7 |
|
/* |
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. |
10 |
|
* malloc(), realloc() and free() use buckets |
11 |
|
* containing blocks in powers of two, similar to CIT routines. |
12 |
+ |
* bfree() puts memory from any source into malloc free lists. |
13 |
+ |
* bmalloc() doesn't keep track of free lists -- it's usually |
14 |
+ |
* just a buffered call to sbrk(2). However, bmalloc will |
15 |
+ |
* call mscrounge() if sbrk fails. |
16 |
+ |
* mscrounge() returns whatever free memory it can find to satisfy the |
17 |
+ |
* request along with the number of bytes (modified). |
18 |
|
* |
19 |
|
* Greg Ward Lawrence Berkeley Laboratory |
20 |
|
*/ |
21 |
|
|
22 |
+ |
#include <errno.h> |
23 |
+ |
|
24 |
+ |
#ifdef MSTATS |
25 |
+ |
#include <stdio.h> |
26 |
+ |
static unsigned b_nalloced = 0; |
27 |
+ |
static unsigned b_nfreed = 0; |
28 |
+ |
static unsigned b_nscrounged = 0; |
29 |
+ |
static unsigned m_nalloced = 0; |
30 |
+ |
static unsigned m_nfreed = 0; |
31 |
+ |
static unsigned m_nwasted = 0; |
32 |
+ |
#else |
33 |
|
#define NULL 0 |
34 |
+ |
#endif |
35 |
|
|
36 |
|
#ifndef ALIGN |
37 |
|
#define ALIGN int /* align type */ |
38 |
|
#endif |
39 |
|
#define BYTES_WORD sizeof(ALIGN) |
40 |
|
|
41 |
+ |
#define MAXINCR (1<<16) /* largest sbrk(2) increment */ |
42 |
+ |
|
43 |
|
#ifdef NOVMEM |
44 |
|
#define getpagesize() BYTES_WORD |
45 |
|
#endif |
29 |
– |
|
46 |
|
/* malloc free lists */ |
47 |
|
typedef union m_head { |
48 |
|
union m_head *next; |
55 |
|
|
56 |
|
static M_HEAD *free_list[NBUCKETS]; |
57 |
|
|
58 |
+ |
static char DUMMYLOC[BYTES_WORD]; |
59 |
|
|
60 |
+ |
|
61 |
|
char * |
62 |
+ |
mscrounge(np) /* search free lists to satisfy request */ |
63 |
+ |
register unsigned *np; |
64 |
+ |
{ |
65 |
+ |
char *p; |
66 |
+ |
register int bucket; |
67 |
+ |
register unsigned bsiz; |
68 |
+ |
|
69 |
+ |
for (bucket = FIRSTBUCKET, bsiz = 1<<FIRSTBUCKET; |
70 |
+ |
bucket < NBUCKETS; bucket++, bsiz <<= 1) |
71 |
+ |
if (free_list[bucket] != NULL && bsiz+sizeof(M_HEAD) >= *np) { |
72 |
+ |
*np = bsiz+sizeof(M_HEAD); |
73 |
+ |
p = (char *)free_list[bucket]; |
74 |
+ |
free_list[bucket] = free_list[bucket]->next; |
75 |
+ |
#ifdef MSTATS |
76 |
+ |
b_nscrounged += *np; |
77 |
+ |
#endif |
78 |
+ |
return(p); |
79 |
+ |
} |
80 |
+ |
*np = 0; |
81 |
+ |
return(NULL); |
82 |
+ |
} |
83 |
+ |
|
84 |
+ |
|
85 |
+ |
char * |
86 |
|
bmalloc(n) /* allocate a block of n bytes, sans header */ |
87 |
|
register unsigned n; |
88 |
|
{ |
89 |
|
extern char *sbrk(); |
90 |
< |
static int pagesz = 0; |
91 |
< |
static int amnt; |
90 |
> |
static unsigned pagesz = 0; |
91 |
> |
static unsigned amnt; |
92 |
|
static char *bpos; |
93 |
< |
static int nrem; |
93 |
> |
static unsigned nrem; |
94 |
> |
unsigned thisamnt; |
95 |
|
register char *p; |
96 |
|
|
97 |
+ |
#ifdef MSTATS |
98 |
+ |
b_nalloced += n; |
99 |
+ |
#endif |
100 |
|
if (pagesz == 0) { /* initialize */ |
101 |
< |
amnt = pagesz = getpagesize(); |
101 |
> |
pagesz = amnt = getpagesize(); |
102 |
|
nrem = (int)sbrk(0); /* page align break */ |
103 |
|
nrem = pagesz - (nrem&(pagesz-1)); |
104 |
|
bpos = sbrk(nrem); /* word aligned! */ |
109 |
|
n = (n+(BYTES_WORD-1))&~(BYTES_WORD-1); /* word align rqst. */ |
110 |
|
|
111 |
|
if (n > nrem) { /* need more core */ |
112 |
< |
if (n > amnt) /* increase amount */ |
113 |
< |
amnt = (n+(pagesz-1))&~(pagesz-1); |
114 |
< |
p = sbrk(amnt); |
115 |
< |
if ((int)p == -1) |
70 |
< |
return(NULL); |
71 |
< |
if (p != bpos+nrem) { /* someone called sbrk()! */ |
72 |
< |
bfree(bpos, nrem); |
73 |
< |
bpos = p; |
74 |
< |
nrem = amnt; |
112 |
> |
if (n > amnt) { /* big chunk */ |
113 |
> |
thisamnt = (n+(pagesz-1))&~(pagesz-1); |
114 |
> |
if (thisamnt <= MAXINCR) /* increase amnt */ |
115 |
> |
amnt = thisamnt; |
116 |
|
} else |
117 |
< |
nrem += amnt; |
117 |
> |
thisamnt = amnt; |
118 |
> |
p = sbrk(thisamnt); |
119 |
> |
if ((int)p == -1) { /* uh-oh, ENOMEM */ |
120 |
> |
thisamnt = n; /* search free lists */ |
121 |
> |
p = mscrounge(&thisamnt); |
122 |
> |
if (p == NULL) /* we're really out */ |
123 |
> |
return(NULL); |
124 |
> |
} |
125 |
> |
if (p != bpos+nrem) { /* not an increment */ |
126 |
> |
bfree(bpos, nrem); /* free what we have */ |
127 |
> |
bpos = p; |
128 |
> |
nrem = thisamnt; |
129 |
> |
} else /* otherwise tack on */ |
130 |
> |
nrem += thisamnt; |
131 |
|
} |
132 |
|
p = bpos; |
133 |
|
bpos += n; /* advance */ |
137 |
|
|
138 |
|
|
139 |
|
bfree(p, n) /* free n bytes of random memory */ |
140 |
< |
char *p; |
141 |
< |
unsigned n; |
140 |
> |
register char *p; |
141 |
> |
register unsigned n; |
142 |
|
{ |
89 |
– |
register M_HEAD *mp; |
143 |
|
register int bucket; |
144 |
|
register unsigned bsiz; |
145 |
< |
/* find largest bucket */ |
146 |
< |
bucket = 0; |
147 |
< |
for (bsiz = 1; bsiz+sizeof(M_HEAD) <= n; bsiz <<= 1) |
148 |
< |
bucket++; |
149 |
< |
mp = (M_HEAD *)p; |
150 |
< |
while (bucket > FIRSTBUCKET) { |
151 |
< |
bsiz >>= 1; |
152 |
< |
bucket--; |
153 |
< |
if (n < bsiz+sizeof(M_HEAD)) /* nothing for this bucket */ |
101 |
< |
continue; |
102 |
< |
mp->next = free_list[bucket]; |
103 |
< |
free_list[bucket] = mp; |
104 |
< |
(char *)mp += bsiz+sizeof(M_HEAD); |
105 |
< |
n -= bsiz+sizeof(M_HEAD); |
145 |
> |
|
146 |
> |
#ifdef MSTATS |
147 |
> |
b_nfreed += n; |
148 |
> |
#endif |
149 |
> |
/* align pointer */ |
150 |
> |
bsiz = BYTES_WORD - ((unsigned)p&(BYTES_WORD-1)); |
151 |
> |
if (bsiz < BYTES_WORD) { |
152 |
> |
p += bsiz; |
153 |
> |
n -= bsiz; |
154 |
|
} |
155 |
+ |
/* fill big buckets first */ |
156 |
+ |
for (bucket = NBUCKETS-1, bsiz = 1<<(NBUCKETS-1); |
157 |
+ |
bucket >= FIRSTBUCKET; bucket--, bsiz >>= 1) |
158 |
+ |
if (n >= bsiz+sizeof(M_HEAD)) { |
159 |
+ |
((M_HEAD *)p)->next = free_list[bucket]; |
160 |
+ |
free_list[bucket] = (M_HEAD *)p; |
161 |
+ |
p += bsiz+sizeof(M_HEAD); |
162 |
+ |
n -= bsiz+sizeof(M_HEAD); |
163 |
+ |
} |
164 |
|
} |
165 |
|
|
166 |
|
|
168 |
|
malloc(n) /* allocate n bytes of memory */ |
169 |
|
unsigned n; |
170 |
|
{ |
171 |
+ |
extern int errno; |
172 |
|
register M_HEAD *mp; |
173 |
|
register int bucket; |
174 |
|
register unsigned bsiz; |
175 |
< |
|
176 |
< |
bucket = FIRSTBUCKET; |
177 |
< |
for (bsiz = 1<<FIRSTBUCKET; bsiz < n; bsiz <<= 1) |
178 |
< |
bucket++; |
179 |
< |
if (free_list[bucket] == NULL) { |
175 |
> |
/* don't return NULL on 0 request */ |
176 |
> |
if (n == 0) |
177 |
> |
return(DUMMYLOC); |
178 |
> |
/* find first bucket that fits */ |
179 |
> |
for (bucket = FIRSTBUCKET, bsiz = 1<<FIRSTBUCKET; |
180 |
> |
bucket < NBUCKETS; bucket++, bsiz <<= 1) |
181 |
> |
if (bsiz >= n) |
182 |
> |
break; |
183 |
> |
if (bucket >= NBUCKETS) { |
184 |
> |
errno = EINVAL; |
185 |
> |
return(NULL); |
186 |
> |
} |
187 |
> |
#ifdef MSTATS |
188 |
> |
m_nalloced += bsiz + sizeof(M_HEAD); |
189 |
> |
m_nwasted += bsiz + sizeof(M_HEAD) - n; |
190 |
> |
#endif |
191 |
> |
if (free_list[bucket] == NULL) { /* need more core */ |
192 |
|
mp = (M_HEAD *)bmalloc(bsiz+sizeof(M_HEAD)); |
193 |
|
if (mp == NULL) |
194 |
|
return(NULL); |
195 |
< |
} else { |
195 |
> |
} else { /* got it */ |
196 |
|
mp = free_list[bucket]; |
197 |
|
free_list[bucket] = mp->next; |
198 |
|
} |
199 |
< |
mp->bucket = bucket; |
199 |
> |
mp->bucket = bucket; /* tag block */ |
200 |
|
return((char *)(mp+1)); |
201 |
|
} |
202 |
|
|
203 |
|
|
204 |
|
char * |
205 |
|
realloc(op, n) /* reallocate memory using malloc() */ |
206 |
< |
char *op; |
206 |
> |
register char *op; |
207 |
|
unsigned n; |
208 |
|
{ |
209 |
< |
register char *p; |
209 |
> |
char *p; |
210 |
|
register unsigned on; |
211 |
< |
|
212 |
< |
if (op != NULL) |
211 |
> |
/* get old size */ |
212 |
> |
if (op != NULL && op != DUMMYLOC) |
213 |
|
on = 1 << ((M_HEAD *)op-1)->bucket; |
214 |
|
else |
215 |
|
on = 0; |
216 |
< |
if (n <= on && n > on>>1) |
216 |
> |
if (n <= on && (n > on>>1 || on == 1<<FIRSTBUCKET)) |
217 |
|
return(op); /* same bucket */ |
218 |
|
p = malloc(n); |
219 |
< |
if (p == NULL) |
150 |
< |
return(NULL); |
219 |
> |
if (p != NULL) |
220 |
|
#ifdef BSD |
221 |
< |
bcopy(op, p, n>on ? on : n); |
221 |
> |
bcopy(op, p, n>on ? on : n); |
222 |
|
#else |
223 |
< |
(void)memcpy(p, op, n>on ? on : n); |
223 |
> |
(void)memcpy(p, op, n>on ? on : n); |
224 |
|
#endif |
225 |
|
free(op); |
226 |
|
return(p); |
233 |
|
register M_HEAD *mp; |
234 |
|
register int bucket; |
235 |
|
|
236 |
+ |
if (p == NULL || p == DUMMYLOC) |
237 |
+ |
return; |
238 |
|
mp = (M_HEAD *)p - 1; |
239 |
|
bucket = mp->bucket; |
240 |
|
mp->next = free_list[bucket]; |
241 |
|
free_list[bucket] = mp; |
242 |
+ |
#ifdef MSTATS |
243 |
+ |
m_nfreed += (1 << bucket) + sizeof(M_HEAD); |
244 |
+ |
#endif |
245 |
|
} |
246 |
|
|
247 |
|
|
251 |
|
int |
252 |
|
getpagesize() /* use SYSV var structure to get page size */ |
253 |
|
{ |
180 |
– |
static int pagesz = 0; |
254 |
|
struct var v; |
255 |
|
|
256 |
< |
if (pagesz == 0) { |
257 |
< |
uvar(&v); |
185 |
< |
pagesz = 1 << v.v_pageshift; |
186 |
< |
} |
187 |
< |
return(pagesz); |
256 |
> |
uvar(&v); |
257 |
> |
return(1 << v.v_pageshift); |
258 |
|
} |
259 |
|
#endif |
260 |
+ |
#endif |
261 |
+ |
|
262 |
+ |
|
263 |
+ |
#ifdef MSTATS |
264 |
+ |
printmemstats(fp) /* print memory statistics to stream */ |
265 |
+ |
FILE *fp; |
266 |
+ |
{ |
267 |
+ |
register int i; |
268 |
+ |
int n; |
269 |
+ |
register M_HEAD *mp; |
270 |
+ |
unsigned int total = 0; |
271 |
+ |
|
272 |
+ |
fprintf(fp, "Memory statistics:\n"); |
273 |
+ |
fprintf(fp, "\tbmalloc: %d bytes allocated\n", b_nalloced); |
274 |
+ |
fprintf(fp, "\tbmalloc: %d bytes freed\n", b_nfreed); |
275 |
+ |
fprintf(fp, "\tbmalloc: %d bytes scrounged\n", b_nscrounged); |
276 |
+ |
fprintf(fp, "\tmalloc: %d bytes allocated\n", m_nalloced); |
277 |
+ |
fprintf(fp, "\tmalloc: %d bytes wasted (%.1f%%)\n", m_nwasted, |
278 |
+ |
100.0*m_nwasted/m_nalloced); |
279 |
+ |
fprintf(fp, "\tmalloc: %d bytes freed\n", m_nfreed); |
280 |
+ |
for (i = NBUCKETS-1; i >= FIRSTBUCKET; i--) { |
281 |
+ |
n = 0; |
282 |
+ |
for (mp = free_list[i]; mp != NULL; mp = mp->next) |
283 |
+ |
n++; |
284 |
+ |
if (n) { |
285 |
+ |
fprintf(fp, "\t%d * %u\n", n, 1<<i); |
286 |
+ |
total += n * ((1<<i) + sizeof(M_HEAD)); |
287 |
+ |
} |
288 |
+ |
} |
289 |
+ |
fprintf(fp, "\t %u total bytes in free list\n", total); |
290 |
+ |
} |
291 |
|
#endif |