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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> | |
312fcae2 | 81 | #include <linux/sched.h> |
61989a80 NG |
82 | #include <linux/bitops.h> |
83 | #include <linux/errno.h> | |
84 | #include <linux/highmem.h> | |
61989a80 NG |
85 | #include <linux/string.h> |
86 | #include <linux/slab.h> | |
87 | #include <asm/tlbflush.h> | |
88 | #include <asm/pgtable.h> | |
89 | #include <linux/cpumask.h> | |
90 | #include <linux/cpu.h> | |
0cbb613f | 91 | #include <linux/vmalloc.h> |
c60369f0 | 92 | #include <linux/hardirq.h> |
0959c63f SJ |
93 | #include <linux/spinlock.h> |
94 | #include <linux/types.h> | |
0f050d99 | 95 | #include <linux/debugfs.h> |
bcf1647d | 96 | #include <linux/zsmalloc.h> |
c795779d | 97 | #include <linux/zpool.h> |
0959c63f SJ |
98 | |
99 | /* | |
100 | * This must be power of 2 and greater than of equal to sizeof(link_free). | |
101 | * These two conditions ensure that any 'struct link_free' itself doesn't | |
102 | * span more than 1 page which avoids complex case of mapping 2 pages simply | |
103 | * to restore link_free pointer values. | |
104 | */ | |
105 | #define ZS_ALIGN 8 | |
106 | ||
107 | /* | |
108 | * A single 'zspage' is composed of up to 2^N discontiguous 0-order (single) | |
109 | * pages. ZS_MAX_ZSPAGE_ORDER defines upper limit on N. | |
110 | */ | |
111 | #define ZS_MAX_ZSPAGE_ORDER 2 | |
112 | #define ZS_MAX_PAGES_PER_ZSPAGE (_AC(1, UL) << ZS_MAX_ZSPAGE_ORDER) | |
113 | ||
2e40e163 MK |
114 | #define ZS_HANDLE_SIZE (sizeof(unsigned long)) |
115 | ||
0959c63f SJ |
116 | /* |
117 | * Object location (<PFN>, <obj_idx>) is encoded as | |
c3e3e88a | 118 | * as single (unsigned long) handle value. |
0959c63f SJ |
119 | * |
120 | * Note that object index <obj_idx> is relative to system | |
121 | * page <PFN> it is stored in, so for each sub-page belonging | |
122 | * to a zspage, obj_idx starts with 0. | |
123 | * | |
124 | * This is made more complicated by various memory models and PAE. | |
125 | */ | |
126 | ||
127 | #ifndef MAX_PHYSMEM_BITS | |
128 | #ifdef CONFIG_HIGHMEM64G | |
129 | #define MAX_PHYSMEM_BITS 36 | |
130 | #else /* !CONFIG_HIGHMEM64G */ | |
131 | /* | |
132 | * If this definition of MAX_PHYSMEM_BITS is used, OBJ_INDEX_BITS will just | |
133 | * be PAGE_SHIFT | |
134 | */ | |
135 | #define MAX_PHYSMEM_BITS BITS_PER_LONG | |
136 | #endif | |
137 | #endif | |
138 | #define _PFN_BITS (MAX_PHYSMEM_BITS - PAGE_SHIFT) | |
312fcae2 MK |
139 | |
140 | /* | |
141 | * Memory for allocating for handle keeps object position by | |
142 | * encoding <page, obj_idx> and the encoded value has a room | |
143 | * in least bit(ie, look at obj_to_location). | |
144 | * We use the bit to synchronize between object access by | |
145 | * user and migration. | |
146 | */ | |
147 | #define HANDLE_PIN_BIT 0 | |
148 | ||
149 | /* | |
150 | * Head in allocated object should have OBJ_ALLOCATED_TAG | |
151 | * to identify the object was allocated or not. | |
152 | * It's okay to add the status bit in the least bit because | |
153 | * header keeps handle which is 4byte-aligned address so we | |
154 | * have room for two bit at least. | |
155 | */ | |
156 | #define OBJ_ALLOCATED_TAG 1 | |
157 | #define OBJ_TAG_BITS 1 | |
158 | #define OBJ_INDEX_BITS (BITS_PER_LONG - _PFN_BITS - OBJ_TAG_BITS) | |
0959c63f SJ |
159 | #define OBJ_INDEX_MASK ((_AC(1, UL) << OBJ_INDEX_BITS) - 1) |
160 | ||
161 | #define MAX(a, b) ((a) >= (b) ? (a) : (b)) | |
162 | /* ZS_MIN_ALLOC_SIZE must be multiple of ZS_ALIGN */ | |
163 | #define ZS_MIN_ALLOC_SIZE \ | |
164 | MAX(32, (ZS_MAX_PAGES_PER_ZSPAGE << PAGE_SHIFT >> OBJ_INDEX_BITS)) | |
2e40e163 MK |
165 | /* each chunk includes extra space to keep handle */ |
166 | #define ZS_MAX_ALLOC_SIZE (PAGE_SIZE + ZS_HANDLE_SIZE) | |
0959c63f SJ |
167 | |
168 | /* | |
7eb52512 | 169 | * On systems with 4K page size, this gives 255 size classes! There is a |
0959c63f SJ |
170 | * trader-off here: |
171 | * - Large number of size classes is potentially wasteful as free page are | |
172 | * spread across these classes | |
173 | * - Small number of size classes causes large internal fragmentation | |
174 | * - Probably its better to use specific size classes (empirically | |
175 | * determined). NOTE: all those class sizes must be set as multiple of | |
176 | * ZS_ALIGN to make sure link_free itself never has to span 2 pages. | |
177 | * | |
178 | * ZS_MIN_ALLOC_SIZE and ZS_SIZE_CLASS_DELTA must be multiple of ZS_ALIGN | |
179 | * (reason above) | |
180 | */ | |
d662b8eb | 181 | #define ZS_SIZE_CLASS_DELTA (PAGE_SIZE >> 8) |
0959c63f SJ |
182 | |
183 | /* | |
184 | * We do not maintain any list for completely empty or full pages | |
185 | */ | |
186 | enum fullness_group { | |
187 | ZS_ALMOST_FULL, | |
188 | ZS_ALMOST_EMPTY, | |
189 | _ZS_NR_FULLNESS_GROUPS, | |
190 | ||
191 | ZS_EMPTY, | |
192 | ZS_FULL | |
193 | }; | |
194 | ||
0f050d99 GM |
195 | enum zs_stat_type { |
196 | OBJ_ALLOCATED, | |
197 | OBJ_USED, | |
198 | NR_ZS_STAT_TYPE, | |
199 | }; | |
200 | ||
201 | #ifdef CONFIG_ZSMALLOC_STAT | |
202 | ||
203 | static struct dentry *zs_stat_root; | |
204 | ||
205 | struct zs_size_stat { | |
206 | unsigned long objs[NR_ZS_STAT_TYPE]; | |
207 | }; | |
208 | ||
209 | #endif | |
210 | ||
40f9fb8c MG |
211 | /* |
212 | * number of size_classes | |
213 | */ | |
214 | static int zs_size_classes; | |
215 | ||
0959c63f SJ |
216 | /* |
217 | * We assign a page to ZS_ALMOST_EMPTY fullness group when: | |
218 | * n <= N / f, where | |
219 | * n = number of allocated objects | |
220 | * N = total number of objects zspage can store | |
6dd9737e | 221 | * f = fullness_threshold_frac |
0959c63f SJ |
222 | * |
223 | * Similarly, we assign zspage to: | |
224 | * ZS_ALMOST_FULL when n > N / f | |
225 | * ZS_EMPTY when n == 0 | |
226 | * ZS_FULL when n == N | |
227 | * | |
228 | * (see: fix_fullness_group()) | |
229 | */ | |
230 | static const int fullness_threshold_frac = 4; | |
231 | ||
232 | struct size_class { | |
233 | /* | |
234 | * Size of objects stored in this class. Must be multiple | |
235 | * of ZS_ALIGN. | |
236 | */ | |
237 | int size; | |
238 | unsigned int index; | |
239 | ||
240 | /* Number of PAGE_SIZE sized pages to combine to form a 'zspage' */ | |
241 | int pages_per_zspage; | |
242 | ||
0f050d99 GM |
243 | #ifdef CONFIG_ZSMALLOC_STAT |
244 | struct zs_size_stat stats; | |
245 | #endif | |
246 | ||
0959c63f SJ |
247 | spinlock_t lock; |
248 | ||
0959c63f SJ |
249 | struct page *fullness_list[_ZS_NR_FULLNESS_GROUPS]; |
250 | }; | |
251 | ||
252 | /* | |
253 | * Placed within free objects to form a singly linked list. | |
254 | * For every zspage, first_page->freelist gives head of this list. | |
255 | * | |
256 | * This must be power of 2 and less than or equal to ZS_ALIGN | |
257 | */ | |
258 | struct link_free { | |
2e40e163 MK |
259 | union { |
260 | /* | |
261 | * Position of next free chunk (encodes <PFN, obj_idx>) | |
262 | * It's valid for non-allocated object | |
263 | */ | |
264 | void *next; | |
265 | /* | |
266 | * Handle of allocated object. | |
267 | */ | |
268 | unsigned long handle; | |
269 | }; | |
0959c63f SJ |
270 | }; |
271 | ||
272 | struct zs_pool { | |
0f050d99 GM |
273 | char *name; |
274 | ||
40f9fb8c | 275 | struct size_class **size_class; |
2e40e163 | 276 | struct kmem_cache *handle_cachep; |
0959c63f SJ |
277 | |
278 | gfp_t flags; /* allocation flags used when growing pool */ | |
13de8933 | 279 | atomic_long_t pages_allocated; |
0f050d99 GM |
280 | |
281 | #ifdef CONFIG_ZSMALLOC_STAT | |
282 | struct dentry *stat_dentry; | |
283 | #endif | |
0959c63f | 284 | }; |
61989a80 NG |
285 | |
286 | /* | |
287 | * A zspage's class index and fullness group | |
288 | * are encoded in its (first)page->mapping | |
289 | */ | |
290 | #define CLASS_IDX_BITS 28 | |
291 | #define FULLNESS_BITS 4 | |
292 | #define CLASS_IDX_MASK ((1 << CLASS_IDX_BITS) - 1) | |
293 | #define FULLNESS_MASK ((1 << FULLNESS_BITS) - 1) | |
294 | ||
f553646a | 295 | struct mapping_area { |
1b945aee | 296 | #ifdef CONFIG_PGTABLE_MAPPING |
f553646a SJ |
297 | struct vm_struct *vm; /* vm area for mapping object that span pages */ |
298 | #else | |
299 | char *vm_buf; /* copy buffer for objects that span pages */ | |
300 | #endif | |
301 | char *vm_addr; /* address of kmap_atomic()'ed pages */ | |
302 | enum zs_mapmode vm_mm; /* mapping mode */ | |
303 | }; | |
304 | ||
2e40e163 MK |
305 | static int create_handle_cache(struct zs_pool *pool) |
306 | { | |
307 | pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_SIZE, | |
308 | 0, 0, NULL); | |
309 | return pool->handle_cachep ? 0 : 1; | |
310 | } | |
311 | ||
312 | static void destroy_handle_cache(struct zs_pool *pool) | |
313 | { | |
314 | kmem_cache_destroy(pool->handle_cachep); | |
315 | } | |
316 | ||
317 | static unsigned long alloc_handle(struct zs_pool *pool) | |
318 | { | |
319 | return (unsigned long)kmem_cache_alloc(pool->handle_cachep, | |
320 | pool->flags & ~__GFP_HIGHMEM); | |
321 | } | |
322 | ||
323 | static void free_handle(struct zs_pool *pool, unsigned long handle) | |
324 | { | |
325 | kmem_cache_free(pool->handle_cachep, (void *)handle); | |
326 | } | |
327 | ||
328 | static void record_obj(unsigned long handle, unsigned long obj) | |
329 | { | |
330 | *(unsigned long *)handle = obj; | |
331 | } | |
332 | ||
c795779d DS |
333 | /* zpool driver */ |
334 | ||
335 | #ifdef CONFIG_ZPOOL | |
336 | ||
3eba0c6a | 337 | static void *zs_zpool_create(char *name, gfp_t gfp, struct zpool_ops *zpool_ops) |
c795779d | 338 | { |
3eba0c6a | 339 | return zs_create_pool(name, gfp); |
c795779d DS |
340 | } |
341 | ||
342 | static void zs_zpool_destroy(void *pool) | |
343 | { | |
344 | zs_destroy_pool(pool); | |
345 | } | |
346 | ||
347 | static int zs_zpool_malloc(void *pool, size_t size, gfp_t gfp, | |
348 | unsigned long *handle) | |
349 | { | |
350 | *handle = zs_malloc(pool, size); | |
351 | return *handle ? 0 : -1; | |
352 | } | |
353 | static void zs_zpool_free(void *pool, unsigned long handle) | |
354 | { | |
355 | zs_free(pool, handle); | |
356 | } | |
357 | ||
358 | static int zs_zpool_shrink(void *pool, unsigned int pages, | |
359 | unsigned int *reclaimed) | |
360 | { | |
361 | return -EINVAL; | |
362 | } | |
363 | ||
364 | static void *zs_zpool_map(void *pool, unsigned long handle, | |
365 | enum zpool_mapmode mm) | |
366 | { | |
367 | enum zs_mapmode zs_mm; | |
368 | ||
369 | switch (mm) { | |
370 | case ZPOOL_MM_RO: | |
371 | zs_mm = ZS_MM_RO; | |
372 | break; | |
373 | case ZPOOL_MM_WO: | |
374 | zs_mm = ZS_MM_WO; | |
375 | break; | |
376 | case ZPOOL_MM_RW: /* fallthru */ | |
377 | default: | |
378 | zs_mm = ZS_MM_RW; | |
379 | break; | |
380 | } | |
381 | ||
382 | return zs_map_object(pool, handle, zs_mm); | |
383 | } | |
384 | static void zs_zpool_unmap(void *pool, unsigned long handle) | |
385 | { | |
386 | zs_unmap_object(pool, handle); | |
387 | } | |
388 | ||
389 | static u64 zs_zpool_total_size(void *pool) | |
390 | { | |
722cdc17 | 391 | return zs_get_total_pages(pool) << PAGE_SHIFT; |
c795779d DS |
392 | } |
393 | ||
394 | static struct zpool_driver zs_zpool_driver = { | |
395 | .type = "zsmalloc", | |
396 | .owner = THIS_MODULE, | |
397 | .create = zs_zpool_create, | |
398 | .destroy = zs_zpool_destroy, | |
399 | .malloc = zs_zpool_malloc, | |
400 | .free = zs_zpool_free, | |
401 | .shrink = zs_zpool_shrink, | |
402 | .map = zs_zpool_map, | |
403 | .unmap = zs_zpool_unmap, | |
404 | .total_size = zs_zpool_total_size, | |
405 | }; | |
406 | ||
137f8cff | 407 | MODULE_ALIAS("zpool-zsmalloc"); |
c795779d DS |
408 | #endif /* CONFIG_ZPOOL */ |
409 | ||
61989a80 NG |
410 | /* per-cpu VM mapping areas for zspage accesses that cross page boundaries */ |
411 | static DEFINE_PER_CPU(struct mapping_area, zs_map_area); | |
412 | ||
413 | static int is_first_page(struct page *page) | |
414 | { | |
a27545bf | 415 | return PagePrivate(page); |
61989a80 NG |
416 | } |
417 | ||
418 | static int is_last_page(struct page *page) | |
419 | { | |
a27545bf | 420 | return PagePrivate2(page); |
61989a80 NG |
421 | } |
422 | ||
423 | static void get_zspage_mapping(struct page *page, unsigned int *class_idx, | |
424 | enum fullness_group *fullness) | |
425 | { | |
426 | unsigned long m; | |
427 | BUG_ON(!is_first_page(page)); | |
428 | ||
429 | m = (unsigned long)page->mapping; | |
430 | *fullness = m & FULLNESS_MASK; | |
431 | *class_idx = (m >> FULLNESS_BITS) & CLASS_IDX_MASK; | |
432 | } | |
433 | ||
434 | static void set_zspage_mapping(struct page *page, unsigned int class_idx, | |
435 | enum fullness_group fullness) | |
436 | { | |
437 | unsigned long m; | |
438 | BUG_ON(!is_first_page(page)); | |
439 | ||
440 | m = ((class_idx & CLASS_IDX_MASK) << FULLNESS_BITS) | | |
441 | (fullness & FULLNESS_MASK); | |
442 | page->mapping = (struct address_space *)m; | |
443 | } | |
444 | ||
c3e3e88a NC |
445 | /* |
446 | * zsmalloc divides the pool into various size classes where each | |
447 | * class maintains a list of zspages where each zspage is divided | |
448 | * into equal sized chunks. Each allocation falls into one of these | |
449 | * classes depending on its size. This function returns index of the | |
450 | * size class which has chunk size big enough to hold the give size. | |
451 | */ | |
61989a80 NG |
452 | static int get_size_class_index(int size) |
453 | { | |
454 | int idx = 0; | |
455 | ||
456 | if (likely(size > ZS_MIN_ALLOC_SIZE)) | |
457 | idx = DIV_ROUND_UP(size - ZS_MIN_ALLOC_SIZE, | |
458 | ZS_SIZE_CLASS_DELTA); | |
459 | ||
460 | return idx; | |
461 | } | |
462 | ||
c3e3e88a NC |
463 | /* |
464 | * For each size class, zspages are divided into different groups | |
465 | * depending on how "full" they are. This was done so that we could | |
466 | * easily find empty or nearly empty zspages when we try to shrink | |
467 | * the pool (not yet implemented). This function returns fullness | |
468 | * status of the given page. | |
469 | */ | |
61989a80 NG |
470 | static enum fullness_group get_fullness_group(struct page *page) |
471 | { | |
472 | int inuse, max_objects; | |
473 | enum fullness_group fg; | |
474 | BUG_ON(!is_first_page(page)); | |
475 | ||
476 | inuse = page->inuse; | |
477 | max_objects = page->objects; | |
478 | ||
479 | if (inuse == 0) | |
480 | fg = ZS_EMPTY; | |
481 | else if (inuse == max_objects) | |
482 | fg = ZS_FULL; | |
d3d07c92 | 483 | else if (inuse <= 3 * max_objects / fullness_threshold_frac) |
61989a80 NG |
484 | fg = ZS_ALMOST_EMPTY; |
485 | else | |
486 | fg = ZS_ALMOST_FULL; | |
487 | ||
488 | return fg; | |
489 | } | |
490 | ||
c3e3e88a NC |
491 | /* |
492 | * Each size class maintains various freelists and zspages are assigned | |
493 | * to one of these freelists based on the number of live objects they | |
494 | * have. This functions inserts the given zspage into the freelist | |
495 | * identified by <class, fullness_group>. | |
496 | */ | |
61989a80 NG |
497 | static void insert_zspage(struct page *page, struct size_class *class, |
498 | enum fullness_group fullness) | |
499 | { | |
500 | struct page **head; | |
501 | ||
502 | BUG_ON(!is_first_page(page)); | |
503 | ||
504 | if (fullness >= _ZS_NR_FULLNESS_GROUPS) | |
505 | return; | |
506 | ||
507 | head = &class->fullness_list[fullness]; | |
508 | if (*head) | |
509 | list_add_tail(&page->lru, &(*head)->lru); | |
510 | ||
511 | *head = page; | |
512 | } | |
513 | ||
c3e3e88a NC |
514 | /* |
515 | * This function removes the given zspage from the freelist identified | |
516 | * by <class, fullness_group>. | |
517 | */ | |
61989a80 NG |
518 | static void remove_zspage(struct page *page, struct size_class *class, |
519 | enum fullness_group fullness) | |
520 | { | |
521 | struct page **head; | |
522 | ||
523 | BUG_ON(!is_first_page(page)); | |
524 | ||
525 | if (fullness >= _ZS_NR_FULLNESS_GROUPS) | |
526 | return; | |
527 | ||
528 | head = &class->fullness_list[fullness]; | |
529 | BUG_ON(!*head); | |
530 | if (list_empty(&(*head)->lru)) | |
531 | *head = NULL; | |
532 | else if (*head == page) | |
533 | *head = (struct page *)list_entry((*head)->lru.next, | |
534 | struct page, lru); | |
535 | ||
536 | list_del_init(&page->lru); | |
537 | } | |
538 | ||
c3e3e88a NC |
539 | /* |
540 | * Each size class maintains zspages in different fullness groups depending | |
541 | * on the number of live objects they contain. When allocating or freeing | |
542 | * objects, the fullness status of the page can change, say, from ALMOST_FULL | |
543 | * to ALMOST_EMPTY when freeing an object. This function checks if such | |
544 | * a status change has occurred for the given page and accordingly moves the | |
545 | * page from the freelist of the old fullness group to that of the new | |
546 | * fullness group. | |
547 | */ | |
c7806261 | 548 | static enum fullness_group fix_fullness_group(struct size_class *class, |
61989a80 NG |
549 | struct page *page) |
550 | { | |
551 | int class_idx; | |
61989a80 NG |
552 | enum fullness_group currfg, newfg; |
553 | ||
554 | BUG_ON(!is_first_page(page)); | |
555 | ||
556 | get_zspage_mapping(page, &class_idx, &currfg); | |
557 | newfg = get_fullness_group(page); | |
558 | if (newfg == currfg) | |
559 | goto out; | |
560 | ||
61989a80 NG |
561 | remove_zspage(page, class, currfg); |
562 | insert_zspage(page, class, newfg); | |
563 | set_zspage_mapping(page, class_idx, newfg); | |
564 | ||
565 | out: | |
566 | return newfg; | |
567 | } | |
568 | ||
569 | /* | |
570 | * We have to decide on how many pages to link together | |
571 | * to form a zspage for each size class. This is important | |
572 | * to reduce wastage due to unusable space left at end of | |
573 | * each zspage which is given as: | |
574 | * wastage = Zp - Zp % size_class | |
575 | * where Zp = zspage size = k * PAGE_SIZE where k = 1, 2, ... | |
576 | * | |
577 | * For example, for size class of 3/8 * PAGE_SIZE, we should | |
578 | * link together 3 PAGE_SIZE sized pages to form a zspage | |
579 | * since then we can perfectly fit in 8 such objects. | |
580 | */ | |
2e3b6154 | 581 | static int get_pages_per_zspage(int class_size) |
61989a80 NG |
582 | { |
583 | int i, max_usedpc = 0; | |
584 | /* zspage order which gives maximum used size per KB */ | |
585 | int max_usedpc_order = 1; | |
586 | ||
84d4faab | 587 | for (i = 1; i <= ZS_MAX_PAGES_PER_ZSPAGE; i++) { |
61989a80 NG |
588 | int zspage_size; |
589 | int waste, usedpc; | |
590 | ||
591 | zspage_size = i * PAGE_SIZE; | |
592 | waste = zspage_size % class_size; | |
593 | usedpc = (zspage_size - waste) * 100 / zspage_size; | |
594 | ||
595 | if (usedpc > max_usedpc) { | |
596 | max_usedpc = usedpc; | |
597 | max_usedpc_order = i; | |
598 | } | |
599 | } | |
600 | ||
601 | return max_usedpc_order; | |
602 | } | |
603 | ||
604 | /* | |
605 | * A single 'zspage' is composed of many system pages which are | |
606 | * linked together using fields in struct page. This function finds | |
607 | * the first/head page, given any component page of a zspage. | |
608 | */ | |
609 | static struct page *get_first_page(struct page *page) | |
610 | { | |
611 | if (is_first_page(page)) | |
612 | return page; | |
613 | else | |
614 | return page->first_page; | |
615 | } | |
616 | ||
617 | static struct page *get_next_page(struct page *page) | |
618 | { | |
619 | struct page *next; | |
620 | ||
621 | if (is_last_page(page)) | |
622 | next = NULL; | |
623 | else if (is_first_page(page)) | |
e842b976 | 624 | next = (struct page *)page_private(page); |
61989a80 NG |
625 | else |
626 | next = list_entry(page->lru.next, struct page, lru); | |
627 | ||
628 | return next; | |
629 | } | |
630 | ||
67296874 OH |
631 | /* |
632 | * Encode <page, obj_idx> as a single handle value. | |
312fcae2 | 633 | * We use the least bit of handle for tagging. |
67296874 | 634 | */ |
312fcae2 | 635 | static void *location_to_obj(struct page *page, unsigned long obj_idx) |
61989a80 | 636 | { |
312fcae2 | 637 | unsigned long obj; |
61989a80 NG |
638 | |
639 | if (!page) { | |
640 | BUG_ON(obj_idx); | |
641 | return NULL; | |
642 | } | |
643 | ||
312fcae2 MK |
644 | obj = page_to_pfn(page) << OBJ_INDEX_BITS; |
645 | obj |= ((obj_idx) & OBJ_INDEX_MASK); | |
646 | obj <<= OBJ_TAG_BITS; | |
61989a80 | 647 | |
312fcae2 | 648 | return (void *)obj; |
61989a80 NG |
649 | } |
650 | ||
67296874 OH |
651 | /* |
652 | * Decode <page, obj_idx> pair from the given object handle. We adjust the | |
653 | * decoded obj_idx back to its original value since it was adjusted in | |
312fcae2 | 654 | * location_to_obj(). |
67296874 | 655 | */ |
312fcae2 | 656 | static void obj_to_location(unsigned long obj, struct page **page, |
61989a80 NG |
657 | unsigned long *obj_idx) |
658 | { | |
312fcae2 MK |
659 | obj >>= OBJ_TAG_BITS; |
660 | *page = pfn_to_page(obj >> OBJ_INDEX_BITS); | |
661 | *obj_idx = (obj & OBJ_INDEX_MASK); | |
61989a80 NG |
662 | } |
663 | ||
2e40e163 MK |
664 | static unsigned long handle_to_obj(unsigned long handle) |
665 | { | |
666 | return *(unsigned long *)handle; | |
667 | } | |
668 | ||
312fcae2 MK |
669 | unsigned long obj_to_head(void *obj) |
670 | { | |
671 | return *(unsigned long *)obj; | |
672 | } | |
673 | ||
61989a80 NG |
674 | static unsigned long obj_idx_to_offset(struct page *page, |
675 | unsigned long obj_idx, int class_size) | |
676 | { | |
677 | unsigned long off = 0; | |
678 | ||
679 | if (!is_first_page(page)) | |
680 | off = page->index; | |
681 | ||
682 | return off + obj_idx * class_size; | |
683 | } | |
684 | ||
312fcae2 MK |
685 | static inline int trypin_tag(unsigned long handle) |
686 | { | |
687 | unsigned long *ptr = (unsigned long *)handle; | |
688 | ||
689 | return !test_and_set_bit_lock(HANDLE_PIN_BIT, ptr); | |
690 | } | |
691 | ||
692 | static void pin_tag(unsigned long handle) | |
693 | { | |
694 | while (!trypin_tag(handle)); | |
695 | } | |
696 | ||
697 | static void unpin_tag(unsigned long handle) | |
698 | { | |
699 | unsigned long *ptr = (unsigned long *)handle; | |
700 | ||
701 | clear_bit_unlock(HANDLE_PIN_BIT, ptr); | |
702 | } | |
703 | ||
f4477e90 NG |
704 | static void reset_page(struct page *page) |
705 | { | |
706 | clear_bit(PG_private, &page->flags); | |
707 | clear_bit(PG_private_2, &page->flags); | |
708 | set_page_private(page, 0); | |
709 | page->mapping = NULL; | |
710 | page->freelist = NULL; | |
22b751c3 | 711 | page_mapcount_reset(page); |
f4477e90 NG |
712 | } |
713 | ||
61989a80 NG |
714 | static void free_zspage(struct page *first_page) |
715 | { | |
f4477e90 | 716 | struct page *nextp, *tmp, *head_extra; |
61989a80 NG |
717 | |
718 | BUG_ON(!is_first_page(first_page)); | |
719 | BUG_ON(first_page->inuse); | |
720 | ||
f4477e90 | 721 | head_extra = (struct page *)page_private(first_page); |
61989a80 | 722 | |
f4477e90 | 723 | reset_page(first_page); |
61989a80 NG |
724 | __free_page(first_page); |
725 | ||
726 | /* zspage with only 1 system page */ | |
f4477e90 | 727 | if (!head_extra) |
61989a80 NG |
728 | return; |
729 | ||
f4477e90 | 730 | list_for_each_entry_safe(nextp, tmp, &head_extra->lru, lru) { |
61989a80 | 731 | list_del(&nextp->lru); |
f4477e90 | 732 | reset_page(nextp); |
61989a80 NG |
733 | __free_page(nextp); |
734 | } | |
f4477e90 NG |
735 | reset_page(head_extra); |
736 | __free_page(head_extra); | |
61989a80 NG |
737 | } |
738 | ||
739 | /* Initialize a newly allocated zspage */ | |
740 | static void init_zspage(struct page *first_page, struct size_class *class) | |
741 | { | |
742 | unsigned long off = 0; | |
743 | struct page *page = first_page; | |
744 | ||
745 | BUG_ON(!is_first_page(first_page)); | |
746 | while (page) { | |
747 | struct page *next_page; | |
748 | struct link_free *link; | |
5538c562 | 749 | unsigned int i = 1; |
af4ee5e9 | 750 | void *vaddr; |
61989a80 NG |
751 | |
752 | /* | |
753 | * page->index stores offset of first object starting | |
754 | * in the page. For the first page, this is always 0, | |
755 | * so we use first_page->index (aka ->freelist) to store | |
756 | * head of corresponding zspage's freelist. | |
757 | */ | |
758 | if (page != first_page) | |
759 | page->index = off; | |
760 | ||
af4ee5e9 MK |
761 | vaddr = kmap_atomic(page); |
762 | link = (struct link_free *)vaddr + off / sizeof(*link); | |
5538c562 DS |
763 | |
764 | while ((off += class->size) < PAGE_SIZE) { | |
312fcae2 | 765 | link->next = location_to_obj(page, i++); |
5538c562 | 766 | link += class->size / sizeof(*link); |
61989a80 NG |
767 | } |
768 | ||
769 | /* | |
770 | * We now come to the last (full or partial) object on this | |
771 | * page, which must point to the first object on the next | |
772 | * page (if present) | |
773 | */ | |
774 | next_page = get_next_page(page); | |
312fcae2 | 775 | link->next = location_to_obj(next_page, 0); |
af4ee5e9 | 776 | kunmap_atomic(vaddr); |
61989a80 | 777 | page = next_page; |
5538c562 | 778 | off %= PAGE_SIZE; |
61989a80 NG |
779 | } |
780 | } | |
781 | ||
782 | /* | |
783 | * Allocate a zspage for the given size class | |
784 | */ | |
785 | static struct page *alloc_zspage(struct size_class *class, gfp_t flags) | |
786 | { | |
787 | int i, error; | |
b4b700c5 | 788 | struct page *first_page = NULL, *uninitialized_var(prev_page); |
61989a80 NG |
789 | |
790 | /* | |
791 | * Allocate individual pages and link them together as: | |
792 | * 1. first page->private = first sub-page | |
793 | * 2. all sub-pages are linked together using page->lru | |
794 | * 3. each sub-page is linked to the first page using page->first_page | |
795 | * | |
796 | * For each size class, First/Head pages are linked together using | |
797 | * page->lru. Also, we set PG_private to identify the first page | |
798 | * (i.e. no other sub-page has this flag set) and PG_private_2 to | |
799 | * identify the last page. | |
800 | */ | |
801 | error = -ENOMEM; | |
2e3b6154 | 802 | for (i = 0; i < class->pages_per_zspage; i++) { |
b4b700c5 | 803 | struct page *page; |
61989a80 NG |
804 | |
805 | page = alloc_page(flags); | |
806 | if (!page) | |
807 | goto cleanup; | |
808 | ||
809 | INIT_LIST_HEAD(&page->lru); | |
810 | if (i == 0) { /* first page */ | |
a27545bf | 811 | SetPagePrivate(page); |
61989a80 NG |
812 | set_page_private(page, 0); |
813 | first_page = page; | |
814 | first_page->inuse = 0; | |
815 | } | |
816 | if (i == 1) | |
e842b976 | 817 | set_page_private(first_page, (unsigned long)page); |
61989a80 NG |
818 | if (i >= 1) |
819 | page->first_page = first_page; | |
820 | if (i >= 2) | |
821 | list_add(&page->lru, &prev_page->lru); | |
2e3b6154 | 822 | if (i == class->pages_per_zspage - 1) /* last page */ |
a27545bf | 823 | SetPagePrivate2(page); |
61989a80 NG |
824 | prev_page = page; |
825 | } | |
826 | ||
827 | init_zspage(first_page, class); | |
828 | ||
312fcae2 | 829 | first_page->freelist = location_to_obj(first_page, 0); |
61989a80 | 830 | /* Maximum number of objects we can store in this zspage */ |
2e3b6154 | 831 | first_page->objects = class->pages_per_zspage * PAGE_SIZE / class->size; |
61989a80 NG |
832 | |
833 | error = 0; /* Success */ | |
834 | ||
835 | cleanup: | |
836 | if (unlikely(error) && first_page) { | |
837 | free_zspage(first_page); | |
838 | first_page = NULL; | |
839 | } | |
840 | ||
841 | return first_page; | |
842 | } | |
843 | ||
844 | static struct page *find_get_zspage(struct size_class *class) | |
845 | { | |
846 | int i; | |
847 | struct page *page; | |
848 | ||
849 | for (i = 0; i < _ZS_NR_FULLNESS_GROUPS; i++) { | |
850 | page = class->fullness_list[i]; | |
851 | if (page) | |
852 | break; | |
853 | } | |
854 | ||
855 | return page; | |
856 | } | |
857 | ||
1b945aee | 858 | #ifdef CONFIG_PGTABLE_MAPPING |
f553646a SJ |
859 | static inline int __zs_cpu_up(struct mapping_area *area) |
860 | { | |
861 | /* | |
862 | * Make sure we don't leak memory if a cpu UP notification | |
863 | * and zs_init() race and both call zs_cpu_up() on the same cpu | |
864 | */ | |
865 | if (area->vm) | |
866 | return 0; | |
867 | area->vm = alloc_vm_area(PAGE_SIZE * 2, NULL); | |
868 | if (!area->vm) | |
869 | return -ENOMEM; | |
870 | return 0; | |
871 | } | |
872 | ||
873 | static inline void __zs_cpu_down(struct mapping_area *area) | |
874 | { | |
875 | if (area->vm) | |
876 | free_vm_area(area->vm); | |
877 | area->vm = NULL; | |
878 | } | |
879 | ||
880 | static inline void *__zs_map_object(struct mapping_area *area, | |
881 | struct page *pages[2], int off, int size) | |
882 | { | |
f6f8ed47 | 883 | BUG_ON(map_vm_area(area->vm, PAGE_KERNEL, pages)); |
f553646a SJ |
884 | area->vm_addr = area->vm->addr; |
885 | return area->vm_addr + off; | |
886 | } | |
887 | ||
888 | static inline void __zs_unmap_object(struct mapping_area *area, | |
889 | struct page *pages[2], int off, int size) | |
890 | { | |
891 | unsigned long addr = (unsigned long)area->vm_addr; | |
f553646a | 892 | |
d95abbbb | 893 | unmap_kernel_range(addr, PAGE_SIZE * 2); |
f553646a SJ |
894 | } |
895 | ||
1b945aee | 896 | #else /* CONFIG_PGTABLE_MAPPING */ |
f553646a SJ |
897 | |
898 | static inline int __zs_cpu_up(struct mapping_area *area) | |
899 | { | |
900 | /* | |
901 | * Make sure we don't leak memory if a cpu UP notification | |
902 | * and zs_init() race and both call zs_cpu_up() on the same cpu | |
903 | */ | |
904 | if (area->vm_buf) | |
905 | return 0; | |
40f9fb8c | 906 | area->vm_buf = kmalloc(ZS_MAX_ALLOC_SIZE, GFP_KERNEL); |
f553646a SJ |
907 | if (!area->vm_buf) |
908 | return -ENOMEM; | |
909 | return 0; | |
910 | } | |
911 | ||
912 | static inline void __zs_cpu_down(struct mapping_area *area) | |
913 | { | |
40f9fb8c | 914 | kfree(area->vm_buf); |
f553646a SJ |
915 | area->vm_buf = NULL; |
916 | } | |
917 | ||
918 | static void *__zs_map_object(struct mapping_area *area, | |
919 | struct page *pages[2], int off, int size) | |
5f601902 | 920 | { |
5f601902 SJ |
921 | int sizes[2]; |
922 | void *addr; | |
f553646a | 923 | char *buf = area->vm_buf; |
5f601902 | 924 | |
f553646a SJ |
925 | /* disable page faults to match kmap_atomic() return conditions */ |
926 | pagefault_disable(); | |
927 | ||
928 | /* no read fastpath */ | |
929 | if (area->vm_mm == ZS_MM_WO) | |
930 | goto out; | |
5f601902 SJ |
931 | |
932 | sizes[0] = PAGE_SIZE - off; | |
933 | sizes[1] = size - sizes[0]; | |
934 | ||
5f601902 SJ |
935 | /* copy object to per-cpu buffer */ |
936 | addr = kmap_atomic(pages[0]); | |
937 | memcpy(buf, addr + off, sizes[0]); | |
938 | kunmap_atomic(addr); | |
939 | addr = kmap_atomic(pages[1]); | |
940 | memcpy(buf + sizes[0], addr, sizes[1]); | |
941 | kunmap_atomic(addr); | |
f553646a SJ |
942 | out: |
943 | return area->vm_buf; | |
5f601902 SJ |
944 | } |
945 | ||
f553646a SJ |
946 | static void __zs_unmap_object(struct mapping_area *area, |
947 | struct page *pages[2], int off, int size) | |
5f601902 | 948 | { |
5f601902 SJ |
949 | int sizes[2]; |
950 | void *addr; | |
2e40e163 | 951 | char *buf; |
5f601902 | 952 | |
f553646a SJ |
953 | /* no write fastpath */ |
954 | if (area->vm_mm == ZS_MM_RO) | |
955 | goto out; | |
5f601902 | 956 | |
2e40e163 MK |
957 | buf = area->vm_buf + ZS_HANDLE_SIZE; |
958 | size -= ZS_HANDLE_SIZE; | |
959 | off += ZS_HANDLE_SIZE; | |
960 | ||
5f601902 SJ |
961 | sizes[0] = PAGE_SIZE - off; |
962 | sizes[1] = size - sizes[0]; | |
963 | ||
964 | /* copy per-cpu buffer to object */ | |
965 | addr = kmap_atomic(pages[0]); | |
966 | memcpy(addr + off, buf, sizes[0]); | |
967 | kunmap_atomic(addr); | |
968 | addr = kmap_atomic(pages[1]); | |
969 | memcpy(addr, buf + sizes[0], sizes[1]); | |
970 | kunmap_atomic(addr); | |
f553646a SJ |
971 | |
972 | out: | |
973 | /* enable page faults to match kunmap_atomic() return conditions */ | |
974 | pagefault_enable(); | |
5f601902 | 975 | } |
61989a80 | 976 | |
1b945aee | 977 | #endif /* CONFIG_PGTABLE_MAPPING */ |
f553646a | 978 | |
61989a80 NG |
979 | static int zs_cpu_notifier(struct notifier_block *nb, unsigned long action, |
980 | void *pcpu) | |
981 | { | |
f553646a | 982 | int ret, cpu = (long)pcpu; |
61989a80 NG |
983 | struct mapping_area *area; |
984 | ||
985 | switch (action) { | |
986 | case CPU_UP_PREPARE: | |
987 | area = &per_cpu(zs_map_area, cpu); | |
f553646a SJ |
988 | ret = __zs_cpu_up(area); |
989 | if (ret) | |
990 | return notifier_from_errno(ret); | |
61989a80 NG |
991 | break; |
992 | case CPU_DEAD: | |
993 | case CPU_UP_CANCELED: | |
994 | area = &per_cpu(zs_map_area, cpu); | |
f553646a | 995 | __zs_cpu_down(area); |
61989a80 NG |
996 | break; |
997 | } | |
998 | ||
999 | return NOTIFY_OK; | |
1000 | } | |
1001 | ||
1002 | static struct notifier_block zs_cpu_nb = { | |
1003 | .notifier_call = zs_cpu_notifier | |
1004 | }; | |
1005 | ||
b1b00a5b | 1006 | static int zs_register_cpu_notifier(void) |
61989a80 | 1007 | { |
b1b00a5b | 1008 | int cpu, uninitialized_var(ret); |
61989a80 | 1009 | |
f0e71fcd SB |
1010 | cpu_notifier_register_begin(); |
1011 | ||
1012 | __register_cpu_notifier(&zs_cpu_nb); | |
61989a80 NG |
1013 | for_each_online_cpu(cpu) { |
1014 | ret = zs_cpu_notifier(NULL, CPU_UP_PREPARE, (void *)(long)cpu); | |
b1b00a5b SS |
1015 | if (notifier_to_errno(ret)) |
1016 | break; | |
61989a80 | 1017 | } |
f0e71fcd SB |
1018 | |
1019 | cpu_notifier_register_done(); | |
b1b00a5b SS |
1020 | return notifier_to_errno(ret); |
1021 | } | |
f0e71fcd | 1022 | |
66cdef66 | 1023 | static void zs_unregister_cpu_notifier(void) |
40f9fb8c | 1024 | { |
66cdef66 | 1025 | int cpu; |
40f9fb8c | 1026 | |
66cdef66 | 1027 | cpu_notifier_register_begin(); |
40f9fb8c | 1028 | |
66cdef66 GM |
1029 | for_each_online_cpu(cpu) |
1030 | zs_cpu_notifier(NULL, CPU_DEAD, (void *)(long)cpu); | |
1031 | __unregister_cpu_notifier(&zs_cpu_nb); | |
40f9fb8c | 1032 | |
66cdef66 | 1033 | cpu_notifier_register_done(); |
b1b00a5b SS |
1034 | } |
1035 | ||
66cdef66 | 1036 | static void init_zs_size_classes(void) |
b1b00a5b | 1037 | { |
66cdef66 | 1038 | int nr; |
c795779d | 1039 | |
66cdef66 GM |
1040 | nr = (ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE) / ZS_SIZE_CLASS_DELTA + 1; |
1041 | if ((ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE) % ZS_SIZE_CLASS_DELTA) | |
1042 | nr += 1; | |
40f9fb8c | 1043 | |
66cdef66 | 1044 | zs_size_classes = nr; |
61989a80 NG |
1045 | } |
1046 | ||
9eec4cd5 JK |
1047 | static unsigned int get_maxobj_per_zspage(int size, int pages_per_zspage) |
1048 | { | |
1049 | return pages_per_zspage * PAGE_SIZE / size; | |
1050 | } | |
1051 | ||
1052 | static bool can_merge(struct size_class *prev, int size, int pages_per_zspage) | |
1053 | { | |
1054 | if (prev->pages_per_zspage != pages_per_zspage) | |
1055 | return false; | |
1056 | ||
1057 | if (get_maxobj_per_zspage(prev->size, prev->pages_per_zspage) | |
1058 | != get_maxobj_per_zspage(size, pages_per_zspage)) | |
1059 | return false; | |
1060 | ||
1061 | return true; | |
1062 | } | |
1063 | ||
312fcae2 MK |
1064 | static bool zspage_full(struct page *page) |
1065 | { | |
1066 | BUG_ON(!is_first_page(page)); | |
1067 | ||
1068 | return page->inuse == page->objects; | |
1069 | } | |
1070 | ||
0f050d99 GM |
1071 | #ifdef CONFIG_ZSMALLOC_STAT |
1072 | ||
1073 | static inline void zs_stat_inc(struct size_class *class, | |
1074 | enum zs_stat_type type, unsigned long cnt) | |
1075 | { | |
1076 | class->stats.objs[type] += cnt; | |
1077 | } | |
1078 | ||
1079 | static inline void zs_stat_dec(struct size_class *class, | |
1080 | enum zs_stat_type type, unsigned long cnt) | |
1081 | { | |
1082 | class->stats.objs[type] -= cnt; | |
1083 | } | |
1084 | ||
1085 | static inline unsigned long zs_stat_get(struct size_class *class, | |
1086 | enum zs_stat_type type) | |
1087 | { | |
1088 | return class->stats.objs[type]; | |
1089 | } | |
1090 | ||
1091 | static int __init zs_stat_init(void) | |
1092 | { | |
1093 | if (!debugfs_initialized()) | |
1094 | return -ENODEV; | |
1095 | ||
1096 | zs_stat_root = debugfs_create_dir("zsmalloc", NULL); | |
1097 | if (!zs_stat_root) | |
1098 | return -ENOMEM; | |
1099 | ||
1100 | return 0; | |
1101 | } | |
1102 | ||
1103 | static void __exit zs_stat_exit(void) | |
1104 | { | |
1105 | debugfs_remove_recursive(zs_stat_root); | |
1106 | } | |
1107 | ||
1108 | static int zs_stats_size_show(struct seq_file *s, void *v) | |
1109 | { | |
1110 | int i; | |
1111 | struct zs_pool *pool = s->private; | |
1112 | struct size_class *class; | |
1113 | int objs_per_zspage; | |
1114 | unsigned long obj_allocated, obj_used, pages_used; | |
1115 | unsigned long total_objs = 0, total_used_objs = 0, total_pages = 0; | |
1116 | ||
1117 | seq_printf(s, " %5s %5s %13s %10s %10s\n", "class", "size", | |
1118 | "obj_allocated", "obj_used", "pages_used"); | |
1119 | ||
1120 | for (i = 0; i < zs_size_classes; i++) { | |
1121 | class = pool->size_class[i]; | |
1122 | ||
1123 | if (class->index != i) | |
1124 | continue; | |
1125 | ||
1126 | spin_lock(&class->lock); | |
1127 | obj_allocated = zs_stat_get(class, OBJ_ALLOCATED); | |
1128 | obj_used = zs_stat_get(class, OBJ_USED); | |
1129 | spin_unlock(&class->lock); | |
1130 | ||
1131 | objs_per_zspage = get_maxobj_per_zspage(class->size, | |
1132 | class->pages_per_zspage); | |
1133 | pages_used = obj_allocated / objs_per_zspage * | |
1134 | class->pages_per_zspage; | |
1135 | ||
1136 | seq_printf(s, " %5u %5u %10lu %10lu %10lu\n", i, | |
1137 | class->size, obj_allocated, obj_used, pages_used); | |
1138 | ||
1139 | total_objs += obj_allocated; | |
1140 | total_used_objs += obj_used; | |
1141 | total_pages += pages_used; | |
1142 | } | |
1143 | ||
1144 | seq_puts(s, "\n"); | |
1145 | seq_printf(s, " %5s %5s %10lu %10lu %10lu\n", "Total", "", | |
1146 | total_objs, total_used_objs, total_pages); | |
1147 | ||
1148 | return 0; | |
1149 | } | |
1150 | ||
1151 | static int zs_stats_size_open(struct inode *inode, struct file *file) | |
1152 | { | |
1153 | return single_open(file, zs_stats_size_show, inode->i_private); | |
1154 | } | |
1155 | ||
1156 | static const struct file_operations zs_stat_size_ops = { | |
1157 | .open = zs_stats_size_open, | |
1158 | .read = seq_read, | |
1159 | .llseek = seq_lseek, | |
1160 | .release = single_release, | |
1161 | }; | |
1162 | ||
1163 | static int zs_pool_stat_create(char *name, struct zs_pool *pool) | |
1164 | { | |
1165 | struct dentry *entry; | |
1166 | ||
1167 | if (!zs_stat_root) | |
1168 | return -ENODEV; | |
1169 | ||
1170 | entry = debugfs_create_dir(name, zs_stat_root); | |
1171 | if (!entry) { | |
1172 | pr_warn("debugfs dir <%s> creation failed\n", name); | |
1173 | return -ENOMEM; | |
1174 | } | |
1175 | pool->stat_dentry = entry; | |
1176 | ||
1177 | entry = debugfs_create_file("obj_in_classes", S_IFREG | S_IRUGO, | |
1178 | pool->stat_dentry, pool, &zs_stat_size_ops); | |
1179 | if (!entry) { | |
1180 | pr_warn("%s: debugfs file entry <%s> creation failed\n", | |
1181 | name, "obj_in_classes"); | |
1182 | return -ENOMEM; | |
1183 | } | |
1184 | ||
1185 | return 0; | |
1186 | } | |
1187 | ||
1188 | static void zs_pool_stat_destroy(struct zs_pool *pool) | |
1189 | { | |
1190 | debugfs_remove_recursive(pool->stat_dentry); | |
1191 | } | |
1192 | ||
1193 | #else /* CONFIG_ZSMALLOC_STAT */ | |
1194 | ||
1195 | static inline void zs_stat_inc(struct size_class *class, | |
1196 | enum zs_stat_type type, unsigned long cnt) | |
1197 | { | |
1198 | } | |
1199 | ||
1200 | static inline void zs_stat_dec(struct size_class *class, | |
1201 | enum zs_stat_type type, unsigned long cnt) | |
1202 | { | |
1203 | } | |
1204 | ||
1205 | static inline unsigned long zs_stat_get(struct size_class *class, | |
1206 | enum zs_stat_type type) | |
1207 | { | |
1208 | return 0; | |
1209 | } | |
1210 | ||
1211 | static int __init zs_stat_init(void) | |
1212 | { | |
1213 | return 0; | |
1214 | } | |
1215 | ||
1216 | static void __exit zs_stat_exit(void) | |
1217 | { | |
1218 | } | |
1219 | ||
1220 | static inline int zs_pool_stat_create(char *name, struct zs_pool *pool) | |
1221 | { | |
1222 | return 0; | |
1223 | } | |
1224 | ||
1225 | static inline void zs_pool_stat_destroy(struct zs_pool *pool) | |
1226 | { | |
1227 | } | |
1228 | ||
1229 | #endif | |
1230 | ||
66cdef66 GM |
1231 | unsigned long zs_get_total_pages(struct zs_pool *pool) |
1232 | { | |
1233 | return atomic_long_read(&pool->pages_allocated); | |
1234 | } | |
1235 | EXPORT_SYMBOL_GPL(zs_get_total_pages); | |
1236 | ||
4bbc0bc0 | 1237 | /** |
66cdef66 GM |
1238 | * zs_map_object - get address of allocated object from handle. |
1239 | * @pool: pool from which the object was allocated | |
1240 | * @handle: handle returned from zs_malloc | |
4bbc0bc0 | 1241 | * |
66cdef66 GM |
1242 | * Before using an object allocated from zs_malloc, it must be mapped using |
1243 | * this function. When done with the object, it must be unmapped using | |
1244 | * zs_unmap_object. | |
4bbc0bc0 | 1245 | * |
66cdef66 GM |
1246 | * Only one object can be mapped per cpu at a time. There is no protection |
1247 | * against nested mappings. | |
1248 | * | |
1249 | * This function returns with preemption and page faults disabled. | |
4bbc0bc0 | 1250 | */ |
66cdef66 GM |
1251 | void *zs_map_object(struct zs_pool *pool, unsigned long handle, |
1252 | enum zs_mapmode mm) | |
61989a80 | 1253 | { |
66cdef66 | 1254 | struct page *page; |
2e40e163 | 1255 | unsigned long obj, obj_idx, off; |
61989a80 | 1256 | |
66cdef66 GM |
1257 | unsigned int class_idx; |
1258 | enum fullness_group fg; | |
1259 | struct size_class *class; | |
1260 | struct mapping_area *area; | |
1261 | struct page *pages[2]; | |
2e40e163 | 1262 | void *ret; |
61989a80 | 1263 | |
66cdef66 | 1264 | BUG_ON(!handle); |
40f9fb8c | 1265 | |
9eec4cd5 | 1266 | /* |
66cdef66 GM |
1267 | * Because we use per-cpu mapping areas shared among the |
1268 | * pools/users, we can't allow mapping in interrupt context | |
1269 | * because it can corrupt another users mappings. | |
9eec4cd5 | 1270 | */ |
66cdef66 | 1271 | BUG_ON(in_interrupt()); |
61989a80 | 1272 | |
312fcae2 MK |
1273 | /* From now on, migration cannot move the object */ |
1274 | pin_tag(handle); | |
1275 | ||
2e40e163 MK |
1276 | obj = handle_to_obj(handle); |
1277 | obj_to_location(obj, &page, &obj_idx); | |
66cdef66 GM |
1278 | get_zspage_mapping(get_first_page(page), &class_idx, &fg); |
1279 | class = pool->size_class[class_idx]; | |
1280 | off = obj_idx_to_offset(page, obj_idx, class->size); | |
df8b5bb9 | 1281 | |
66cdef66 GM |
1282 | area = &get_cpu_var(zs_map_area); |
1283 | area->vm_mm = mm; | |
1284 | if (off + class->size <= PAGE_SIZE) { | |
1285 | /* this object is contained entirely within a page */ | |
1286 | area->vm_addr = kmap_atomic(page); | |
2e40e163 MK |
1287 | ret = area->vm_addr + off; |
1288 | goto out; | |
61989a80 NG |
1289 | } |
1290 | ||
66cdef66 GM |
1291 | /* this object spans two pages */ |
1292 | pages[0] = page; | |
1293 | pages[1] = get_next_page(page); | |
1294 | BUG_ON(!pages[1]); | |
9eec4cd5 | 1295 | |
2e40e163 MK |
1296 | ret = __zs_map_object(area, pages, off, class->size); |
1297 | out: | |
1298 | return ret + ZS_HANDLE_SIZE; | |
61989a80 | 1299 | } |
66cdef66 | 1300 | EXPORT_SYMBOL_GPL(zs_map_object); |
61989a80 | 1301 | |
66cdef66 | 1302 | void zs_unmap_object(struct zs_pool *pool, unsigned long handle) |
61989a80 | 1303 | { |
66cdef66 | 1304 | struct page *page; |
2e40e163 | 1305 | unsigned long obj, obj_idx, off; |
61989a80 | 1306 | |
66cdef66 GM |
1307 | unsigned int class_idx; |
1308 | enum fullness_group fg; | |
1309 | struct size_class *class; | |
1310 | struct mapping_area *area; | |
9eec4cd5 | 1311 | |
66cdef66 | 1312 | BUG_ON(!handle); |
9eec4cd5 | 1313 | |
2e40e163 MK |
1314 | obj = handle_to_obj(handle); |
1315 | obj_to_location(obj, &page, &obj_idx); | |
66cdef66 GM |
1316 | get_zspage_mapping(get_first_page(page), &class_idx, &fg); |
1317 | class = pool->size_class[class_idx]; | |
1318 | off = obj_idx_to_offset(page, obj_idx, class->size); | |
61989a80 | 1319 | |
66cdef66 GM |
1320 | area = this_cpu_ptr(&zs_map_area); |
1321 | if (off + class->size <= PAGE_SIZE) | |
1322 | kunmap_atomic(area->vm_addr); | |
1323 | else { | |
1324 | struct page *pages[2]; | |
40f9fb8c | 1325 | |
66cdef66 GM |
1326 | pages[0] = page; |
1327 | pages[1] = get_next_page(page); | |
1328 | BUG_ON(!pages[1]); | |
1329 | ||
1330 | __zs_unmap_object(area, pages, off, class->size); | |
1331 | } | |
1332 | put_cpu_var(zs_map_area); | |
312fcae2 | 1333 | unpin_tag(handle); |
61989a80 | 1334 | } |
66cdef66 | 1335 | EXPORT_SYMBOL_GPL(zs_unmap_object); |
61989a80 | 1336 | |
c7806261 MK |
1337 | static unsigned long obj_malloc(struct page *first_page, |
1338 | struct size_class *class, unsigned long handle) | |
1339 | { | |
1340 | unsigned long obj; | |
1341 | struct link_free *link; | |
1342 | ||
1343 | struct page *m_page; | |
1344 | unsigned long m_objidx, m_offset; | |
1345 | void *vaddr; | |
1346 | ||
312fcae2 | 1347 | handle |= OBJ_ALLOCATED_TAG; |
c7806261 MK |
1348 | obj = (unsigned long)first_page->freelist; |
1349 | obj_to_location(obj, &m_page, &m_objidx); | |
1350 | m_offset = obj_idx_to_offset(m_page, m_objidx, class->size); | |
1351 | ||
1352 | vaddr = kmap_atomic(m_page); | |
1353 | link = (struct link_free *)vaddr + m_offset / sizeof(*link); | |
1354 | first_page->freelist = link->next; | |
1355 | /* record handle in the header of allocated chunk */ | |
1356 | link->handle = handle; | |
1357 | kunmap_atomic(vaddr); | |
1358 | first_page->inuse++; | |
1359 | zs_stat_inc(class, OBJ_USED, 1); | |
1360 | ||
1361 | return obj; | |
1362 | } | |
1363 | ||
1364 | ||
61989a80 NG |
1365 | /** |
1366 | * zs_malloc - Allocate block of given size from pool. | |
1367 | * @pool: pool to allocate from | |
1368 | * @size: size of block to allocate | |
61989a80 | 1369 | * |
00a61d86 | 1370 | * On success, handle to the allocated object is returned, |
c2344348 | 1371 | * otherwise 0. |
61989a80 NG |
1372 | * Allocation requests with size > ZS_MAX_ALLOC_SIZE will fail. |
1373 | */ | |
c2344348 | 1374 | unsigned long zs_malloc(struct zs_pool *pool, size_t size) |
61989a80 | 1375 | { |
2e40e163 | 1376 | unsigned long handle, obj; |
61989a80 | 1377 | struct size_class *class; |
c7806261 | 1378 | struct page *first_page; |
61989a80 | 1379 | |
2e40e163 MK |
1380 | if (unlikely(!size || (size + ZS_HANDLE_SIZE) > ZS_MAX_ALLOC_SIZE)) |
1381 | return 0; | |
1382 | ||
1383 | handle = alloc_handle(pool); | |
1384 | if (!handle) | |
c2344348 | 1385 | return 0; |
61989a80 | 1386 | |
2e40e163 MK |
1387 | /* extra space in chunk to keep the handle */ |
1388 | size += ZS_HANDLE_SIZE; | |
9eec4cd5 | 1389 | class = pool->size_class[get_size_class_index(size)]; |
61989a80 NG |
1390 | |
1391 | spin_lock(&class->lock); | |
1392 | first_page = find_get_zspage(class); | |
1393 | ||
1394 | if (!first_page) { | |
1395 | spin_unlock(&class->lock); | |
1396 | first_page = alloc_zspage(class, pool->flags); | |
2e40e163 MK |
1397 | if (unlikely(!first_page)) { |
1398 | free_handle(pool, handle); | |
c2344348 | 1399 | return 0; |
2e40e163 | 1400 | } |
61989a80 NG |
1401 | |
1402 | set_zspage_mapping(first_page, class->index, ZS_EMPTY); | |
13de8933 MK |
1403 | atomic_long_add(class->pages_per_zspage, |
1404 | &pool->pages_allocated); | |
0f050d99 | 1405 | |
61989a80 | 1406 | spin_lock(&class->lock); |
0f050d99 GM |
1407 | zs_stat_inc(class, OBJ_ALLOCATED, get_maxobj_per_zspage( |
1408 | class->size, class->pages_per_zspage)); | |
61989a80 NG |
1409 | } |
1410 | ||
c7806261 | 1411 | obj = obj_malloc(first_page, class, handle); |
61989a80 | 1412 | /* Now move the zspage to another fullness group, if required */ |
c7806261 | 1413 | fix_fullness_group(class, first_page); |
2e40e163 | 1414 | record_obj(handle, obj); |
61989a80 NG |
1415 | spin_unlock(&class->lock); |
1416 | ||
2e40e163 | 1417 | return handle; |
61989a80 NG |
1418 | } |
1419 | EXPORT_SYMBOL_GPL(zs_malloc); | |
1420 | ||
c7806261 MK |
1421 | static void obj_free(struct zs_pool *pool, struct size_class *class, |
1422 | unsigned long obj) | |
61989a80 NG |
1423 | { |
1424 | struct link_free *link; | |
1425 | struct page *first_page, *f_page; | |
c7806261 | 1426 | unsigned long f_objidx, f_offset; |
af4ee5e9 | 1427 | void *vaddr; |
61989a80 | 1428 | int class_idx; |
61989a80 NG |
1429 | enum fullness_group fullness; |
1430 | ||
c7806261 | 1431 | BUG_ON(!obj); |
61989a80 | 1432 | |
312fcae2 | 1433 | obj &= ~OBJ_ALLOCATED_TAG; |
2e40e163 | 1434 | obj_to_location(obj, &f_page, &f_objidx); |
61989a80 NG |
1435 | first_page = get_first_page(f_page); |
1436 | ||
1437 | get_zspage_mapping(first_page, &class_idx, &fullness); | |
61989a80 NG |
1438 | f_offset = obj_idx_to_offset(f_page, f_objidx, class->size); |
1439 | ||
c7806261 | 1440 | vaddr = kmap_atomic(f_page); |
61989a80 NG |
1441 | |
1442 | /* Insert this object in containing zspage's freelist */ | |
af4ee5e9 | 1443 | link = (struct link_free *)(vaddr + f_offset); |
61989a80 | 1444 | link->next = first_page->freelist; |
af4ee5e9 | 1445 | kunmap_atomic(vaddr); |
c2344348 | 1446 | first_page->freelist = (void *)obj; |
61989a80 | 1447 | first_page->inuse--; |
0f050d99 | 1448 | zs_stat_dec(class, OBJ_USED, 1); |
c7806261 MK |
1449 | } |
1450 | ||
1451 | void zs_free(struct zs_pool *pool, unsigned long handle) | |
1452 | { | |
1453 | struct page *first_page, *f_page; | |
1454 | unsigned long obj, f_objidx; | |
1455 | int class_idx; | |
1456 | struct size_class *class; | |
1457 | enum fullness_group fullness; | |
1458 | ||
1459 | if (unlikely(!handle)) | |
1460 | return; | |
1461 | ||
312fcae2 | 1462 | pin_tag(handle); |
c7806261 | 1463 | obj = handle_to_obj(handle); |
c7806261 MK |
1464 | obj_to_location(obj, &f_page, &f_objidx); |
1465 | first_page = get_first_page(f_page); | |
1466 | ||
1467 | get_zspage_mapping(first_page, &class_idx, &fullness); | |
1468 | class = pool->size_class[class_idx]; | |
1469 | ||
1470 | spin_lock(&class->lock); | |
1471 | obj_free(pool, class, obj); | |
1472 | fullness = fix_fullness_group(class, first_page); | |
312fcae2 | 1473 | if (fullness == ZS_EMPTY) { |
0f050d99 GM |
1474 | zs_stat_dec(class, OBJ_ALLOCATED, get_maxobj_per_zspage( |
1475 | class->size, class->pages_per_zspage)); | |
312fcae2 MK |
1476 | atomic_long_sub(class->pages_per_zspage, |
1477 | &pool->pages_allocated); | |
1478 | free_zspage(first_page); | |
1479 | } | |
61989a80 | 1480 | spin_unlock(&class->lock); |
312fcae2 | 1481 | unpin_tag(handle); |
61989a80 | 1482 | |
312fcae2 MK |
1483 | free_handle(pool, handle); |
1484 | } | |
1485 | EXPORT_SYMBOL_GPL(zs_free); | |
1486 | ||
1487 | static void zs_object_copy(unsigned long src, unsigned long dst, | |
1488 | struct size_class *class) | |
1489 | { | |
1490 | struct page *s_page, *d_page; | |
1491 | unsigned long s_objidx, d_objidx; | |
1492 | unsigned long s_off, d_off; | |
1493 | void *s_addr, *d_addr; | |
1494 | int s_size, d_size, size; | |
1495 | int written = 0; | |
1496 | ||
1497 | s_size = d_size = class->size; | |
1498 | ||
1499 | obj_to_location(src, &s_page, &s_objidx); | |
1500 | obj_to_location(dst, &d_page, &d_objidx); | |
1501 | ||
1502 | s_off = obj_idx_to_offset(s_page, s_objidx, class->size); | |
1503 | d_off = obj_idx_to_offset(d_page, d_objidx, class->size); | |
1504 | ||
1505 | if (s_off + class->size > PAGE_SIZE) | |
1506 | s_size = PAGE_SIZE - s_off; | |
1507 | ||
1508 | if (d_off + class->size > PAGE_SIZE) | |
1509 | d_size = PAGE_SIZE - d_off; | |
1510 | ||
1511 | s_addr = kmap_atomic(s_page); | |
1512 | d_addr = kmap_atomic(d_page); | |
1513 | ||
1514 | while (1) { | |
1515 | size = min(s_size, d_size); | |
1516 | memcpy(d_addr + d_off, s_addr + s_off, size); | |
1517 | written += size; | |
1518 | ||
1519 | if (written == class->size) | |
1520 | break; | |
1521 | ||
1522 | if (s_off + size >= PAGE_SIZE) { | |
1523 | kunmap_atomic(d_addr); | |
1524 | kunmap_atomic(s_addr); | |
1525 | s_page = get_next_page(s_page); | |
1526 | BUG_ON(!s_page); | |
1527 | s_addr = kmap_atomic(s_page); | |
1528 | d_addr = kmap_atomic(d_page); | |
1529 | s_size = class->size - written; | |
1530 | s_off = 0; | |
1531 | } else { | |
1532 | s_off += size; | |
1533 | s_size -= size; | |
1534 | } | |
1535 | ||
1536 | if (d_off + size >= PAGE_SIZE) { | |
1537 | kunmap_atomic(d_addr); | |
1538 | d_page = get_next_page(d_page); | |
1539 | BUG_ON(!d_page); | |
1540 | d_addr = kmap_atomic(d_page); | |
1541 | d_size = class->size - written; | |
1542 | d_off = 0; | |
1543 | } else { | |
1544 | d_off += size; | |
1545 | d_size -= size; | |
1546 | } | |
1547 | } | |
1548 | ||
1549 | kunmap_atomic(d_addr); | |
1550 | kunmap_atomic(s_addr); | |
1551 | } | |
1552 | ||
1553 | /* | |
1554 | * Find alloced object in zspage from index object and | |
1555 | * return handle. | |
1556 | */ | |
1557 | static unsigned long find_alloced_obj(struct page *page, int index, | |
1558 | struct size_class *class) | |
1559 | { | |
1560 | unsigned long head; | |
1561 | int offset = 0; | |
1562 | unsigned long handle = 0; | |
1563 | void *addr = kmap_atomic(page); | |
1564 | ||
1565 | if (!is_first_page(page)) | |
1566 | offset = page->index; | |
1567 | offset += class->size * index; | |
1568 | ||
1569 | while (offset < PAGE_SIZE) { | |
1570 | head = obj_to_head(addr + offset); | |
1571 | if (head & OBJ_ALLOCATED_TAG) { | |
1572 | handle = head & ~OBJ_ALLOCATED_TAG; | |
1573 | if (trypin_tag(handle)) | |
1574 | break; | |
1575 | handle = 0; | |
1576 | } | |
1577 | ||
1578 | offset += class->size; | |
1579 | index++; | |
1580 | } | |
1581 | ||
1582 | kunmap_atomic(addr); | |
1583 | return handle; | |
1584 | } | |
1585 | ||
1586 | struct zs_compact_control { | |
1587 | /* Source page for migration which could be a subpage of zspage. */ | |
1588 | struct page *s_page; | |
1589 | /* Destination page for migration which should be a first page | |
1590 | * of zspage. */ | |
1591 | struct page *d_page; | |
1592 | /* Starting object index within @s_page which used for live object | |
1593 | * in the subpage. */ | |
1594 | int index; | |
1595 | /* how many of objects are migrated */ | |
1596 | int nr_migrated; | |
1597 | }; | |
1598 | ||
1599 | static int migrate_zspage(struct zs_pool *pool, struct size_class *class, | |
1600 | struct zs_compact_control *cc) | |
1601 | { | |
1602 | unsigned long used_obj, free_obj; | |
1603 | unsigned long handle; | |
1604 | struct page *s_page = cc->s_page; | |
1605 | struct page *d_page = cc->d_page; | |
1606 | unsigned long index = cc->index; | |
1607 | int nr_migrated = 0; | |
1608 | int ret = 0; | |
1609 | ||
1610 | while (1) { | |
1611 | handle = find_alloced_obj(s_page, index, class); | |
1612 | if (!handle) { | |
1613 | s_page = get_next_page(s_page); | |
1614 | if (!s_page) | |
1615 | break; | |
1616 | index = 0; | |
1617 | continue; | |
1618 | } | |
1619 | ||
1620 | /* Stop if there is no more space */ | |
1621 | if (zspage_full(d_page)) { | |
1622 | unpin_tag(handle); | |
1623 | ret = -ENOMEM; | |
1624 | break; | |
1625 | } | |
1626 | ||
1627 | used_obj = handle_to_obj(handle); | |
1628 | free_obj = obj_malloc(d_page, class, handle); | |
1629 | zs_object_copy(used_obj, free_obj, class); | |
1630 | index++; | |
1631 | record_obj(handle, free_obj); | |
1632 | unpin_tag(handle); | |
1633 | obj_free(pool, class, used_obj); | |
1634 | nr_migrated++; | |
1635 | } | |
1636 | ||
1637 | /* Remember last position in this iteration */ | |
1638 | cc->s_page = s_page; | |
1639 | cc->index = index; | |
1640 | cc->nr_migrated = nr_migrated; | |
1641 | ||
1642 | return ret; | |
1643 | } | |
1644 | ||
1645 | static struct page *alloc_target_page(struct size_class *class) | |
1646 | { | |
1647 | int i; | |
1648 | struct page *page; | |
1649 | ||
1650 | for (i = 0; i < _ZS_NR_FULLNESS_GROUPS; i++) { | |
1651 | page = class->fullness_list[i]; | |
1652 | if (page) { | |
1653 | remove_zspage(page, class, i); | |
1654 | break; | |
1655 | } | |
1656 | } | |
1657 | ||
1658 | return page; | |
1659 | } | |
1660 | ||
1661 | static void putback_zspage(struct zs_pool *pool, struct size_class *class, | |
1662 | struct page *first_page) | |
1663 | { | |
1664 | int class_idx; | |
1665 | enum fullness_group fullness; | |
1666 | ||
1667 | BUG_ON(!is_first_page(first_page)); | |
1668 | ||
1669 | get_zspage_mapping(first_page, &class_idx, &fullness); | |
1670 | insert_zspage(first_page, class, fullness); | |
1671 | fullness = fix_fullness_group(class, first_page); | |
13de8933 | 1672 | if (fullness == ZS_EMPTY) { |
312fcae2 MK |
1673 | zs_stat_dec(class, OBJ_ALLOCATED, get_maxobj_per_zspage( |
1674 | class->size, class->pages_per_zspage)); | |
13de8933 MK |
1675 | atomic_long_sub(class->pages_per_zspage, |
1676 | &pool->pages_allocated); | |
312fcae2 | 1677 | |
61989a80 | 1678 | free_zspage(first_page); |
13de8933 | 1679 | } |
61989a80 | 1680 | } |
312fcae2 MK |
1681 | |
1682 | static struct page *isolate_source_page(struct size_class *class) | |
1683 | { | |
1684 | struct page *page; | |
1685 | ||
1686 | page = class->fullness_list[ZS_ALMOST_EMPTY]; | |
1687 | if (page) | |
1688 | remove_zspage(page, class, ZS_ALMOST_EMPTY); | |
1689 | ||
1690 | return page; | |
1691 | } | |
1692 | ||
1693 | static unsigned long __zs_compact(struct zs_pool *pool, | |
1694 | struct size_class *class) | |
1695 | { | |
1696 | int nr_to_migrate; | |
1697 | struct zs_compact_control cc; | |
1698 | struct page *src_page; | |
1699 | struct page *dst_page = NULL; | |
1700 | unsigned long nr_total_migrated = 0; | |
1701 | ||
1702 | cond_resched(); | |
1703 | ||
1704 | spin_lock(&class->lock); | |
1705 | while ((src_page = isolate_source_page(class))) { | |
1706 | ||
1707 | BUG_ON(!is_first_page(src_page)); | |
1708 | ||
1709 | /* The goal is to migrate all live objects in source page */ | |
1710 | nr_to_migrate = src_page->inuse; | |
1711 | cc.index = 0; | |
1712 | cc.s_page = src_page; | |
1713 | ||
1714 | while ((dst_page = alloc_target_page(class))) { | |
1715 | cc.d_page = dst_page; | |
1716 | /* | |
1717 | * If there is no more space in dst_page, try to | |
1718 | * allocate another zspage. | |
1719 | */ | |
1720 | if (!migrate_zspage(pool, class, &cc)) | |
1721 | break; | |
1722 | ||
1723 | putback_zspage(pool, class, dst_page); | |
1724 | nr_total_migrated += cc.nr_migrated; | |
1725 | nr_to_migrate -= cc.nr_migrated; | |
1726 | } | |
1727 | ||
1728 | /* Stop if we couldn't find slot */ | |
1729 | if (dst_page == NULL) | |
1730 | break; | |
1731 | ||
1732 | putback_zspage(pool, class, dst_page); | |
1733 | putback_zspage(pool, class, src_page); | |
1734 | spin_unlock(&class->lock); | |
1735 | nr_total_migrated += cc.nr_migrated; | |
1736 | cond_resched(); | |
1737 | spin_lock(&class->lock); | |
1738 | } | |
1739 | ||
1740 | if (src_page) | |
1741 | putback_zspage(pool, class, src_page); | |
1742 | ||
1743 | spin_unlock(&class->lock); | |
1744 | ||
1745 | return nr_total_migrated; | |
1746 | } | |
1747 | ||
1748 | unsigned long zs_compact(struct zs_pool *pool) | |
1749 | { | |
1750 | int i; | |
1751 | unsigned long nr_migrated = 0; | |
1752 | struct size_class *class; | |
1753 | ||
1754 | for (i = zs_size_classes - 1; i >= 0; i--) { | |
1755 | class = pool->size_class[i]; | |
1756 | if (!class) | |
1757 | continue; | |
1758 | if (class->index != i) | |
1759 | continue; | |
1760 | nr_migrated += __zs_compact(pool, class); | |
1761 | } | |
1762 | ||
1763 | synchronize_rcu(); | |
1764 | ||
1765 | return nr_migrated; | |
1766 | } | |
1767 | EXPORT_SYMBOL_GPL(zs_compact); | |
61989a80 | 1768 | |
00a61d86 | 1769 | /** |
66cdef66 GM |
1770 | * zs_create_pool - Creates an allocation pool to work from. |
1771 | * @flags: allocation flags used to allocate pool metadata | |
166cfda7 | 1772 | * |
66cdef66 GM |
1773 | * This function must be called before anything when using |
1774 | * the zsmalloc allocator. | |
166cfda7 | 1775 | * |
66cdef66 GM |
1776 | * On success, a pointer to the newly created pool is returned, |
1777 | * otherwise NULL. | |
396b7fd6 | 1778 | */ |
3eba0c6a | 1779 | struct zs_pool *zs_create_pool(char *name, gfp_t flags) |
61989a80 | 1780 | { |
66cdef66 GM |
1781 | int i; |
1782 | struct zs_pool *pool; | |
1783 | struct size_class *prev_class = NULL; | |
61989a80 | 1784 | |
66cdef66 GM |
1785 | pool = kzalloc(sizeof(*pool), GFP_KERNEL); |
1786 | if (!pool) | |
1787 | return NULL; | |
61989a80 | 1788 | |
66cdef66 GM |
1789 | pool->size_class = kcalloc(zs_size_classes, sizeof(struct size_class *), |
1790 | GFP_KERNEL); | |
1791 | if (!pool->size_class) { | |
1792 | kfree(pool); | |
1793 | return NULL; | |
1794 | } | |
61989a80 | 1795 | |
2e40e163 MK |
1796 | pool->name = kstrdup(name, GFP_KERNEL); |
1797 | if (!pool->name) | |
1798 | goto err; | |
1799 | ||
1800 | if (create_handle_cache(pool)) | |
1801 | goto err; | |
1802 | ||
c60369f0 | 1803 | /* |
66cdef66 GM |
1804 | * Iterate reversly, because, size of size_class that we want to use |
1805 | * for merging should be larger or equal to current size. | |
c60369f0 | 1806 | */ |
66cdef66 GM |
1807 | for (i = zs_size_classes - 1; i >= 0; i--) { |
1808 | int size; | |
1809 | int pages_per_zspage; | |
1810 | struct size_class *class; | |
c60369f0 | 1811 | |
66cdef66 GM |
1812 | size = ZS_MIN_ALLOC_SIZE + i * ZS_SIZE_CLASS_DELTA; |
1813 | if (size > ZS_MAX_ALLOC_SIZE) | |
1814 | size = ZS_MAX_ALLOC_SIZE; | |
1815 | pages_per_zspage = get_pages_per_zspage(size); | |
61989a80 | 1816 | |
66cdef66 GM |
1817 | /* |
1818 | * size_class is used for normal zsmalloc operation such | |
1819 | * as alloc/free for that size. Although it is natural that we | |
1820 | * have one size_class for each size, there is a chance that we | |
1821 | * can get more memory utilization if we use one size_class for | |
1822 | * many different sizes whose size_class have same | |
1823 | * characteristics. So, we makes size_class point to | |
1824 | * previous size_class if possible. | |
1825 | */ | |
1826 | if (prev_class) { | |
1827 | if (can_merge(prev_class, size, pages_per_zspage)) { | |
1828 | pool->size_class[i] = prev_class; | |
1829 | continue; | |
1830 | } | |
1831 | } | |
1832 | ||
1833 | class = kzalloc(sizeof(struct size_class), GFP_KERNEL); | |
1834 | if (!class) | |
1835 | goto err; | |
1836 | ||
1837 | class->size = size; | |
1838 | class->index = i; | |
1839 | class->pages_per_zspage = pages_per_zspage; | |
1840 | spin_lock_init(&class->lock); | |
1841 | pool->size_class[i] = class; | |
1842 | ||
1843 | prev_class = class; | |
61989a80 NG |
1844 | } |
1845 | ||
66cdef66 | 1846 | pool->flags = flags; |
b7418510 | 1847 | |
0f050d99 GM |
1848 | if (zs_pool_stat_create(name, pool)) |
1849 | goto err; | |
1850 | ||
66cdef66 GM |
1851 | return pool; |
1852 | ||
1853 | err: | |
1854 | zs_destroy_pool(pool); | |
1855 | return NULL; | |
61989a80 | 1856 | } |
66cdef66 | 1857 | EXPORT_SYMBOL_GPL(zs_create_pool); |
61989a80 | 1858 | |
66cdef66 | 1859 | void zs_destroy_pool(struct zs_pool *pool) |
61989a80 | 1860 | { |
66cdef66 | 1861 | int i; |
61989a80 | 1862 | |
0f050d99 GM |
1863 | zs_pool_stat_destroy(pool); |
1864 | ||
66cdef66 GM |
1865 | for (i = 0; i < zs_size_classes; i++) { |
1866 | int fg; | |
1867 | struct size_class *class = pool->size_class[i]; | |
61989a80 | 1868 | |
66cdef66 GM |
1869 | if (!class) |
1870 | continue; | |
61989a80 | 1871 | |
66cdef66 GM |
1872 | if (class->index != i) |
1873 | continue; | |
61989a80 | 1874 | |
66cdef66 GM |
1875 | for (fg = 0; fg < _ZS_NR_FULLNESS_GROUPS; fg++) { |
1876 | if (class->fullness_list[fg]) { | |
1877 | pr_info("Freeing non-empty class with size %db, fullness group %d\n", | |
1878 | class->size, fg); | |
1879 | } | |
1880 | } | |
1881 | kfree(class); | |
1882 | } | |
f553646a | 1883 | |
2e40e163 | 1884 | destroy_handle_cache(pool); |
66cdef66 | 1885 | kfree(pool->size_class); |
0f050d99 | 1886 | kfree(pool->name); |
66cdef66 GM |
1887 | kfree(pool); |
1888 | } | |
1889 | EXPORT_SYMBOL_GPL(zs_destroy_pool); | |
b7418510 | 1890 | |
66cdef66 GM |
1891 | static int __init zs_init(void) |
1892 | { | |
1893 | int ret = zs_register_cpu_notifier(); | |
1894 | ||
0f050d99 GM |
1895 | if (ret) |
1896 | goto notifier_fail; | |
66cdef66 GM |
1897 | |
1898 | init_zs_size_classes(); | |
1899 | ||
1900 | #ifdef CONFIG_ZPOOL | |
1901 | zpool_register_driver(&zs_zpool_driver); | |
1902 | #endif | |
0f050d99 GM |
1903 | |
1904 | ret = zs_stat_init(); | |
1905 | if (ret) { | |
1906 | pr_err("zs stat initialization failed\n"); | |
1907 | goto stat_fail; | |
1908 | } | |
66cdef66 | 1909 | return 0; |
0f050d99 GM |
1910 | |
1911 | stat_fail: | |
1912 | #ifdef CONFIG_ZPOOL | |
1913 | zpool_unregister_driver(&zs_zpool_driver); | |
1914 | #endif | |
1915 | notifier_fail: | |
1916 | zs_unregister_cpu_notifier(); | |
1917 | ||
1918 | return ret; | |
61989a80 | 1919 | } |
61989a80 | 1920 | |
66cdef66 | 1921 | static void __exit zs_exit(void) |
61989a80 | 1922 | { |
66cdef66 GM |
1923 | #ifdef CONFIG_ZPOOL |
1924 | zpool_unregister_driver(&zs_zpool_driver); | |
1925 | #endif | |
1926 | zs_unregister_cpu_notifier(); | |
0f050d99 GM |
1927 | |
1928 | zs_stat_exit(); | |
61989a80 | 1929 | } |
069f101f BH |
1930 | |
1931 | module_init(zs_init); | |
1932 | module_exit(zs_exit); | |
1933 | ||
1934 | MODULE_LICENSE("Dual BSD/GPL"); | |
1935 | MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>"); |