Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1 | /* |
| 2 | * zcache.c |
| 3 | * |
| 4 | * Copyright (c) 2010,2011, Dan Magenheimer, Oracle Corp. |
| 5 | * Copyright (c) 2010,2011, Nitin Gupta |
| 6 | * |
| 7 | * Zcache provides an in-kernel "host implementation" for transcendent memory |
| 8 | * and, thus indirectly, for cleancache and frontswap. Zcache includes two |
| 9 | * page-accessible memory [1] interfaces, both utilizing lzo1x compression: |
| 10 | * 1) "compression buddies" ("zbud") is used for ephemeral pages |
| 11 | * 2) xvmalloc is used for persistent pages. |
| 12 | * Xvmalloc (based on the TLSF allocator) has very low fragmentation |
| 13 | * so maximizes space efficiency, while zbud allows pairs (and potentially, |
| 14 | * in the future, more than a pair of) compressed pages to be closely linked |
| 15 | * so that reclaiming can be done via the kernel's physical-page-oriented |
| 16 | * "shrinker" interface. |
| 17 | * |
| 18 | * [1] For a definition of page-accessible memory (aka PAM), see: |
| 19 | * http://marc.info/?l=linux-mm&m=127811271605009 |
| 20 | */ |
| 21 | |
Thadeu Lima de Souza Cascardo | 12623f0 | 2011-08-03 11:00:40 -0300 | [diff] [blame] | 22 | #include <linux/module.h> |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 23 | #include <linux/cpu.h> |
| 24 | #include <linux/highmem.h> |
| 25 | #include <linux/list.h> |
| 26 | #include <linux/lzo.h> |
| 27 | #include <linux/slab.h> |
| 28 | #include <linux/spinlock.h> |
| 29 | #include <linux/types.h> |
| 30 | #include <linux/atomic.h> |
Thadeu Lima de Souza Cascardo | 3ca15c4 | 2011-08-04 19:00:33 -0300 | [diff] [blame] | 31 | #include <linux/math64.h> |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 32 | #include "tmem.h" |
| 33 | |
| 34 | #include "../zram/xvmalloc.h" /* if built in drivers/staging */ |
| 35 | |
| 36 | #if (!defined(CONFIG_CLEANCACHE) && !defined(CONFIG_FRONTSWAP)) |
| 37 | #error "zcache is useless without CONFIG_CLEANCACHE or CONFIG_FRONTSWAP" |
| 38 | #endif |
| 39 | #ifdef CONFIG_CLEANCACHE |
| 40 | #include <linux/cleancache.h> |
| 41 | #endif |
| 42 | #ifdef CONFIG_FRONTSWAP |
| 43 | #include <linux/frontswap.h> |
| 44 | #endif |
| 45 | |
| 46 | #if 0 |
| 47 | /* this is more aggressive but may cause other problems? */ |
| 48 | #define ZCACHE_GFP_MASK (GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN) |
| 49 | #else |
| 50 | #define ZCACHE_GFP_MASK \ |
| 51 | (__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC) |
| 52 | #endif |
| 53 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 54 | #define MAX_POOLS_PER_CLIENT 16 |
| 55 | |
| 56 | #define MAX_CLIENTS 16 |
| 57 | #define LOCAL_CLIENT ((uint16_t)-1) |
Thadeu Lima de Souza Cascardo | fd6b68b | 2011-08-02 14:20:27 -0300 | [diff] [blame] | 58 | |
| 59 | MODULE_LICENSE("GPL"); |
| 60 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 61 | struct zcache_client { |
| 62 | struct tmem_pool *tmem_pools[MAX_POOLS_PER_CLIENT]; |
| 63 | struct xv_pool *xvpool; |
| 64 | bool allocated; |
| 65 | atomic_t refcount; |
| 66 | }; |
| 67 | |
| 68 | static struct zcache_client zcache_host; |
| 69 | static struct zcache_client zcache_clients[MAX_CLIENTS]; |
| 70 | |
| 71 | static inline uint16_t get_client_id_from_client(struct zcache_client *cli) |
| 72 | { |
| 73 | BUG_ON(cli == NULL); |
| 74 | if (cli == &zcache_host) |
| 75 | return LOCAL_CLIENT; |
| 76 | return cli - &zcache_clients[0]; |
| 77 | } |
| 78 | |
| 79 | static inline bool is_local_client(struct zcache_client *cli) |
| 80 | { |
| 81 | return cli == &zcache_host; |
| 82 | } |
| 83 | |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 84 | /********** |
| 85 | * Compression buddies ("zbud") provides for packing two (or, possibly |
| 86 | * in the future, more) compressed ephemeral pages into a single "raw" |
| 87 | * (physical) page and tracking them with data structures so that |
| 88 | * the raw pages can be easily reclaimed. |
| 89 | * |
| 90 | * A zbud page ("zbpg") is an aligned page containing a list_head, |
| 91 | * a lock, and two "zbud headers". The remainder of the physical |
| 92 | * page is divided up into aligned 64-byte "chunks" which contain |
| 93 | * the compressed data for zero, one, or two zbuds. Each zbpg |
| 94 | * resides on: (1) an "unused list" if it has no zbuds; (2) a |
| 95 | * "buddied" list if it is fully populated with two zbuds; or |
| 96 | * (3) one of PAGE_SIZE/64 "unbuddied" lists indexed by how many chunks |
| 97 | * the one unbuddied zbud uses. The data inside a zbpg cannot be |
| 98 | * read or written unless the zbpg's lock is held. |
| 99 | */ |
| 100 | |
| 101 | #define ZBH_SENTINEL 0x43214321 |
| 102 | #define ZBPG_SENTINEL 0xdeadbeef |
| 103 | |
| 104 | #define ZBUD_MAX_BUDS 2 |
| 105 | |
| 106 | struct zbud_hdr { |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 107 | uint16_t client_id; |
| 108 | uint16_t pool_id; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 109 | struct tmem_oid oid; |
| 110 | uint32_t index; |
| 111 | uint16_t size; /* compressed size in bytes, zero means unused */ |
| 112 | DECL_SENTINEL |
| 113 | }; |
| 114 | |
| 115 | struct zbud_page { |
| 116 | struct list_head bud_list; |
| 117 | spinlock_t lock; |
| 118 | struct zbud_hdr buddy[ZBUD_MAX_BUDS]; |
| 119 | DECL_SENTINEL |
| 120 | /* followed by NUM_CHUNK aligned CHUNK_SIZE-byte chunks */ |
| 121 | }; |
| 122 | |
| 123 | #define CHUNK_SHIFT 6 |
| 124 | #define CHUNK_SIZE (1 << CHUNK_SHIFT) |
| 125 | #define CHUNK_MASK (~(CHUNK_SIZE-1)) |
| 126 | #define NCHUNKS (((PAGE_SIZE - sizeof(struct zbud_page)) & \ |
| 127 | CHUNK_MASK) >> CHUNK_SHIFT) |
| 128 | #define MAX_CHUNK (NCHUNKS-1) |
| 129 | |
| 130 | static struct { |
| 131 | struct list_head list; |
| 132 | unsigned count; |
| 133 | } zbud_unbuddied[NCHUNKS]; |
| 134 | /* list N contains pages with N chunks USED and NCHUNKS-N unused */ |
| 135 | /* element 0 is never used but optimizing that isn't worth it */ |
| 136 | static unsigned long zbud_cumul_chunk_counts[NCHUNKS]; |
| 137 | |
| 138 | struct list_head zbud_buddied_list; |
| 139 | static unsigned long zcache_zbud_buddied_count; |
| 140 | |
| 141 | /* protects the buddied list and all unbuddied lists */ |
| 142 | static DEFINE_SPINLOCK(zbud_budlists_spinlock); |
| 143 | |
| 144 | static LIST_HEAD(zbpg_unused_list); |
| 145 | static unsigned long zcache_zbpg_unused_list_count; |
| 146 | |
| 147 | /* protects the unused page list */ |
| 148 | static DEFINE_SPINLOCK(zbpg_unused_list_spinlock); |
| 149 | |
| 150 | static atomic_t zcache_zbud_curr_raw_pages; |
| 151 | static atomic_t zcache_zbud_curr_zpages; |
| 152 | static unsigned long zcache_zbud_curr_zbytes; |
| 153 | static unsigned long zcache_zbud_cumul_zpages; |
| 154 | static unsigned long zcache_zbud_cumul_zbytes; |
| 155 | static unsigned long zcache_compress_poor; |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 156 | static unsigned long zcache_mean_compress_poor; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 157 | |
| 158 | /* forward references */ |
| 159 | static void *zcache_get_free_page(void); |
| 160 | static void zcache_free_page(void *p); |
| 161 | |
| 162 | /* |
| 163 | * zbud helper functions |
| 164 | */ |
| 165 | |
| 166 | static inline unsigned zbud_max_buddy_size(void) |
| 167 | { |
| 168 | return MAX_CHUNK << CHUNK_SHIFT; |
| 169 | } |
| 170 | |
| 171 | static inline unsigned zbud_size_to_chunks(unsigned size) |
| 172 | { |
| 173 | BUG_ON(size == 0 || size > zbud_max_buddy_size()); |
| 174 | return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT; |
| 175 | } |
| 176 | |
| 177 | static inline int zbud_budnum(struct zbud_hdr *zh) |
| 178 | { |
| 179 | unsigned offset = (unsigned long)zh & (PAGE_SIZE - 1); |
| 180 | struct zbud_page *zbpg = NULL; |
| 181 | unsigned budnum = -1U; |
| 182 | int i; |
| 183 | |
| 184 | for (i = 0; i < ZBUD_MAX_BUDS; i++) |
| 185 | if (offset == offsetof(typeof(*zbpg), buddy[i])) { |
| 186 | budnum = i; |
| 187 | break; |
| 188 | } |
| 189 | BUG_ON(budnum == -1U); |
| 190 | return budnum; |
| 191 | } |
| 192 | |
| 193 | static char *zbud_data(struct zbud_hdr *zh, unsigned size) |
| 194 | { |
| 195 | struct zbud_page *zbpg; |
| 196 | char *p; |
| 197 | unsigned budnum; |
| 198 | |
| 199 | ASSERT_SENTINEL(zh, ZBH); |
| 200 | budnum = zbud_budnum(zh); |
| 201 | BUG_ON(size == 0 || size > zbud_max_buddy_size()); |
| 202 | zbpg = container_of(zh, struct zbud_page, buddy[budnum]); |
| 203 | ASSERT_SPINLOCK(&zbpg->lock); |
| 204 | p = (char *)zbpg; |
| 205 | if (budnum == 0) |
| 206 | p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) & |
| 207 | CHUNK_MASK); |
| 208 | else if (budnum == 1) |
| 209 | p += PAGE_SIZE - ((size + CHUNK_SIZE - 1) & CHUNK_MASK); |
| 210 | return p; |
| 211 | } |
| 212 | |
| 213 | /* |
| 214 | * zbud raw page management |
| 215 | */ |
| 216 | |
| 217 | static struct zbud_page *zbud_alloc_raw_page(void) |
| 218 | { |
| 219 | struct zbud_page *zbpg = NULL; |
| 220 | struct zbud_hdr *zh0, *zh1; |
| 221 | bool recycled = 0; |
| 222 | |
| 223 | /* if any pages on the zbpg list, use one */ |
| 224 | spin_lock(&zbpg_unused_list_spinlock); |
| 225 | if (!list_empty(&zbpg_unused_list)) { |
| 226 | zbpg = list_first_entry(&zbpg_unused_list, |
| 227 | struct zbud_page, bud_list); |
| 228 | list_del_init(&zbpg->bud_list); |
| 229 | zcache_zbpg_unused_list_count--; |
| 230 | recycled = 1; |
| 231 | } |
| 232 | spin_unlock(&zbpg_unused_list_spinlock); |
| 233 | if (zbpg == NULL) |
| 234 | /* none on zbpg list, try to get a kernel page */ |
| 235 | zbpg = zcache_get_free_page(); |
| 236 | if (likely(zbpg != NULL)) { |
| 237 | INIT_LIST_HEAD(&zbpg->bud_list); |
| 238 | zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1]; |
| 239 | spin_lock_init(&zbpg->lock); |
| 240 | if (recycled) { |
| 241 | ASSERT_INVERTED_SENTINEL(zbpg, ZBPG); |
| 242 | SET_SENTINEL(zbpg, ZBPG); |
| 243 | BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid)); |
| 244 | BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid)); |
| 245 | } else { |
| 246 | atomic_inc(&zcache_zbud_curr_raw_pages); |
| 247 | INIT_LIST_HEAD(&zbpg->bud_list); |
| 248 | SET_SENTINEL(zbpg, ZBPG); |
| 249 | zh0->size = 0; zh1->size = 0; |
| 250 | tmem_oid_set_invalid(&zh0->oid); |
| 251 | tmem_oid_set_invalid(&zh1->oid); |
| 252 | } |
| 253 | } |
| 254 | return zbpg; |
| 255 | } |
| 256 | |
| 257 | static void zbud_free_raw_page(struct zbud_page *zbpg) |
| 258 | { |
| 259 | struct zbud_hdr *zh0 = &zbpg->buddy[0], *zh1 = &zbpg->buddy[1]; |
| 260 | |
| 261 | ASSERT_SENTINEL(zbpg, ZBPG); |
| 262 | BUG_ON(!list_empty(&zbpg->bud_list)); |
| 263 | ASSERT_SPINLOCK(&zbpg->lock); |
| 264 | BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid)); |
| 265 | BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid)); |
| 266 | INVERT_SENTINEL(zbpg, ZBPG); |
| 267 | spin_unlock(&zbpg->lock); |
| 268 | spin_lock(&zbpg_unused_list_spinlock); |
| 269 | list_add(&zbpg->bud_list, &zbpg_unused_list); |
| 270 | zcache_zbpg_unused_list_count++; |
| 271 | spin_unlock(&zbpg_unused_list_spinlock); |
| 272 | } |
| 273 | |
| 274 | /* |
| 275 | * core zbud handling routines |
| 276 | */ |
| 277 | |
| 278 | static unsigned zbud_free(struct zbud_hdr *zh) |
| 279 | { |
| 280 | unsigned size; |
| 281 | |
| 282 | ASSERT_SENTINEL(zh, ZBH); |
| 283 | BUG_ON(!tmem_oid_valid(&zh->oid)); |
| 284 | size = zh->size; |
| 285 | BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size()); |
| 286 | zh->size = 0; |
| 287 | tmem_oid_set_invalid(&zh->oid); |
| 288 | INVERT_SENTINEL(zh, ZBH); |
| 289 | zcache_zbud_curr_zbytes -= size; |
| 290 | atomic_dec(&zcache_zbud_curr_zpages); |
| 291 | return size; |
| 292 | } |
| 293 | |
| 294 | static void zbud_free_and_delist(struct zbud_hdr *zh) |
| 295 | { |
| 296 | unsigned chunks; |
| 297 | struct zbud_hdr *zh_other; |
| 298 | unsigned budnum = zbud_budnum(zh), size; |
| 299 | struct zbud_page *zbpg = |
| 300 | container_of(zh, struct zbud_page, buddy[budnum]); |
| 301 | |
| 302 | spin_lock(&zbpg->lock); |
| 303 | if (list_empty(&zbpg->bud_list)) { |
| 304 | /* ignore zombie page... see zbud_evict_pages() */ |
| 305 | spin_unlock(&zbpg->lock); |
| 306 | return; |
| 307 | } |
| 308 | size = zbud_free(zh); |
| 309 | ASSERT_SPINLOCK(&zbpg->lock); |
| 310 | zh_other = &zbpg->buddy[(budnum == 0) ? 1 : 0]; |
| 311 | if (zh_other->size == 0) { /* was unbuddied: unlist and free */ |
| 312 | chunks = zbud_size_to_chunks(size) ; |
| 313 | spin_lock(&zbud_budlists_spinlock); |
| 314 | BUG_ON(list_empty(&zbud_unbuddied[chunks].list)); |
| 315 | list_del_init(&zbpg->bud_list); |
| 316 | zbud_unbuddied[chunks].count--; |
| 317 | spin_unlock(&zbud_budlists_spinlock); |
| 318 | zbud_free_raw_page(zbpg); |
| 319 | } else { /* was buddied: move remaining buddy to unbuddied list */ |
| 320 | chunks = zbud_size_to_chunks(zh_other->size) ; |
| 321 | spin_lock(&zbud_budlists_spinlock); |
| 322 | list_del_init(&zbpg->bud_list); |
| 323 | zcache_zbud_buddied_count--; |
| 324 | list_add_tail(&zbpg->bud_list, &zbud_unbuddied[chunks].list); |
| 325 | zbud_unbuddied[chunks].count++; |
| 326 | spin_unlock(&zbud_budlists_spinlock); |
| 327 | spin_unlock(&zbpg->lock); |
| 328 | } |
| 329 | } |
| 330 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 331 | static struct zbud_hdr *zbud_create(uint16_t client_id, uint16_t pool_id, |
| 332 | struct tmem_oid *oid, |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 333 | uint32_t index, struct page *page, |
| 334 | void *cdata, unsigned size) |
| 335 | { |
| 336 | struct zbud_hdr *zh0, *zh1, *zh = NULL; |
| 337 | struct zbud_page *zbpg = NULL, *ztmp; |
| 338 | unsigned nchunks; |
| 339 | char *to; |
| 340 | int i, found_good_buddy = 0; |
| 341 | |
| 342 | nchunks = zbud_size_to_chunks(size) ; |
| 343 | for (i = MAX_CHUNK - nchunks + 1; i > 0; i--) { |
| 344 | spin_lock(&zbud_budlists_spinlock); |
| 345 | if (!list_empty(&zbud_unbuddied[i].list)) { |
| 346 | list_for_each_entry_safe(zbpg, ztmp, |
| 347 | &zbud_unbuddied[i].list, bud_list) { |
| 348 | if (spin_trylock(&zbpg->lock)) { |
| 349 | found_good_buddy = i; |
| 350 | goto found_unbuddied; |
| 351 | } |
| 352 | } |
| 353 | } |
| 354 | spin_unlock(&zbud_budlists_spinlock); |
| 355 | } |
| 356 | /* didn't find a good buddy, try allocating a new page */ |
| 357 | zbpg = zbud_alloc_raw_page(); |
| 358 | if (unlikely(zbpg == NULL)) |
| 359 | goto out; |
| 360 | /* ok, have a page, now compress the data before taking locks */ |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 361 | spin_lock(&zbud_budlists_spinlock); |
Dan Magenheimer | 9256a47 | 2012-01-25 14:32:51 -0800 | [diff] [blame] | 362 | spin_lock(&zbpg->lock); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 363 | list_add_tail(&zbpg->bud_list, &zbud_unbuddied[nchunks].list); |
| 364 | zbud_unbuddied[nchunks].count++; |
| 365 | zh = &zbpg->buddy[0]; |
| 366 | goto init_zh; |
| 367 | |
| 368 | found_unbuddied: |
| 369 | ASSERT_SPINLOCK(&zbpg->lock); |
| 370 | zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1]; |
| 371 | BUG_ON(!((zh0->size == 0) ^ (zh1->size == 0))); |
| 372 | if (zh0->size != 0) { /* buddy0 in use, buddy1 is vacant */ |
| 373 | ASSERT_SENTINEL(zh0, ZBH); |
| 374 | zh = zh1; |
| 375 | } else if (zh1->size != 0) { /* buddy1 in use, buddy0 is vacant */ |
| 376 | ASSERT_SENTINEL(zh1, ZBH); |
| 377 | zh = zh0; |
| 378 | } else |
| 379 | BUG(); |
| 380 | list_del_init(&zbpg->bud_list); |
| 381 | zbud_unbuddied[found_good_buddy].count--; |
| 382 | list_add_tail(&zbpg->bud_list, &zbud_buddied_list); |
| 383 | zcache_zbud_buddied_count++; |
| 384 | |
| 385 | init_zh: |
| 386 | SET_SENTINEL(zh, ZBH); |
| 387 | zh->size = size; |
| 388 | zh->index = index; |
| 389 | zh->oid = *oid; |
| 390 | zh->pool_id = pool_id; |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 391 | zh->client_id = client_id; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 392 | to = zbud_data(zh, size); |
| 393 | memcpy(to, cdata, size); |
| 394 | spin_unlock(&zbpg->lock); |
Dan Magenheimer | 9256a47 | 2012-01-25 14:32:51 -0800 | [diff] [blame] | 395 | spin_unlock(&zbud_budlists_spinlock); |
| 396 | |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 397 | zbud_cumul_chunk_counts[nchunks]++; |
| 398 | atomic_inc(&zcache_zbud_curr_zpages); |
| 399 | zcache_zbud_cumul_zpages++; |
| 400 | zcache_zbud_curr_zbytes += size; |
| 401 | zcache_zbud_cumul_zbytes += size; |
| 402 | out: |
| 403 | return zh; |
| 404 | } |
| 405 | |
| 406 | static int zbud_decompress(struct page *page, struct zbud_hdr *zh) |
| 407 | { |
| 408 | struct zbud_page *zbpg; |
| 409 | unsigned budnum = zbud_budnum(zh); |
| 410 | size_t out_len = PAGE_SIZE; |
| 411 | char *to_va, *from_va; |
| 412 | unsigned size; |
| 413 | int ret = 0; |
| 414 | |
| 415 | zbpg = container_of(zh, struct zbud_page, buddy[budnum]); |
| 416 | spin_lock(&zbpg->lock); |
| 417 | if (list_empty(&zbpg->bud_list)) { |
| 418 | /* ignore zombie page... see zbud_evict_pages() */ |
| 419 | ret = -EINVAL; |
| 420 | goto out; |
| 421 | } |
| 422 | ASSERT_SENTINEL(zh, ZBH); |
| 423 | BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size()); |
| 424 | to_va = kmap_atomic(page, KM_USER0); |
| 425 | size = zh->size; |
| 426 | from_va = zbud_data(zh, size); |
| 427 | ret = lzo1x_decompress_safe(from_va, size, to_va, &out_len); |
| 428 | BUG_ON(ret != LZO_E_OK); |
| 429 | BUG_ON(out_len != PAGE_SIZE); |
| 430 | kunmap_atomic(to_va, KM_USER0); |
| 431 | out: |
| 432 | spin_unlock(&zbpg->lock); |
| 433 | return ret; |
| 434 | } |
| 435 | |
| 436 | /* |
| 437 | * The following routines handle shrinking of ephemeral pages by evicting |
| 438 | * pages "least valuable" first. |
| 439 | */ |
| 440 | |
| 441 | static unsigned long zcache_evicted_raw_pages; |
| 442 | static unsigned long zcache_evicted_buddied_pages; |
| 443 | static unsigned long zcache_evicted_unbuddied_pages; |
| 444 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 445 | static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id, |
| 446 | uint16_t poolid); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 447 | static void zcache_put_pool(struct tmem_pool *pool); |
| 448 | |
| 449 | /* |
| 450 | * Flush and free all zbuds in a zbpg, then free the pageframe |
| 451 | */ |
| 452 | static void zbud_evict_zbpg(struct zbud_page *zbpg) |
| 453 | { |
| 454 | struct zbud_hdr *zh; |
| 455 | int i, j; |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 456 | uint32_t pool_id[ZBUD_MAX_BUDS], client_id[ZBUD_MAX_BUDS]; |
| 457 | uint32_t index[ZBUD_MAX_BUDS]; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 458 | struct tmem_oid oid[ZBUD_MAX_BUDS]; |
| 459 | struct tmem_pool *pool; |
| 460 | |
| 461 | ASSERT_SPINLOCK(&zbpg->lock); |
| 462 | BUG_ON(!list_empty(&zbpg->bud_list)); |
| 463 | for (i = 0, j = 0; i < ZBUD_MAX_BUDS; i++) { |
| 464 | zh = &zbpg->buddy[i]; |
| 465 | if (zh->size) { |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 466 | client_id[j] = zh->client_id; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 467 | pool_id[j] = zh->pool_id; |
| 468 | oid[j] = zh->oid; |
| 469 | index[j] = zh->index; |
| 470 | j++; |
| 471 | zbud_free(zh); |
| 472 | } |
| 473 | } |
| 474 | spin_unlock(&zbpg->lock); |
| 475 | for (i = 0; i < j; i++) { |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 476 | pool = zcache_get_pool_by_id(client_id[i], pool_id[i]); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 477 | if (pool != NULL) { |
| 478 | tmem_flush_page(pool, &oid[i], index[i]); |
| 479 | zcache_put_pool(pool); |
| 480 | } |
| 481 | } |
| 482 | ASSERT_SENTINEL(zbpg, ZBPG); |
| 483 | spin_lock(&zbpg->lock); |
| 484 | zbud_free_raw_page(zbpg); |
| 485 | } |
| 486 | |
| 487 | /* |
| 488 | * Free nr pages. This code is funky because we want to hold the locks |
| 489 | * protecting various lists for as short a time as possible, and in some |
| 490 | * circumstances the list may change asynchronously when the list lock is |
| 491 | * not held. In some cases we also trylock not only to avoid waiting on a |
| 492 | * page in use by another cpu, but also to avoid potential deadlock due to |
| 493 | * lock inversion. |
| 494 | */ |
| 495 | static void zbud_evict_pages(int nr) |
| 496 | { |
| 497 | struct zbud_page *zbpg; |
| 498 | int i; |
| 499 | |
| 500 | /* first try freeing any pages on unused list */ |
| 501 | retry_unused_list: |
| 502 | spin_lock_bh(&zbpg_unused_list_spinlock); |
| 503 | if (!list_empty(&zbpg_unused_list)) { |
| 504 | /* can't walk list here, since it may change when unlocked */ |
| 505 | zbpg = list_first_entry(&zbpg_unused_list, |
| 506 | struct zbud_page, bud_list); |
| 507 | list_del_init(&zbpg->bud_list); |
| 508 | zcache_zbpg_unused_list_count--; |
| 509 | atomic_dec(&zcache_zbud_curr_raw_pages); |
| 510 | spin_unlock_bh(&zbpg_unused_list_spinlock); |
| 511 | zcache_free_page(zbpg); |
| 512 | zcache_evicted_raw_pages++; |
| 513 | if (--nr <= 0) |
| 514 | goto out; |
| 515 | goto retry_unused_list; |
| 516 | } |
| 517 | spin_unlock_bh(&zbpg_unused_list_spinlock); |
| 518 | |
| 519 | /* now try freeing unbuddied pages, starting with least space avail */ |
| 520 | for (i = 0; i < MAX_CHUNK; i++) { |
| 521 | retry_unbud_list_i: |
| 522 | spin_lock_bh(&zbud_budlists_spinlock); |
| 523 | if (list_empty(&zbud_unbuddied[i].list)) { |
| 524 | spin_unlock_bh(&zbud_budlists_spinlock); |
| 525 | continue; |
| 526 | } |
| 527 | list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) { |
| 528 | if (unlikely(!spin_trylock(&zbpg->lock))) |
| 529 | continue; |
| 530 | list_del_init(&zbpg->bud_list); |
| 531 | zbud_unbuddied[i].count--; |
| 532 | spin_unlock(&zbud_budlists_spinlock); |
| 533 | zcache_evicted_unbuddied_pages++; |
| 534 | /* want budlists unlocked when doing zbpg eviction */ |
| 535 | zbud_evict_zbpg(zbpg); |
| 536 | local_bh_enable(); |
| 537 | if (--nr <= 0) |
| 538 | goto out; |
| 539 | goto retry_unbud_list_i; |
| 540 | } |
| 541 | spin_unlock_bh(&zbud_budlists_spinlock); |
| 542 | } |
| 543 | |
| 544 | /* as a last resort, free buddied pages */ |
| 545 | retry_bud_list: |
| 546 | spin_lock_bh(&zbud_budlists_spinlock); |
| 547 | if (list_empty(&zbud_buddied_list)) { |
| 548 | spin_unlock_bh(&zbud_budlists_spinlock); |
| 549 | goto out; |
| 550 | } |
| 551 | list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) { |
| 552 | if (unlikely(!spin_trylock(&zbpg->lock))) |
| 553 | continue; |
| 554 | list_del_init(&zbpg->bud_list); |
| 555 | zcache_zbud_buddied_count--; |
| 556 | spin_unlock(&zbud_budlists_spinlock); |
| 557 | zcache_evicted_buddied_pages++; |
| 558 | /* want budlists unlocked when doing zbpg eviction */ |
| 559 | zbud_evict_zbpg(zbpg); |
| 560 | local_bh_enable(); |
| 561 | if (--nr <= 0) |
| 562 | goto out; |
| 563 | goto retry_bud_list; |
| 564 | } |
| 565 | spin_unlock_bh(&zbud_budlists_spinlock); |
| 566 | out: |
| 567 | return; |
| 568 | } |
| 569 | |
| 570 | static void zbud_init(void) |
| 571 | { |
| 572 | int i; |
| 573 | |
| 574 | INIT_LIST_HEAD(&zbud_buddied_list); |
| 575 | zcache_zbud_buddied_count = 0; |
| 576 | for (i = 0; i < NCHUNKS; i++) { |
| 577 | INIT_LIST_HEAD(&zbud_unbuddied[i].list); |
| 578 | zbud_unbuddied[i].count = 0; |
| 579 | } |
| 580 | } |
| 581 | |
| 582 | #ifdef CONFIG_SYSFS |
| 583 | /* |
| 584 | * These sysfs routines show a nice distribution of how many zbpg's are |
| 585 | * currently (and have ever been placed) in each unbuddied list. It's fun |
| 586 | * to watch but can probably go away before final merge. |
| 587 | */ |
| 588 | static int zbud_show_unbuddied_list_counts(char *buf) |
| 589 | { |
| 590 | int i; |
| 591 | char *p = buf; |
| 592 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 593 | for (i = 0; i < NCHUNKS; i++) |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 594 | p += sprintf(p, "%u ", zbud_unbuddied[i].count); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 595 | return p - buf; |
| 596 | } |
| 597 | |
| 598 | static int zbud_show_cumul_chunk_counts(char *buf) |
| 599 | { |
| 600 | unsigned long i, chunks = 0, total_chunks = 0, sum_total_chunks = 0; |
| 601 | unsigned long total_chunks_lte_21 = 0, total_chunks_lte_32 = 0; |
| 602 | unsigned long total_chunks_lte_42 = 0; |
| 603 | char *p = buf; |
| 604 | |
| 605 | for (i = 0; i < NCHUNKS; i++) { |
| 606 | p += sprintf(p, "%lu ", zbud_cumul_chunk_counts[i]); |
| 607 | chunks += zbud_cumul_chunk_counts[i]; |
| 608 | total_chunks += zbud_cumul_chunk_counts[i]; |
| 609 | sum_total_chunks += i * zbud_cumul_chunk_counts[i]; |
| 610 | if (i == 21) |
| 611 | total_chunks_lte_21 = total_chunks; |
| 612 | if (i == 32) |
| 613 | total_chunks_lte_32 = total_chunks; |
| 614 | if (i == 42) |
| 615 | total_chunks_lte_42 = total_chunks; |
| 616 | } |
| 617 | p += sprintf(p, "<=21:%lu <=32:%lu <=42:%lu, mean:%lu\n", |
| 618 | total_chunks_lte_21, total_chunks_lte_32, total_chunks_lte_42, |
| 619 | chunks == 0 ? 0 : sum_total_chunks / chunks); |
| 620 | return p - buf; |
| 621 | } |
| 622 | #endif |
| 623 | |
| 624 | /********** |
| 625 | * This "zv" PAM implementation combines the TLSF-based xvMalloc |
| 626 | * with lzo1x compression to maximize the amount of data that can |
| 627 | * be packed into a physical page. |
| 628 | * |
| 629 | * Zv represents a PAM page with the index and object (plus a "size" value |
| 630 | * necessary for decompression) immediately preceding the compressed data. |
| 631 | */ |
| 632 | |
| 633 | #define ZVH_SENTINEL 0x43214321 |
| 634 | |
| 635 | struct zv_hdr { |
| 636 | uint32_t pool_id; |
| 637 | struct tmem_oid oid; |
| 638 | uint32_t index; |
| 639 | DECL_SENTINEL |
| 640 | }; |
| 641 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 642 | /* rudimentary policy limits */ |
| 643 | /* total number of persistent pages may not exceed this percentage */ |
| 644 | static unsigned int zv_page_count_policy_percent = 75; |
| 645 | /* |
| 646 | * byte count defining poor compression; pages with greater zsize will be |
| 647 | * rejected |
| 648 | */ |
| 649 | static unsigned int zv_max_zsize = (PAGE_SIZE / 8) * 7; |
| 650 | /* |
| 651 | * byte count defining poor *mean* compression; pages with greater zsize |
| 652 | * will be rejected until sufficient better-compressed pages are accepted |
Seth Jennings | 0428fec | 2011-08-22 13:50:08 -0500 | [diff] [blame] | 653 | * driving the mean below this threshold |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 654 | */ |
| 655 | static unsigned int zv_max_mean_zsize = (PAGE_SIZE / 8) * 5; |
| 656 | |
| 657 | static unsigned long zv_curr_dist_counts[NCHUNKS]; |
| 658 | static unsigned long zv_cumul_dist_counts[NCHUNKS]; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 659 | |
| 660 | static struct zv_hdr *zv_create(struct xv_pool *xvpool, uint32_t pool_id, |
| 661 | struct tmem_oid *oid, uint32_t index, |
| 662 | void *cdata, unsigned clen) |
| 663 | { |
| 664 | struct page *page; |
| 665 | struct zv_hdr *zv = NULL; |
| 666 | uint32_t offset; |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 667 | int alloc_size = clen + sizeof(struct zv_hdr); |
| 668 | int chunks = (alloc_size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 669 | int ret; |
| 670 | |
| 671 | BUG_ON(!irqs_disabled()); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 672 | BUG_ON(chunks >= NCHUNKS); |
| 673 | ret = xv_malloc(xvpool, alloc_size, |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 674 | &page, &offset, ZCACHE_GFP_MASK); |
| 675 | if (unlikely(ret)) |
| 676 | goto out; |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 677 | zv_curr_dist_counts[chunks]++; |
| 678 | zv_cumul_dist_counts[chunks]++; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 679 | zv = kmap_atomic(page, KM_USER0) + offset; |
| 680 | zv->index = index; |
| 681 | zv->oid = *oid; |
| 682 | zv->pool_id = pool_id; |
| 683 | SET_SENTINEL(zv, ZVH); |
| 684 | memcpy((char *)zv + sizeof(struct zv_hdr), cdata, clen); |
| 685 | kunmap_atomic(zv, KM_USER0); |
| 686 | out: |
| 687 | return zv; |
| 688 | } |
| 689 | |
| 690 | static void zv_free(struct xv_pool *xvpool, struct zv_hdr *zv) |
| 691 | { |
| 692 | unsigned long flags; |
| 693 | struct page *page; |
| 694 | uint32_t offset; |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 695 | uint16_t size = xv_get_object_size(zv); |
| 696 | int chunks = (size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 697 | |
| 698 | ASSERT_SENTINEL(zv, ZVH); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 699 | BUG_ON(chunks >= NCHUNKS); |
| 700 | zv_curr_dist_counts[chunks]--; |
| 701 | size -= sizeof(*zv); |
| 702 | BUG_ON(size == 0); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 703 | INVERT_SENTINEL(zv, ZVH); |
| 704 | page = virt_to_page(zv); |
| 705 | offset = (unsigned long)zv & ~PAGE_MASK; |
| 706 | local_irq_save(flags); |
| 707 | xv_free(xvpool, page, offset); |
| 708 | local_irq_restore(flags); |
| 709 | } |
| 710 | |
| 711 | static void zv_decompress(struct page *page, struct zv_hdr *zv) |
| 712 | { |
| 713 | size_t clen = PAGE_SIZE; |
| 714 | char *to_va; |
| 715 | unsigned size; |
| 716 | int ret; |
| 717 | |
| 718 | ASSERT_SENTINEL(zv, ZVH); |
| 719 | size = xv_get_object_size(zv) - sizeof(*zv); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 720 | BUG_ON(size == 0); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 721 | to_va = kmap_atomic(page, KM_USER0); |
| 722 | ret = lzo1x_decompress_safe((char *)zv + sizeof(*zv), |
| 723 | size, to_va, &clen); |
| 724 | kunmap_atomic(to_va, KM_USER0); |
| 725 | BUG_ON(ret != LZO_E_OK); |
| 726 | BUG_ON(clen != PAGE_SIZE); |
| 727 | } |
| 728 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 729 | #ifdef CONFIG_SYSFS |
| 730 | /* |
| 731 | * show a distribution of compression stats for zv pages. |
| 732 | */ |
| 733 | |
| 734 | static int zv_curr_dist_counts_show(char *buf) |
| 735 | { |
| 736 | unsigned long i, n, chunks = 0, sum_total_chunks = 0; |
| 737 | char *p = buf; |
| 738 | |
| 739 | for (i = 0; i < NCHUNKS; i++) { |
| 740 | n = zv_curr_dist_counts[i]; |
| 741 | p += sprintf(p, "%lu ", n); |
| 742 | chunks += n; |
| 743 | sum_total_chunks += i * n; |
| 744 | } |
| 745 | p += sprintf(p, "mean:%lu\n", |
| 746 | chunks == 0 ? 0 : sum_total_chunks / chunks); |
| 747 | return p - buf; |
| 748 | } |
| 749 | |
| 750 | static int zv_cumul_dist_counts_show(char *buf) |
| 751 | { |
| 752 | unsigned long i, n, chunks = 0, sum_total_chunks = 0; |
| 753 | char *p = buf; |
| 754 | |
| 755 | for (i = 0; i < NCHUNKS; i++) { |
| 756 | n = zv_cumul_dist_counts[i]; |
| 757 | p += sprintf(p, "%lu ", n); |
| 758 | chunks += n; |
| 759 | sum_total_chunks += i * n; |
| 760 | } |
| 761 | p += sprintf(p, "mean:%lu\n", |
| 762 | chunks == 0 ? 0 : sum_total_chunks / chunks); |
| 763 | return p - buf; |
| 764 | } |
| 765 | |
| 766 | /* |
| 767 | * setting zv_max_zsize via sysfs causes all persistent (e.g. swap) |
| 768 | * pages that don't compress to less than this value (including metadata |
| 769 | * overhead) to be rejected. We don't allow the value to get too close |
| 770 | * to PAGE_SIZE. |
| 771 | */ |
| 772 | static ssize_t zv_max_zsize_show(struct kobject *kobj, |
| 773 | struct kobj_attribute *attr, |
| 774 | char *buf) |
| 775 | { |
| 776 | return sprintf(buf, "%u\n", zv_max_zsize); |
| 777 | } |
| 778 | |
| 779 | static ssize_t zv_max_zsize_store(struct kobject *kobj, |
| 780 | struct kobj_attribute *attr, |
| 781 | const char *buf, size_t count) |
| 782 | { |
| 783 | unsigned long val; |
| 784 | int err; |
| 785 | |
| 786 | if (!capable(CAP_SYS_ADMIN)) |
| 787 | return -EPERM; |
| 788 | |
Bernhard Heinloth | ebadb73 | 2011-11-23 16:39:53 +0100 | [diff] [blame] | 789 | err = kstrtoul(buf, 10, &val); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 790 | if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7)) |
| 791 | return -EINVAL; |
| 792 | zv_max_zsize = val; |
| 793 | return count; |
| 794 | } |
| 795 | |
| 796 | /* |
| 797 | * setting zv_max_mean_zsize via sysfs causes all persistent (e.g. swap) |
| 798 | * pages that don't compress to less than this value (including metadata |
| 799 | * overhead) to be rejected UNLESS the mean compression is also smaller |
| 800 | * than this value. In other words, we are load-balancing-by-zsize the |
| 801 | * accepted pages. Again, we don't allow the value to get too close |
| 802 | * to PAGE_SIZE. |
| 803 | */ |
| 804 | static ssize_t zv_max_mean_zsize_show(struct kobject *kobj, |
| 805 | struct kobj_attribute *attr, |
| 806 | char *buf) |
| 807 | { |
| 808 | return sprintf(buf, "%u\n", zv_max_mean_zsize); |
| 809 | } |
| 810 | |
| 811 | static ssize_t zv_max_mean_zsize_store(struct kobject *kobj, |
| 812 | struct kobj_attribute *attr, |
| 813 | const char *buf, size_t count) |
| 814 | { |
| 815 | unsigned long val; |
| 816 | int err; |
| 817 | |
| 818 | if (!capable(CAP_SYS_ADMIN)) |
| 819 | return -EPERM; |
| 820 | |
Bernhard Heinloth | ebadb73 | 2011-11-23 16:39:53 +0100 | [diff] [blame] | 821 | err = kstrtoul(buf, 10, &val); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 822 | if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7)) |
| 823 | return -EINVAL; |
| 824 | zv_max_mean_zsize = val; |
| 825 | return count; |
| 826 | } |
| 827 | |
| 828 | /* |
| 829 | * setting zv_page_count_policy_percent via sysfs sets an upper bound of |
| 830 | * persistent (e.g. swap) pages that will be retained according to: |
| 831 | * (zv_page_count_policy_percent * totalram_pages) / 100) |
| 832 | * when that limit is reached, further puts will be rejected (until |
| 833 | * some pages have been flushed). Note that, due to compression, |
| 834 | * this number may exceed 100; it defaults to 75 and we set an |
| 835 | * arbitary limit of 150. A poor choice will almost certainly result |
| 836 | * in OOM's, so this value should only be changed prudently. |
| 837 | */ |
| 838 | static ssize_t zv_page_count_policy_percent_show(struct kobject *kobj, |
| 839 | struct kobj_attribute *attr, |
| 840 | char *buf) |
| 841 | { |
| 842 | return sprintf(buf, "%u\n", zv_page_count_policy_percent); |
| 843 | } |
| 844 | |
| 845 | static ssize_t zv_page_count_policy_percent_store(struct kobject *kobj, |
| 846 | struct kobj_attribute *attr, |
| 847 | const char *buf, size_t count) |
| 848 | { |
| 849 | unsigned long val; |
| 850 | int err; |
| 851 | |
| 852 | if (!capable(CAP_SYS_ADMIN)) |
| 853 | return -EPERM; |
| 854 | |
Bernhard Heinloth | ebadb73 | 2011-11-23 16:39:53 +0100 | [diff] [blame] | 855 | err = kstrtoul(buf, 10, &val); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 856 | if (err || (val == 0) || (val > 150)) |
| 857 | return -EINVAL; |
| 858 | zv_page_count_policy_percent = val; |
| 859 | return count; |
| 860 | } |
| 861 | |
| 862 | static struct kobj_attribute zcache_zv_max_zsize_attr = { |
| 863 | .attr = { .name = "zv_max_zsize", .mode = 0644 }, |
| 864 | .show = zv_max_zsize_show, |
| 865 | .store = zv_max_zsize_store, |
| 866 | }; |
| 867 | |
| 868 | static struct kobj_attribute zcache_zv_max_mean_zsize_attr = { |
| 869 | .attr = { .name = "zv_max_mean_zsize", .mode = 0644 }, |
| 870 | .show = zv_max_mean_zsize_show, |
| 871 | .store = zv_max_mean_zsize_store, |
| 872 | }; |
| 873 | |
| 874 | static struct kobj_attribute zcache_zv_page_count_policy_percent_attr = { |
| 875 | .attr = { .name = "zv_page_count_policy_percent", |
| 876 | .mode = 0644 }, |
| 877 | .show = zv_page_count_policy_percent_show, |
| 878 | .store = zv_page_count_policy_percent_store, |
| 879 | }; |
| 880 | #endif |
| 881 | |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 882 | /* |
| 883 | * zcache core code starts here |
| 884 | */ |
| 885 | |
| 886 | /* useful stats not collected by cleancache or frontswap */ |
| 887 | static unsigned long zcache_flush_total; |
| 888 | static unsigned long zcache_flush_found; |
| 889 | static unsigned long zcache_flobj_total; |
| 890 | static unsigned long zcache_flobj_found; |
| 891 | static unsigned long zcache_failed_eph_puts; |
| 892 | static unsigned long zcache_failed_pers_puts; |
| 893 | |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 894 | /* |
| 895 | * Tmem operations assume the poolid implies the invoking client. |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 896 | * Zcache only has one client (the kernel itself): LOCAL_CLIENT. |
| 897 | * RAMster has each client numbered by cluster node, and a KVM version |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 898 | * of zcache would have one client per guest and each client might |
| 899 | * have a poolid==N. |
| 900 | */ |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 901 | static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id, uint16_t poolid) |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 902 | { |
| 903 | struct tmem_pool *pool = NULL; |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 904 | struct zcache_client *cli = NULL; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 905 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 906 | if (cli_id == LOCAL_CLIENT) |
| 907 | cli = &zcache_host; |
| 908 | else { |
| 909 | if (cli_id >= MAX_CLIENTS) |
| 910 | goto out; |
| 911 | cli = &zcache_clients[cli_id]; |
| 912 | if (cli == NULL) |
| 913 | goto out; |
| 914 | atomic_inc(&cli->refcount); |
| 915 | } |
| 916 | if (poolid < MAX_POOLS_PER_CLIENT) { |
| 917 | pool = cli->tmem_pools[poolid]; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 918 | if (pool != NULL) |
| 919 | atomic_inc(&pool->refcount); |
| 920 | } |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 921 | out: |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 922 | return pool; |
| 923 | } |
| 924 | |
| 925 | static void zcache_put_pool(struct tmem_pool *pool) |
| 926 | { |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 927 | struct zcache_client *cli = NULL; |
| 928 | |
| 929 | if (pool == NULL) |
| 930 | BUG(); |
| 931 | cli = pool->client; |
| 932 | atomic_dec(&pool->refcount); |
| 933 | atomic_dec(&cli->refcount); |
| 934 | } |
| 935 | |
| 936 | int zcache_new_client(uint16_t cli_id) |
| 937 | { |
| 938 | struct zcache_client *cli = NULL; |
| 939 | int ret = -1; |
| 940 | |
| 941 | if (cli_id == LOCAL_CLIENT) |
| 942 | cli = &zcache_host; |
| 943 | else if ((unsigned int)cli_id < MAX_CLIENTS) |
| 944 | cli = &zcache_clients[cli_id]; |
| 945 | if (cli == NULL) |
| 946 | goto out; |
| 947 | if (cli->allocated) |
| 948 | goto out; |
| 949 | cli->allocated = 1; |
| 950 | #ifdef CONFIG_FRONTSWAP |
| 951 | cli->xvpool = xv_create_pool(); |
| 952 | if (cli->xvpool == NULL) |
| 953 | goto out; |
| 954 | #endif |
| 955 | ret = 0; |
| 956 | out: |
| 957 | return ret; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 958 | } |
| 959 | |
| 960 | /* counters for debugging */ |
| 961 | static unsigned long zcache_failed_get_free_pages; |
| 962 | static unsigned long zcache_failed_alloc; |
| 963 | static unsigned long zcache_put_to_flush; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 964 | |
| 965 | /* |
| 966 | * for now, used named slabs so can easily track usage; later can |
| 967 | * either just use kmalloc, or perhaps add a slab-like allocator |
| 968 | * to more carefully manage total memory utilization |
| 969 | */ |
| 970 | static struct kmem_cache *zcache_objnode_cache; |
| 971 | static struct kmem_cache *zcache_obj_cache; |
| 972 | static atomic_t zcache_curr_obj_count = ATOMIC_INIT(0); |
| 973 | static unsigned long zcache_curr_obj_count_max; |
| 974 | static atomic_t zcache_curr_objnode_count = ATOMIC_INIT(0); |
| 975 | static unsigned long zcache_curr_objnode_count_max; |
| 976 | |
| 977 | /* |
| 978 | * to avoid memory allocation recursion (e.g. due to direct reclaim), we |
| 979 | * preload all necessary data structures so the hostops callbacks never |
| 980 | * actually do a malloc |
| 981 | */ |
| 982 | struct zcache_preload { |
| 983 | void *page; |
| 984 | struct tmem_obj *obj; |
| 985 | int nr; |
| 986 | struct tmem_objnode *objnodes[OBJNODE_TREE_MAX_PATH]; |
| 987 | }; |
| 988 | static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, }; |
| 989 | |
| 990 | static int zcache_do_preload(struct tmem_pool *pool) |
| 991 | { |
| 992 | struct zcache_preload *kp; |
| 993 | struct tmem_objnode *objnode; |
| 994 | struct tmem_obj *obj; |
| 995 | void *page; |
| 996 | int ret = -ENOMEM; |
| 997 | |
| 998 | if (unlikely(zcache_objnode_cache == NULL)) |
| 999 | goto out; |
| 1000 | if (unlikely(zcache_obj_cache == NULL)) |
| 1001 | goto out; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1002 | preempt_disable(); |
| 1003 | kp = &__get_cpu_var(zcache_preloads); |
| 1004 | while (kp->nr < ARRAY_SIZE(kp->objnodes)) { |
| 1005 | preempt_enable_no_resched(); |
| 1006 | objnode = kmem_cache_alloc(zcache_objnode_cache, |
| 1007 | ZCACHE_GFP_MASK); |
| 1008 | if (unlikely(objnode == NULL)) { |
| 1009 | zcache_failed_alloc++; |
Seth Jennings | 00bf256 | 2011-10-12 14:41:00 -0500 | [diff] [blame] | 1010 | goto out; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1011 | } |
| 1012 | preempt_disable(); |
| 1013 | kp = &__get_cpu_var(zcache_preloads); |
| 1014 | if (kp->nr < ARRAY_SIZE(kp->objnodes)) |
| 1015 | kp->objnodes[kp->nr++] = objnode; |
| 1016 | else |
| 1017 | kmem_cache_free(zcache_objnode_cache, objnode); |
| 1018 | } |
| 1019 | preempt_enable_no_resched(); |
| 1020 | obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK); |
| 1021 | if (unlikely(obj == NULL)) { |
| 1022 | zcache_failed_alloc++; |
Seth Jennings | 00bf256 | 2011-10-12 14:41:00 -0500 | [diff] [blame] | 1023 | goto out; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1024 | } |
| 1025 | page = (void *)__get_free_page(ZCACHE_GFP_MASK); |
| 1026 | if (unlikely(page == NULL)) { |
| 1027 | zcache_failed_get_free_pages++; |
Vasiliy Kulikov | 69648be | 2011-02-10 21:00:39 +0300 | [diff] [blame] | 1028 | kmem_cache_free(zcache_obj_cache, obj); |
Seth Jennings | 00bf256 | 2011-10-12 14:41:00 -0500 | [diff] [blame] | 1029 | goto out; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1030 | } |
| 1031 | preempt_disable(); |
| 1032 | kp = &__get_cpu_var(zcache_preloads); |
| 1033 | if (kp->obj == NULL) |
| 1034 | kp->obj = obj; |
| 1035 | else |
| 1036 | kmem_cache_free(zcache_obj_cache, obj); |
| 1037 | if (kp->page == NULL) |
| 1038 | kp->page = page; |
| 1039 | else |
| 1040 | free_page((unsigned long)page); |
| 1041 | ret = 0; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1042 | out: |
| 1043 | return ret; |
| 1044 | } |
| 1045 | |
| 1046 | static void *zcache_get_free_page(void) |
| 1047 | { |
| 1048 | struct zcache_preload *kp; |
| 1049 | void *page; |
| 1050 | |
| 1051 | kp = &__get_cpu_var(zcache_preloads); |
| 1052 | page = kp->page; |
| 1053 | BUG_ON(page == NULL); |
| 1054 | kp->page = NULL; |
| 1055 | return page; |
| 1056 | } |
| 1057 | |
| 1058 | static void zcache_free_page(void *p) |
| 1059 | { |
| 1060 | free_page((unsigned long)p); |
| 1061 | } |
| 1062 | |
| 1063 | /* |
| 1064 | * zcache implementation for tmem host ops |
| 1065 | */ |
| 1066 | |
| 1067 | static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool) |
| 1068 | { |
| 1069 | struct tmem_objnode *objnode = NULL; |
| 1070 | unsigned long count; |
| 1071 | struct zcache_preload *kp; |
| 1072 | |
| 1073 | kp = &__get_cpu_var(zcache_preloads); |
| 1074 | if (kp->nr <= 0) |
| 1075 | goto out; |
| 1076 | objnode = kp->objnodes[kp->nr - 1]; |
| 1077 | BUG_ON(objnode == NULL); |
| 1078 | kp->objnodes[kp->nr - 1] = NULL; |
| 1079 | kp->nr--; |
| 1080 | count = atomic_inc_return(&zcache_curr_objnode_count); |
| 1081 | if (count > zcache_curr_objnode_count_max) |
| 1082 | zcache_curr_objnode_count_max = count; |
| 1083 | out: |
| 1084 | return objnode; |
| 1085 | } |
| 1086 | |
| 1087 | static void zcache_objnode_free(struct tmem_objnode *objnode, |
| 1088 | struct tmem_pool *pool) |
| 1089 | { |
| 1090 | atomic_dec(&zcache_curr_objnode_count); |
| 1091 | BUG_ON(atomic_read(&zcache_curr_objnode_count) < 0); |
| 1092 | kmem_cache_free(zcache_objnode_cache, objnode); |
| 1093 | } |
| 1094 | |
| 1095 | static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool) |
| 1096 | { |
| 1097 | struct tmem_obj *obj = NULL; |
| 1098 | unsigned long count; |
| 1099 | struct zcache_preload *kp; |
| 1100 | |
| 1101 | kp = &__get_cpu_var(zcache_preloads); |
| 1102 | obj = kp->obj; |
| 1103 | BUG_ON(obj == NULL); |
| 1104 | kp->obj = NULL; |
| 1105 | count = atomic_inc_return(&zcache_curr_obj_count); |
| 1106 | if (count > zcache_curr_obj_count_max) |
| 1107 | zcache_curr_obj_count_max = count; |
| 1108 | return obj; |
| 1109 | } |
| 1110 | |
| 1111 | static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool) |
| 1112 | { |
| 1113 | atomic_dec(&zcache_curr_obj_count); |
| 1114 | BUG_ON(atomic_read(&zcache_curr_obj_count) < 0); |
| 1115 | kmem_cache_free(zcache_obj_cache, obj); |
| 1116 | } |
| 1117 | |
| 1118 | static struct tmem_hostops zcache_hostops = { |
| 1119 | .obj_alloc = zcache_obj_alloc, |
| 1120 | .obj_free = zcache_obj_free, |
| 1121 | .objnode_alloc = zcache_objnode_alloc, |
| 1122 | .objnode_free = zcache_objnode_free, |
| 1123 | }; |
| 1124 | |
| 1125 | /* |
| 1126 | * zcache implementations for PAM page descriptor ops |
| 1127 | */ |
| 1128 | |
| 1129 | static atomic_t zcache_curr_eph_pampd_count = ATOMIC_INIT(0); |
| 1130 | static unsigned long zcache_curr_eph_pampd_count_max; |
| 1131 | static atomic_t zcache_curr_pers_pampd_count = ATOMIC_INIT(0); |
| 1132 | static unsigned long zcache_curr_pers_pampd_count_max; |
| 1133 | |
| 1134 | /* forward reference */ |
| 1135 | static int zcache_compress(struct page *from, void **out_va, size_t *out_len); |
| 1136 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1137 | static void *zcache_pampd_create(char *data, size_t size, bool raw, int eph, |
| 1138 | struct tmem_pool *pool, struct tmem_oid *oid, |
| 1139 | uint32_t index) |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1140 | { |
| 1141 | void *pampd = NULL, *cdata; |
| 1142 | size_t clen; |
| 1143 | int ret; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1144 | unsigned long count; |
Seth Jennings | c5f5c4d | 2011-08-10 12:56:49 -0500 | [diff] [blame] | 1145 | struct page *page = (struct page *)(data); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1146 | struct zcache_client *cli = pool->client; |
| 1147 | uint16_t client_id = get_client_id_from_client(cli); |
| 1148 | unsigned long zv_mean_zsize; |
| 1149 | unsigned long curr_pers_pampd_count; |
Thadeu Lima de Souza Cascardo | 3ca15c4 | 2011-08-04 19:00:33 -0300 | [diff] [blame] | 1150 | u64 total_zsize; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1151 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1152 | if (eph) { |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1153 | ret = zcache_compress(page, &cdata, &clen); |
| 1154 | if (ret == 0) |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1155 | goto out; |
| 1156 | if (clen == 0 || clen > zbud_max_buddy_size()) { |
| 1157 | zcache_compress_poor++; |
| 1158 | goto out; |
| 1159 | } |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1160 | pampd = (void *)zbud_create(client_id, pool->pool_id, oid, |
| 1161 | index, page, cdata, clen); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1162 | if (pampd != NULL) { |
| 1163 | count = atomic_inc_return(&zcache_curr_eph_pampd_count); |
| 1164 | if (count > zcache_curr_eph_pampd_count_max) |
| 1165 | zcache_curr_eph_pampd_count_max = count; |
| 1166 | } |
| 1167 | } else { |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1168 | curr_pers_pampd_count = |
| 1169 | atomic_read(&zcache_curr_pers_pampd_count); |
| 1170 | if (curr_pers_pampd_count > |
| 1171 | (zv_page_count_policy_percent * totalram_pages) / 100) |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1172 | goto out; |
| 1173 | ret = zcache_compress(page, &cdata, &clen); |
| 1174 | if (ret == 0) |
| 1175 | goto out; |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1176 | /* reject if compression is too poor */ |
| 1177 | if (clen > zv_max_zsize) { |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1178 | zcache_compress_poor++; |
| 1179 | goto out; |
| 1180 | } |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1181 | /* reject if mean compression is too poor */ |
| 1182 | if ((clen > zv_max_mean_zsize) && (curr_pers_pampd_count > 0)) { |
Thadeu Lima de Souza Cascardo | 3ca15c4 | 2011-08-04 19:00:33 -0300 | [diff] [blame] | 1183 | total_zsize = xv_get_total_size_bytes(cli->xvpool); |
| 1184 | zv_mean_zsize = div_u64(total_zsize, |
| 1185 | curr_pers_pampd_count); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1186 | if (zv_mean_zsize > zv_max_mean_zsize) { |
| 1187 | zcache_mean_compress_poor++; |
| 1188 | goto out; |
| 1189 | } |
| 1190 | } |
| 1191 | pampd = (void *)zv_create(cli->xvpool, pool->pool_id, |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1192 | oid, index, cdata, clen); |
| 1193 | if (pampd == NULL) |
| 1194 | goto out; |
| 1195 | count = atomic_inc_return(&zcache_curr_pers_pampd_count); |
| 1196 | if (count > zcache_curr_pers_pampd_count_max) |
| 1197 | zcache_curr_pers_pampd_count_max = count; |
| 1198 | } |
| 1199 | out: |
| 1200 | return pampd; |
| 1201 | } |
| 1202 | |
| 1203 | /* |
| 1204 | * fill the pageframe corresponding to the struct page with the data |
| 1205 | * from the passed pampd |
| 1206 | */ |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1207 | static int zcache_pampd_get_data(char *data, size_t *bufsize, bool raw, |
| 1208 | void *pampd, struct tmem_pool *pool, |
| 1209 | struct tmem_oid *oid, uint32_t index) |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1210 | { |
| 1211 | int ret = 0; |
| 1212 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1213 | BUG_ON(is_ephemeral(pool)); |
Seth Jennings | c5f5c4d | 2011-08-10 12:56:49 -0500 | [diff] [blame] | 1214 | zv_decompress((struct page *)(data), pampd); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1215 | return ret; |
| 1216 | } |
| 1217 | |
| 1218 | /* |
| 1219 | * fill the pageframe corresponding to the struct page with the data |
| 1220 | * from the passed pampd |
| 1221 | */ |
| 1222 | static int zcache_pampd_get_data_and_free(char *data, size_t *bufsize, bool raw, |
| 1223 | void *pampd, struct tmem_pool *pool, |
| 1224 | struct tmem_oid *oid, uint32_t index) |
| 1225 | { |
| 1226 | int ret = 0; |
| 1227 | |
| 1228 | BUG_ON(!is_ephemeral(pool)); |
Seth Jennings | 8097680 | 2011-09-20 13:09:56 -0700 | [diff] [blame] | 1229 | zbud_decompress((struct page *)(data), pampd); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1230 | zbud_free_and_delist((struct zbud_hdr *)pampd); |
| 1231 | atomic_dec(&zcache_curr_eph_pampd_count); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1232 | return ret; |
| 1233 | } |
| 1234 | |
| 1235 | /* |
| 1236 | * free the pampd and remove it from any zcache lists |
| 1237 | * pampd must no longer be pointed to from any tmem data structures! |
| 1238 | */ |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1239 | static void zcache_pampd_free(void *pampd, struct tmem_pool *pool, |
| 1240 | struct tmem_oid *oid, uint32_t index) |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1241 | { |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1242 | struct zcache_client *cli = pool->client; |
| 1243 | |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1244 | if (is_ephemeral(pool)) { |
| 1245 | zbud_free_and_delist((struct zbud_hdr *)pampd); |
| 1246 | atomic_dec(&zcache_curr_eph_pampd_count); |
| 1247 | BUG_ON(atomic_read(&zcache_curr_eph_pampd_count) < 0); |
| 1248 | } else { |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1249 | zv_free(cli->xvpool, (struct zv_hdr *)pampd); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1250 | atomic_dec(&zcache_curr_pers_pampd_count); |
| 1251 | BUG_ON(atomic_read(&zcache_curr_pers_pampd_count) < 0); |
| 1252 | } |
| 1253 | } |
| 1254 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1255 | static void zcache_pampd_free_obj(struct tmem_pool *pool, struct tmem_obj *obj) |
| 1256 | { |
| 1257 | } |
| 1258 | |
| 1259 | static void zcache_pampd_new_obj(struct tmem_obj *obj) |
| 1260 | { |
| 1261 | } |
| 1262 | |
| 1263 | static int zcache_pampd_replace_in_obj(void *pampd, struct tmem_obj *obj) |
| 1264 | { |
| 1265 | return -1; |
| 1266 | } |
| 1267 | |
| 1268 | static bool zcache_pampd_is_remote(void *pampd) |
| 1269 | { |
| 1270 | return 0; |
| 1271 | } |
| 1272 | |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1273 | static struct tmem_pamops zcache_pamops = { |
| 1274 | .create = zcache_pampd_create, |
| 1275 | .get_data = zcache_pampd_get_data, |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1276 | .get_data_and_free = zcache_pampd_get_data_and_free, |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1277 | .free = zcache_pampd_free, |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1278 | .free_obj = zcache_pampd_free_obj, |
| 1279 | .new_obj = zcache_pampd_new_obj, |
| 1280 | .replace_in_obj = zcache_pampd_replace_in_obj, |
| 1281 | .is_remote = zcache_pampd_is_remote, |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1282 | }; |
| 1283 | |
| 1284 | /* |
| 1285 | * zcache compression/decompression and related per-cpu stuff |
| 1286 | */ |
| 1287 | |
| 1288 | #define LZO_WORKMEM_BYTES LZO1X_1_MEM_COMPRESS |
| 1289 | #define LZO_DSTMEM_PAGE_ORDER 1 |
| 1290 | static DEFINE_PER_CPU(unsigned char *, zcache_workmem); |
| 1291 | static DEFINE_PER_CPU(unsigned char *, zcache_dstmem); |
| 1292 | |
| 1293 | static int zcache_compress(struct page *from, void **out_va, size_t *out_len) |
| 1294 | { |
| 1295 | int ret = 0; |
| 1296 | unsigned char *dmem = __get_cpu_var(zcache_dstmem); |
| 1297 | unsigned char *wmem = __get_cpu_var(zcache_workmem); |
| 1298 | char *from_va; |
| 1299 | |
| 1300 | BUG_ON(!irqs_disabled()); |
| 1301 | if (unlikely(dmem == NULL || wmem == NULL)) |
| 1302 | goto out; /* no buffer, so can't compress */ |
| 1303 | from_va = kmap_atomic(from, KM_USER0); |
| 1304 | mb(); |
| 1305 | ret = lzo1x_1_compress(from_va, PAGE_SIZE, dmem, out_len, wmem); |
| 1306 | BUG_ON(ret != LZO_E_OK); |
| 1307 | *out_va = dmem; |
| 1308 | kunmap_atomic(from_va, KM_USER0); |
| 1309 | ret = 1; |
| 1310 | out: |
| 1311 | return ret; |
| 1312 | } |
| 1313 | |
| 1314 | |
| 1315 | static int zcache_cpu_notifier(struct notifier_block *nb, |
| 1316 | unsigned long action, void *pcpu) |
| 1317 | { |
| 1318 | int cpu = (long)pcpu; |
| 1319 | struct zcache_preload *kp; |
| 1320 | |
| 1321 | switch (action) { |
| 1322 | case CPU_UP_PREPARE: |
| 1323 | per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages( |
| 1324 | GFP_KERNEL | __GFP_REPEAT, |
| 1325 | LZO_DSTMEM_PAGE_ORDER), |
| 1326 | per_cpu(zcache_workmem, cpu) = |
| 1327 | kzalloc(LZO1X_MEM_COMPRESS, |
| 1328 | GFP_KERNEL | __GFP_REPEAT); |
| 1329 | break; |
| 1330 | case CPU_DEAD: |
| 1331 | case CPU_UP_CANCELED: |
| 1332 | free_pages((unsigned long)per_cpu(zcache_dstmem, cpu), |
| 1333 | LZO_DSTMEM_PAGE_ORDER); |
| 1334 | per_cpu(zcache_dstmem, cpu) = NULL; |
| 1335 | kfree(per_cpu(zcache_workmem, cpu)); |
| 1336 | per_cpu(zcache_workmem, cpu) = NULL; |
| 1337 | kp = &per_cpu(zcache_preloads, cpu); |
| 1338 | while (kp->nr) { |
| 1339 | kmem_cache_free(zcache_objnode_cache, |
| 1340 | kp->objnodes[kp->nr - 1]); |
| 1341 | kp->objnodes[kp->nr - 1] = NULL; |
| 1342 | kp->nr--; |
| 1343 | } |
Seth Jennings | 8550be0 | 2011-10-06 14:28:26 -0500 | [diff] [blame] | 1344 | if (kp->obj) { |
| 1345 | kmem_cache_free(zcache_obj_cache, kp->obj); |
| 1346 | kp->obj = NULL; |
| 1347 | } |
| 1348 | if (kp->page) { |
| 1349 | free_page((unsigned long)kp->page); |
| 1350 | kp->page = NULL; |
| 1351 | } |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1352 | break; |
| 1353 | default: |
| 1354 | break; |
| 1355 | } |
| 1356 | return NOTIFY_OK; |
| 1357 | } |
| 1358 | |
| 1359 | static struct notifier_block zcache_cpu_notifier_block = { |
| 1360 | .notifier_call = zcache_cpu_notifier |
| 1361 | }; |
| 1362 | |
| 1363 | #ifdef CONFIG_SYSFS |
| 1364 | #define ZCACHE_SYSFS_RO(_name) \ |
| 1365 | static ssize_t zcache_##_name##_show(struct kobject *kobj, \ |
| 1366 | struct kobj_attribute *attr, char *buf) \ |
| 1367 | { \ |
| 1368 | return sprintf(buf, "%lu\n", zcache_##_name); \ |
| 1369 | } \ |
| 1370 | static struct kobj_attribute zcache_##_name##_attr = { \ |
| 1371 | .attr = { .name = __stringify(_name), .mode = 0444 }, \ |
| 1372 | .show = zcache_##_name##_show, \ |
| 1373 | } |
| 1374 | |
| 1375 | #define ZCACHE_SYSFS_RO_ATOMIC(_name) \ |
| 1376 | static ssize_t zcache_##_name##_show(struct kobject *kobj, \ |
| 1377 | struct kobj_attribute *attr, char *buf) \ |
| 1378 | { \ |
| 1379 | return sprintf(buf, "%d\n", atomic_read(&zcache_##_name)); \ |
| 1380 | } \ |
| 1381 | static struct kobj_attribute zcache_##_name##_attr = { \ |
| 1382 | .attr = { .name = __stringify(_name), .mode = 0444 }, \ |
| 1383 | .show = zcache_##_name##_show, \ |
| 1384 | } |
| 1385 | |
| 1386 | #define ZCACHE_SYSFS_RO_CUSTOM(_name, _func) \ |
| 1387 | static ssize_t zcache_##_name##_show(struct kobject *kobj, \ |
| 1388 | struct kobj_attribute *attr, char *buf) \ |
| 1389 | { \ |
| 1390 | return _func(buf); \ |
| 1391 | } \ |
| 1392 | static struct kobj_attribute zcache_##_name##_attr = { \ |
| 1393 | .attr = { .name = __stringify(_name), .mode = 0444 }, \ |
| 1394 | .show = zcache_##_name##_show, \ |
| 1395 | } |
| 1396 | |
| 1397 | ZCACHE_SYSFS_RO(curr_obj_count_max); |
| 1398 | ZCACHE_SYSFS_RO(curr_objnode_count_max); |
| 1399 | ZCACHE_SYSFS_RO(flush_total); |
| 1400 | ZCACHE_SYSFS_RO(flush_found); |
| 1401 | ZCACHE_SYSFS_RO(flobj_total); |
| 1402 | ZCACHE_SYSFS_RO(flobj_found); |
| 1403 | ZCACHE_SYSFS_RO(failed_eph_puts); |
| 1404 | ZCACHE_SYSFS_RO(failed_pers_puts); |
| 1405 | ZCACHE_SYSFS_RO(zbud_curr_zbytes); |
| 1406 | ZCACHE_SYSFS_RO(zbud_cumul_zpages); |
| 1407 | ZCACHE_SYSFS_RO(zbud_cumul_zbytes); |
| 1408 | ZCACHE_SYSFS_RO(zbud_buddied_count); |
| 1409 | ZCACHE_SYSFS_RO(zbpg_unused_list_count); |
| 1410 | ZCACHE_SYSFS_RO(evicted_raw_pages); |
| 1411 | ZCACHE_SYSFS_RO(evicted_unbuddied_pages); |
| 1412 | ZCACHE_SYSFS_RO(evicted_buddied_pages); |
| 1413 | ZCACHE_SYSFS_RO(failed_get_free_pages); |
| 1414 | ZCACHE_SYSFS_RO(failed_alloc); |
| 1415 | ZCACHE_SYSFS_RO(put_to_flush); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1416 | ZCACHE_SYSFS_RO(compress_poor); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1417 | ZCACHE_SYSFS_RO(mean_compress_poor); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1418 | ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_raw_pages); |
| 1419 | ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_zpages); |
| 1420 | ZCACHE_SYSFS_RO_ATOMIC(curr_obj_count); |
| 1421 | ZCACHE_SYSFS_RO_ATOMIC(curr_objnode_count); |
| 1422 | ZCACHE_SYSFS_RO_CUSTOM(zbud_unbuddied_list_counts, |
| 1423 | zbud_show_unbuddied_list_counts); |
| 1424 | ZCACHE_SYSFS_RO_CUSTOM(zbud_cumul_chunk_counts, |
| 1425 | zbud_show_cumul_chunk_counts); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1426 | ZCACHE_SYSFS_RO_CUSTOM(zv_curr_dist_counts, |
| 1427 | zv_curr_dist_counts_show); |
| 1428 | ZCACHE_SYSFS_RO_CUSTOM(zv_cumul_dist_counts, |
| 1429 | zv_cumul_dist_counts_show); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1430 | |
| 1431 | static struct attribute *zcache_attrs[] = { |
| 1432 | &zcache_curr_obj_count_attr.attr, |
| 1433 | &zcache_curr_obj_count_max_attr.attr, |
| 1434 | &zcache_curr_objnode_count_attr.attr, |
| 1435 | &zcache_curr_objnode_count_max_attr.attr, |
| 1436 | &zcache_flush_total_attr.attr, |
| 1437 | &zcache_flobj_total_attr.attr, |
| 1438 | &zcache_flush_found_attr.attr, |
| 1439 | &zcache_flobj_found_attr.attr, |
| 1440 | &zcache_failed_eph_puts_attr.attr, |
| 1441 | &zcache_failed_pers_puts_attr.attr, |
| 1442 | &zcache_compress_poor_attr.attr, |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1443 | &zcache_mean_compress_poor_attr.attr, |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1444 | &zcache_zbud_curr_raw_pages_attr.attr, |
| 1445 | &zcache_zbud_curr_zpages_attr.attr, |
| 1446 | &zcache_zbud_curr_zbytes_attr.attr, |
| 1447 | &zcache_zbud_cumul_zpages_attr.attr, |
| 1448 | &zcache_zbud_cumul_zbytes_attr.attr, |
| 1449 | &zcache_zbud_buddied_count_attr.attr, |
| 1450 | &zcache_zbpg_unused_list_count_attr.attr, |
| 1451 | &zcache_evicted_raw_pages_attr.attr, |
| 1452 | &zcache_evicted_unbuddied_pages_attr.attr, |
| 1453 | &zcache_evicted_buddied_pages_attr.attr, |
| 1454 | &zcache_failed_get_free_pages_attr.attr, |
| 1455 | &zcache_failed_alloc_attr.attr, |
| 1456 | &zcache_put_to_flush_attr.attr, |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1457 | &zcache_zbud_unbuddied_list_counts_attr.attr, |
| 1458 | &zcache_zbud_cumul_chunk_counts_attr.attr, |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1459 | &zcache_zv_curr_dist_counts_attr.attr, |
| 1460 | &zcache_zv_cumul_dist_counts_attr.attr, |
| 1461 | &zcache_zv_max_zsize_attr.attr, |
| 1462 | &zcache_zv_max_mean_zsize_attr.attr, |
| 1463 | &zcache_zv_page_count_policy_percent_attr.attr, |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1464 | NULL, |
| 1465 | }; |
| 1466 | |
| 1467 | static struct attribute_group zcache_attr_group = { |
| 1468 | .attrs = zcache_attrs, |
| 1469 | .name = "zcache", |
| 1470 | }; |
| 1471 | |
| 1472 | #endif /* CONFIG_SYSFS */ |
| 1473 | /* |
| 1474 | * When zcache is disabled ("frozen"), pools can be created and destroyed, |
| 1475 | * but all puts (and thus all other operations that require memory allocation) |
| 1476 | * must fail. If zcache is unfrozen, accepts puts, then frozen again, |
| 1477 | * data consistency requires all puts while frozen to be converted into |
| 1478 | * flushes. |
| 1479 | */ |
| 1480 | static bool zcache_freeze; |
| 1481 | |
| 1482 | /* |
| 1483 | * zcache shrinker interface (only useful for ephemeral pages, so zbud only) |
| 1484 | */ |
Ying Han | 1495f23 | 2011-05-24 17:12:27 -0700 | [diff] [blame] | 1485 | static int shrink_zcache_memory(struct shrinker *shrink, |
| 1486 | struct shrink_control *sc) |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1487 | { |
| 1488 | int ret = -1; |
Ying Han | 1495f23 | 2011-05-24 17:12:27 -0700 | [diff] [blame] | 1489 | int nr = sc->nr_to_scan; |
| 1490 | gfp_t gfp_mask = sc->gfp_mask; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1491 | |
| 1492 | if (nr >= 0) { |
| 1493 | if (!(gfp_mask & __GFP_FS)) |
| 1494 | /* does this case really need to be skipped? */ |
| 1495 | goto out; |
Seth Jennings | 00bf256 | 2011-10-12 14:41:00 -0500 | [diff] [blame] | 1496 | zbud_evict_pages(nr); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1497 | } |
| 1498 | ret = (int)atomic_read(&zcache_zbud_curr_raw_pages); |
| 1499 | out: |
| 1500 | return ret; |
| 1501 | } |
| 1502 | |
| 1503 | static struct shrinker zcache_shrinker = { |
| 1504 | .shrink = shrink_zcache_memory, |
| 1505 | .seeks = DEFAULT_SEEKS, |
| 1506 | }; |
| 1507 | |
| 1508 | /* |
| 1509 | * zcache shims between cleancache/frontswap ops and tmem |
| 1510 | */ |
| 1511 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1512 | static int zcache_put_page(int cli_id, int pool_id, struct tmem_oid *oidp, |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1513 | uint32_t index, struct page *page) |
| 1514 | { |
| 1515 | struct tmem_pool *pool; |
| 1516 | int ret = -1; |
| 1517 | |
| 1518 | BUG_ON(!irqs_disabled()); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1519 | pool = zcache_get_pool_by_id(cli_id, pool_id); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1520 | if (unlikely(pool == NULL)) |
| 1521 | goto out; |
| 1522 | if (!zcache_freeze && zcache_do_preload(pool) == 0) { |
| 1523 | /* preload does preempt_disable on success */ |
Seth Jennings | c5f5c4d | 2011-08-10 12:56:49 -0500 | [diff] [blame] | 1524 | ret = tmem_put(pool, oidp, index, (char *)(page), |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1525 | PAGE_SIZE, 0, is_ephemeral(pool)); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1526 | if (ret < 0) { |
| 1527 | if (is_ephemeral(pool)) |
| 1528 | zcache_failed_eph_puts++; |
| 1529 | else |
| 1530 | zcache_failed_pers_puts++; |
| 1531 | } |
| 1532 | zcache_put_pool(pool); |
| 1533 | preempt_enable_no_resched(); |
| 1534 | } else { |
| 1535 | zcache_put_to_flush++; |
| 1536 | if (atomic_read(&pool->obj_count) > 0) |
| 1537 | /* the put fails whether the flush succeeds or not */ |
| 1538 | (void)tmem_flush_page(pool, oidp, index); |
| 1539 | zcache_put_pool(pool); |
| 1540 | } |
| 1541 | out: |
| 1542 | return ret; |
| 1543 | } |
| 1544 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1545 | static int zcache_get_page(int cli_id, int pool_id, struct tmem_oid *oidp, |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1546 | uint32_t index, struct page *page) |
| 1547 | { |
| 1548 | struct tmem_pool *pool; |
| 1549 | int ret = -1; |
| 1550 | unsigned long flags; |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1551 | size_t size = PAGE_SIZE; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1552 | |
| 1553 | local_irq_save(flags); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1554 | pool = zcache_get_pool_by_id(cli_id, pool_id); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1555 | if (likely(pool != NULL)) { |
| 1556 | if (atomic_read(&pool->obj_count) > 0) |
Seth Jennings | c5f5c4d | 2011-08-10 12:56:49 -0500 | [diff] [blame] | 1557 | ret = tmem_get(pool, oidp, index, (char *)(page), |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1558 | &size, 0, is_ephemeral(pool)); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1559 | zcache_put_pool(pool); |
| 1560 | } |
| 1561 | local_irq_restore(flags); |
| 1562 | return ret; |
| 1563 | } |
| 1564 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1565 | static int zcache_flush_page(int cli_id, int pool_id, |
| 1566 | struct tmem_oid *oidp, uint32_t index) |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1567 | { |
| 1568 | struct tmem_pool *pool; |
| 1569 | int ret = -1; |
| 1570 | unsigned long flags; |
| 1571 | |
| 1572 | local_irq_save(flags); |
| 1573 | zcache_flush_total++; |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1574 | pool = zcache_get_pool_by_id(cli_id, pool_id); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1575 | if (likely(pool != NULL)) { |
| 1576 | if (atomic_read(&pool->obj_count) > 0) |
| 1577 | ret = tmem_flush_page(pool, oidp, index); |
| 1578 | zcache_put_pool(pool); |
| 1579 | } |
| 1580 | if (ret >= 0) |
| 1581 | zcache_flush_found++; |
| 1582 | local_irq_restore(flags); |
| 1583 | return ret; |
| 1584 | } |
| 1585 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1586 | static int zcache_flush_object(int cli_id, int pool_id, |
| 1587 | struct tmem_oid *oidp) |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1588 | { |
| 1589 | struct tmem_pool *pool; |
| 1590 | int ret = -1; |
| 1591 | unsigned long flags; |
| 1592 | |
| 1593 | local_irq_save(flags); |
| 1594 | zcache_flobj_total++; |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1595 | pool = zcache_get_pool_by_id(cli_id, pool_id); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1596 | if (likely(pool != NULL)) { |
| 1597 | if (atomic_read(&pool->obj_count) > 0) |
| 1598 | ret = tmem_flush_object(pool, oidp); |
| 1599 | zcache_put_pool(pool); |
| 1600 | } |
| 1601 | if (ret >= 0) |
| 1602 | zcache_flobj_found++; |
| 1603 | local_irq_restore(flags); |
| 1604 | return ret; |
| 1605 | } |
| 1606 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1607 | static int zcache_destroy_pool(int cli_id, int pool_id) |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1608 | { |
| 1609 | struct tmem_pool *pool = NULL; |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1610 | struct zcache_client *cli = NULL; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1611 | int ret = -1; |
| 1612 | |
| 1613 | if (pool_id < 0) |
| 1614 | goto out; |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1615 | if (cli_id == LOCAL_CLIENT) |
| 1616 | cli = &zcache_host; |
| 1617 | else if ((unsigned int)cli_id < MAX_CLIENTS) |
| 1618 | cli = &zcache_clients[cli_id]; |
| 1619 | if (cli == NULL) |
| 1620 | goto out; |
| 1621 | atomic_inc(&cli->refcount); |
| 1622 | pool = cli->tmem_pools[pool_id]; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1623 | if (pool == NULL) |
| 1624 | goto out; |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1625 | cli->tmem_pools[pool_id] = NULL; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1626 | /* wait for pool activity on other cpus to quiesce */ |
| 1627 | while (atomic_read(&pool->refcount) != 0) |
| 1628 | ; |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1629 | atomic_dec(&cli->refcount); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1630 | local_bh_disable(); |
| 1631 | ret = tmem_destroy_pool(pool); |
| 1632 | local_bh_enable(); |
| 1633 | kfree(pool); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1634 | pr_info("zcache: destroyed pool id=%d, cli_id=%d\n", |
| 1635 | pool_id, cli_id); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1636 | out: |
| 1637 | return ret; |
| 1638 | } |
| 1639 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1640 | static int zcache_new_pool(uint16_t cli_id, uint32_t flags) |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1641 | { |
| 1642 | int poolid = -1; |
| 1643 | struct tmem_pool *pool; |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1644 | struct zcache_client *cli = NULL; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1645 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1646 | if (cli_id == LOCAL_CLIENT) |
| 1647 | cli = &zcache_host; |
| 1648 | else if ((unsigned int)cli_id < MAX_CLIENTS) |
| 1649 | cli = &zcache_clients[cli_id]; |
| 1650 | if (cli == NULL) |
| 1651 | goto out; |
| 1652 | atomic_inc(&cli->refcount); |
Seth Jennings | dbe82eb | 2011-08-22 14:30:38 -0500 | [diff] [blame] | 1653 | pool = kmalloc(sizeof(struct tmem_pool), GFP_ATOMIC); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1654 | if (pool == NULL) { |
| 1655 | pr_info("zcache: pool creation failed: out of memory\n"); |
| 1656 | goto out; |
| 1657 | } |
| 1658 | |
| 1659 | for (poolid = 0; poolid < MAX_POOLS_PER_CLIENT; poolid++) |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1660 | if (cli->tmem_pools[poolid] == NULL) |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1661 | break; |
| 1662 | if (poolid >= MAX_POOLS_PER_CLIENT) { |
| 1663 | pr_info("zcache: pool creation failed: max exceeded\n"); |
| 1664 | kfree(pool); |
| 1665 | poolid = -1; |
| 1666 | goto out; |
| 1667 | } |
| 1668 | atomic_set(&pool->refcount, 0); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1669 | pool->client = cli; |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1670 | pool->pool_id = poolid; |
| 1671 | tmem_new_pool(pool, flags); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1672 | cli->tmem_pools[poolid] = pool; |
| 1673 | pr_info("zcache: created %s tmem pool, id=%d, client=%d\n", |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1674 | flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral", |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1675 | poolid, cli_id); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1676 | out: |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1677 | if (cli != NULL) |
| 1678 | atomic_dec(&cli->refcount); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1679 | return poolid; |
| 1680 | } |
| 1681 | |
| 1682 | /********** |
| 1683 | * Two kernel functionalities currently can be layered on top of tmem. |
| 1684 | * These are "cleancache" which is used as a second-chance cache for clean |
| 1685 | * page cache pages; and "frontswap" which is used for swap pages |
| 1686 | * to avoid writes to disk. A generic "shim" is provided here for each |
| 1687 | * to translate in-kernel semantics to zcache semantics. |
| 1688 | */ |
| 1689 | |
| 1690 | #ifdef CONFIG_CLEANCACHE |
| 1691 | static void zcache_cleancache_put_page(int pool_id, |
| 1692 | struct cleancache_filekey key, |
| 1693 | pgoff_t index, struct page *page) |
| 1694 | { |
| 1695 | u32 ind = (u32) index; |
| 1696 | struct tmem_oid oid = *(struct tmem_oid *)&key; |
| 1697 | |
| 1698 | if (likely(ind == index)) |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1699 | (void)zcache_put_page(LOCAL_CLIENT, pool_id, &oid, index, page); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1700 | } |
| 1701 | |
| 1702 | static int zcache_cleancache_get_page(int pool_id, |
| 1703 | struct cleancache_filekey key, |
| 1704 | pgoff_t index, struct page *page) |
| 1705 | { |
| 1706 | u32 ind = (u32) index; |
| 1707 | struct tmem_oid oid = *(struct tmem_oid *)&key; |
| 1708 | int ret = -1; |
| 1709 | |
| 1710 | if (likely(ind == index)) |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1711 | ret = zcache_get_page(LOCAL_CLIENT, pool_id, &oid, index, page); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1712 | return ret; |
| 1713 | } |
| 1714 | |
| 1715 | static void zcache_cleancache_flush_page(int pool_id, |
| 1716 | struct cleancache_filekey key, |
| 1717 | pgoff_t index) |
| 1718 | { |
| 1719 | u32 ind = (u32) index; |
| 1720 | struct tmem_oid oid = *(struct tmem_oid *)&key; |
| 1721 | |
| 1722 | if (likely(ind == index)) |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1723 | (void)zcache_flush_page(LOCAL_CLIENT, pool_id, &oid, ind); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1724 | } |
| 1725 | |
| 1726 | static void zcache_cleancache_flush_inode(int pool_id, |
| 1727 | struct cleancache_filekey key) |
| 1728 | { |
| 1729 | struct tmem_oid oid = *(struct tmem_oid *)&key; |
| 1730 | |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1731 | (void)zcache_flush_object(LOCAL_CLIENT, pool_id, &oid); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1732 | } |
| 1733 | |
| 1734 | static void zcache_cleancache_flush_fs(int pool_id) |
| 1735 | { |
| 1736 | if (pool_id >= 0) |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1737 | (void)zcache_destroy_pool(LOCAL_CLIENT, pool_id); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1738 | } |
| 1739 | |
| 1740 | static int zcache_cleancache_init_fs(size_t pagesize) |
| 1741 | { |
| 1742 | BUG_ON(sizeof(struct cleancache_filekey) != |
| 1743 | sizeof(struct tmem_oid)); |
| 1744 | BUG_ON(pagesize != PAGE_SIZE); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1745 | return zcache_new_pool(LOCAL_CLIENT, 0); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1746 | } |
| 1747 | |
| 1748 | static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize) |
| 1749 | { |
| 1750 | /* shared pools are unsupported and map to private */ |
| 1751 | BUG_ON(sizeof(struct cleancache_filekey) != |
| 1752 | sizeof(struct tmem_oid)); |
| 1753 | BUG_ON(pagesize != PAGE_SIZE); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1754 | return zcache_new_pool(LOCAL_CLIENT, 0); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1755 | } |
| 1756 | |
| 1757 | static struct cleancache_ops zcache_cleancache_ops = { |
| 1758 | .put_page = zcache_cleancache_put_page, |
| 1759 | .get_page = zcache_cleancache_get_page, |
| 1760 | .flush_page = zcache_cleancache_flush_page, |
| 1761 | .flush_inode = zcache_cleancache_flush_inode, |
| 1762 | .flush_fs = zcache_cleancache_flush_fs, |
| 1763 | .init_shared_fs = zcache_cleancache_init_shared_fs, |
| 1764 | .init_fs = zcache_cleancache_init_fs |
| 1765 | }; |
| 1766 | |
| 1767 | struct cleancache_ops zcache_cleancache_register_ops(void) |
| 1768 | { |
| 1769 | struct cleancache_ops old_ops = |
| 1770 | cleancache_register_ops(&zcache_cleancache_ops); |
| 1771 | |
| 1772 | return old_ops; |
| 1773 | } |
| 1774 | #endif |
| 1775 | |
| 1776 | #ifdef CONFIG_FRONTSWAP |
| 1777 | /* a single tmem poolid is used for all frontswap "types" (swapfiles) */ |
| 1778 | static int zcache_frontswap_poolid = -1; |
| 1779 | |
| 1780 | /* |
| 1781 | * Swizzling increases objects per swaptype, increasing tmem concurrency |
| 1782 | * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS |
Seth Jennings | 3d65c85 | 2011-10-04 08:21:32 -0500 | [diff] [blame] | 1783 | * Setting SWIZ_BITS to 27 basically reconstructs the swap entry from |
Dan Magenheimer | e8b4553 | 2012-01-23 16:52:20 -0500 | [diff] [blame^] | 1784 | * frontswap_get_page(), but has side-effects. Hence using 8. |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1785 | */ |
Dan Magenheimer | e8b4553 | 2012-01-23 16:52:20 -0500 | [diff] [blame^] | 1786 | #define SWIZ_BITS 8 |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1787 | #define SWIZ_MASK ((1 << SWIZ_BITS) - 1) |
| 1788 | #define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK)) |
| 1789 | #define iswiz(_ind) (_ind >> SWIZ_BITS) |
| 1790 | |
| 1791 | static inline struct tmem_oid oswiz(unsigned type, u32 ind) |
| 1792 | { |
| 1793 | struct tmem_oid oid = { .oid = { 0 } }; |
| 1794 | oid.oid[0] = _oswiz(type, ind); |
| 1795 | return oid; |
| 1796 | } |
| 1797 | |
| 1798 | static int zcache_frontswap_put_page(unsigned type, pgoff_t offset, |
| 1799 | struct page *page) |
| 1800 | { |
| 1801 | u64 ind64 = (u64)offset; |
| 1802 | u32 ind = (u32)offset; |
| 1803 | struct tmem_oid oid = oswiz(type, ind); |
| 1804 | int ret = -1; |
| 1805 | unsigned long flags; |
| 1806 | |
| 1807 | BUG_ON(!PageLocked(page)); |
| 1808 | if (likely(ind64 == ind)) { |
| 1809 | local_irq_save(flags); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1810 | ret = zcache_put_page(LOCAL_CLIENT, zcache_frontswap_poolid, |
| 1811 | &oid, iswiz(ind), page); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1812 | local_irq_restore(flags); |
| 1813 | } |
| 1814 | return ret; |
| 1815 | } |
| 1816 | |
| 1817 | /* returns 0 if the page was successfully gotten from frontswap, -1 if |
| 1818 | * was not present (should never happen!) */ |
| 1819 | static int zcache_frontswap_get_page(unsigned type, pgoff_t offset, |
| 1820 | struct page *page) |
| 1821 | { |
| 1822 | u64 ind64 = (u64)offset; |
| 1823 | u32 ind = (u32)offset; |
| 1824 | struct tmem_oid oid = oswiz(type, ind); |
| 1825 | int ret = -1; |
| 1826 | |
| 1827 | BUG_ON(!PageLocked(page)); |
| 1828 | if (likely(ind64 == ind)) |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1829 | ret = zcache_get_page(LOCAL_CLIENT, zcache_frontswap_poolid, |
| 1830 | &oid, iswiz(ind), page); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1831 | return ret; |
| 1832 | } |
| 1833 | |
| 1834 | /* flush a single page from frontswap */ |
| 1835 | static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset) |
| 1836 | { |
| 1837 | u64 ind64 = (u64)offset; |
| 1838 | u32 ind = (u32)offset; |
| 1839 | struct tmem_oid oid = oswiz(type, ind); |
| 1840 | |
| 1841 | if (likely(ind64 == ind)) |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1842 | (void)zcache_flush_page(LOCAL_CLIENT, zcache_frontswap_poolid, |
| 1843 | &oid, iswiz(ind)); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1844 | } |
| 1845 | |
| 1846 | /* flush all pages from the passed swaptype */ |
| 1847 | static void zcache_frontswap_flush_area(unsigned type) |
| 1848 | { |
| 1849 | struct tmem_oid oid; |
| 1850 | int ind; |
| 1851 | |
| 1852 | for (ind = SWIZ_MASK; ind >= 0; ind--) { |
| 1853 | oid = oswiz(type, ind); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1854 | (void)zcache_flush_object(LOCAL_CLIENT, |
| 1855 | zcache_frontswap_poolid, &oid); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1856 | } |
| 1857 | } |
| 1858 | |
| 1859 | static void zcache_frontswap_init(unsigned ignored) |
| 1860 | { |
| 1861 | /* a single tmem poolid is used for all frontswap "types" (swapfiles) */ |
| 1862 | if (zcache_frontswap_poolid < 0) |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1863 | zcache_frontswap_poolid = |
| 1864 | zcache_new_pool(LOCAL_CLIENT, TMEM_POOL_PERSIST); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1865 | } |
| 1866 | |
| 1867 | static struct frontswap_ops zcache_frontswap_ops = { |
| 1868 | .put_page = zcache_frontswap_put_page, |
| 1869 | .get_page = zcache_frontswap_get_page, |
| 1870 | .flush_page = zcache_frontswap_flush_page, |
| 1871 | .flush_area = zcache_frontswap_flush_area, |
| 1872 | .init = zcache_frontswap_init |
| 1873 | }; |
| 1874 | |
| 1875 | struct frontswap_ops zcache_frontswap_register_ops(void) |
| 1876 | { |
| 1877 | struct frontswap_ops old_ops = |
| 1878 | frontswap_register_ops(&zcache_frontswap_ops); |
| 1879 | |
| 1880 | return old_ops; |
| 1881 | } |
| 1882 | #endif |
| 1883 | |
| 1884 | /* |
| 1885 | * zcache initialization |
| 1886 | * NOTE FOR NOW zcache MUST BE PROVIDED AS A KERNEL BOOT PARAMETER OR |
| 1887 | * NOTHING HAPPENS! |
| 1888 | */ |
| 1889 | |
| 1890 | static int zcache_enabled; |
| 1891 | |
| 1892 | static int __init enable_zcache(char *s) |
| 1893 | { |
| 1894 | zcache_enabled = 1; |
| 1895 | return 1; |
| 1896 | } |
| 1897 | __setup("zcache", enable_zcache); |
| 1898 | |
| 1899 | /* allow independent dynamic disabling of cleancache and frontswap */ |
| 1900 | |
| 1901 | static int use_cleancache = 1; |
| 1902 | |
| 1903 | static int __init no_cleancache(char *s) |
| 1904 | { |
| 1905 | use_cleancache = 0; |
| 1906 | return 1; |
| 1907 | } |
| 1908 | |
| 1909 | __setup("nocleancache", no_cleancache); |
| 1910 | |
| 1911 | static int use_frontswap = 1; |
| 1912 | |
| 1913 | static int __init no_frontswap(char *s) |
| 1914 | { |
| 1915 | use_frontswap = 0; |
| 1916 | return 1; |
| 1917 | } |
| 1918 | |
| 1919 | __setup("nofrontswap", no_frontswap); |
| 1920 | |
| 1921 | static int __init zcache_init(void) |
| 1922 | { |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1923 | int ret = 0; |
| 1924 | |
Nitin Gupta | d8c778f | 2011-08-04 15:05:24 -0700 | [diff] [blame] | 1925 | #ifdef CONFIG_SYSFS |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1926 | ret = sysfs_create_group(mm_kobj, &zcache_attr_group); |
| 1927 | if (ret) { |
| 1928 | pr_err("zcache: can't create sysfs\n"); |
| 1929 | goto out; |
| 1930 | } |
| 1931 | #endif /* CONFIG_SYSFS */ |
| 1932 | #if defined(CONFIG_CLEANCACHE) || defined(CONFIG_FRONTSWAP) |
| 1933 | if (zcache_enabled) { |
| 1934 | unsigned int cpu; |
| 1935 | |
| 1936 | tmem_register_hostops(&zcache_hostops); |
| 1937 | tmem_register_pamops(&zcache_pamops); |
| 1938 | ret = register_cpu_notifier(&zcache_cpu_notifier_block); |
| 1939 | if (ret) { |
| 1940 | pr_err("zcache: can't register cpu notifier\n"); |
| 1941 | goto out; |
| 1942 | } |
| 1943 | for_each_online_cpu(cpu) { |
| 1944 | void *pcpu = (void *)(long)cpu; |
| 1945 | zcache_cpu_notifier(&zcache_cpu_notifier_block, |
| 1946 | CPU_UP_PREPARE, pcpu); |
| 1947 | } |
| 1948 | } |
| 1949 | zcache_objnode_cache = kmem_cache_create("zcache_objnode", |
| 1950 | sizeof(struct tmem_objnode), 0, 0, NULL); |
| 1951 | zcache_obj_cache = kmem_cache_create("zcache_obj", |
| 1952 | sizeof(struct tmem_obj), 0, 0, NULL); |
Dan Magenheimer | 966b901 | 2011-07-07 07:37:19 -0700 | [diff] [blame] | 1953 | ret = zcache_new_client(LOCAL_CLIENT); |
| 1954 | if (ret) { |
| 1955 | pr_err("zcache: can't create client\n"); |
| 1956 | goto out; |
| 1957 | } |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1958 | #endif |
| 1959 | #ifdef CONFIG_CLEANCACHE |
| 1960 | if (zcache_enabled && use_cleancache) { |
| 1961 | struct cleancache_ops old_ops; |
| 1962 | |
| 1963 | zbud_init(); |
| 1964 | register_shrinker(&zcache_shrinker); |
| 1965 | old_ops = zcache_cleancache_register_ops(); |
| 1966 | pr_info("zcache: cleancache enabled using kernel " |
| 1967 | "transcendent memory and compression buddies\n"); |
| 1968 | if (old_ops.init_fs != NULL) |
| 1969 | pr_warning("zcache: cleancache_ops overridden"); |
| 1970 | } |
| 1971 | #endif |
| 1972 | #ifdef CONFIG_FRONTSWAP |
| 1973 | if (zcache_enabled && use_frontswap) { |
| 1974 | struct frontswap_ops old_ops; |
| 1975 | |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1976 | old_ops = zcache_frontswap_register_ops(); |
| 1977 | pr_info("zcache: frontswap enabled using kernel " |
| 1978 | "transcendent memory and xvmalloc\n"); |
| 1979 | if (old_ops.init != NULL) |
Seth Jennings | 0428fec | 2011-08-22 13:50:08 -0500 | [diff] [blame] | 1980 | pr_warning("zcache: frontswap_ops overridden"); |
Dan Magenheimer | 9cc06bf | 2011-02-06 19:26:08 -0800 | [diff] [blame] | 1981 | } |
| 1982 | #endif |
| 1983 | out: |
| 1984 | return ret; |
| 1985 | } |
| 1986 | |
| 1987 | module_init(zcache_init) |