Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 1 | /* |
| 2 | * z3fold.c |
| 3 | * |
| 4 | * Author: Vitaly Wool <vitaly.wool@konsulko.com> |
| 5 | * Copyright (C) 2016, Sony Mobile Communications Inc. |
| 6 | * |
| 7 | * This implementation is based on zbud written by Seth Jennings. |
| 8 | * |
| 9 | * z3fold is an special purpose allocator for storing compressed pages. It |
| 10 | * can store up to three compressed pages per page which improves the |
| 11 | * compression ratio of zbud while retaining its main concepts (e. g. always |
| 12 | * storing an integral number of objects per page) and simplicity. |
| 13 | * It still has simple and deterministic reclaim properties that make it |
| 14 | * preferable to a higher density approach (with no requirement on integral |
| 15 | * number of object per page) when reclaim is used. |
| 16 | * |
| 17 | * As in zbud, pages are divided into "chunks". The size of the chunks is |
| 18 | * fixed at compile time and is determined by NCHUNKS_ORDER below. |
| 19 | * |
| 20 | * z3fold doesn't export any API and is meant to be used via zpool API. |
| 21 | */ |
| 22 | |
| 23 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 24 | |
| 25 | #include <linux/atomic.h> |
| 26 | #include <linux/list.h> |
| 27 | #include <linux/mm.h> |
| 28 | #include <linux/module.h> |
| 29 | #include <linux/preempt.h> |
| 30 | #include <linux/slab.h> |
| 31 | #include <linux/spinlock.h> |
| 32 | #include <linux/zpool.h> |
| 33 | |
| 34 | /***************** |
| 35 | * Structures |
| 36 | *****************/ |
Vitaly Wool | ede9321 | 2017-02-24 14:57:17 -0800 | [diff] [blame] | 37 | struct z3fold_pool; |
| 38 | struct z3fold_ops { |
| 39 | int (*evict)(struct z3fold_pool *pool, unsigned long handle); |
| 40 | }; |
| 41 | |
| 42 | enum buddy { |
| 43 | HEADLESS = 0, |
| 44 | FIRST, |
| 45 | MIDDLE, |
| 46 | LAST, |
| 47 | BUDDIES_MAX |
| 48 | }; |
| 49 | |
| 50 | /* |
| 51 | * struct z3fold_header - z3fold page metadata occupying the first chunk of each |
| 52 | * z3fold page, except for HEADLESS pages |
| 53 | * @buddy: links the z3fold page into the relevant list in the pool |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 54 | * @page_lock: per-page lock |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 55 | * @refcount: reference cound for the z3fold page |
Vitaly Wool | ede9321 | 2017-02-24 14:57:17 -0800 | [diff] [blame] | 56 | * @first_chunks: the size of the first buddy in chunks, 0 if free |
| 57 | * @middle_chunks: the size of the middle buddy in chunks, 0 if free |
| 58 | * @last_chunks: the size of the last buddy in chunks, 0 if free |
| 59 | * @first_num: the starting number (for the first handle) |
| 60 | */ |
| 61 | struct z3fold_header { |
| 62 | struct list_head buddy; |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 63 | spinlock_t page_lock; |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 64 | struct kref refcount; |
Vitaly Wool | ede9321 | 2017-02-24 14:57:17 -0800 | [diff] [blame] | 65 | unsigned short first_chunks; |
| 66 | unsigned short middle_chunks; |
| 67 | unsigned short last_chunks; |
| 68 | unsigned short start_middle; |
| 69 | unsigned short first_num:2; |
| 70 | }; |
| 71 | |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 72 | /* |
| 73 | * NCHUNKS_ORDER determines the internal allocation granularity, effectively |
| 74 | * adjusting internal fragmentation. It also determines the number of |
| 75 | * freelists maintained in each pool. NCHUNKS_ORDER of 6 means that the |
Vitaly Wool | ede9321 | 2017-02-24 14:57:17 -0800 | [diff] [blame] | 76 | * allocation granularity will be in chunks of size PAGE_SIZE/64. Some chunks |
| 77 | * in the beginning of an allocated page are occupied by z3fold header, so |
| 78 | * NCHUNKS will be calculated to 63 (or 62 in case CONFIG_DEBUG_SPINLOCK=y), |
| 79 | * which shows the max number of free chunks in z3fold page, also there will |
| 80 | * be 63, or 62, respectively, freelists per pool. |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 81 | */ |
| 82 | #define NCHUNKS_ORDER 6 |
| 83 | |
| 84 | #define CHUNK_SHIFT (PAGE_SHIFT - NCHUNKS_ORDER) |
| 85 | #define CHUNK_SIZE (1 << CHUNK_SHIFT) |
Vitaly Wool | ede9321 | 2017-02-24 14:57:17 -0800 | [diff] [blame] | 86 | #define ZHDR_SIZE_ALIGNED round_up(sizeof(struct z3fold_header), CHUNK_SIZE) |
| 87 | #define ZHDR_CHUNKS (ZHDR_SIZE_ALIGNED >> CHUNK_SHIFT) |
| 88 | #define TOTAL_CHUNKS (PAGE_SIZE >> CHUNK_SHIFT) |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 89 | #define NCHUNKS ((PAGE_SIZE - ZHDR_SIZE_ALIGNED) >> CHUNK_SHIFT) |
| 90 | |
zhong jiang | f201ebd | 2017-02-22 15:46:51 -0800 | [diff] [blame] | 91 | #define BUDDY_MASK (0x3) |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 92 | |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 93 | /** |
| 94 | * struct z3fold_pool - stores metadata for each z3fold pool |
| 95 | * @lock: protects all pool fields and first|last_chunk fields of any |
| 96 | * z3fold page in the pool |
| 97 | * @unbuddied: array of lists tracking z3fold pages that contain 2- buddies; |
| 98 | * the lists each z3fold page is added to depends on the size of |
| 99 | * its free region. |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 100 | * @lru: list tracking the z3fold pages in LRU order by most recently |
| 101 | * added buddy. |
| 102 | * @pages_nr: number of z3fold pages in the pool. |
| 103 | * @ops: pointer to a structure of user defined operations specified at |
| 104 | * pool creation time. |
| 105 | * |
| 106 | * This structure is allocated at pool creation time and maintains metadata |
| 107 | * pertaining to a particular z3fold pool. |
| 108 | */ |
| 109 | struct z3fold_pool { |
| 110 | spinlock_t lock; |
| 111 | struct list_head unbuddied[NCHUNKS]; |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 112 | struct list_head lru; |
Vitaly Wool | 12d59ae | 2017-02-24 14:57:15 -0800 | [diff] [blame] | 113 | atomic64_t pages_nr; |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 114 | const struct z3fold_ops *ops; |
| 115 | struct zpool *zpool; |
| 116 | const struct zpool_ops *zpool_ops; |
| 117 | }; |
| 118 | |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 119 | /* |
| 120 | * Internal z3fold page flags |
| 121 | */ |
| 122 | enum z3fold_page_flags { |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 123 | PAGE_HEADLESS = 0, |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 124 | MIDDLE_CHUNK_MAPPED, |
| 125 | }; |
| 126 | |
Vitaly Wool | ede9321 | 2017-02-24 14:57:17 -0800 | [diff] [blame] | 127 | |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 128 | /***************** |
| 129 | * Helpers |
| 130 | *****************/ |
| 131 | |
| 132 | /* Converts an allocation size in bytes to size in z3fold chunks */ |
| 133 | static int size_to_chunks(size_t size) |
| 134 | { |
| 135 | return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT; |
| 136 | } |
| 137 | |
| 138 | #define for_each_unbuddied_list(_iter, _begin) \ |
| 139 | for ((_iter) = (_begin); (_iter) < NCHUNKS; (_iter)++) |
| 140 | |
| 141 | /* Initializes the z3fold header of a newly allocated z3fold page */ |
| 142 | static struct z3fold_header *init_z3fold_page(struct page *page) |
| 143 | { |
| 144 | struct z3fold_header *zhdr = page_address(page); |
| 145 | |
| 146 | INIT_LIST_HEAD(&page->lru); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 147 | clear_bit(PAGE_HEADLESS, &page->private); |
| 148 | clear_bit(MIDDLE_CHUNK_MAPPED, &page->private); |
| 149 | |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 150 | spin_lock_init(&zhdr->page_lock); |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 151 | kref_init(&zhdr->refcount); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 152 | zhdr->first_chunks = 0; |
| 153 | zhdr->middle_chunks = 0; |
| 154 | zhdr->last_chunks = 0; |
| 155 | zhdr->first_num = 0; |
| 156 | zhdr->start_middle = 0; |
| 157 | INIT_LIST_HEAD(&zhdr->buddy); |
| 158 | return zhdr; |
| 159 | } |
| 160 | |
| 161 | /* Resets the struct page fields and frees the page */ |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 162 | static void free_z3fold_page(struct page *page) |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 163 | { |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 164 | __free_page(page); |
| 165 | } |
| 166 | |
| 167 | static void release_z3fold_page(struct kref *ref) |
| 168 | { |
| 169 | struct z3fold_header *zhdr; |
| 170 | struct page *page; |
| 171 | |
| 172 | zhdr = container_of(ref, struct z3fold_header, refcount); |
| 173 | page = virt_to_page(zhdr); |
| 174 | |
| 175 | if (!list_empty(&zhdr->buddy)) |
| 176 | list_del(&zhdr->buddy); |
| 177 | if (!list_empty(&page->lru)) |
| 178 | list_del(&page->lru); |
| 179 | free_z3fold_page(page); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 180 | } |
| 181 | |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 182 | /* Lock a z3fold page */ |
| 183 | static inline void z3fold_page_lock(struct z3fold_header *zhdr) |
| 184 | { |
| 185 | spin_lock(&zhdr->page_lock); |
| 186 | } |
| 187 | |
| 188 | /* Unlock a z3fold page */ |
| 189 | static inline void z3fold_page_unlock(struct z3fold_header *zhdr) |
| 190 | { |
| 191 | spin_unlock(&zhdr->page_lock); |
| 192 | } |
| 193 | |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 194 | /* |
| 195 | * Encodes the handle of a particular buddy within a z3fold page |
| 196 | * Pool lock should be held as this function accesses first_num |
| 197 | */ |
| 198 | static unsigned long encode_handle(struct z3fold_header *zhdr, enum buddy bud) |
| 199 | { |
| 200 | unsigned long handle; |
| 201 | |
| 202 | handle = (unsigned long)zhdr; |
| 203 | if (bud != HEADLESS) |
| 204 | handle += (bud + zhdr->first_num) & BUDDY_MASK; |
| 205 | return handle; |
| 206 | } |
| 207 | |
| 208 | /* Returns the z3fold page where a given handle is stored */ |
| 209 | static struct z3fold_header *handle_to_z3fold_header(unsigned long handle) |
| 210 | { |
| 211 | return (struct z3fold_header *)(handle & PAGE_MASK); |
| 212 | } |
| 213 | |
zhong jiang | f201ebd | 2017-02-22 15:46:51 -0800 | [diff] [blame] | 214 | /* |
| 215 | * (handle & BUDDY_MASK) < zhdr->first_num is possible in encode_handle |
| 216 | * but that doesn't matter. because the masking will result in the |
| 217 | * correct buddy number. |
| 218 | */ |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 219 | static enum buddy handle_to_buddy(unsigned long handle) |
| 220 | { |
| 221 | struct z3fold_header *zhdr = handle_to_z3fold_header(handle); |
| 222 | return (handle - zhdr->first_num) & BUDDY_MASK; |
| 223 | } |
| 224 | |
| 225 | /* |
| 226 | * Returns the number of free chunks in a z3fold page. |
| 227 | * NB: can't be used with HEADLESS pages. |
| 228 | */ |
| 229 | static int num_free_chunks(struct z3fold_header *zhdr) |
| 230 | { |
| 231 | int nfree; |
| 232 | /* |
| 233 | * If there is a middle object, pick up the bigger free space |
| 234 | * either before or after it. Otherwise just subtract the number |
| 235 | * of chunks occupied by the first and the last objects. |
| 236 | */ |
| 237 | if (zhdr->middle_chunks != 0) { |
| 238 | int nfree_before = zhdr->first_chunks ? |
Vitaly Wool | ede9321 | 2017-02-24 14:57:17 -0800 | [diff] [blame] | 239 | 0 : zhdr->start_middle - ZHDR_CHUNKS; |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 240 | int nfree_after = zhdr->last_chunks ? |
Vitaly Wool | ede9321 | 2017-02-24 14:57:17 -0800 | [diff] [blame] | 241 | 0 : TOTAL_CHUNKS - |
| 242 | (zhdr->start_middle + zhdr->middle_chunks); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 243 | nfree = max(nfree_before, nfree_after); |
| 244 | } else |
| 245 | nfree = NCHUNKS - zhdr->first_chunks - zhdr->last_chunks; |
| 246 | return nfree; |
| 247 | } |
| 248 | |
| 249 | /***************** |
| 250 | * API Functions |
| 251 | *****************/ |
| 252 | /** |
| 253 | * z3fold_create_pool() - create a new z3fold pool |
| 254 | * @gfp: gfp flags when allocating the z3fold pool structure |
| 255 | * @ops: user-defined operations for the z3fold pool |
| 256 | * |
| 257 | * Return: pointer to the new z3fold pool or NULL if the metadata allocation |
| 258 | * failed. |
| 259 | */ |
| 260 | static struct z3fold_pool *z3fold_create_pool(gfp_t gfp, |
| 261 | const struct z3fold_ops *ops) |
| 262 | { |
| 263 | struct z3fold_pool *pool; |
| 264 | int i; |
| 265 | |
| 266 | pool = kzalloc(sizeof(struct z3fold_pool), gfp); |
| 267 | if (!pool) |
| 268 | return NULL; |
| 269 | spin_lock_init(&pool->lock); |
| 270 | for_each_unbuddied_list(i, 0) |
| 271 | INIT_LIST_HEAD(&pool->unbuddied[i]); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 272 | INIT_LIST_HEAD(&pool->lru); |
Vitaly Wool | 12d59ae | 2017-02-24 14:57:15 -0800 | [diff] [blame] | 273 | atomic64_set(&pool->pages_nr, 0); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 274 | pool->ops = ops; |
| 275 | return pool; |
| 276 | } |
| 277 | |
| 278 | /** |
| 279 | * z3fold_destroy_pool() - destroys an existing z3fold pool |
| 280 | * @pool: the z3fold pool to be destroyed |
| 281 | * |
| 282 | * The pool should be emptied before this function is called. |
| 283 | */ |
| 284 | static void z3fold_destroy_pool(struct z3fold_pool *pool) |
| 285 | { |
| 286 | kfree(pool); |
| 287 | } |
| 288 | |
Vitaly Wool | ede9321 | 2017-02-24 14:57:17 -0800 | [diff] [blame] | 289 | static inline void *mchunk_memmove(struct z3fold_header *zhdr, |
| 290 | unsigned short dst_chunk) |
| 291 | { |
| 292 | void *beg = zhdr; |
| 293 | return memmove(beg + (dst_chunk << CHUNK_SHIFT), |
| 294 | beg + (zhdr->start_middle << CHUNK_SHIFT), |
| 295 | zhdr->middle_chunks << CHUNK_SHIFT); |
| 296 | } |
| 297 | |
Vitaly Wool | 1b096e5 | 2017-02-24 14:57:20 -0800 | [diff] [blame] | 298 | #define BIG_CHUNK_GAP 3 |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 299 | /* Has to be called with lock held */ |
| 300 | static int z3fold_compact_page(struct z3fold_header *zhdr) |
| 301 | { |
| 302 | struct page *page = virt_to_page(zhdr); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 303 | |
Vitaly Wool | ede9321 | 2017-02-24 14:57:17 -0800 | [diff] [blame] | 304 | if (test_bit(MIDDLE_CHUNK_MAPPED, &page->private)) |
| 305 | return 0; /* can't move middle chunk, it's used */ |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 306 | |
Vitaly Wool | ede9321 | 2017-02-24 14:57:17 -0800 | [diff] [blame] | 307 | if (zhdr->middle_chunks == 0) |
| 308 | return 0; /* nothing to compact */ |
| 309 | |
| 310 | if (zhdr->first_chunks == 0 && zhdr->last_chunks == 0) { |
| 311 | /* move to the beginning */ |
| 312 | mchunk_memmove(zhdr, ZHDR_CHUNKS); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 313 | zhdr->first_chunks = zhdr->middle_chunks; |
| 314 | zhdr->middle_chunks = 0; |
| 315 | zhdr->start_middle = 0; |
| 316 | zhdr->first_num++; |
Vitaly Wool | 1b096e5 | 2017-02-24 14:57:20 -0800 | [diff] [blame] | 317 | return 1; |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 318 | } |
Vitaly Wool | 1b096e5 | 2017-02-24 14:57:20 -0800 | [diff] [blame] | 319 | |
| 320 | /* |
| 321 | * moving data is expensive, so let's only do that if |
| 322 | * there's substantial gain (at least BIG_CHUNK_GAP chunks) |
| 323 | */ |
| 324 | if (zhdr->first_chunks != 0 && zhdr->last_chunks == 0 && |
| 325 | zhdr->start_middle - (zhdr->first_chunks + ZHDR_CHUNKS) >= |
| 326 | BIG_CHUNK_GAP) { |
| 327 | mchunk_memmove(zhdr, zhdr->first_chunks + ZHDR_CHUNKS); |
| 328 | zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS; |
| 329 | return 1; |
| 330 | } else if (zhdr->last_chunks != 0 && zhdr->first_chunks == 0 && |
| 331 | TOTAL_CHUNKS - (zhdr->last_chunks + zhdr->start_middle |
| 332 | + zhdr->middle_chunks) >= |
| 333 | BIG_CHUNK_GAP) { |
| 334 | unsigned short new_start = TOTAL_CHUNKS - zhdr->last_chunks - |
| 335 | zhdr->middle_chunks; |
| 336 | mchunk_memmove(zhdr, new_start); |
| 337 | zhdr->start_middle = new_start; |
| 338 | return 1; |
| 339 | } |
| 340 | |
| 341 | return 0; |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 342 | } |
| 343 | |
| 344 | /** |
| 345 | * z3fold_alloc() - allocates a region of a given size |
| 346 | * @pool: z3fold pool from which to allocate |
| 347 | * @size: size in bytes of the desired allocation |
| 348 | * @gfp: gfp flags used if the pool needs to grow |
| 349 | * @handle: handle of the new allocation |
| 350 | * |
| 351 | * This function will attempt to find a free region in the pool large enough to |
| 352 | * satisfy the allocation request. A search of the unbuddied lists is |
| 353 | * performed first. If no suitable free region is found, then a new page is |
| 354 | * allocated and added to the pool to satisfy the request. |
| 355 | * |
| 356 | * gfp should not set __GFP_HIGHMEM as highmem pages cannot be used |
| 357 | * as z3fold pool pages. |
| 358 | * |
| 359 | * Return: 0 if success and handle is set, otherwise -EINVAL if the size or |
| 360 | * gfp arguments are invalid or -ENOMEM if the pool was unable to allocate |
| 361 | * a new page. |
| 362 | */ |
| 363 | static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp, |
| 364 | unsigned long *handle) |
| 365 | { |
| 366 | int chunks = 0, i, freechunks; |
| 367 | struct z3fold_header *zhdr = NULL; |
| 368 | enum buddy bud; |
| 369 | struct page *page; |
| 370 | |
| 371 | if (!size || (gfp & __GFP_HIGHMEM)) |
| 372 | return -EINVAL; |
| 373 | |
| 374 | if (size > PAGE_SIZE) |
| 375 | return -ENOSPC; |
| 376 | |
| 377 | if (size > PAGE_SIZE - ZHDR_SIZE_ALIGNED - CHUNK_SIZE) |
| 378 | bud = HEADLESS; |
| 379 | else { |
| 380 | chunks = size_to_chunks(size); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 381 | |
| 382 | /* First, try to find an unbuddied z3fold page. */ |
| 383 | zhdr = NULL; |
| 384 | for_each_unbuddied_list(i, chunks) { |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 385 | spin_lock(&pool->lock); |
| 386 | zhdr = list_first_entry_or_null(&pool->unbuddied[i], |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 387 | struct z3fold_header, buddy); |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 388 | if (!zhdr) { |
| 389 | spin_unlock(&pool->lock); |
| 390 | continue; |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 391 | } |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 392 | kref_get(&zhdr->refcount); |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 393 | list_del_init(&zhdr->buddy); |
| 394 | spin_unlock(&pool->lock); |
| 395 | |
| 396 | page = virt_to_page(zhdr); |
| 397 | z3fold_page_lock(zhdr); |
| 398 | if (zhdr->first_chunks == 0) { |
| 399 | if (zhdr->middle_chunks != 0 && |
| 400 | chunks >= zhdr->start_middle) |
| 401 | bud = LAST; |
| 402 | else |
| 403 | bud = FIRST; |
| 404 | } else if (zhdr->last_chunks == 0) |
| 405 | bud = LAST; |
| 406 | else if (zhdr->middle_chunks == 0) |
| 407 | bud = MIDDLE; |
| 408 | else { |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 409 | z3fold_page_unlock(zhdr); |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 410 | spin_lock(&pool->lock); |
| 411 | if (kref_put(&zhdr->refcount, |
| 412 | release_z3fold_page)) |
| 413 | atomic64_dec(&pool->pages_nr); |
| 414 | spin_unlock(&pool->lock); |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 415 | pr_err("No free chunks in unbuddied\n"); |
| 416 | WARN_ON(1); |
| 417 | continue; |
| 418 | } |
| 419 | goto found; |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 420 | } |
| 421 | bud = FIRST; |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 422 | } |
| 423 | |
| 424 | /* Couldn't find unbuddied z3fold page, create new one */ |
| 425 | page = alloc_page(gfp); |
| 426 | if (!page) |
| 427 | return -ENOMEM; |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 428 | |
Vitaly Wool | 12d59ae | 2017-02-24 14:57:15 -0800 | [diff] [blame] | 429 | atomic64_inc(&pool->pages_nr); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 430 | zhdr = init_z3fold_page(page); |
| 431 | |
| 432 | if (bud == HEADLESS) { |
| 433 | set_bit(PAGE_HEADLESS, &page->private); |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 434 | spin_lock(&pool->lock); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 435 | goto headless; |
| 436 | } |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 437 | z3fold_page_lock(zhdr); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 438 | |
| 439 | found: |
| 440 | if (bud == FIRST) |
| 441 | zhdr->first_chunks = chunks; |
| 442 | else if (bud == LAST) |
| 443 | zhdr->last_chunks = chunks; |
| 444 | else { |
| 445 | zhdr->middle_chunks = chunks; |
Vitaly Wool | ede9321 | 2017-02-24 14:57:17 -0800 | [diff] [blame] | 446 | zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS; |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 447 | } |
| 448 | |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 449 | spin_lock(&pool->lock); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 450 | if (zhdr->first_chunks == 0 || zhdr->last_chunks == 0 || |
| 451 | zhdr->middle_chunks == 0) { |
| 452 | /* Add to unbuddied list */ |
| 453 | freechunks = num_free_chunks(zhdr); |
| 454 | list_add(&zhdr->buddy, &pool->unbuddied[freechunks]); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 455 | } |
| 456 | |
| 457 | headless: |
| 458 | /* Add/move z3fold page to beginning of LRU */ |
| 459 | if (!list_empty(&page->lru)) |
| 460 | list_del(&page->lru); |
| 461 | |
| 462 | list_add(&page->lru, &pool->lru); |
| 463 | |
| 464 | *handle = encode_handle(zhdr, bud); |
| 465 | spin_unlock(&pool->lock); |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 466 | if (bud != HEADLESS) |
| 467 | z3fold_page_unlock(zhdr); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 468 | |
| 469 | return 0; |
| 470 | } |
| 471 | |
| 472 | /** |
| 473 | * z3fold_free() - frees the allocation associated with the given handle |
| 474 | * @pool: pool in which the allocation resided |
| 475 | * @handle: handle associated with the allocation returned by z3fold_alloc() |
| 476 | * |
| 477 | * In the case that the z3fold page in which the allocation resides is under |
| 478 | * reclaim, as indicated by the PG_reclaim flag being set, this function |
| 479 | * only sets the first|last_chunks to 0. The page is actually freed |
| 480 | * once both buddies are evicted (see z3fold_reclaim_page() below). |
| 481 | */ |
| 482 | static void z3fold_free(struct z3fold_pool *pool, unsigned long handle) |
| 483 | { |
| 484 | struct z3fold_header *zhdr; |
| 485 | int freechunks; |
| 486 | struct page *page; |
| 487 | enum buddy bud; |
| 488 | |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 489 | zhdr = handle_to_z3fold_header(handle); |
| 490 | page = virt_to_page(zhdr); |
| 491 | |
| 492 | if (test_bit(PAGE_HEADLESS, &page->private)) { |
| 493 | /* HEADLESS page stored */ |
| 494 | bud = HEADLESS; |
| 495 | } else { |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 496 | z3fold_page_lock(zhdr); |
Vitaly Wool | 43afc19 | 2016-06-03 14:55:47 -0700 | [diff] [blame] | 497 | bud = handle_to_buddy(handle); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 498 | |
| 499 | switch (bud) { |
| 500 | case FIRST: |
| 501 | zhdr->first_chunks = 0; |
| 502 | break; |
| 503 | case MIDDLE: |
| 504 | zhdr->middle_chunks = 0; |
| 505 | zhdr->start_middle = 0; |
| 506 | break; |
| 507 | case LAST: |
| 508 | zhdr->last_chunks = 0; |
| 509 | break; |
| 510 | default: |
| 511 | pr_err("%s: unknown bud %d\n", __func__, bud); |
| 512 | WARN_ON(1); |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 513 | z3fold_page_unlock(zhdr); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 514 | return; |
| 515 | } |
| 516 | } |
| 517 | |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 518 | if (bud == HEADLESS) { |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 519 | spin_lock(&pool->lock); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 520 | list_del(&page->lru); |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 521 | spin_unlock(&pool->lock); |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 522 | free_z3fold_page(page); |
Vitaly Wool | 12d59ae | 2017-02-24 14:57:15 -0800 | [diff] [blame] | 523 | atomic64_dec(&pool->pages_nr); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 524 | } else { |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 525 | if (zhdr->first_chunks != 0 || zhdr->middle_chunks != 0 || |
| 526 | zhdr->last_chunks != 0) { |
| 527 | z3fold_compact_page(zhdr); |
| 528 | /* Add to the unbuddied list */ |
| 529 | spin_lock(&pool->lock); |
| 530 | if (!list_empty(&zhdr->buddy)) |
| 531 | list_del(&zhdr->buddy); |
| 532 | freechunks = num_free_chunks(zhdr); |
| 533 | list_add(&zhdr->buddy, &pool->unbuddied[freechunks]); |
| 534 | spin_unlock(&pool->lock); |
| 535 | } |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 536 | z3fold_page_unlock(zhdr); |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 537 | spin_lock(&pool->lock); |
| 538 | if (kref_put(&zhdr->refcount, release_z3fold_page)) |
| 539 | atomic64_dec(&pool->pages_nr); |
| 540 | spin_unlock(&pool->lock); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 541 | } |
| 542 | |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 543 | } |
| 544 | |
| 545 | /** |
| 546 | * z3fold_reclaim_page() - evicts allocations from a pool page and frees it |
| 547 | * @pool: pool from which a page will attempt to be evicted |
| 548 | * @retires: number of pages on the LRU list for which eviction will |
| 549 | * be attempted before failing |
| 550 | * |
| 551 | * z3fold reclaim is different from normal system reclaim in that it is done |
| 552 | * from the bottom, up. This is because only the bottom layer, z3fold, has |
| 553 | * information on how the allocations are organized within each z3fold page. |
| 554 | * This has the potential to create interesting locking situations between |
| 555 | * z3fold and the user, however. |
| 556 | * |
| 557 | * To avoid these, this is how z3fold_reclaim_page() should be called: |
| 558 | |
| 559 | * The user detects a page should be reclaimed and calls z3fold_reclaim_page(). |
| 560 | * z3fold_reclaim_page() will remove a z3fold page from the pool LRU list and |
| 561 | * call the user-defined eviction handler with the pool and handle as |
| 562 | * arguments. |
| 563 | * |
| 564 | * If the handle can not be evicted, the eviction handler should return |
| 565 | * non-zero. z3fold_reclaim_page() will add the z3fold page back to the |
| 566 | * appropriate list and try the next z3fold page on the LRU up to |
| 567 | * a user defined number of retries. |
| 568 | * |
| 569 | * If the handle is successfully evicted, the eviction handler should |
| 570 | * return 0 _and_ should have called z3fold_free() on the handle. z3fold_free() |
| 571 | * contains logic to delay freeing the page if the page is under reclaim, |
| 572 | * as indicated by the setting of the PG_reclaim flag on the underlying page. |
| 573 | * |
| 574 | * If all buddies in the z3fold page are successfully evicted, then the |
| 575 | * z3fold page can be freed. |
| 576 | * |
| 577 | * Returns: 0 if page is successfully freed, otherwise -EINVAL if there are |
| 578 | * no pages to evict or an eviction handler is not registered, -EAGAIN if |
| 579 | * the retry limit was hit. |
| 580 | */ |
| 581 | static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries) |
| 582 | { |
| 583 | int i, ret = 0, freechunks; |
| 584 | struct z3fold_header *zhdr; |
| 585 | struct page *page; |
| 586 | unsigned long first_handle = 0, middle_handle = 0, last_handle = 0; |
| 587 | |
| 588 | spin_lock(&pool->lock); |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 589 | if (!pool->ops || !pool->ops->evict || retries == 0) { |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 590 | spin_unlock(&pool->lock); |
| 591 | return -EINVAL; |
| 592 | } |
| 593 | for (i = 0; i < retries; i++) { |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 594 | if (list_empty(&pool->lru)) { |
| 595 | spin_unlock(&pool->lock); |
| 596 | return -EINVAL; |
| 597 | } |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 598 | page = list_last_entry(&pool->lru, struct page, lru); |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 599 | list_del_init(&page->lru); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 600 | |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 601 | zhdr = page_address(page); |
| 602 | if (!test_bit(PAGE_HEADLESS, &page->private)) { |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 603 | if (!list_empty(&zhdr->buddy)) |
| 604 | list_del_init(&zhdr->buddy); |
| 605 | kref_get(&zhdr->refcount); |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 606 | spin_unlock(&pool->lock); |
| 607 | z3fold_page_lock(zhdr); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 608 | /* |
| 609 | * We need encode the handles before unlocking, since |
| 610 | * we can race with free that will set |
| 611 | * (first|last)_chunks to 0 |
| 612 | */ |
| 613 | first_handle = 0; |
| 614 | last_handle = 0; |
| 615 | middle_handle = 0; |
| 616 | if (zhdr->first_chunks) |
| 617 | first_handle = encode_handle(zhdr, FIRST); |
| 618 | if (zhdr->middle_chunks) |
| 619 | middle_handle = encode_handle(zhdr, MIDDLE); |
| 620 | if (zhdr->last_chunks) |
| 621 | last_handle = encode_handle(zhdr, LAST); |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 622 | z3fold_page_unlock(zhdr); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 623 | } else { |
| 624 | first_handle = encode_handle(zhdr, HEADLESS); |
| 625 | last_handle = middle_handle = 0; |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 626 | spin_unlock(&pool->lock); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 627 | } |
| 628 | |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 629 | /* Issue the eviction callback(s) */ |
| 630 | if (middle_handle) { |
| 631 | ret = pool->ops->evict(pool, middle_handle); |
| 632 | if (ret) |
| 633 | goto next; |
| 634 | } |
| 635 | if (first_handle) { |
| 636 | ret = pool->ops->evict(pool, first_handle); |
| 637 | if (ret) |
| 638 | goto next; |
| 639 | } |
| 640 | if (last_handle) { |
| 641 | ret = pool->ops->evict(pool, last_handle); |
| 642 | if (ret) |
| 643 | goto next; |
| 644 | } |
| 645 | next: |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 646 | if (test_bit(PAGE_HEADLESS, &page->private)) { |
| 647 | if (ret == 0) { |
| 648 | free_z3fold_page(page); |
| 649 | return 0; |
Vitaly Wool | 43afc19 | 2016-06-03 14:55:47 -0700 | [diff] [blame] | 650 | } else { |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 651 | spin_lock(&pool->lock); |
| 652 | } |
| 653 | } else { |
| 654 | z3fold_page_lock(zhdr); |
| 655 | if ((zhdr->first_chunks || zhdr->last_chunks || |
| 656 | zhdr->middle_chunks) && |
| 657 | !(zhdr->first_chunks && zhdr->last_chunks && |
| 658 | zhdr->middle_chunks)) { |
Vitaly Wool | 43afc19 | 2016-06-03 14:55:47 -0700 | [diff] [blame] | 659 | z3fold_compact_page(zhdr); |
| 660 | /* add to unbuddied list */ |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 661 | spin_lock(&pool->lock); |
Vitaly Wool | 43afc19 | 2016-06-03 14:55:47 -0700 | [diff] [blame] | 662 | freechunks = num_free_chunks(zhdr); |
| 663 | list_add(&zhdr->buddy, |
| 664 | &pool->unbuddied[freechunks]); |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 665 | spin_unlock(&pool->lock); |
Vitaly Wool | 43afc19 | 2016-06-03 14:55:47 -0700 | [diff] [blame] | 666 | } |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 667 | z3fold_page_unlock(zhdr); |
| 668 | spin_lock(&pool->lock); |
| 669 | if (kref_put(&zhdr->refcount, release_z3fold_page)) { |
| 670 | atomic64_dec(&pool->pages_nr); |
| 671 | return 0; |
| 672 | } |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 673 | } |
| 674 | |
Vitaly Wool | 5a27aa8 | 2017-02-24 14:57:26 -0800 | [diff] [blame] | 675 | /* |
| 676 | * Add to the beginning of LRU. |
| 677 | * Pool lock has to be kept here to ensure the page has |
| 678 | * not already been released |
| 679 | */ |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 680 | list_add(&page->lru, &pool->lru); |
| 681 | } |
| 682 | spin_unlock(&pool->lock); |
| 683 | return -EAGAIN; |
| 684 | } |
| 685 | |
| 686 | /** |
| 687 | * z3fold_map() - maps the allocation associated with the given handle |
| 688 | * @pool: pool in which the allocation resides |
| 689 | * @handle: handle associated with the allocation to be mapped |
| 690 | * |
| 691 | * Extracts the buddy number from handle and constructs the pointer to the |
| 692 | * correct starting chunk within the page. |
| 693 | * |
| 694 | * Returns: a pointer to the mapped allocation |
| 695 | */ |
| 696 | static void *z3fold_map(struct z3fold_pool *pool, unsigned long handle) |
| 697 | { |
| 698 | struct z3fold_header *zhdr; |
| 699 | struct page *page; |
| 700 | void *addr; |
| 701 | enum buddy buddy; |
| 702 | |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 703 | zhdr = handle_to_z3fold_header(handle); |
| 704 | addr = zhdr; |
| 705 | page = virt_to_page(zhdr); |
| 706 | |
| 707 | if (test_bit(PAGE_HEADLESS, &page->private)) |
| 708 | goto out; |
| 709 | |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 710 | z3fold_page_lock(zhdr); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 711 | buddy = handle_to_buddy(handle); |
| 712 | switch (buddy) { |
| 713 | case FIRST: |
| 714 | addr += ZHDR_SIZE_ALIGNED; |
| 715 | break; |
| 716 | case MIDDLE: |
| 717 | addr += zhdr->start_middle << CHUNK_SHIFT; |
| 718 | set_bit(MIDDLE_CHUNK_MAPPED, &page->private); |
| 719 | break; |
| 720 | case LAST: |
| 721 | addr += PAGE_SIZE - (zhdr->last_chunks << CHUNK_SHIFT); |
| 722 | break; |
| 723 | default: |
| 724 | pr_err("unknown buddy id %d\n", buddy); |
| 725 | WARN_ON(1); |
| 726 | addr = NULL; |
| 727 | break; |
| 728 | } |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 729 | |
| 730 | z3fold_page_unlock(zhdr); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 731 | out: |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 732 | return addr; |
| 733 | } |
| 734 | |
| 735 | /** |
| 736 | * z3fold_unmap() - unmaps the allocation associated with the given handle |
| 737 | * @pool: pool in which the allocation resides |
| 738 | * @handle: handle associated with the allocation to be unmapped |
| 739 | */ |
| 740 | static void z3fold_unmap(struct z3fold_pool *pool, unsigned long handle) |
| 741 | { |
| 742 | struct z3fold_header *zhdr; |
| 743 | struct page *page; |
| 744 | enum buddy buddy; |
| 745 | |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 746 | zhdr = handle_to_z3fold_header(handle); |
| 747 | page = virt_to_page(zhdr); |
| 748 | |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 749 | if (test_bit(PAGE_HEADLESS, &page->private)) |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 750 | return; |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 751 | |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 752 | z3fold_page_lock(zhdr); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 753 | buddy = handle_to_buddy(handle); |
| 754 | if (buddy == MIDDLE) |
| 755 | clear_bit(MIDDLE_CHUNK_MAPPED, &page->private); |
Vitaly Wool | 2f1e5e4 | 2017-02-24 14:57:23 -0800 | [diff] [blame] | 756 | z3fold_page_unlock(zhdr); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 757 | } |
| 758 | |
| 759 | /** |
| 760 | * z3fold_get_pool_size() - gets the z3fold pool size in pages |
| 761 | * @pool: pool whose size is being queried |
| 762 | * |
Vitaly Wool | 12d59ae | 2017-02-24 14:57:15 -0800 | [diff] [blame] | 763 | * Returns: size in pages of the given pool. |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 764 | */ |
| 765 | static u64 z3fold_get_pool_size(struct z3fold_pool *pool) |
| 766 | { |
Vitaly Wool | 12d59ae | 2017-02-24 14:57:15 -0800 | [diff] [blame] | 767 | return atomic64_read(&pool->pages_nr); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 768 | } |
| 769 | |
| 770 | /***************** |
| 771 | * zpool |
| 772 | ****************/ |
| 773 | |
| 774 | static int z3fold_zpool_evict(struct z3fold_pool *pool, unsigned long handle) |
| 775 | { |
| 776 | if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict) |
| 777 | return pool->zpool_ops->evict(pool->zpool, handle); |
| 778 | else |
| 779 | return -ENOENT; |
| 780 | } |
| 781 | |
| 782 | static const struct z3fold_ops z3fold_zpool_ops = { |
| 783 | .evict = z3fold_zpool_evict |
| 784 | }; |
| 785 | |
| 786 | static void *z3fold_zpool_create(const char *name, gfp_t gfp, |
| 787 | const struct zpool_ops *zpool_ops, |
| 788 | struct zpool *zpool) |
| 789 | { |
| 790 | struct z3fold_pool *pool; |
| 791 | |
| 792 | pool = z3fold_create_pool(gfp, zpool_ops ? &z3fold_zpool_ops : NULL); |
| 793 | if (pool) { |
| 794 | pool->zpool = zpool; |
| 795 | pool->zpool_ops = zpool_ops; |
| 796 | } |
| 797 | return pool; |
| 798 | } |
| 799 | |
| 800 | static void z3fold_zpool_destroy(void *pool) |
| 801 | { |
| 802 | z3fold_destroy_pool(pool); |
| 803 | } |
| 804 | |
| 805 | static int z3fold_zpool_malloc(void *pool, size_t size, gfp_t gfp, |
| 806 | unsigned long *handle) |
| 807 | { |
| 808 | return z3fold_alloc(pool, size, gfp, handle); |
| 809 | } |
| 810 | static void z3fold_zpool_free(void *pool, unsigned long handle) |
| 811 | { |
| 812 | z3fold_free(pool, handle); |
| 813 | } |
| 814 | |
| 815 | static int z3fold_zpool_shrink(void *pool, unsigned int pages, |
| 816 | unsigned int *reclaimed) |
| 817 | { |
| 818 | unsigned int total = 0; |
| 819 | int ret = -EINVAL; |
| 820 | |
| 821 | while (total < pages) { |
| 822 | ret = z3fold_reclaim_page(pool, 8); |
| 823 | if (ret < 0) |
| 824 | break; |
| 825 | total++; |
| 826 | } |
| 827 | |
| 828 | if (reclaimed) |
| 829 | *reclaimed = total; |
| 830 | |
| 831 | return ret; |
| 832 | } |
| 833 | |
| 834 | static void *z3fold_zpool_map(void *pool, unsigned long handle, |
| 835 | enum zpool_mapmode mm) |
| 836 | { |
| 837 | return z3fold_map(pool, handle); |
| 838 | } |
| 839 | static void z3fold_zpool_unmap(void *pool, unsigned long handle) |
| 840 | { |
| 841 | z3fold_unmap(pool, handle); |
| 842 | } |
| 843 | |
| 844 | static u64 z3fold_zpool_total_size(void *pool) |
| 845 | { |
| 846 | return z3fold_get_pool_size(pool) * PAGE_SIZE; |
| 847 | } |
| 848 | |
| 849 | static struct zpool_driver z3fold_zpool_driver = { |
| 850 | .type = "z3fold", |
| 851 | .owner = THIS_MODULE, |
| 852 | .create = z3fold_zpool_create, |
| 853 | .destroy = z3fold_zpool_destroy, |
| 854 | .malloc = z3fold_zpool_malloc, |
| 855 | .free = z3fold_zpool_free, |
| 856 | .shrink = z3fold_zpool_shrink, |
| 857 | .map = z3fold_zpool_map, |
| 858 | .unmap = z3fold_zpool_unmap, |
| 859 | .total_size = z3fold_zpool_total_size, |
| 860 | }; |
| 861 | |
| 862 | MODULE_ALIAS("zpool-z3fold"); |
| 863 | |
| 864 | static int __init init_z3fold(void) |
| 865 | { |
Vitaly Wool | ede9321 | 2017-02-24 14:57:17 -0800 | [diff] [blame] | 866 | /* Make sure the z3fold header is not larger than the page size */ |
| 867 | BUILD_BUG_ON(ZHDR_SIZE_ALIGNED > PAGE_SIZE); |
Vitaly Wool | 9a001fc | 2016-05-20 16:58:30 -0700 | [diff] [blame] | 868 | zpool_register_driver(&z3fold_zpool_driver); |
| 869 | |
| 870 | return 0; |
| 871 | } |
| 872 | |
| 873 | static void __exit exit_z3fold(void) |
| 874 | { |
| 875 | zpool_unregister_driver(&z3fold_zpool_driver); |
| 876 | } |
| 877 | |
| 878 | module_init(init_z3fold); |
| 879 | module_exit(exit_z3fold); |
| 880 | |
| 881 | MODULE_LICENSE("GPL"); |
| 882 | MODULE_AUTHOR("Vitaly Wool <vitalywool@gmail.com>"); |
| 883 | MODULE_DESCRIPTION("3-Fold Allocator for Compressed Pages"); |