX_ARENA_BITS + 3) 89 #define EXTENT_BITS_STATE_MASK \ 90 ((uint64_t)0x3U << EXTENT_BITS_STATE_SHIFT) 91 92 #define EXTENT_BITS_SZIND_SHIFT (MALLOCX_ARENA_BITS + 5) 93 #define EXTENT_BITS_SZIND_MASK \ 94 (((uint64_t)(1U << LG_CEIL_NSIZES) - 1) << EXTENT_BITS_SZIND_SHIFT) 95 96 #define EXTENT_BITS_NFREE_SHIFT \ 97 (MALLOCX_ARENA_BITS + 5 + LG_CEIL_NSIZES) 98 #define EXTENT_BITS_NFREE_MASK \ 99 ((uint64_t)((1U << (LG_SLAB_MAXREGS + 1)) - 1) << EXTENT_BITS_NFREE_SHIFT) 100 101 #define EXTENT_BITS_SN_SHIFT \ 102 (MALLOCX_ARENA_BITS + 5 + LG_CEIL_NSIZES + (LG_SLAB_MAXREGS + 1)) 103 #define EXTENT_BITS_SN_MASK (UINT64_MAX << EXTENT_BITS_SN_SHIFT) 104 105 /* Pointer to the extent that this structure is responsible for. */ 106 void *e_addr; 107 108 union { 109 /* 110 * Extent size and serial number associated with the extent 111 * structure (different than the serial number for the extent at 112 * e_addr). 113 * 114 * ssssssss [...] ssssssss ssssnnnn nnnnnnnn 115 */ 116 size_t e_size_esn; 117 #define EXTENT_SIZE_MASK ((size_t)~(PAGE-1)) 118 #define EXTENT_ESN_MASK ((size_t)PAGE-1) 119 /* Base extent size, which may not be a multiple of PAGE. */ 120 size_t e_bsize; 121 }; 122 123 union { 124 /* 125 * List linkage, used by a variety of lists: 126 * - arena_bin_t's slabs_full 127 * - extents_t's LRU 128 * - stashed dirty extents 129 * - arena's large allocations 130 */ 131 ql_elm(extent_t) ql_link; 132 /* Red-black tree linkage, used by arena's extent_avail. */ 133 rb_node(extent_t) rb_link; 134 }; 135 136 /* Linkage for per size class sn/address-ordered heaps. */ 137 phn(extent_t) ph_link; 138 139 union { 140 /* Small region slab metadata. */ 141 arena_slab_data_t e_slab_data; 142 143 /* 144 * Profile counters, used for large objects. Points to a 145 * prof_tctx_t. 146 */ 147 atomic_p_t e_prof_tctx; 148 }; 149 }; 150 typedef ql_head(extent_t) extent_list_t; 151 typedef rb_tree(extent_t) extent_tree_t; 152 typedef ph(extent_t) extent_heap_t; 153 154 /* Quantized collection of extents, with built-in LRU queue. */ 155 struct extents_s { 156 malloc_mutex_t mtx; 157 158 /* 159 * Quantized per size class heaps of extents. 160 * 161 * Synchronization: mtx. 162 */ 163 extent_heap_t heaps[NPSIZES+1]; 164 165 /* 166 * Bitmap for which set bits correspond to non-empty heaps. 167 * 168 * Synchronization: mtx. 169 */ 170 bitmap_t bitmap[BITMAP_GROUPS(NPSIZES+1)]; 171 172 /* 173 * LRU of all extents in heaps. 174 * 175 * Synchronization: mtx. 176 */ 177 extent_list_t lru; 178 179 /* 180 * Page sum for all extents in heaps. 181 * 182 * The synchronization here is a little tricky. Modifications to npages 183 * must hold mtx, but reads need not (though, a reader who sees npages 184 * without holding the mutex can't assume anything about the rest of the 185 * state of the extents_t). 186 */ 187 atomic_zu_t npages; 188 189 /* All stored extents must be in the same state. */ 190 extent_state_t state; 191 192 /* 193 * If true, delay coalescing until eviction; otherwise coalesce during 194 * deallocation. 195 */ 196 bool delay_coalesce; 197 }; 198 199 #endif /* JEMALLOC_INTERNAL_EXTENT_STRUCTS_H */ 200