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34 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/malloc.h>
45 hash_mflags(int flags)
48 return ((flags & HASH_NOWAIT) ? M_NOWAIT : M_WAITOK);
52 * General routine to allocate a hash table with control of memory flags.
55 hashinit_flags(int elements, struct malloc_type *type, u_long *hashmask,
59 LIST_HEAD(generic, generic) *hashtbl;
62 KASSERT(elements > 0, ("%s: bad elements", __func__));
63 /* Exactly one of HASH_WAITOK and HASH_NOWAIT must be set. */
64 KASSERT((flags & HASH_WAITOK) ^ (flags & HASH_NOWAIT),
65 ("Bad flags (0x%x) passed to hashinit_flags", flags));
67 for (hashsize = 1; hashsize <= elements; hashsize <<= 1)
71 hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type,
73 if (hashtbl != NULL) {
74 for (i = 0; i < hashsize; i++)
75 LIST_INIT(&hashtbl[i]);
76 *hashmask = hashsize - 1;
82 * Allocate and initialize a hash table with default flag: may sleep.
85 hashinit(int elements, struct malloc_type *type, u_long *hashmask)
88 return (hashinit_flags(elements, type, hashmask, HASH_WAITOK));
92 hashdestroy(void *vhashtbl, struct malloc_type *type, u_long hashmask)
94 LIST_HEAD(generic, generic) *hashtbl, *hp;
97 for (hp = hashtbl; hp <= &hashtbl[hashmask]; hp++)
98 KASSERT(LIST_EMPTY(hp), ("%s: hashtbl %p not empty "
99 "(malloc type %s)", __func__, hashtbl, type->ks_shortdesc));
103 static const int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531,
104 2039, 2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143,
105 6653, 7159, 7673, 8191, 12281, 16381, 24571, 32749 };
106 #define NPRIMES nitems(primes)
109 * General routine to allocate a prime number sized hash table with control of
113 phashinit_flags(int elements, struct malloc_type *type, u_long *nentries, int flags)
116 LIST_HEAD(generic, generic) *hashtbl;
119 KASSERT(elements > 0, ("%s: bad elements", __func__));
120 /* Exactly one of HASH_WAITOK and HASH_NOWAIT must be set. */
121 KASSERT((flags & HASH_WAITOK) ^ (flags & HASH_NOWAIT),
122 ("Bad flags (0x%x) passed to phashinit_flags", flags));
124 for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
128 hashsize = primes[i];
130 hashsize = primes[i - 1];
132 hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type,
137 for (i = 0; i < hashsize; i++)
138 LIST_INIT(&hashtbl[i]);
139 *nentries = hashsize;
144 * Allocate and initialize a prime number sized hash table with default flag:
148 phashinit(int elements, struct malloc_type *type, u_long *nentries)
151 return (phashinit_flags(elements, type, nentries, HASH_WAITOK));