8 |
|
* Fast malloc for memory hogs and VM environments. |
9 |
|
* Performs a minimum of searching through free lists. |
10 |
|
* bmalloc() doesn't keep track of free lists -- it's basically |
11 |
< |
* just a buffered call to sbrk(). |
12 |
< |
* bfree() puts memory from any source into malloc() free lists. |
11 |
> |
* just a buffered call to sbrk(2). However, bmalloc will |
12 |
> |
* call mscrounge() if sbrk fails. |
13 |
> |
* bfree() puts memory from any source into malloc free lists. |
14 |
|
* malloc(), realloc() and free() use buckets |
15 |
|
* containing blocks in powers of two, similar to CIT routines. |
16 |
+ |
* mscrounge() returns whatever memory it can find to satisfy the |
17 |
+ |
* request along with the number of bytes (modified). |
18 |
|
* |
19 |
|
* Greg Ward Lawrence Berkeley Laboratory |
20 |
|
*/ |
26 |
|
#endif |
27 |
|
#define BYTES_WORD sizeof(ALIGN) |
28 |
|
|
29 |
+ |
#define MAXINCR (1<<18) /* largest sbrk(2) increment */ |
30 |
+ |
|
31 |
|
#ifdef NOVMEM |
32 |
|
#define getpagesize() BYTES_WORD |
33 |
|
#endif |
29 |
– |
|
34 |
|
/* malloc free lists */ |
35 |
|
typedef union m_head { |
36 |
|
union m_head *next; |
45 |
|
|
46 |
|
|
47 |
|
char * |
48 |
+ |
mscrounge(np) /* search free lists trying to satisfy request */ |
49 |
+ |
register unsigned *np; |
50 |
+ |
{ |
51 |
+ |
char *p; |
52 |
+ |
register int bucket; |
53 |
+ |
register unsigned bsiz; |
54 |
+ |
|
55 |
+ |
for (bucket = FIRSTBUCKET, bsiz = 1<<FIRSTBUCKET; |
56 |
+ |
bucket < NBUCKETS; bucket++, bsiz <<= 1) |
57 |
+ |
if (free_list[bucket] != NULL && bsiz+sizeof(M_HEAD) >= *np) { |
58 |
+ |
*np = bsiz+sizeof(M_HEAD); |
59 |
+ |
p = (char *)free_list[bucket]; |
60 |
+ |
free_list[bucket] = free_list[bucket]->next; |
61 |
+ |
return(p); |
62 |
+ |
} |
63 |
+ |
*np = 0; |
64 |
+ |
return(NULL); |
65 |
+ |
} |
66 |
+ |
|
67 |
+ |
|
68 |
+ |
char * |
69 |
|
bmalloc(n) /* allocate a block of n bytes, sans header */ |
70 |
|
register unsigned n; |
71 |
|
{ |
72 |
|
extern char *sbrk(); |
73 |
< |
static int pagesz = 0; |
74 |
< |
static int amnt; |
73 |
> |
static unsigned pagesz = 0; |
74 |
> |
static unsigned amnt; |
75 |
|
static char *bpos; |
76 |
< |
static int nrem; |
76 |
> |
static unsigned nrem; |
77 |
> |
unsigned thisamnt; |
78 |
|
register char *p; |
79 |
|
|
80 |
|
if (pagesz == 0) { /* initialize */ |
81 |
< |
amnt = pagesz = getpagesize(); |
81 |
> |
pagesz = amnt = getpagesize(); |
82 |
|
nrem = (int)sbrk(0); /* page align break */ |
83 |
|
nrem = pagesz - (nrem&(pagesz-1)); |
84 |
|
bpos = sbrk(nrem); /* word aligned! */ |
89 |
|
n = (n+(BYTES_WORD-1))&~(BYTES_WORD-1); /* word align rqst. */ |
90 |
|
|
91 |
|
if (n > nrem) { /* need more core */ |
92 |
< |
if (n > amnt) /* increase amount */ |
93 |
< |
amnt = (n+(pagesz-1))&~(pagesz-1); |
94 |
< |
p = sbrk(amnt); |
95 |
< |
if ((int)p == -1) |
96 |
< |
return(NULL); |
97 |
< |
if (p != bpos+nrem) { /* someone called sbrk()! */ |
92 |
> |
if (n > amnt) { /* big chunk */ |
93 |
> |
thisamnt = (n+(pagesz-1))&~(pagesz-1); |
94 |
> |
if (thisamnt <= MAXINCR) /* increase amnt */ |
95 |
> |
amnt = thisamnt; |
96 |
> |
} else |
97 |
> |
thisamnt = amnt; |
98 |
> |
p = sbrk(thisamnt); |
99 |
> |
if ((int)p == -1) { /* uh-oh */ |
100 |
> |
thisamnt = n; /* search free lists */ |
101 |
> |
p = mscrounge(&thisamnt); |
102 |
> |
if (p == NULL) /* we're really out */ |
103 |
> |
return(NULL); |
104 |
> |
} |
105 |
> |
if (p != bpos+nrem) { /* not an increment */ |
106 |
|
bfree(bpos, nrem); |
107 |
|
bpos = p; |
108 |
< |
nrem = amnt; |
108 |
> |
nrem = thisamnt; |
109 |
|
} else |
110 |
< |
nrem += amnt; |
110 |
> |
nrem += thisamnt; |
111 |
|
} |
112 |
|
p = bpos; |
113 |
|
bpos += n; /* advance */ |
117 |
|
|
118 |
|
|
119 |
|
bfree(p, n) /* free n bytes of random memory */ |
120 |
< |
char *p; |
121 |
< |
unsigned n; |
120 |
> |
register char *p; |
121 |
> |
register unsigned n; |
122 |
|
{ |
89 |
– |
register M_HEAD *mp; |
123 |
|
register int bucket; |
124 |
|
register unsigned bsiz; |
125 |
|
/* find largest bucket */ |
126 |
|
bucket = 0; |
127 |
|
for (bsiz = 1; bsiz+sizeof(M_HEAD) <= n; bsiz <<= 1) |
128 |
|
bucket++; |
96 |
– |
mp = (M_HEAD *)p; |
129 |
|
while (bucket > FIRSTBUCKET) { |
130 |
|
bsiz >>= 1; |
131 |
|
bucket--; |
132 |
|
if (n < bsiz+sizeof(M_HEAD)) /* nothing for this bucket */ |
133 |
|
continue; |
134 |
< |
mp->next = free_list[bucket]; |
135 |
< |
free_list[bucket] = mp; |
136 |
< |
(char *)mp += bsiz+sizeof(M_HEAD); |
134 |
> |
((M_HEAD *)p)->next = free_list[bucket]; |
135 |
> |
free_list[bucket] = (M_HEAD *)p; |
136 |
> |
p += bsiz+sizeof(M_HEAD); |
137 |
|
n -= bsiz+sizeof(M_HEAD); |
138 |
|
} |
139 |
|
} |
147 |
|
register int bucket; |
148 |
|
register unsigned bsiz; |
149 |
|
|
150 |
+ |
if (n == 0) |
151 |
+ |
return(NULL); |
152 |
+ |
/* find first bucket that fits */ |
153 |
|
bucket = FIRSTBUCKET; |
154 |
|
for (bsiz = 1<<FIRSTBUCKET; bsiz < n; bsiz <<= 1) |
155 |
|
bucket++; |
181 |
|
if (n <= on && n > on>>1) |
182 |
|
return(op); /* same bucket */ |
183 |
|
p = malloc(n); |
184 |
< |
if (p == NULL) |
150 |
< |
return(NULL); |
184 |
> |
if (p != NULL) |
185 |
|
#ifdef BSD |
186 |
< |
bcopy(op, p, n>on ? on : n); |
186 |
> |
bcopy(op, p, n>on ? on : n); |
187 |
|
#else |
188 |
< |
(void)memcpy(p, op, n>on ? on : n); |
188 |
> |
(void)memcpy(p, op, n>on ? on : n); |
189 |
|
#endif |
190 |
|
free(op); |
191 |
|
return(p); |
198 |
|
register M_HEAD *mp; |
199 |
|
register int bucket; |
200 |
|
|
201 |
+ |
if (p == NULL) |
202 |
+ |
return; |
203 |
|
mp = (M_HEAD *)p - 1; |
204 |
|
bucket = mp->bucket; |
205 |
|
mp->next = free_list[bucket]; |