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 | ||
16 | #undef ENABLE_RESIZE /* define to enable pool resizing */ | |
17 | #define MP_SAFE /* define to made allocator thread safe */ | |
18 | ||
19 | #define INITIAL_SIZE 65536 /* new pool size */ | |
20 | #define MAX_POOLS 32 /* maximum number of pools to setup */ | |
21 | ||
22 | #ifdef ENABLE_RESIZE | |
23 | #define MAX_SIZE 8 * INITIAL_SIZE | |
24 | static unsigned int resize_error; | |
25 | #endif | |
26 | ||
27 | struct pool { | |
28 | struct fio_mutex *lock; /* protects this pool */ | |
29 | void *map; /* map of blocks */ | |
30 | void *last; /* next free block hint */ | |
31 | unsigned int size; /* size of pool */ | |
32 | unsigned int room; /* size left in pool */ | |
33 | unsigned int largest_block; /* largest block free */ | |
34 | unsigned int free_since_compact; /* sfree() since compact() */ | |
35 | int fd; /* memory backing fd */ | |
36 | char file[PATH_MAX]; /* filename for fd */ | |
37 | }; | |
38 | ||
39 | static struct pool mp[MAX_POOLS]; | |
40 | static unsigned int nr_pools; | |
41 | static unsigned int last_pool; | |
42 | static struct fio_mutex *lock; | |
43 | ||
44 | struct mem_hdr { | |
45 | unsigned int size; | |
46 | }; | |
47 | ||
48 | static inline void pool_lock(struct pool *pool) | |
49 | { | |
50 | if (pool->lock) | |
51 | fio_mutex_down(pool->lock); | |
52 | } | |
53 | ||
54 | static inline void pool_unlock(struct pool *pool) | |
55 | { | |
56 | if (pool->lock) | |
57 | fio_mutex_up(pool->lock); | |
58 | } | |
59 | ||
65864cf7 | 60 | static inline void global_read_lock(void) |
d24c33a4 JA |
61 | { |
62 | if (lock) | |
65864cf7 | 63 | fio_mutex_down_read(lock); |
d24c33a4 JA |
64 | } |
65 | ||
65864cf7 | 66 | static inline void global_read_unlock(void) |
d24c33a4 JA |
67 | { |
68 | if (lock) | |
65864cf7 JA |
69 | fio_mutex_up_read(lock); |
70 | } | |
71 | ||
72 | static inline void global_write_lock(void) | |
73 | { | |
74 | if (lock) | |
75 | fio_mutex_down_write(lock); | |
76 | } | |
77 | ||
78 | static inline void global_write_unlock(void) | |
79 | { | |
80 | if (lock) | |
81 | fio_mutex_up_write(lock); | |
d24c33a4 JA |
82 | } |
83 | ||
84 | #define hdr_free(hdr) ((hdr)->size & 0x80000000) | |
85 | #define hdr_size(hdr) ((hdr)->size & ~0x80000000) | |
86 | #define hdr_mark_free(hdr) ((hdr)->size |= 0x80000000) | |
87 | ||
88 | static inline int ptr_valid(struct pool *pool, void *ptr) | |
89 | { | |
90 | return (ptr >= pool->map) && (ptr < pool->map + pool->size); | |
91 | } | |
92 | ||
93 | static inline int __hdr_valid(struct pool *pool, struct mem_hdr *hdr, | |
94 | unsigned int size) | |
95 | { | |
96 | return ptr_valid(pool, hdr) && ptr_valid(pool, (void *) hdr + size - 1); | |
97 | } | |
98 | ||
99 | static inline int hdr_valid(struct pool *pool, struct mem_hdr *hdr) | |
100 | { | |
101 | return __hdr_valid(pool, hdr, hdr_size(hdr)); | |
102 | } | |
103 | ||
104 | static inline int region_free(struct mem_hdr *hdr) | |
105 | { | |
106 | return hdr_free(hdr) || (!hdr_free(hdr) && !hdr_size(hdr)); | |
107 | } | |
108 | ||
109 | static inline struct mem_hdr *__hdr_nxt(struct pool *pool, struct mem_hdr *hdr, | |
110 | unsigned int size) | |
111 | { | |
112 | struct mem_hdr *nxt = (void *) hdr + size + sizeof(*hdr); | |
113 | ||
114 | if (__hdr_valid(pool, nxt, size)) | |
115 | return nxt; | |
116 | ||
117 | return NULL; | |
118 | } | |
119 | ||
120 | static inline struct mem_hdr *hdr_nxt(struct pool *pool, struct mem_hdr *hdr) | |
121 | { | |
122 | return __hdr_nxt(pool, hdr, hdr_size(hdr)); | |
123 | } | |
124 | ||
125 | static void merge(struct pool *pool, struct mem_hdr *hdr, struct mem_hdr *nxt) | |
126 | { | |
127 | unsigned int hfree = hdr_free(hdr); | |
128 | unsigned int nfree = hdr_free(nxt); | |
129 | ||
130 | hdr->size = hdr_size(hdr) + hdr_size(nxt) + sizeof(*nxt); | |
131 | nxt->size = 0; | |
132 | ||
133 | if (hfree) | |
134 | hdr_mark_free(hdr); | |
135 | if (nfree) | |
136 | hdr_mark_free(nxt); | |
137 | ||
138 | if (pool->last == nxt) | |
139 | pool->last = hdr; | |
140 | } | |
141 | ||
142 | static int combine(struct pool *pool, struct mem_hdr *prv, struct mem_hdr *hdr) | |
143 | { | |
144 | if (prv && hdr_free(prv) && hdr_free(hdr)) { | |
145 | merge(pool, prv, hdr); | |
146 | return 1; | |
147 | } | |
148 | ||
149 | return 0; | |
150 | } | |
151 | ||
152 | static int compact_pool(struct pool *pool) | |
153 | { | |
154 | struct mem_hdr *hdr = pool->map, *nxt; | |
155 | unsigned int compacted = 0; | |
156 | ||
157 | if (pool->free_since_compact < 50) | |
158 | return 1; | |
159 | ||
160 | while (hdr) { | |
161 | nxt = hdr_nxt(pool, hdr); | |
162 | if (!nxt) | |
163 | break; | |
164 | if (hdr_free(nxt) && hdr_free(hdr)) { | |
165 | merge(pool, hdr, nxt); | |
166 | compacted++; | |
167 | continue; | |
168 | } | |
169 | hdr = hdr_nxt(pool, hdr); | |
170 | } | |
171 | ||
172 | pool->free_since_compact = 0; | |
173 | return !!compacted; | |
174 | } | |
175 | ||
176 | static int resize_pool(struct pool *pool) | |
177 | { | |
178 | #ifdef ENABLE_RESIZE | |
179 | unsigned int new_size = pool->size << 1; | |
180 | struct mem_hdr *hdr, *last_hdr; | |
181 | void *ptr; | |
182 | ||
183 | if (new_size >= MAX_SIZE || resize_error) | |
184 | return 1; | |
185 | ||
186 | if (ftruncate(pool->fd, new_size) < 0) | |
187 | goto fail; | |
188 | ||
189 | ptr = mremap(pool->map, pool->size, new_size, 0); | |
190 | if (ptr == MAP_FAILED) | |
191 | goto fail; | |
192 | ||
193 | pool->map = ptr; | |
194 | hdr = pool; | |
195 | do { | |
196 | last_hdr = hdr; | |
197 | } while ((hdr = hdr_nxt(hdr)) != NULL); | |
198 | ||
199 | if (hdr_free(last_hdr)) { | |
200 | last_hdr->size = hdr_size(last_hdr) + new_size - pool_size; | |
201 | hdr_mark_free(last_hdr); | |
202 | } else { | |
203 | struct mem_hdr *nxt; | |
204 | ||
205 | nxt = (void *) last_hdr + hdr_size(last_hdr) + sizeof(*hdr); | |
206 | nxt->size = new_size - pool_size - sizeof(*hdr); | |
207 | hdr_mark_free(nxt); | |
208 | } | |
209 | ||
210 | pool_room += new_size - pool_size; | |
211 | pool_size = new_size; | |
212 | return 0; | |
213 | fail: | |
214 | perror("resize"); | |
215 | resize_error = 1; | |
216 | #else | |
217 | return 1; | |
218 | #endif | |
219 | } | |
220 | ||
221 | static int add_pool(struct pool *pool) | |
222 | { | |
223 | struct mem_hdr *hdr; | |
224 | void *ptr; | |
225 | int fd; | |
226 | ||
227 | strcpy(pool->file, "/tmp/.fio_smalloc.XXXXXX"); | |
228 | fd = mkstemp(pool->file); | |
229 | if (fd < 0) | |
230 | goto out_close; | |
231 | ||
232 | pool->size = INITIAL_SIZE; | |
233 | if (ftruncate(fd, pool->size) < 0) | |
234 | goto out_unlink; | |
235 | ||
236 | ptr = mmap(NULL, pool->size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); | |
237 | if (ptr == MAP_FAILED) | |
238 | goto out_unlink; | |
239 | ||
240 | memset(ptr, 0, pool->size); | |
241 | pool->map = pool->last = ptr; | |
242 | ||
243 | #ifdef MP_SAFE | |
244 | pool->lock = fio_mutex_init(1); | |
245 | if (!pool->lock) | |
246 | goto out_unlink; | |
247 | #endif | |
248 | ||
249 | pool->fd = fd; | |
250 | ||
251 | hdr = pool->map; | |
252 | pool->room = hdr->size = pool->size - sizeof(*hdr); | |
253 | pool->largest_block = pool->room; | |
254 | hdr_mark_free(hdr); | |
65864cf7 | 255 | global_write_lock(); |
d24c33a4 | 256 | nr_pools++; |
65864cf7 | 257 | global_write_unlock(); |
d24c33a4 JA |
258 | return 0; |
259 | out_unlink: | |
260 | if (pool->map) | |
261 | munmap(pool->map, pool->size); | |
262 | unlink(pool->file); | |
263 | out_close: | |
264 | if (fd >= 0) | |
265 | close(fd); | |
266 | return 1; | |
267 | } | |
268 | ||
269 | void sinit(void) | |
270 | { | |
4d4e80f2 | 271 | int ret; |
d24c33a4 JA |
272 | |
273 | #ifdef MP_SAFE | |
9c5b5290 | 274 | lock = fio_mutex_rw_init(); |
d24c33a4 | 275 | #endif |
4d4e80f2 | 276 | ret = add_pool(&mp[0]); |
d24c33a4 JA |
277 | assert(!ret); |
278 | } | |
279 | ||
280 | static void cleanup_pool(struct pool *pool) | |
281 | { | |
282 | unlink(pool->file); | |
283 | close(pool->fd); | |
284 | munmap(pool->map, pool->size); | |
285 | ||
286 | if (pool->lock) | |
287 | fio_mutex_remove(pool->lock); | |
288 | } | |
289 | ||
290 | void scleanup(void) | |
291 | { | |
292 | unsigned int i; | |
293 | ||
294 | for (i = 0; i < nr_pools; i++) | |
295 | cleanup_pool(&mp[i]); | |
296 | ||
297 | if (lock) | |
298 | fio_mutex_remove(lock); | |
299 | } | |
300 | ||
301 | static void sfree_pool(struct pool *pool, void *ptr) | |
302 | { | |
303 | struct mem_hdr *hdr, *nxt; | |
304 | ||
305 | if (!ptr) | |
306 | return; | |
307 | ||
308 | assert(ptr_valid(pool, ptr)); | |
309 | ||
310 | pool_lock(pool); | |
311 | hdr = ptr - sizeof(*hdr); | |
312 | assert(!hdr_free(hdr)); | |
313 | hdr_mark_free(hdr); | |
314 | pool->room -= hdr_size(hdr); | |
315 | ||
316 | nxt = hdr_nxt(pool, hdr); | |
317 | if (nxt && hdr_free(nxt)) | |
318 | merge(pool, hdr, nxt); | |
319 | ||
320 | if (hdr_size(hdr) > pool->largest_block) | |
321 | pool->largest_block = hdr_size(hdr); | |
322 | ||
323 | pool->free_since_compact++; | |
324 | pool_unlock(pool); | |
325 | } | |
326 | ||
327 | void sfree(void *ptr) | |
328 | { | |
329 | struct pool *pool = NULL; | |
330 | unsigned int i; | |
331 | ||
65864cf7 | 332 | global_read_lock(); |
d24c33a4 JA |
333 | |
334 | for (i = 0; i < nr_pools; i++) { | |
335 | if (ptr_valid(&mp[i], ptr)) { | |
336 | pool = &mp[i]; | |
337 | break; | |
338 | } | |
339 | } | |
340 | ||
65864cf7 | 341 | global_read_unlock(); |
d24c33a4 JA |
342 | |
343 | assert(pool); | |
344 | sfree_pool(pool, ptr); | |
345 | } | |
346 | ||
347 | static void *smalloc_pool(struct pool *pool, unsigned int size) | |
348 | { | |
349 | struct mem_hdr *hdr, *prv; | |
350 | int did_restart = 0; | |
351 | void *ret; | |
352 | ||
353 | /* | |
354 | * slight chance of race with sfree() here, but acceptable | |
355 | */ | |
356 | if (!size || size > pool->room + sizeof(*hdr) || | |
357 | ((size > pool->largest_block) && pool->largest_block)) | |
358 | return NULL; | |
359 | ||
360 | pool_lock(pool); | |
361 | restart: | |
362 | hdr = pool->last; | |
363 | prv = NULL; | |
364 | do { | |
365 | if (combine(pool, prv, hdr)) | |
366 | hdr = prv; | |
5ec10eaa | 367 | |
d24c33a4 JA |
368 | if (hdr_free(hdr) && hdr_size(hdr) >= size) |
369 | break; | |
370 | ||
371 | prv = hdr; | |
372 | } while ((hdr = hdr_nxt(pool, hdr)) != NULL); | |
373 | ||
374 | if (!hdr) | |
375 | goto fail; | |
376 | ||
377 | /* | |
378 | * more room, adjust next header if any | |
379 | */ | |
380 | if (hdr_size(hdr) - size >= 2 * sizeof(*hdr)) { | |
381 | struct mem_hdr *nxt = __hdr_nxt(pool, hdr, size); | |
382 | ||
383 | if (nxt) { | |
384 | nxt->size = hdr_size(hdr) - size - sizeof(*hdr); | |
385 | if (hdr_size(hdr) == pool->largest_block) | |
386 | pool->largest_block = hdr_size(nxt); | |
387 | hdr_mark_free(nxt); | |
388 | } else | |
389 | size = hdr_size(hdr); | |
390 | } else | |
391 | size = hdr_size(hdr); | |
392 | ||
393 | if (size == hdr_size(hdr) && size == pool->largest_block) | |
394 | pool->largest_block = 0; | |
395 | ||
396 | /* | |
397 | * also clears free bit | |
398 | */ | |
399 | hdr->size = size; | |
400 | pool->last = hdr_nxt(pool, hdr); | |
401 | if (!pool->last) | |
402 | pool->last = pool->map; | |
403 | pool->room -= size; | |
404 | pool_unlock(pool); | |
405 | ||
406 | ret = (void *) hdr + sizeof(*hdr); | |
407 | memset(ret, 0, size); | |
408 | return ret; | |
409 | fail: | |
410 | /* | |
411 | * if we fail to allocate, first compact the entries that we missed. | |
412 | * if that also fails, increase the size of the pool | |
413 | */ | |
414 | ++did_restart; | |
415 | if (did_restart <= 1) { | |
416 | if (!compact_pool(pool)) { | |
417 | pool->last = pool->map; | |
418 | goto restart; | |
419 | } | |
420 | } | |
421 | ++did_restart; | |
422 | if (did_restart <= 2) { | |
423 | if (!resize_pool(pool)) { | |
424 | pool->last = pool->map; | |
425 | goto restart; | |
426 | } | |
427 | } | |
428 | pool_unlock(pool); | |
429 | return NULL; | |
430 | } | |
431 | ||
432 | void *smalloc(unsigned int size) | |
433 | { | |
434 | unsigned int i; | |
435 | ||
65864cf7 | 436 | global_read_lock(); |
d24c33a4 JA |
437 | i = last_pool; |
438 | ||
439 | do { | |
440 | for (; i < nr_pools; i++) { | |
441 | void *ptr = smalloc_pool(&mp[i], size); | |
442 | ||
443 | if (ptr) { | |
444 | last_pool = i; | |
65864cf7 | 445 | global_read_unlock(); |
d24c33a4 JA |
446 | return ptr; |
447 | } | |
448 | } | |
449 | if (last_pool) { | |
450 | last_pool = 0; | |
451 | continue; | |
452 | } | |
453 | ||
454 | if (nr_pools + 1 >= MAX_POOLS) | |
455 | break; | |
456 | else { | |
457 | i = nr_pools; | |
65864cf7 | 458 | global_read_unlock(); |
d24c33a4 | 459 | if (add_pool(&mp[nr_pools])) |
65864cf7 JA |
460 | goto out; |
461 | global_read_lock(); | |
d24c33a4 JA |
462 | } |
463 | } while (1); | |
464 | ||
65864cf7 JA |
465 | global_read_unlock(); |
466 | out: | |
d24c33a4 JA |
467 | return NULL; |
468 | } | |
469 | ||
470 | char *smalloc_strdup(const char *str) | |
471 | { | |
472 | char *ptr; | |
473 | ||
474 | ptr = smalloc(strlen(str) + 1); | |
475 | strcpy(ptr, str); | |
476 | return ptr; | |
477 | } |