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