Commit | Line | Data |
---|---|---|
d24c33a4 JA |
1 | /* |
2 | * simple memory allocator, backed by mmap() so that it hands out memory | |
3 | * that can be shared across processes and threads | |
4 | */ | |
5 | #include <sys/mman.h> | |
6 | #include <stdio.h> | |
7 | #include <stdlib.h> | |
8 | #include <assert.h> | |
9 | #include <string.h> | |
10 | #include <unistd.h> | |
11 | #include <sys/types.h> | |
12 | #include <limits.h> | |
13 | ||
14 | #include "mutex.h" | |
15 | ||
d24c33a4 JA |
16 | #define MP_SAFE /* define to made allocator thread safe */ |
17 | ||
85f46703 | 18 | #define INITIAL_SIZE 1048576 /* new pool size */ |
d24c33a4 JA |
19 | #define MAX_POOLS 32 /* maximum number of pools to setup */ |
20 | ||
2b386d25 JA |
21 | unsigned int smalloc_pool_size = INITIAL_SIZE; |
22 | ||
d24c33a4 JA |
23 | struct pool { |
24 | struct fio_mutex *lock; /* protects this pool */ | |
25 | void *map; /* map of blocks */ | |
26 | void *last; /* next free block hint */ | |
27 | unsigned int size; /* size of pool */ | |
28 | unsigned int room; /* size left in pool */ | |
29 | unsigned int largest_block; /* largest block free */ | |
30 | unsigned int free_since_compact; /* sfree() since compact() */ | |
31 | int fd; /* memory backing fd */ | |
32 | char file[PATH_MAX]; /* filename for fd */ | |
33 | }; | |
34 | ||
35 | static struct pool mp[MAX_POOLS]; | |
36 | static unsigned int nr_pools; | |
37 | static unsigned int last_pool; | |
38 | static struct fio_mutex *lock; | |
39 | ||
40 | struct mem_hdr { | |
41 | unsigned int size; | |
42 | }; | |
43 | ||
44 | static inline void pool_lock(struct pool *pool) | |
45 | { | |
46 | if (pool->lock) | |
47 | fio_mutex_down(pool->lock); | |
48 | } | |
49 | ||
50 | static inline void pool_unlock(struct pool *pool) | |
51 | { | |
52 | if (pool->lock) | |
53 | fio_mutex_up(pool->lock); | |
54 | } | |
55 | ||
65864cf7 | 56 | static inline void global_read_lock(void) |
d24c33a4 JA |
57 | { |
58 | if (lock) | |
65864cf7 | 59 | fio_mutex_down_read(lock); |
d24c33a4 JA |
60 | } |
61 | ||
65864cf7 | 62 | static inline void global_read_unlock(void) |
d24c33a4 JA |
63 | { |
64 | if (lock) | |
65864cf7 JA |
65 | fio_mutex_up_read(lock); |
66 | } | |
67 | ||
68 | static inline void global_write_lock(void) | |
69 | { | |
70 | if (lock) | |
71 | fio_mutex_down_write(lock); | |
72 | } | |
73 | ||
74 | static inline void global_write_unlock(void) | |
75 | { | |
76 | if (lock) | |
77 | fio_mutex_up_write(lock); | |
d24c33a4 JA |
78 | } |
79 | ||
80 | #define hdr_free(hdr) ((hdr)->size & 0x80000000) | |
81 | #define hdr_size(hdr) ((hdr)->size & ~0x80000000) | |
82 | #define hdr_mark_free(hdr) ((hdr)->size |= 0x80000000) | |
83 | ||
84 | static inline int ptr_valid(struct pool *pool, void *ptr) | |
85 | { | |
86 | return (ptr >= pool->map) && (ptr < pool->map + pool->size); | |
87 | } | |
88 | ||
89 | static inline int __hdr_valid(struct pool *pool, struct mem_hdr *hdr, | |
90 | unsigned int size) | |
91 | { | |
92 | return ptr_valid(pool, hdr) && ptr_valid(pool, (void *) hdr + size - 1); | |
93 | } | |
94 | ||
95 | static inline int hdr_valid(struct pool *pool, struct mem_hdr *hdr) | |
96 | { | |
97 | return __hdr_valid(pool, hdr, hdr_size(hdr)); | |
98 | } | |
99 | ||
100 | static inline int region_free(struct mem_hdr *hdr) | |
101 | { | |
102 | return hdr_free(hdr) || (!hdr_free(hdr) && !hdr_size(hdr)); | |
103 | } | |
104 | ||
105 | static inline struct mem_hdr *__hdr_nxt(struct pool *pool, struct mem_hdr *hdr, | |
106 | unsigned int size) | |
107 | { | |
108 | struct mem_hdr *nxt = (void *) hdr + size + sizeof(*hdr); | |
109 | ||
110 | if (__hdr_valid(pool, nxt, size)) | |
111 | return nxt; | |
112 | ||
113 | return NULL; | |
114 | } | |
115 | ||
116 | static inline struct mem_hdr *hdr_nxt(struct pool *pool, struct mem_hdr *hdr) | |
117 | { | |
118 | return __hdr_nxt(pool, hdr, hdr_size(hdr)); | |
119 | } | |
120 | ||
121 | static void merge(struct pool *pool, struct mem_hdr *hdr, struct mem_hdr *nxt) | |
122 | { | |
123 | unsigned int hfree = hdr_free(hdr); | |
124 | unsigned int nfree = hdr_free(nxt); | |
125 | ||
126 | hdr->size = hdr_size(hdr) + hdr_size(nxt) + sizeof(*nxt); | |
127 | nxt->size = 0; | |
128 | ||
129 | if (hfree) | |
130 | hdr_mark_free(hdr); | |
131 | if (nfree) | |
132 | hdr_mark_free(nxt); | |
133 | ||
134 | if (pool->last == nxt) | |
135 | pool->last = hdr; | |
136 | } | |
137 | ||
138 | static int combine(struct pool *pool, struct mem_hdr *prv, struct mem_hdr *hdr) | |
139 | { | |
140 | if (prv && hdr_free(prv) && hdr_free(hdr)) { | |
141 | merge(pool, prv, hdr); | |
142 | return 1; | |
143 | } | |
144 | ||
145 | return 0; | |
146 | } | |
147 | ||
148 | static int compact_pool(struct pool *pool) | |
149 | { | |
150 | struct mem_hdr *hdr = pool->map, *nxt; | |
151 | unsigned int compacted = 0; | |
152 | ||
153 | if (pool->free_since_compact < 50) | |
154 | return 1; | |
155 | ||
156 | while (hdr) { | |
157 | nxt = hdr_nxt(pool, hdr); | |
158 | if (!nxt) | |
159 | break; | |
160 | if (hdr_free(nxt) && hdr_free(hdr)) { | |
161 | merge(pool, hdr, nxt); | |
162 | compacted++; | |
163 | continue; | |
164 | } | |
165 | hdr = hdr_nxt(pool, hdr); | |
166 | } | |
167 | ||
168 | pool->free_since_compact = 0; | |
169 | return !!compacted; | |
170 | } | |
171 | ||
adf57099 | 172 | static int add_pool(struct pool *pool, unsigned int alloc_size) |
d24c33a4 JA |
173 | { |
174 | struct mem_hdr *hdr; | |
175 | void *ptr; | |
176 | int fd; | |
177 | ||
178 | strcpy(pool->file, "/tmp/.fio_smalloc.XXXXXX"); | |
179 | fd = mkstemp(pool->file); | |
180 | if (fd < 0) | |
181 | goto out_close; | |
182 | ||
c08e194d | 183 | alloc_size += sizeof(*hdr); |
adf57099 JA |
184 | if (alloc_size > smalloc_pool_size) |
185 | pool->size = alloc_size; | |
186 | else | |
187 | pool->size = smalloc_pool_size; | |
188 | ||
d24c33a4 JA |
189 | if (ftruncate(fd, pool->size) < 0) |
190 | goto out_unlink; | |
191 | ||
192 | ptr = mmap(NULL, pool->size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); | |
193 | if (ptr == MAP_FAILED) | |
194 | goto out_unlink; | |
195 | ||
196 | memset(ptr, 0, pool->size); | |
197 | pool->map = pool->last = ptr; | |
198 | ||
199 | #ifdef MP_SAFE | |
200 | pool->lock = fio_mutex_init(1); | |
201 | if (!pool->lock) | |
202 | goto out_unlink; | |
203 | #endif | |
204 | ||
205 | pool->fd = fd; | |
206 | ||
207 | hdr = pool->map; | |
208 | pool->room = hdr->size = pool->size - sizeof(*hdr); | |
209 | pool->largest_block = pool->room; | |
210 | hdr_mark_free(hdr); | |
65864cf7 | 211 | global_write_lock(); |
d24c33a4 | 212 | nr_pools++; |
65864cf7 | 213 | global_write_unlock(); |
d24c33a4 JA |
214 | return 0; |
215 | out_unlink: | |
216 | if (pool->map) | |
217 | munmap(pool->map, pool->size); | |
218 | unlink(pool->file); | |
219 | out_close: | |
220 | if (fd >= 0) | |
221 | close(fd); | |
222 | return 1; | |
223 | } | |
224 | ||
225 | void sinit(void) | |
226 | { | |
4d4e80f2 | 227 | int ret; |
d24c33a4 JA |
228 | |
229 | #ifdef MP_SAFE | |
9c5b5290 | 230 | lock = fio_mutex_rw_init(); |
d24c33a4 | 231 | #endif |
adf57099 | 232 | ret = add_pool(&mp[0], INITIAL_SIZE); |
d24c33a4 JA |
233 | assert(!ret); |
234 | } | |
235 | ||
236 | static void cleanup_pool(struct pool *pool) | |
237 | { | |
238 | unlink(pool->file); | |
239 | close(pool->fd); | |
240 | munmap(pool->map, pool->size); | |
241 | ||
242 | if (pool->lock) | |
243 | fio_mutex_remove(pool->lock); | |
244 | } | |
245 | ||
246 | void scleanup(void) | |
247 | { | |
248 | unsigned int i; | |
249 | ||
250 | for (i = 0; i < nr_pools; i++) | |
251 | cleanup_pool(&mp[i]); | |
252 | ||
253 | if (lock) | |
254 | fio_mutex_remove(lock); | |
255 | } | |
256 | ||
257 | static void sfree_pool(struct pool *pool, void *ptr) | |
258 | { | |
259 | struct mem_hdr *hdr, *nxt; | |
260 | ||
261 | if (!ptr) | |
262 | return; | |
263 | ||
264 | assert(ptr_valid(pool, ptr)); | |
265 | ||
266 | pool_lock(pool); | |
267 | hdr = ptr - sizeof(*hdr); | |
268 | assert(!hdr_free(hdr)); | |
269 | hdr_mark_free(hdr); | |
270 | pool->room -= hdr_size(hdr); | |
271 | ||
272 | nxt = hdr_nxt(pool, hdr); | |
273 | if (nxt && hdr_free(nxt)) | |
274 | merge(pool, hdr, nxt); | |
275 | ||
276 | if (hdr_size(hdr) > pool->largest_block) | |
277 | pool->largest_block = hdr_size(hdr); | |
278 | ||
279 | pool->free_since_compact++; | |
280 | pool_unlock(pool); | |
281 | } | |
282 | ||
283 | void sfree(void *ptr) | |
284 | { | |
285 | struct pool *pool = NULL; | |
286 | unsigned int i; | |
287 | ||
8e5732e5 JA |
288 | if (!ptr) |
289 | return; | |
290 | ||
65864cf7 | 291 | global_read_lock(); |
d24c33a4 JA |
292 | |
293 | for (i = 0; i < nr_pools; i++) { | |
294 | if (ptr_valid(&mp[i], ptr)) { | |
295 | pool = &mp[i]; | |
296 | break; | |
297 | } | |
298 | } | |
299 | ||
65864cf7 | 300 | global_read_unlock(); |
d24c33a4 JA |
301 | |
302 | assert(pool); | |
303 | sfree_pool(pool, ptr); | |
304 | } | |
305 | ||
306 | static void *smalloc_pool(struct pool *pool, unsigned int size) | |
307 | { | |
308 | struct mem_hdr *hdr, *prv; | |
309 | int did_restart = 0; | |
310 | void *ret; | |
311 | ||
8e5732e5 | 312 | if (!size) |
d24c33a4 JA |
313 | return NULL; |
314 | ||
315 | pool_lock(pool); | |
8e5732e5 JA |
316 | if (size > pool->room + sizeof(*hdr)) |
317 | goto fail; | |
318 | if ((size > pool->largest_block) && pool->largest_block) | |
319 | goto fail; | |
d24c33a4 JA |
320 | restart: |
321 | hdr = pool->last; | |
322 | prv = NULL; | |
323 | do { | |
324 | if (combine(pool, prv, hdr)) | |
325 | hdr = prv; | |
5ec10eaa | 326 | |
d24c33a4 JA |
327 | if (hdr_free(hdr) && hdr_size(hdr) >= size) |
328 | break; | |
329 | ||
330 | prv = hdr; | |
331 | } while ((hdr = hdr_nxt(pool, hdr)) != NULL); | |
332 | ||
333 | if (!hdr) | |
334 | goto fail; | |
335 | ||
336 | /* | |
337 | * more room, adjust next header if any | |
338 | */ | |
339 | if (hdr_size(hdr) - size >= 2 * sizeof(*hdr)) { | |
340 | struct mem_hdr *nxt = __hdr_nxt(pool, hdr, size); | |
341 | ||
342 | if (nxt) { | |
343 | nxt->size = hdr_size(hdr) - size - sizeof(*hdr); | |
344 | if (hdr_size(hdr) == pool->largest_block) | |
345 | pool->largest_block = hdr_size(nxt); | |
346 | hdr_mark_free(nxt); | |
347 | } else | |
348 | size = hdr_size(hdr); | |
349 | } else | |
350 | size = hdr_size(hdr); | |
351 | ||
352 | if (size == hdr_size(hdr) && size == pool->largest_block) | |
353 | pool->largest_block = 0; | |
354 | ||
355 | /* | |
356 | * also clears free bit | |
357 | */ | |
358 | hdr->size = size; | |
359 | pool->last = hdr_nxt(pool, hdr); | |
360 | if (!pool->last) | |
361 | pool->last = pool->map; | |
362 | pool->room -= size; | |
363 | pool_unlock(pool); | |
364 | ||
365 | ret = (void *) hdr + sizeof(*hdr); | |
366 | memset(ret, 0, size); | |
367 | return ret; | |
368 | fail: | |
369 | /* | |
370 | * if we fail to allocate, first compact the entries that we missed. | |
371 | * if that also fails, increase the size of the pool | |
372 | */ | |
136f6b79 | 373 | if (++did_restart <= 1) { |
d24c33a4 JA |
374 | if (!compact_pool(pool)) { |
375 | pool->last = pool->map; | |
376 | goto restart; | |
377 | } | |
378 | } | |
d24c33a4 JA |
379 | pool_unlock(pool); |
380 | return NULL; | |
381 | } | |
382 | ||
383 | void *smalloc(unsigned int size) | |
384 | { | |
385 | unsigned int i; | |
386 | ||
65864cf7 | 387 | global_read_lock(); |
d24c33a4 JA |
388 | i = last_pool; |
389 | ||
390 | do { | |
391 | for (; i < nr_pools; i++) { | |
392 | void *ptr = smalloc_pool(&mp[i], size); | |
393 | ||
394 | if (ptr) { | |
395 | last_pool = i; | |
65864cf7 | 396 | global_read_unlock(); |
d24c33a4 JA |
397 | return ptr; |
398 | } | |
399 | } | |
400 | if (last_pool) { | |
401 | last_pool = 0; | |
402 | continue; | |
403 | } | |
404 | ||
405 | if (nr_pools + 1 >= MAX_POOLS) | |
406 | break; | |
407 | else { | |
408 | i = nr_pools; | |
65864cf7 | 409 | global_read_unlock(); |
adf57099 | 410 | if (add_pool(&mp[nr_pools], size)) |
65864cf7 JA |
411 | goto out; |
412 | global_read_lock(); | |
d24c33a4 JA |
413 | } |
414 | } while (1); | |
415 | ||
65864cf7 JA |
416 | global_read_unlock(); |
417 | out: | |
d24c33a4 JA |
418 | return NULL; |
419 | } | |
420 | ||
421 | char *smalloc_strdup(const char *str) | |
422 | { | |
423 | char *ptr; | |
424 | ||
425 | ptr = smalloc(strlen(str) + 1); | |
426 | strcpy(ptr, str); | |
427 | return ptr; | |
428 | } |