1 #define JEMALLOC_BITMAP_C_ 2 #include "jemalloc/internal/jemalloc_internal.h" 3 4 /******************************************************************************/ 5 6 #ifdef USE_TREE 7 8 void 9 bitmap_info_init(bitmap_info_t *binfo, size_t nbits) 10 { 11 unsigned i; 12 size_t group_count; 13 14 assert(nbits > 0); 15 assert(nbits <= (ZU(1) << LG_BITMAP_MAXBITS)); 16 17 /* 18 * Compute the number of groups necessary to store nbits bits, and 19 * progressively work upward through the levels until reaching a level 20 * that requires only one group. 21 */ 22 binfo->levels[0].group_offset = 0; 23 group_count = BITMAP_BITS2GROUPS(nbits); 24 for (i = 1; group_count > 1; i++) { 25 assert(i < BITMAP_MAX_LEVELS); 26 binfo->levels[i].group_offset = binfo->levels[i-1].group_offset 27 + group_count; 28 group_count = BITMAP_BITS2GROUPS(group_count); 29 } 30 binfo->levels[i].group_offset = binfo->levels[i-1].group_offset 31 + group_count; 32 assert(binfo->levels[i].group_offset <= BITMAP_GROUPS_MAX); 33 binfo->nlevels = i; 34 binfo->nbits = nbits; 35 } 36 37 static size_t 38 bitmap_info_ngroups(const bitmap_info_t *binfo) 39 { 40 41 return (binfo->levels[binfo->nlevels].group_offset); 42 } 43 44 void 45 bitmap_init(bitmap_t *bitmap, const bitmap_info_t *binfo) 46 { 47 size_t extra; 48 unsigned i; 49 50 /* 51 * Bits are actually inverted with regard to the external bitmap 52 * interface, so the bitmap starts out with all 1 bits, except for 53 * trailing unused bits (if any). Note that each group uses bit 0 to 54 * correspond to the first logical bit in the group, so extra bits 55 * are the most significant bits of the last group. 56 */ 57 memset(bitmap, 0xffU, bitmap_size(binfo)); 58 extra = (BITMAP_GROUP_NBITS - (binfo->nbits & BITMAP_GROUP_NBITS_MASK)) 59 & BITMAP_GROUP_NBITS_MASK; 60 if (extra != 0) 61 bitmap[binfo->levels[1].group_offset - 1] >>= extra; 62 for (i = 1; i < binfo->nlevels; i++) { 63 size_t group_count = binfo->levels[i].group_offset - 64 binfo->levels[i-1].group_offset; 65 extra = (BITMAP_GROUP_NBITS - (group_count & 66 BITMAP_GROUP_NBITS_MASK)) & BITMAP_GROUP_NBITS_MASK; 67 if (extra != 0) 68 bitmap[binfo->levels[i+1].group_offset - 1] >>= extra; 69 } 70 } 71 72 #else /* USE_TREE */ 73 74 void 75 bitmap_info_init(bitmap_info_t *binfo, size_t nbits) 76 { 77 size_t i; 78 79 assert(nbits > 0); 80 assert(nbits <= (ZU(1) << LG_BITMAP_MAXBITS)); 81 82 i = nbits >> LG_BITMAP_GROUP_NBITS; 83 if (nbits % BITMAP_GROUP_NBITS != 0) 84 i++; 85 binfo->ngroups = i; 86 binfo->nbits = nbits; 87 } 88 89 static size_t 90 bitmap_info_ngroups(const bitmap_info_t *binfo) 91 { 92 93 return (binfo->ngroups); 94 } 95 96 void 97 bitmap_init(bitmap_t *bitmap, const bitmap_info_t *binfo) 98 { 99 size_t extra; 100 101 memset(bitmap, 0xffU, bitmap_size(binfo)); 102 extra = (binfo->nbits % (binfo->ngroups * BITMAP_GROUP_NBITS)); 103 if (extra != 0) 104 bitmap[binfo->ngroups - 1] >>= (BITMAP_GROUP_NBITS - extra); 105 } 106 107 #endif /* USE_TREE */ 108 109 size_t 110 bitmap_size(const bitmap_info_t *binfo) 111 { 112 113 return (bitmap_info_ngroups(binfo) << LG_SIZEOF_BITMAP); 114 } 115