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61989a80 NG |
1 | /* |
2 | * zsmalloc memory allocator | |
3 | * | |
4 | * Copyright (C) 2011 Nitin Gupta | |
31fc00bb | 5 | * Copyright (C) 2012, 2013 Minchan Kim |
61989a80 NG |
6 | * |
7 | * This code is released using a dual license strategy: BSD/GPL | |
8 | * You can choose the license that better fits your requirements. | |
9 | * | |
10 | * Released under the terms of 3-clause BSD License | |
11 | * Released under the terms of GNU General Public License Version 2.0 | |
12 | */ | |
13 | ||
2db51dae | 14 | /* |
c3e3e88a NC |
15 | * This allocator is designed for use with zram. Thus, the allocator is |
16 | * supposed to work well under low memory conditions. In particular, it | |
17 | * never attempts higher order page allocation which is very likely to | |
18 | * fail under memory pressure. On the other hand, if we just use single | |
19 | * (0-order) pages, it would suffer from very high fragmentation -- | |
20 | * any object of size PAGE_SIZE/2 or larger would occupy an entire page. | |
21 | * This was one of the major issues with its predecessor (xvmalloc). | |
2db51dae NG |
22 | * |
23 | * To overcome these issues, zsmalloc allocates a bunch of 0-order pages | |
24 | * and links them together using various 'struct page' fields. These linked | |
25 | * pages act as a single higher-order page i.e. an object can span 0-order | |
26 | * page boundaries. The code refers to these linked pages as a single entity | |
27 | * called zspage. | |
28 | * | |
c3e3e88a NC |
29 | * For simplicity, zsmalloc can only allocate objects of size up to PAGE_SIZE |
30 | * since this satisfies the requirements of all its current users (in the | |
31 | * worst case, page is incompressible and is thus stored "as-is" i.e. in | |
32 | * uncompressed form). For allocation requests larger than this size, failure | |
33 | * is returned (see zs_malloc). | |
34 | * | |
35 | * Additionally, zs_malloc() does not return a dereferenceable pointer. | |
36 | * Instead, it returns an opaque handle (unsigned long) which encodes actual | |
37 | * location of the allocated object. The reason for this indirection is that | |
38 | * zsmalloc does not keep zspages permanently mapped since that would cause | |
39 | * issues on 32-bit systems where the VA region for kernel space mappings | |
40 | * is very small. So, before using the allocating memory, the object has to | |
41 | * be mapped using zs_map_object() to get a usable pointer and subsequently | |
42 | * unmapped using zs_unmap_object(). | |
43 | * | |
2db51dae NG |
44 | * Following is how we use various fields and flags of underlying |
45 | * struct page(s) to form a zspage. | |
46 | * | |
47 | * Usage of struct page fields: | |
48 | * page->first_page: points to the first component (0-order) page | |
49 | * page->index (union with page->freelist): offset of the first object | |
50 | * starting in this page. For the first page, this is | |
51 | * always 0, so we use this field (aka freelist) to point | |
52 | * to the first free object in zspage. | |
53 | * page->lru: links together all component pages (except the first page) | |
54 | * of a zspage | |
55 | * | |
56 | * For _first_ page only: | |
57 | * | |
58 | * page->private (union with page->first_page): refers to the | |
59 | * component page after the first page | |
60 | * page->freelist: points to the first free object in zspage. | |
61 | * Free objects are linked together using in-place | |
62 | * metadata. | |
63 | * page->objects: maximum number of objects we can store in this | |
64 | * zspage (class->zspage_order * PAGE_SIZE / class->size) | |
65 | * page->lru: links together first pages of various zspages. | |
66 | * Basically forming list of zspages in a fullness group. | |
67 | * page->mapping: class index and fullness group of the zspage | |
68 | * | |
69 | * Usage of struct page flags: | |
70 | * PG_private: identifies the first component page | |
71 | * PG_private2: identifies the last component page | |
72 | * | |
73 | */ | |
74 | ||
61989a80 NG |
75 | #ifdef CONFIG_ZSMALLOC_DEBUG |
76 | #define DEBUG | |
77 | #endif | |
78 | ||
79 | #include <linux/module.h> | |
80 | #include <linux/kernel.h> | |
81 | #include <linux/bitops.h> | |
82 | #include <linux/errno.h> | |
83 | #include <linux/highmem.h> | |
61989a80 NG |
84 | #include <linux/string.h> |
85 | #include <linux/slab.h> | |
86 | #include <asm/tlbflush.h> | |
87 | #include <asm/pgtable.h> | |
88 | #include <linux/cpumask.h> | |
89 | #include <linux/cpu.h> | |
0cbb613f | 90 | #include <linux/vmalloc.h> |
c60369f0 | 91 | #include <linux/hardirq.h> |
0959c63f SJ |
92 | #include <linux/spinlock.h> |
93 | #include <linux/types.h> | |
bcf1647d | 94 | #include <linux/zsmalloc.h> |
c795779d | 95 | #include <linux/zpool.h> |
0959c63f SJ |
96 | |
97 | /* | |
98 | * This must be power of 2 and greater than of equal to sizeof(link_free). | |
99 | * These two conditions ensure that any 'struct link_free' itself doesn't | |
100 | * span more than 1 page which avoids complex case of mapping 2 pages simply | |
101 | * to restore link_free pointer values. | |
102 | */ | |
103 | #define ZS_ALIGN 8 | |
104 | ||
105 | /* | |
106 | * A single 'zspage' is composed of up to 2^N discontiguous 0-order (single) | |
107 | * pages. ZS_MAX_ZSPAGE_ORDER defines upper limit on N. | |
108 | */ | |
109 | #define ZS_MAX_ZSPAGE_ORDER 2 | |
110 | #define ZS_MAX_PAGES_PER_ZSPAGE (_AC(1, UL) << ZS_MAX_ZSPAGE_ORDER) | |
111 | ||
112 | /* | |
113 | * Object location (<PFN>, <obj_idx>) is encoded as | |
c3e3e88a | 114 | * as single (unsigned long) handle value. |
0959c63f SJ |
115 | * |
116 | * Note that object index <obj_idx> is relative to system | |
117 | * page <PFN> it is stored in, so for each sub-page belonging | |
118 | * to a zspage, obj_idx starts with 0. | |
119 | * | |
120 | * This is made more complicated by various memory models and PAE. | |
121 | */ | |
122 | ||
123 | #ifndef MAX_PHYSMEM_BITS | |
124 | #ifdef CONFIG_HIGHMEM64G | |
125 | #define MAX_PHYSMEM_BITS 36 | |
126 | #else /* !CONFIG_HIGHMEM64G */ | |
127 | /* | |
128 | * If this definition of MAX_PHYSMEM_BITS is used, OBJ_INDEX_BITS will just | |
129 | * be PAGE_SHIFT | |
130 | */ | |
131 | #define MAX_PHYSMEM_BITS BITS_PER_LONG | |
132 | #endif | |
133 | #endif | |
134 | #define _PFN_BITS (MAX_PHYSMEM_BITS - PAGE_SHIFT) | |
135 | #define OBJ_INDEX_BITS (BITS_PER_LONG - _PFN_BITS) | |
136 | #define OBJ_INDEX_MASK ((_AC(1, UL) << OBJ_INDEX_BITS) - 1) | |
137 | ||
138 | #define MAX(a, b) ((a) >= (b) ? (a) : (b)) | |
139 | /* ZS_MIN_ALLOC_SIZE must be multiple of ZS_ALIGN */ | |
140 | #define ZS_MIN_ALLOC_SIZE \ | |
141 | MAX(32, (ZS_MAX_PAGES_PER_ZSPAGE << PAGE_SHIFT >> OBJ_INDEX_BITS)) | |
142 | #define ZS_MAX_ALLOC_SIZE PAGE_SIZE | |
143 | ||
144 | /* | |
7eb52512 | 145 | * On systems with 4K page size, this gives 255 size classes! There is a |
0959c63f SJ |
146 | * trader-off here: |
147 | * - Large number of size classes is potentially wasteful as free page are | |
148 | * spread across these classes | |
149 | * - Small number of size classes causes large internal fragmentation | |
150 | * - Probably its better to use specific size classes (empirically | |
151 | * determined). NOTE: all those class sizes must be set as multiple of | |
152 | * ZS_ALIGN to make sure link_free itself never has to span 2 pages. | |
153 | * | |
154 | * ZS_MIN_ALLOC_SIZE and ZS_SIZE_CLASS_DELTA must be multiple of ZS_ALIGN | |
155 | * (reason above) | |
156 | */ | |
d662b8eb | 157 | #define ZS_SIZE_CLASS_DELTA (PAGE_SIZE >> 8) |
0959c63f SJ |
158 | #define ZS_SIZE_CLASSES ((ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE) / \ |
159 | ZS_SIZE_CLASS_DELTA + 1) | |
160 | ||
161 | /* | |
162 | * We do not maintain any list for completely empty or full pages | |
163 | */ | |
164 | enum fullness_group { | |
165 | ZS_ALMOST_FULL, | |
166 | ZS_ALMOST_EMPTY, | |
167 | _ZS_NR_FULLNESS_GROUPS, | |
168 | ||
169 | ZS_EMPTY, | |
170 | ZS_FULL | |
171 | }; | |
172 | ||
40f9fb8c MG |
173 | /* |
174 | * number of size_classes | |
175 | */ | |
176 | static int zs_size_classes; | |
177 | ||
0959c63f SJ |
178 | /* |
179 | * We assign a page to ZS_ALMOST_EMPTY fullness group when: | |
180 | * n <= N / f, where | |
181 | * n = number of allocated objects | |
182 | * N = total number of objects zspage can store | |
6dd9737e | 183 | * f = fullness_threshold_frac |
0959c63f SJ |
184 | * |
185 | * Similarly, we assign zspage to: | |
186 | * ZS_ALMOST_FULL when n > N / f | |
187 | * ZS_EMPTY when n == 0 | |
188 | * ZS_FULL when n == N | |
189 | * | |
190 | * (see: fix_fullness_group()) | |
191 | */ | |
192 | static const int fullness_threshold_frac = 4; | |
193 | ||
194 | struct size_class { | |
195 | /* | |
196 | * Size of objects stored in this class. Must be multiple | |
197 | * of ZS_ALIGN. | |
198 | */ | |
199 | int size; | |
200 | unsigned int index; | |
201 | ||
202 | /* Number of PAGE_SIZE sized pages to combine to form a 'zspage' */ | |
203 | int pages_per_zspage; | |
204 | ||
205 | spinlock_t lock; | |
206 | ||
0959c63f SJ |
207 | struct page *fullness_list[_ZS_NR_FULLNESS_GROUPS]; |
208 | }; | |
209 | ||
210 | /* | |
211 | * Placed within free objects to form a singly linked list. | |
212 | * For every zspage, first_page->freelist gives head of this list. | |
213 | * | |
214 | * This must be power of 2 and less than or equal to ZS_ALIGN | |
215 | */ | |
216 | struct link_free { | |
217 | /* Handle of next free chunk (encodes <PFN, obj_idx>) */ | |
218 | void *next; | |
219 | }; | |
220 | ||
221 | struct zs_pool { | |
40f9fb8c | 222 | struct size_class **size_class; |
0959c63f SJ |
223 | |
224 | gfp_t flags; /* allocation flags used when growing pool */ | |
13de8933 | 225 | atomic_long_t pages_allocated; |
0959c63f | 226 | }; |
61989a80 NG |
227 | |
228 | /* | |
229 | * A zspage's class index and fullness group | |
230 | * are encoded in its (first)page->mapping | |
231 | */ | |
232 | #define CLASS_IDX_BITS 28 | |
233 | #define FULLNESS_BITS 4 | |
234 | #define CLASS_IDX_MASK ((1 << CLASS_IDX_BITS) - 1) | |
235 | #define FULLNESS_MASK ((1 << FULLNESS_BITS) - 1) | |
236 | ||
f553646a | 237 | struct mapping_area { |
1b945aee | 238 | #ifdef CONFIG_PGTABLE_MAPPING |
f553646a SJ |
239 | struct vm_struct *vm; /* vm area for mapping object that span pages */ |
240 | #else | |
241 | char *vm_buf; /* copy buffer for objects that span pages */ | |
242 | #endif | |
243 | char *vm_addr; /* address of kmap_atomic()'ed pages */ | |
244 | enum zs_mapmode vm_mm; /* mapping mode */ | |
245 | }; | |
246 | ||
c795779d DS |
247 | /* zpool driver */ |
248 | ||
249 | #ifdef CONFIG_ZPOOL | |
250 | ||
251 | static void *zs_zpool_create(gfp_t gfp, struct zpool_ops *zpool_ops) | |
252 | { | |
253 | return zs_create_pool(gfp); | |
254 | } | |
255 | ||
256 | static void zs_zpool_destroy(void *pool) | |
257 | { | |
258 | zs_destroy_pool(pool); | |
259 | } | |
260 | ||
261 | static int zs_zpool_malloc(void *pool, size_t size, gfp_t gfp, | |
262 | unsigned long *handle) | |
263 | { | |
264 | *handle = zs_malloc(pool, size); | |
265 | return *handle ? 0 : -1; | |
266 | } | |
267 | static void zs_zpool_free(void *pool, unsigned long handle) | |
268 | { | |
269 | zs_free(pool, handle); | |
270 | } | |
271 | ||
272 | static int zs_zpool_shrink(void *pool, unsigned int pages, | |
273 | unsigned int *reclaimed) | |
274 | { | |
275 | return -EINVAL; | |
276 | } | |
277 | ||
278 | static void *zs_zpool_map(void *pool, unsigned long handle, | |
279 | enum zpool_mapmode mm) | |
280 | { | |
281 | enum zs_mapmode zs_mm; | |
282 | ||
283 | switch (mm) { | |
284 | case ZPOOL_MM_RO: | |
285 | zs_mm = ZS_MM_RO; | |
286 | break; | |
287 | case ZPOOL_MM_WO: | |
288 | zs_mm = ZS_MM_WO; | |
289 | break; | |
290 | case ZPOOL_MM_RW: /* fallthru */ | |
291 | default: | |
292 | zs_mm = ZS_MM_RW; | |
293 | break; | |
294 | } | |
295 | ||
296 | return zs_map_object(pool, handle, zs_mm); | |
297 | } | |
298 | static void zs_zpool_unmap(void *pool, unsigned long handle) | |
299 | { | |
300 | zs_unmap_object(pool, handle); | |
301 | } | |
302 | ||
303 | static u64 zs_zpool_total_size(void *pool) | |
304 | { | |
722cdc17 | 305 | return zs_get_total_pages(pool) << PAGE_SHIFT; |
c795779d DS |
306 | } |
307 | ||
308 | static struct zpool_driver zs_zpool_driver = { | |
309 | .type = "zsmalloc", | |
310 | .owner = THIS_MODULE, | |
311 | .create = zs_zpool_create, | |
312 | .destroy = zs_zpool_destroy, | |
313 | .malloc = zs_zpool_malloc, | |
314 | .free = zs_zpool_free, | |
315 | .shrink = zs_zpool_shrink, | |
316 | .map = zs_zpool_map, | |
317 | .unmap = zs_zpool_unmap, | |
318 | .total_size = zs_zpool_total_size, | |
319 | }; | |
320 | ||
137f8cff | 321 | MODULE_ALIAS("zpool-zsmalloc"); |
c795779d DS |
322 | #endif /* CONFIG_ZPOOL */ |
323 | ||
61989a80 NG |
324 | /* per-cpu VM mapping areas for zspage accesses that cross page boundaries */ |
325 | static DEFINE_PER_CPU(struct mapping_area, zs_map_area); | |
326 | ||
327 | static int is_first_page(struct page *page) | |
328 | { | |
a27545bf | 329 | return PagePrivate(page); |
61989a80 NG |
330 | } |
331 | ||
332 | static int is_last_page(struct page *page) | |
333 | { | |
a27545bf | 334 | return PagePrivate2(page); |
61989a80 NG |
335 | } |
336 | ||
337 | static void get_zspage_mapping(struct page *page, unsigned int *class_idx, | |
338 | enum fullness_group *fullness) | |
339 | { | |
340 | unsigned long m; | |
341 | BUG_ON(!is_first_page(page)); | |
342 | ||
343 | m = (unsigned long)page->mapping; | |
344 | *fullness = m & FULLNESS_MASK; | |
345 | *class_idx = (m >> FULLNESS_BITS) & CLASS_IDX_MASK; | |
346 | } | |
347 | ||
348 | static void set_zspage_mapping(struct page *page, unsigned int class_idx, | |
349 | enum fullness_group fullness) | |
350 | { | |
351 | unsigned long m; | |
352 | BUG_ON(!is_first_page(page)); | |
353 | ||
354 | m = ((class_idx & CLASS_IDX_MASK) << FULLNESS_BITS) | | |
355 | (fullness & FULLNESS_MASK); | |
356 | page->mapping = (struct address_space *)m; | |
357 | } | |
358 | ||
c3e3e88a NC |
359 | /* |
360 | * zsmalloc divides the pool into various size classes where each | |
361 | * class maintains a list of zspages where each zspage is divided | |
362 | * into equal sized chunks. Each allocation falls into one of these | |
363 | * classes depending on its size. This function returns index of the | |
364 | * size class which has chunk size big enough to hold the give size. | |
365 | */ | |
61989a80 NG |
366 | static int get_size_class_index(int size) |
367 | { | |
368 | int idx = 0; | |
369 | ||
370 | if (likely(size > ZS_MIN_ALLOC_SIZE)) | |
371 | idx = DIV_ROUND_UP(size - ZS_MIN_ALLOC_SIZE, | |
372 | ZS_SIZE_CLASS_DELTA); | |
373 | ||
374 | return idx; | |
375 | } | |
376 | ||
c3e3e88a NC |
377 | /* |
378 | * For each size class, zspages are divided into different groups | |
379 | * depending on how "full" they are. This was done so that we could | |
380 | * easily find empty or nearly empty zspages when we try to shrink | |
381 | * the pool (not yet implemented). This function returns fullness | |
382 | * status of the given page. | |
383 | */ | |
61989a80 NG |
384 | static enum fullness_group get_fullness_group(struct page *page) |
385 | { | |
386 | int inuse, max_objects; | |
387 | enum fullness_group fg; | |
388 | BUG_ON(!is_first_page(page)); | |
389 | ||
390 | inuse = page->inuse; | |
391 | max_objects = page->objects; | |
392 | ||
393 | if (inuse == 0) | |
394 | fg = ZS_EMPTY; | |
395 | else if (inuse == max_objects) | |
396 | fg = ZS_FULL; | |
397 | else if (inuse <= max_objects / fullness_threshold_frac) | |
398 | fg = ZS_ALMOST_EMPTY; | |
399 | else | |
400 | fg = ZS_ALMOST_FULL; | |
401 | ||
402 | return fg; | |
403 | } | |
404 | ||
c3e3e88a NC |
405 | /* |
406 | * Each size class maintains various freelists and zspages are assigned | |
407 | * to one of these freelists based on the number of live objects they | |
408 | * have. This functions inserts the given zspage into the freelist | |
409 | * identified by <class, fullness_group>. | |
410 | */ | |
61989a80 NG |
411 | static void insert_zspage(struct page *page, struct size_class *class, |
412 | enum fullness_group fullness) | |
413 | { | |
414 | struct page **head; | |
415 | ||
416 | BUG_ON(!is_first_page(page)); | |
417 | ||
418 | if (fullness >= _ZS_NR_FULLNESS_GROUPS) | |
419 | return; | |
420 | ||
421 | head = &class->fullness_list[fullness]; | |
422 | if (*head) | |
423 | list_add_tail(&page->lru, &(*head)->lru); | |
424 | ||
425 | *head = page; | |
426 | } | |
427 | ||
c3e3e88a NC |
428 | /* |
429 | * This function removes the given zspage from the freelist identified | |
430 | * by <class, fullness_group>. | |
431 | */ | |
61989a80 NG |
432 | static void remove_zspage(struct page *page, struct size_class *class, |
433 | enum fullness_group fullness) | |
434 | { | |
435 | struct page **head; | |
436 | ||
437 | BUG_ON(!is_first_page(page)); | |
438 | ||
439 | if (fullness >= _ZS_NR_FULLNESS_GROUPS) | |
440 | return; | |
441 | ||
442 | head = &class->fullness_list[fullness]; | |
443 | BUG_ON(!*head); | |
444 | if (list_empty(&(*head)->lru)) | |
445 | *head = NULL; | |
446 | else if (*head == page) | |
447 | *head = (struct page *)list_entry((*head)->lru.next, | |
448 | struct page, lru); | |
449 | ||
450 | list_del_init(&page->lru); | |
451 | } | |
452 | ||
c3e3e88a NC |
453 | /* |
454 | * Each size class maintains zspages in different fullness groups depending | |
455 | * on the number of live objects they contain. When allocating or freeing | |
456 | * objects, the fullness status of the page can change, say, from ALMOST_FULL | |
457 | * to ALMOST_EMPTY when freeing an object. This function checks if such | |
458 | * a status change has occurred for the given page and accordingly moves the | |
459 | * page from the freelist of the old fullness group to that of the new | |
460 | * fullness group. | |
461 | */ | |
61989a80 NG |
462 | static enum fullness_group fix_fullness_group(struct zs_pool *pool, |
463 | struct page *page) | |
464 | { | |
465 | int class_idx; | |
466 | struct size_class *class; | |
467 | enum fullness_group currfg, newfg; | |
468 | ||
469 | BUG_ON(!is_first_page(page)); | |
470 | ||
471 | get_zspage_mapping(page, &class_idx, &currfg); | |
472 | newfg = get_fullness_group(page); | |
473 | if (newfg == currfg) | |
474 | goto out; | |
475 | ||
9eec4cd5 | 476 | class = pool->size_class[class_idx]; |
61989a80 NG |
477 | remove_zspage(page, class, currfg); |
478 | insert_zspage(page, class, newfg); | |
479 | set_zspage_mapping(page, class_idx, newfg); | |
480 | ||
481 | out: | |
482 | return newfg; | |
483 | } | |
484 | ||
485 | /* | |
486 | * We have to decide on how many pages to link together | |
487 | * to form a zspage for each size class. This is important | |
488 | * to reduce wastage due to unusable space left at end of | |
489 | * each zspage which is given as: | |
490 | * wastage = Zp - Zp % size_class | |
491 | * where Zp = zspage size = k * PAGE_SIZE where k = 1, 2, ... | |
492 | * | |
493 | * For example, for size class of 3/8 * PAGE_SIZE, we should | |
494 | * link together 3 PAGE_SIZE sized pages to form a zspage | |
495 | * since then we can perfectly fit in 8 such objects. | |
496 | */ | |
2e3b6154 | 497 | static int get_pages_per_zspage(int class_size) |
61989a80 NG |
498 | { |
499 | int i, max_usedpc = 0; | |
500 | /* zspage order which gives maximum used size per KB */ | |
501 | int max_usedpc_order = 1; | |
502 | ||
84d4faab | 503 | for (i = 1; i <= ZS_MAX_PAGES_PER_ZSPAGE; i++) { |
61989a80 NG |
504 | int zspage_size; |
505 | int waste, usedpc; | |
506 | ||
507 | zspage_size = i * PAGE_SIZE; | |
508 | waste = zspage_size % class_size; | |
509 | usedpc = (zspage_size - waste) * 100 / zspage_size; | |
510 | ||
511 | if (usedpc > max_usedpc) { | |
512 | max_usedpc = usedpc; | |
513 | max_usedpc_order = i; | |
514 | } | |
515 | } | |
516 | ||
517 | return max_usedpc_order; | |
518 | } | |
519 | ||
520 | /* | |
521 | * A single 'zspage' is composed of many system pages which are | |
522 | * linked together using fields in struct page. This function finds | |
523 | * the first/head page, given any component page of a zspage. | |
524 | */ | |
525 | static struct page *get_first_page(struct page *page) | |
526 | { | |
527 | if (is_first_page(page)) | |
528 | return page; | |
529 | else | |
530 | return page->first_page; | |
531 | } | |
532 | ||
533 | static struct page *get_next_page(struct page *page) | |
534 | { | |
535 | struct page *next; | |
536 | ||
537 | if (is_last_page(page)) | |
538 | next = NULL; | |
539 | else if (is_first_page(page)) | |
e842b976 | 540 | next = (struct page *)page_private(page); |
61989a80 NG |
541 | else |
542 | next = list_entry(page->lru.next, struct page, lru); | |
543 | ||
544 | return next; | |
545 | } | |
546 | ||
67296874 OH |
547 | /* |
548 | * Encode <page, obj_idx> as a single handle value. | |
549 | * On hardware platforms with physical memory starting at 0x0 the pfn | |
550 | * could be 0 so we ensure that the handle will never be 0 by adjusting the | |
551 | * encoded obj_idx value before encoding. | |
552 | */ | |
61989a80 NG |
553 | static void *obj_location_to_handle(struct page *page, unsigned long obj_idx) |
554 | { | |
555 | unsigned long handle; | |
556 | ||
557 | if (!page) { | |
558 | BUG_ON(obj_idx); | |
559 | return NULL; | |
560 | } | |
561 | ||
562 | handle = page_to_pfn(page) << OBJ_INDEX_BITS; | |
67296874 | 563 | handle |= ((obj_idx + 1) & OBJ_INDEX_MASK); |
61989a80 NG |
564 | |
565 | return (void *)handle; | |
566 | } | |
567 | ||
67296874 OH |
568 | /* |
569 | * Decode <page, obj_idx> pair from the given object handle. We adjust the | |
570 | * decoded obj_idx back to its original value since it was adjusted in | |
571 | * obj_location_to_handle(). | |
572 | */ | |
c2344348 | 573 | static void obj_handle_to_location(unsigned long handle, struct page **page, |
61989a80 NG |
574 | unsigned long *obj_idx) |
575 | { | |
c2344348 | 576 | *page = pfn_to_page(handle >> OBJ_INDEX_BITS); |
67296874 | 577 | *obj_idx = (handle & OBJ_INDEX_MASK) - 1; |
61989a80 NG |
578 | } |
579 | ||
580 | static unsigned long obj_idx_to_offset(struct page *page, | |
581 | unsigned long obj_idx, int class_size) | |
582 | { | |
583 | unsigned long off = 0; | |
584 | ||
585 | if (!is_first_page(page)) | |
586 | off = page->index; | |
587 | ||
588 | return off + obj_idx * class_size; | |
589 | } | |
590 | ||
f4477e90 NG |
591 | static void reset_page(struct page *page) |
592 | { | |
593 | clear_bit(PG_private, &page->flags); | |
594 | clear_bit(PG_private_2, &page->flags); | |
595 | set_page_private(page, 0); | |
596 | page->mapping = NULL; | |
597 | page->freelist = NULL; | |
22b751c3 | 598 | page_mapcount_reset(page); |
f4477e90 NG |
599 | } |
600 | ||
61989a80 NG |
601 | static void free_zspage(struct page *first_page) |
602 | { | |
f4477e90 | 603 | struct page *nextp, *tmp, *head_extra; |
61989a80 NG |
604 | |
605 | BUG_ON(!is_first_page(first_page)); | |
606 | BUG_ON(first_page->inuse); | |
607 | ||
f4477e90 | 608 | head_extra = (struct page *)page_private(first_page); |
61989a80 | 609 | |
f4477e90 | 610 | reset_page(first_page); |
61989a80 NG |
611 | __free_page(first_page); |
612 | ||
613 | /* zspage with only 1 system page */ | |
f4477e90 | 614 | if (!head_extra) |
61989a80 NG |
615 | return; |
616 | ||
f4477e90 | 617 | list_for_each_entry_safe(nextp, tmp, &head_extra->lru, lru) { |
61989a80 | 618 | list_del(&nextp->lru); |
f4477e90 | 619 | reset_page(nextp); |
61989a80 NG |
620 | __free_page(nextp); |
621 | } | |
f4477e90 NG |
622 | reset_page(head_extra); |
623 | __free_page(head_extra); | |
61989a80 NG |
624 | } |
625 | ||
626 | /* Initialize a newly allocated zspage */ | |
627 | static void init_zspage(struct page *first_page, struct size_class *class) | |
628 | { | |
629 | unsigned long off = 0; | |
630 | struct page *page = first_page; | |
631 | ||
632 | BUG_ON(!is_first_page(first_page)); | |
633 | while (page) { | |
634 | struct page *next_page; | |
635 | struct link_free *link; | |
5538c562 | 636 | unsigned int i = 1; |
af4ee5e9 | 637 | void *vaddr; |
61989a80 NG |
638 | |
639 | /* | |
640 | * page->index stores offset of first object starting | |
641 | * in the page. For the first page, this is always 0, | |
642 | * so we use first_page->index (aka ->freelist) to store | |
643 | * head of corresponding zspage's freelist. | |
644 | */ | |
645 | if (page != first_page) | |
646 | page->index = off; | |
647 | ||
af4ee5e9 MK |
648 | vaddr = kmap_atomic(page); |
649 | link = (struct link_free *)vaddr + off / sizeof(*link); | |
5538c562 DS |
650 | |
651 | while ((off += class->size) < PAGE_SIZE) { | |
652 | link->next = obj_location_to_handle(page, i++); | |
653 | link += class->size / sizeof(*link); | |
61989a80 NG |
654 | } |
655 | ||
656 | /* | |
657 | * We now come to the last (full or partial) object on this | |
658 | * page, which must point to the first object on the next | |
659 | * page (if present) | |
660 | */ | |
661 | next_page = get_next_page(page); | |
662 | link->next = obj_location_to_handle(next_page, 0); | |
af4ee5e9 | 663 | kunmap_atomic(vaddr); |
61989a80 | 664 | page = next_page; |
5538c562 | 665 | off %= PAGE_SIZE; |
61989a80 NG |
666 | } |
667 | } | |
668 | ||
669 | /* | |
670 | * Allocate a zspage for the given size class | |
671 | */ | |
672 | static struct page *alloc_zspage(struct size_class *class, gfp_t flags) | |
673 | { | |
674 | int i, error; | |
b4b700c5 | 675 | struct page *first_page = NULL, *uninitialized_var(prev_page); |
61989a80 NG |
676 | |
677 | /* | |
678 | * Allocate individual pages and link them together as: | |
679 | * 1. first page->private = first sub-page | |
680 | * 2. all sub-pages are linked together using page->lru | |
681 | * 3. each sub-page is linked to the first page using page->first_page | |
682 | * | |
683 | * For each size class, First/Head pages are linked together using | |
684 | * page->lru. Also, we set PG_private to identify the first page | |
685 | * (i.e. no other sub-page has this flag set) and PG_private_2 to | |
686 | * identify the last page. | |
687 | */ | |
688 | error = -ENOMEM; | |
2e3b6154 | 689 | for (i = 0; i < class->pages_per_zspage; i++) { |
b4b700c5 | 690 | struct page *page; |
61989a80 NG |
691 | |
692 | page = alloc_page(flags); | |
693 | if (!page) | |
694 | goto cleanup; | |
695 | ||
696 | INIT_LIST_HEAD(&page->lru); | |
697 | if (i == 0) { /* first page */ | |
a27545bf | 698 | SetPagePrivate(page); |
61989a80 NG |
699 | set_page_private(page, 0); |
700 | first_page = page; | |
701 | first_page->inuse = 0; | |
702 | } | |
703 | if (i == 1) | |
e842b976 | 704 | set_page_private(first_page, (unsigned long)page); |
61989a80 NG |
705 | if (i >= 1) |
706 | page->first_page = first_page; | |
707 | if (i >= 2) | |
708 | list_add(&page->lru, &prev_page->lru); | |
2e3b6154 | 709 | if (i == class->pages_per_zspage - 1) /* last page */ |
a27545bf | 710 | SetPagePrivate2(page); |
61989a80 NG |
711 | prev_page = page; |
712 | } | |
713 | ||
714 | init_zspage(first_page, class); | |
715 | ||
716 | first_page->freelist = obj_location_to_handle(first_page, 0); | |
717 | /* Maximum number of objects we can store in this zspage */ | |
2e3b6154 | 718 | first_page->objects = class->pages_per_zspage * PAGE_SIZE / class->size; |
61989a80 NG |
719 | |
720 | error = 0; /* Success */ | |
721 | ||
722 | cleanup: | |
723 | if (unlikely(error) && first_page) { | |
724 | free_zspage(first_page); | |
725 | first_page = NULL; | |
726 | } | |
727 | ||
728 | return first_page; | |
729 | } | |
730 | ||
731 | static struct page *find_get_zspage(struct size_class *class) | |
732 | { | |
733 | int i; | |
734 | struct page *page; | |
735 | ||
736 | for (i = 0; i < _ZS_NR_FULLNESS_GROUPS; i++) { | |
737 | page = class->fullness_list[i]; | |
738 | if (page) | |
739 | break; | |
740 | } | |
741 | ||
742 | return page; | |
743 | } | |
744 | ||
1b945aee | 745 | #ifdef CONFIG_PGTABLE_MAPPING |
f553646a SJ |
746 | static inline int __zs_cpu_up(struct mapping_area *area) |
747 | { | |
748 | /* | |
749 | * Make sure we don't leak memory if a cpu UP notification | |
750 | * and zs_init() race and both call zs_cpu_up() on the same cpu | |
751 | */ | |
752 | if (area->vm) | |
753 | return 0; | |
754 | area->vm = alloc_vm_area(PAGE_SIZE * 2, NULL); | |
755 | if (!area->vm) | |
756 | return -ENOMEM; | |
757 | return 0; | |
758 | } | |
759 | ||
760 | static inline void __zs_cpu_down(struct mapping_area *area) | |
761 | { | |
762 | if (area->vm) | |
763 | free_vm_area(area->vm); | |
764 | area->vm = NULL; | |
765 | } | |
766 | ||
767 | static inline void *__zs_map_object(struct mapping_area *area, | |
768 | struct page *pages[2], int off, int size) | |
769 | { | |
f6f8ed47 | 770 | BUG_ON(map_vm_area(area->vm, PAGE_KERNEL, pages)); |
f553646a SJ |
771 | area->vm_addr = area->vm->addr; |
772 | return area->vm_addr + off; | |
773 | } | |
774 | ||
775 | static inline void __zs_unmap_object(struct mapping_area *area, | |
776 | struct page *pages[2], int off, int size) | |
777 | { | |
778 | unsigned long addr = (unsigned long)area->vm_addr; | |
f553646a | 779 | |
d95abbbb | 780 | unmap_kernel_range(addr, PAGE_SIZE * 2); |
f553646a SJ |
781 | } |
782 | ||
1b945aee | 783 | #else /* CONFIG_PGTABLE_MAPPING */ |
f553646a SJ |
784 | |
785 | static inline int __zs_cpu_up(struct mapping_area *area) | |
786 | { | |
787 | /* | |
788 | * Make sure we don't leak memory if a cpu UP notification | |
789 | * and zs_init() race and both call zs_cpu_up() on the same cpu | |
790 | */ | |
791 | if (area->vm_buf) | |
792 | return 0; | |
40f9fb8c | 793 | area->vm_buf = kmalloc(ZS_MAX_ALLOC_SIZE, GFP_KERNEL); |
f553646a SJ |
794 | if (!area->vm_buf) |
795 | return -ENOMEM; | |
796 | return 0; | |
797 | } | |
798 | ||
799 | static inline void __zs_cpu_down(struct mapping_area *area) | |
800 | { | |
40f9fb8c | 801 | kfree(area->vm_buf); |
f553646a SJ |
802 | area->vm_buf = NULL; |
803 | } | |
804 | ||
805 | static void *__zs_map_object(struct mapping_area *area, | |
806 | struct page *pages[2], int off, int size) | |
5f601902 | 807 | { |
5f601902 SJ |
808 | int sizes[2]; |
809 | void *addr; | |
f553646a | 810 | char *buf = area->vm_buf; |
5f601902 | 811 | |
f553646a SJ |
812 | /* disable page faults to match kmap_atomic() return conditions */ |
813 | pagefault_disable(); | |
814 | ||
815 | /* no read fastpath */ | |
816 | if (area->vm_mm == ZS_MM_WO) | |
817 | goto out; | |
5f601902 SJ |
818 | |
819 | sizes[0] = PAGE_SIZE - off; | |
820 | sizes[1] = size - sizes[0]; | |
821 | ||
5f601902 SJ |
822 | /* copy object to per-cpu buffer */ |
823 | addr = kmap_atomic(pages[0]); | |
824 | memcpy(buf, addr + off, sizes[0]); | |
825 | kunmap_atomic(addr); | |
826 | addr = kmap_atomic(pages[1]); | |
827 | memcpy(buf + sizes[0], addr, sizes[1]); | |
828 | kunmap_atomic(addr); | |
f553646a SJ |
829 | out: |
830 | return area->vm_buf; | |
5f601902 SJ |
831 | } |
832 | ||
f553646a SJ |
833 | static void __zs_unmap_object(struct mapping_area *area, |
834 | struct page *pages[2], int off, int size) | |
5f601902 | 835 | { |
5f601902 SJ |
836 | int sizes[2]; |
837 | void *addr; | |
f553646a | 838 | char *buf = area->vm_buf; |
5f601902 | 839 | |
f553646a SJ |
840 | /* no write fastpath */ |
841 | if (area->vm_mm == ZS_MM_RO) | |
842 | goto out; | |
5f601902 SJ |
843 | |
844 | sizes[0] = PAGE_SIZE - off; | |
845 | sizes[1] = size - sizes[0]; | |
846 | ||
847 | /* copy per-cpu buffer to object */ | |
848 | addr = kmap_atomic(pages[0]); | |
849 | memcpy(addr + off, buf, sizes[0]); | |
850 | kunmap_atomic(addr); | |
851 | addr = kmap_atomic(pages[1]); | |
852 | memcpy(addr, buf + sizes[0], sizes[1]); | |
853 | kunmap_atomic(addr); | |
f553646a SJ |
854 | |
855 | out: | |
856 | /* enable page faults to match kunmap_atomic() return conditions */ | |
857 | pagefault_enable(); | |
5f601902 | 858 | } |
61989a80 | 859 | |
1b945aee | 860 | #endif /* CONFIG_PGTABLE_MAPPING */ |
f553646a | 861 | |
61989a80 NG |
862 | static int zs_cpu_notifier(struct notifier_block *nb, unsigned long action, |
863 | void *pcpu) | |
864 | { | |
f553646a | 865 | int ret, cpu = (long)pcpu; |
61989a80 NG |
866 | struct mapping_area *area; |
867 | ||
868 | switch (action) { | |
869 | case CPU_UP_PREPARE: | |
870 | area = &per_cpu(zs_map_area, cpu); | |
f553646a SJ |
871 | ret = __zs_cpu_up(area); |
872 | if (ret) | |
873 | return notifier_from_errno(ret); | |
61989a80 NG |
874 | break; |
875 | case CPU_DEAD: | |
876 | case CPU_UP_CANCELED: | |
877 | area = &per_cpu(zs_map_area, cpu); | |
f553646a | 878 | __zs_cpu_down(area); |
61989a80 NG |
879 | break; |
880 | } | |
881 | ||
882 | return NOTIFY_OK; | |
883 | } | |
884 | ||
885 | static struct notifier_block zs_cpu_nb = { | |
886 | .notifier_call = zs_cpu_notifier | |
887 | }; | |
888 | ||
b1b00a5b | 889 | static void zs_unregister_cpu_notifier(void) |
61989a80 NG |
890 | { |
891 | int cpu; | |
892 | ||
f0e71fcd SB |
893 | cpu_notifier_register_begin(); |
894 | ||
61989a80 NG |
895 | for_each_online_cpu(cpu) |
896 | zs_cpu_notifier(NULL, CPU_DEAD, (void *)(long)cpu); | |
f0e71fcd SB |
897 | __unregister_cpu_notifier(&zs_cpu_nb); |
898 | ||
899 | cpu_notifier_register_done(); | |
61989a80 NG |
900 | } |
901 | ||
b1b00a5b | 902 | static int zs_register_cpu_notifier(void) |
61989a80 | 903 | { |
b1b00a5b | 904 | int cpu, uninitialized_var(ret); |
61989a80 | 905 | |
f0e71fcd SB |
906 | cpu_notifier_register_begin(); |
907 | ||
908 | __register_cpu_notifier(&zs_cpu_nb); | |
61989a80 NG |
909 | for_each_online_cpu(cpu) { |
910 | ret = zs_cpu_notifier(NULL, CPU_UP_PREPARE, (void *)(long)cpu); | |
b1b00a5b SS |
911 | if (notifier_to_errno(ret)) |
912 | break; | |
61989a80 | 913 | } |
f0e71fcd SB |
914 | |
915 | cpu_notifier_register_done(); | |
b1b00a5b SS |
916 | return notifier_to_errno(ret); |
917 | } | |
f0e71fcd | 918 | |
40f9fb8c MG |
919 | static void init_zs_size_classes(void) |
920 | { | |
921 | int nr; | |
922 | ||
923 | nr = (ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE) / ZS_SIZE_CLASS_DELTA + 1; | |
924 | if ((ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE) % ZS_SIZE_CLASS_DELTA) | |
925 | nr += 1; | |
926 | ||
927 | zs_size_classes = nr; | |
928 | } | |
929 | ||
b1b00a5b SS |
930 | static void __exit zs_exit(void) |
931 | { | |
c795779d | 932 | #ifdef CONFIG_ZPOOL |
b1b00a5b | 933 | zpool_unregister_driver(&zs_zpool_driver); |
c795779d | 934 | #endif |
b1b00a5b SS |
935 | zs_unregister_cpu_notifier(); |
936 | } | |
937 | ||
938 | static int __init zs_init(void) | |
939 | { | |
940 | int ret = zs_register_cpu_notifier(); | |
941 | ||
942 | if (ret) { | |
943 | zs_unregister_cpu_notifier(); | |
944 | return ret; | |
945 | } | |
c795779d | 946 | |
40f9fb8c MG |
947 | init_zs_size_classes(); |
948 | ||
b1b00a5b SS |
949 | #ifdef CONFIG_ZPOOL |
950 | zpool_register_driver(&zs_zpool_driver); | |
951 | #endif | |
61989a80 | 952 | return 0; |
61989a80 NG |
953 | } |
954 | ||
9eec4cd5 JK |
955 | static unsigned int get_maxobj_per_zspage(int size, int pages_per_zspage) |
956 | { | |
957 | return pages_per_zspage * PAGE_SIZE / size; | |
958 | } | |
959 | ||
960 | static bool can_merge(struct size_class *prev, int size, int pages_per_zspage) | |
961 | { | |
962 | if (prev->pages_per_zspage != pages_per_zspage) | |
963 | return false; | |
964 | ||
965 | if (get_maxobj_per_zspage(prev->size, prev->pages_per_zspage) | |
966 | != get_maxobj_per_zspage(size, pages_per_zspage)) | |
967 | return false; | |
968 | ||
969 | return true; | |
970 | } | |
971 | ||
4bbc0bc0 DB |
972 | /** |
973 | * zs_create_pool - Creates an allocation pool to work from. | |
0d145a50 | 974 | * @flags: allocation flags used to allocate pool metadata |
4bbc0bc0 DB |
975 | * |
976 | * This function must be called before anything when using | |
977 | * the zsmalloc allocator. | |
978 | * | |
979 | * On success, a pointer to the newly created pool is returned, | |
980 | * otherwise NULL. | |
981 | */ | |
0d145a50 | 982 | struct zs_pool *zs_create_pool(gfp_t flags) |
61989a80 | 983 | { |
069f101f | 984 | int i, ovhd_size; |
61989a80 NG |
985 | struct zs_pool *pool; |
986 | ||
61989a80 NG |
987 | ovhd_size = roundup(sizeof(*pool), PAGE_SIZE); |
988 | pool = kzalloc(ovhd_size, GFP_KERNEL); | |
989 | if (!pool) | |
990 | return NULL; | |
991 | ||
40f9fb8c MG |
992 | pool->size_class = kcalloc(zs_size_classes, sizeof(struct size_class *), |
993 | GFP_KERNEL); | |
994 | if (!pool->size_class) { | |
995 | kfree(pool); | |
996 | return NULL; | |
997 | } | |
998 | ||
9eec4cd5 JK |
999 | /* |
1000 | * Iterate reversly, because, size of size_class that we want to use | |
1001 | * for merging should be larger or equal to current size. | |
1002 | */ | |
40f9fb8c | 1003 | for (i = zs_size_classes - 1; i >= 0; i--) { |
61989a80 | 1004 | int size; |
9eec4cd5 | 1005 | int pages_per_zspage; |
61989a80 | 1006 | struct size_class *class; |
9eec4cd5 | 1007 | struct size_class *prev_class; |
61989a80 NG |
1008 | |
1009 | size = ZS_MIN_ALLOC_SIZE + i * ZS_SIZE_CLASS_DELTA; | |
1010 | if (size > ZS_MAX_ALLOC_SIZE) | |
1011 | size = ZS_MAX_ALLOC_SIZE; | |
9eec4cd5 JK |
1012 | pages_per_zspage = get_pages_per_zspage(size); |
1013 | ||
1014 | /* | |
1015 | * size_class is used for normal zsmalloc operation such | |
1016 | * as alloc/free for that size. Although it is natural that we | |
1017 | * have one size_class for each size, there is a chance that we | |
1018 | * can get more memory utilization if we use one size_class for | |
1019 | * many different sizes whose size_class have same | |
1020 | * characteristics. So, we makes size_class point to | |
1021 | * previous size_class if possible. | |
1022 | */ | |
1023 | if (i < ZS_SIZE_CLASSES - 1) { | |
1024 | prev_class = pool->size_class[i + 1]; | |
1025 | if (can_merge(prev_class, size, pages_per_zspage)) { | |
1026 | pool->size_class[i] = prev_class; | |
1027 | continue; | |
1028 | } | |
1029 | } | |
1030 | ||
1031 | class = kzalloc(sizeof(struct size_class), GFP_KERNEL); | |
1032 | if (!class) | |
1033 | goto err; | |
61989a80 | 1034 | |
61989a80 NG |
1035 | class->size = size; |
1036 | class->index = i; | |
9eec4cd5 | 1037 | class->pages_per_zspage = pages_per_zspage; |
61989a80 | 1038 | spin_lock_init(&class->lock); |
9eec4cd5 | 1039 | pool->size_class[i] = class; |
61989a80 NG |
1040 | } |
1041 | ||
61989a80 | 1042 | pool->flags = flags; |
61989a80 | 1043 | |
61989a80 | 1044 | return pool; |
9eec4cd5 JK |
1045 | |
1046 | err: | |
1047 | zs_destroy_pool(pool); | |
1048 | return NULL; | |
61989a80 NG |
1049 | } |
1050 | EXPORT_SYMBOL_GPL(zs_create_pool); | |
1051 | ||
1052 | void zs_destroy_pool(struct zs_pool *pool) | |
1053 | { | |
1054 | int i; | |
1055 | ||
40f9fb8c | 1056 | for (i = 0; i < zs_size_classes; i++) { |
61989a80 | 1057 | int fg; |
9eec4cd5 JK |
1058 | struct size_class *class = pool->size_class[i]; |
1059 | ||
1060 | if (!class) | |
1061 | continue; | |
1062 | ||
1063 | if (class->index != i) | |
1064 | continue; | |
61989a80 NG |
1065 | |
1066 | for (fg = 0; fg < _ZS_NR_FULLNESS_GROUPS; fg++) { | |
1067 | if (class->fullness_list[fg]) { | |
93ad5ab5 | 1068 | pr_info("Freeing non-empty class with size %db, fullness group %d\n", |
61989a80 NG |
1069 | class->size, fg); |
1070 | } | |
1071 | } | |
9eec4cd5 | 1072 | kfree(class); |
61989a80 | 1073 | } |
40f9fb8c MG |
1074 | |
1075 | kfree(pool->size_class); | |
61989a80 NG |
1076 | kfree(pool); |
1077 | } | |
1078 | EXPORT_SYMBOL_GPL(zs_destroy_pool); | |
1079 | ||
1080 | /** | |
1081 | * zs_malloc - Allocate block of given size from pool. | |
1082 | * @pool: pool to allocate from | |
1083 | * @size: size of block to allocate | |
61989a80 | 1084 | * |
00a61d86 | 1085 | * On success, handle to the allocated object is returned, |
c2344348 | 1086 | * otherwise 0. |
61989a80 NG |
1087 | * Allocation requests with size > ZS_MAX_ALLOC_SIZE will fail. |
1088 | */ | |
c2344348 | 1089 | unsigned long zs_malloc(struct zs_pool *pool, size_t size) |
61989a80 | 1090 | { |
c2344348 | 1091 | unsigned long obj; |
61989a80 | 1092 | struct link_free *link; |
61989a80 | 1093 | struct size_class *class; |
af4ee5e9 | 1094 | void *vaddr; |
61989a80 NG |
1095 | |
1096 | struct page *first_page, *m_page; | |
1097 | unsigned long m_objidx, m_offset; | |
1098 | ||
1099 | if (unlikely(!size || size > ZS_MAX_ALLOC_SIZE)) | |
c2344348 | 1100 | return 0; |
61989a80 | 1101 | |
9eec4cd5 | 1102 | class = pool->size_class[get_size_class_index(size)]; |
61989a80 NG |
1103 | |
1104 | spin_lock(&class->lock); | |
1105 | first_page = find_get_zspage(class); | |
1106 | ||
1107 | if (!first_page) { | |
1108 | spin_unlock(&class->lock); | |
1109 | first_page = alloc_zspage(class, pool->flags); | |
1110 | if (unlikely(!first_page)) | |
c2344348 | 1111 | return 0; |
61989a80 NG |
1112 | |
1113 | set_zspage_mapping(first_page, class->index, ZS_EMPTY); | |
13de8933 MK |
1114 | atomic_long_add(class->pages_per_zspage, |
1115 | &pool->pages_allocated); | |
61989a80 | 1116 | spin_lock(&class->lock); |
61989a80 NG |
1117 | } |
1118 | ||
c2344348 | 1119 | obj = (unsigned long)first_page->freelist; |
61989a80 NG |
1120 | obj_handle_to_location(obj, &m_page, &m_objidx); |
1121 | m_offset = obj_idx_to_offset(m_page, m_objidx, class->size); | |
1122 | ||
af4ee5e9 MK |
1123 | vaddr = kmap_atomic(m_page); |
1124 | link = (struct link_free *)vaddr + m_offset / sizeof(*link); | |
61989a80 NG |
1125 | first_page->freelist = link->next; |
1126 | memset(link, POISON_INUSE, sizeof(*link)); | |
af4ee5e9 | 1127 | kunmap_atomic(vaddr); |
61989a80 NG |
1128 | |
1129 | first_page->inuse++; | |
1130 | /* Now move the zspage to another fullness group, if required */ | |
1131 | fix_fullness_group(pool, first_page); | |
1132 | spin_unlock(&class->lock); | |
1133 | ||
1134 | return obj; | |
1135 | } | |
1136 | EXPORT_SYMBOL_GPL(zs_malloc); | |
1137 | ||
c2344348 | 1138 | void zs_free(struct zs_pool *pool, unsigned long obj) |
61989a80 NG |
1139 | { |
1140 | struct link_free *link; | |
1141 | struct page *first_page, *f_page; | |
1142 | unsigned long f_objidx, f_offset; | |
af4ee5e9 | 1143 | void *vaddr; |
61989a80 NG |
1144 | |
1145 | int class_idx; | |
1146 | struct size_class *class; | |
1147 | enum fullness_group fullness; | |
1148 | ||
1149 | if (unlikely(!obj)) | |
1150 | return; | |
1151 | ||
1152 | obj_handle_to_location(obj, &f_page, &f_objidx); | |
1153 | first_page = get_first_page(f_page); | |
1154 | ||
1155 | get_zspage_mapping(first_page, &class_idx, &fullness); | |
9eec4cd5 | 1156 | class = pool->size_class[class_idx]; |
61989a80 NG |
1157 | f_offset = obj_idx_to_offset(f_page, f_objidx, class->size); |
1158 | ||
1159 | spin_lock(&class->lock); | |
1160 | ||
1161 | /* Insert this object in containing zspage's freelist */ | |
af4ee5e9 MK |
1162 | vaddr = kmap_atomic(f_page); |
1163 | link = (struct link_free *)(vaddr + f_offset); | |
61989a80 | 1164 | link->next = first_page->freelist; |
af4ee5e9 | 1165 | kunmap_atomic(vaddr); |
c2344348 | 1166 | first_page->freelist = (void *)obj; |
61989a80 NG |
1167 | |
1168 | first_page->inuse--; | |
1169 | fullness = fix_fullness_group(pool, first_page); | |
61989a80 NG |
1170 | spin_unlock(&class->lock); |
1171 | ||
13de8933 MK |
1172 | if (fullness == ZS_EMPTY) { |
1173 | atomic_long_sub(class->pages_per_zspage, | |
1174 | &pool->pages_allocated); | |
61989a80 | 1175 | free_zspage(first_page); |
13de8933 | 1176 | } |
61989a80 NG |
1177 | } |
1178 | EXPORT_SYMBOL_GPL(zs_free); | |
1179 | ||
00a61d86 MK |
1180 | /** |
1181 | * zs_map_object - get address of allocated object from handle. | |
1182 | * @pool: pool from which the object was allocated | |
1183 | * @handle: handle returned from zs_malloc | |
1184 | * | |
1185 | * Before using an object allocated from zs_malloc, it must be mapped using | |
1186 | * this function. When done with the object, it must be unmapped using | |
166cfda7 SJ |
1187 | * zs_unmap_object. |
1188 | * | |
1189 | * Only one object can be mapped per cpu at a time. There is no protection | |
1190 | * against nested mappings. | |
1191 | * | |
1192 | * This function returns with preemption and page faults disabled. | |
396b7fd6 | 1193 | */ |
b7418510 SJ |
1194 | void *zs_map_object(struct zs_pool *pool, unsigned long handle, |
1195 | enum zs_mapmode mm) | |
61989a80 NG |
1196 | { |
1197 | struct page *page; | |
1198 | unsigned long obj_idx, off; | |
1199 | ||
1200 | unsigned int class_idx; | |
1201 | enum fullness_group fg; | |
1202 | struct size_class *class; | |
1203 | struct mapping_area *area; | |
f553646a | 1204 | struct page *pages[2]; |
61989a80 NG |
1205 | |
1206 | BUG_ON(!handle); | |
1207 | ||
c60369f0 SJ |
1208 | /* |
1209 | * Because we use per-cpu mapping areas shared among the | |
1210 | * pools/users, we can't allow mapping in interrupt context | |
1211 | * because it can corrupt another users mappings. | |
1212 | */ | |
1213 | BUG_ON(in_interrupt()); | |
1214 | ||
61989a80 NG |
1215 | obj_handle_to_location(handle, &page, &obj_idx); |
1216 | get_zspage_mapping(get_first_page(page), &class_idx, &fg); | |
9eec4cd5 | 1217 | class = pool->size_class[class_idx]; |
61989a80 NG |
1218 | off = obj_idx_to_offset(page, obj_idx, class->size); |
1219 | ||
1220 | area = &get_cpu_var(zs_map_area); | |
f553646a | 1221 | area->vm_mm = mm; |
61989a80 NG |
1222 | if (off + class->size <= PAGE_SIZE) { |
1223 | /* this object is contained entirely within a page */ | |
1224 | area->vm_addr = kmap_atomic(page); | |
5f601902 | 1225 | return area->vm_addr + off; |
61989a80 NG |
1226 | } |
1227 | ||
f553646a SJ |
1228 | /* this object spans two pages */ |
1229 | pages[0] = page; | |
1230 | pages[1] = get_next_page(page); | |
1231 | BUG_ON(!pages[1]); | |
b7418510 | 1232 | |
f553646a | 1233 | return __zs_map_object(area, pages, off, class->size); |
61989a80 NG |
1234 | } |
1235 | EXPORT_SYMBOL_GPL(zs_map_object); | |
1236 | ||
c2344348 | 1237 | void zs_unmap_object(struct zs_pool *pool, unsigned long handle) |
61989a80 NG |
1238 | { |
1239 | struct page *page; | |
1240 | unsigned long obj_idx, off; | |
1241 | ||
1242 | unsigned int class_idx; | |
1243 | enum fullness_group fg; | |
1244 | struct size_class *class; | |
1245 | struct mapping_area *area; | |
1246 | ||
1247 | BUG_ON(!handle); | |
1248 | ||
1249 | obj_handle_to_location(handle, &page, &obj_idx); | |
1250 | get_zspage_mapping(get_first_page(page), &class_idx, &fg); | |
9eec4cd5 | 1251 | class = pool->size_class[class_idx]; |
61989a80 NG |
1252 | off = obj_idx_to_offset(page, obj_idx, class->size); |
1253 | ||
7c8e0181 | 1254 | area = this_cpu_ptr(&zs_map_area); |
f553646a SJ |
1255 | if (off + class->size <= PAGE_SIZE) |
1256 | kunmap_atomic(area->vm_addr); | |
1257 | else { | |
1258 | struct page *pages[2]; | |
1259 | ||
1260 | pages[0] = page; | |
1261 | pages[1] = get_next_page(page); | |
1262 | BUG_ON(!pages[1]); | |
b7418510 | 1263 | |
f553646a SJ |
1264 | __zs_unmap_object(area, pages, off, class->size); |
1265 | } | |
61989a80 NG |
1266 | put_cpu_var(zs_map_area); |
1267 | } | |
1268 | EXPORT_SYMBOL_GPL(zs_unmap_object); | |
1269 | ||
722cdc17 | 1270 | unsigned long zs_get_total_pages(struct zs_pool *pool) |
61989a80 | 1271 | { |
722cdc17 | 1272 | return atomic_long_read(&pool->pages_allocated); |
61989a80 | 1273 | } |
722cdc17 | 1274 | EXPORT_SYMBOL_GPL(zs_get_total_pages); |
069f101f BH |
1275 | |
1276 | module_init(zs_init); | |
1277 | module_exit(zs_exit); | |
1278 | ||
1279 | MODULE_LICENSE("Dual BSD/GPL"); | |
1280 | MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>"); |