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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 the crypto compression
10 * API:
11 * 1) "compression buddies" ("zbud") is used for ephemeral pages
12 * 2) zsmalloc is used for persistent pages.
13 * Xvmalloc (based on the TLSF allocator) has very low fragmentation
14 * so maximizes space efficiency, while zbud allows pairs (and potentially,
15 * in the future, more than a pair of) compressed pages to be closely linked
16 * so that reclaiming can be done via the kernel's physical-page-oriented
17 * "shrinker" interface.
18 *
19 * [1] For a definition of page-accessible memory (aka PAM), see:
20 * http://marc.info/?l=linux-mm&m=127811271605009
21 */
22
23#include <linux/module.h>
24#include <linux/cpu.h>
25#include <linux/highmem.h>
26#include <linux/list.h>
27#include <linux/slab.h>
28#include <linux/spinlock.h>
29#include <linux/types.h>
30#include <linux/atomic.h>
31#include <linux/math64.h>
32#include <linux/crypto.h>
33#include <linux/string.h>
34#include "tmem.h"
35
36#include "../zsmalloc/zsmalloc.h"
37
38#if (!defined(CONFIG_CLEANCACHE) && !defined(CONFIG_FRONTSWAP))
39#error "zcache is useless without CONFIG_CLEANCACHE or CONFIG_FRONTSWAP"
40#endif
41#ifdef CONFIG_CLEANCACHE
42#include <linux/cleancache.h>
43#endif
44#ifdef CONFIG_FRONTSWAP
45#include <linux/frontswap.h>
46#endif
47
48#if 0
49/* this is more aggressive but may cause other problems? */
50#define ZCACHE_GFP_MASK (GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN)
51#else
52#define ZCACHE_GFP_MASK \
53 (__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC)
54#endif
55
56#define MAX_POOLS_PER_CLIENT 16
57
58#define MAX_CLIENTS 16
59#define LOCAL_CLIENT ((uint16_t)-1)
60
61MODULE_LICENSE("GPL");
62
63struct zcache_client {
64 struct tmem_pool *tmem_pools[MAX_POOLS_PER_CLIENT];
65 struct zs_pool *zspool;
66 bool allocated;
67 atomic_t refcount;
68};
69
70static struct zcache_client zcache_host;
71static struct zcache_client zcache_clients[MAX_CLIENTS];
72
73static inline uint16_t get_client_id_from_client(struct zcache_client *cli)
74{
75 BUG_ON(cli == NULL);
76 if (cli == &zcache_host)
77 return LOCAL_CLIENT;
78 return cli - &zcache_clients[0];
79}
80
81static inline bool is_local_client(struct zcache_client *cli)
82{
83 return cli == &zcache_host;
84}
85
86/* crypto API for zcache */
87#define ZCACHE_COMP_NAME_SZ CRYPTO_MAX_ALG_NAME
88static char zcache_comp_name[ZCACHE_COMP_NAME_SZ];
89static struct crypto_comp * __percpu *zcache_comp_pcpu_tfms;
90
91enum comp_op {
92 ZCACHE_COMPOP_COMPRESS,
93 ZCACHE_COMPOP_DECOMPRESS
94};
95
96static inline int zcache_comp_op(enum comp_op op,
97 const u8 *src, unsigned int slen,
98 u8 *dst, unsigned int *dlen)
99{
100 struct crypto_comp *tfm;
101 int ret;
102
103 BUG_ON(!zcache_comp_pcpu_tfms);
104 tfm = *per_cpu_ptr(zcache_comp_pcpu_tfms, get_cpu());
105 BUG_ON(!tfm);
106 switch (op) {
107 case ZCACHE_COMPOP_COMPRESS:
108 ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
109 break;
110 case ZCACHE_COMPOP_DECOMPRESS:
111 ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
112 break;
113 }
114 put_cpu();
115 return ret;
116}
117
118/**********
119 * Compression buddies ("zbud") provides for packing two (or, possibly
120 * in the future, more) compressed ephemeral pages into a single "raw"
121 * (physical) page and tracking them with data structures so that
122 * the raw pages can be easily reclaimed.
123 *
124 * A zbud page ("zbpg") is an aligned page containing a list_head,
125 * a lock, and two "zbud headers". The remainder of the physical
126 * page is divided up into aligned 64-byte "chunks" which contain
127 * the compressed data for zero, one, or two zbuds. Each zbpg
128 * resides on: (1) an "unused list" if it has no zbuds; (2) a
129 * "buddied" list if it is fully populated with two zbuds; or
130 * (3) one of PAGE_SIZE/64 "unbuddied" lists indexed by how many chunks
131 * the one unbuddied zbud uses. The data inside a zbpg cannot be
132 * read or written unless the zbpg's lock is held.
133 */
134
135#define ZBH_SENTINEL 0x43214321
136#define ZBPG_SENTINEL 0xdeadbeef
137
138#define ZBUD_MAX_BUDS 2
139
140struct zbud_hdr {
141 uint16_t client_id;
142 uint16_t pool_id;
143 struct tmem_oid oid;
144 uint32_t index;
145 uint16_t size; /* compressed size in bytes, zero means unused */
146 DECL_SENTINEL
147};
148
149struct zbud_page {
150 struct list_head bud_list;
151 spinlock_t lock;
152 struct zbud_hdr buddy[ZBUD_MAX_BUDS];
153 DECL_SENTINEL
154 /* followed by NUM_CHUNK aligned CHUNK_SIZE-byte chunks */
155};
156
157#define CHUNK_SHIFT 6
158#define CHUNK_SIZE (1 << CHUNK_SHIFT)
159#define CHUNK_MASK (~(CHUNK_SIZE-1))
160#define NCHUNKS (((PAGE_SIZE - sizeof(struct zbud_page)) & \
161 CHUNK_MASK) >> CHUNK_SHIFT)
162#define MAX_CHUNK (NCHUNKS-1)
163
164static struct {
165 struct list_head list;
166 unsigned count;
167} zbud_unbuddied[NCHUNKS];
168/* list N contains pages with N chunks USED and NCHUNKS-N unused */
169/* element 0 is never used but optimizing that isn't worth it */
170static unsigned long zbud_cumul_chunk_counts[NCHUNKS];
171
172struct list_head zbud_buddied_list;
173static unsigned long zcache_zbud_buddied_count;
174
175/* protects the buddied list and all unbuddied lists */
176static DEFINE_SPINLOCK(zbud_budlists_spinlock);
177
178static LIST_HEAD(zbpg_unused_list);
179static unsigned long zcache_zbpg_unused_list_count;
180
181/* protects the unused page list */
182static DEFINE_SPINLOCK(zbpg_unused_list_spinlock);
183
184static atomic_t zcache_zbud_curr_raw_pages;
185static atomic_t zcache_zbud_curr_zpages;
186static unsigned long zcache_zbud_curr_zbytes;
187static unsigned long zcache_zbud_cumul_zpages;
188static unsigned long zcache_zbud_cumul_zbytes;
189static unsigned long zcache_compress_poor;
190static unsigned long zcache_mean_compress_poor;
191
192/* forward references */
193static void *zcache_get_free_page(void);
194static void zcache_free_page(void *p);
195
196/*
197 * zbud helper functions
198 */
199
200static inline unsigned zbud_max_buddy_size(void)
201{
202 return MAX_CHUNK << CHUNK_SHIFT;
203}
204
205static inline unsigned zbud_size_to_chunks(unsigned size)
206{
207 BUG_ON(size == 0 || size > zbud_max_buddy_size());
208 return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT;
209}
210
211static inline int zbud_budnum(struct zbud_hdr *zh)
212{
213 unsigned offset = (unsigned long)zh & (PAGE_SIZE - 1);
214 struct zbud_page *zbpg = NULL;
215 unsigned budnum = -1U;
216 int i;
217
218 for (i = 0; i < ZBUD_MAX_BUDS; i++)
219 if (offset == offsetof(typeof(*zbpg), buddy[i])) {
220 budnum = i;
221 break;
222 }
223 BUG_ON(budnum == -1U);
224 return budnum;
225}
226
227static char *zbud_data(struct zbud_hdr *zh, unsigned size)
228{
229 struct zbud_page *zbpg;
230 char *p;
231 unsigned budnum;
232
233 ASSERT_SENTINEL(zh, ZBH);
234 budnum = zbud_budnum(zh);
235 BUG_ON(size == 0 || size > zbud_max_buddy_size());
236 zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
237 ASSERT_SPINLOCK(&zbpg->lock);
238 p = (char *)zbpg;
239 if (budnum == 0)
240 p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) &
241 CHUNK_MASK);
242 else if (budnum == 1)
243 p += PAGE_SIZE - ((size + CHUNK_SIZE - 1) & CHUNK_MASK);
244 return p;
245}
246
247/*
248 * zbud raw page management
249 */
250
251static struct zbud_page *zbud_alloc_raw_page(void)
252{
253 struct zbud_page *zbpg = NULL;
254 struct zbud_hdr *zh0, *zh1;
255 bool recycled = 0;
256
257 /* if any pages on the zbpg list, use one */
258 spin_lock(&zbpg_unused_list_spinlock);
259 if (!list_empty(&zbpg_unused_list)) {
260 zbpg = list_first_entry(&zbpg_unused_list,
261 struct zbud_page, bud_list);
262 list_del_init(&zbpg->bud_list);
263 zcache_zbpg_unused_list_count--;
264 recycled = 1;
265 }
266 spin_unlock(&zbpg_unused_list_spinlock);
267 if (zbpg == NULL)
268 /* none on zbpg list, try to get a kernel page */
269 zbpg = zcache_get_free_page();
270 if (likely(zbpg != NULL)) {
271 INIT_LIST_HEAD(&zbpg->bud_list);
272 zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
273 spin_lock_init(&zbpg->lock);
274 if (recycled) {
275 ASSERT_INVERTED_SENTINEL(zbpg, ZBPG);
276 SET_SENTINEL(zbpg, ZBPG);
277 BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
278 BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
279 } else {
280 atomic_inc(&zcache_zbud_curr_raw_pages);
281 INIT_LIST_HEAD(&zbpg->bud_list);
282 SET_SENTINEL(zbpg, ZBPG);
283 zh0->size = 0; zh1->size = 0;
284 tmem_oid_set_invalid(&zh0->oid);
285 tmem_oid_set_invalid(&zh1->oid);
286 }
287 }
288 return zbpg;
289}
290
291static void zbud_free_raw_page(struct zbud_page *zbpg)
292{
293 struct zbud_hdr *zh0 = &zbpg->buddy[0], *zh1 = &zbpg->buddy[1];
294
295 ASSERT_SENTINEL(zbpg, ZBPG);
296 BUG_ON(!list_empty(&zbpg->bud_list));
297 ASSERT_SPINLOCK(&zbpg->lock);
298 BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
299 BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
300 INVERT_SENTINEL(zbpg, ZBPG);
301 spin_unlock(&zbpg->lock);
302 spin_lock(&zbpg_unused_list_spinlock);
303 list_add(&zbpg->bud_list, &zbpg_unused_list);
304 zcache_zbpg_unused_list_count++;
305 spin_unlock(&zbpg_unused_list_spinlock);
306}
307
308/*
309 * core zbud handling routines
310 */
311
312static unsigned zbud_free(struct zbud_hdr *zh)
313{
314 unsigned size;
315
316 ASSERT_SENTINEL(zh, ZBH);
317 BUG_ON(!tmem_oid_valid(&zh->oid));
318 size = zh->size;
319 BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
320 zh->size = 0;
321 tmem_oid_set_invalid(&zh->oid);
322 INVERT_SENTINEL(zh, ZBH);
323 zcache_zbud_curr_zbytes -= size;
324 atomic_dec(&zcache_zbud_curr_zpages);
325 return size;
326}
327
328static void zbud_free_and_delist(struct zbud_hdr *zh)
329{
330 unsigned chunks;
331 struct zbud_hdr *zh_other;
332 unsigned budnum = zbud_budnum(zh), size;
333 struct zbud_page *zbpg =
334 container_of(zh, struct zbud_page, buddy[budnum]);
335
336 spin_lock(&zbud_budlists_spinlock);
337 spin_lock(&zbpg->lock);
338 if (list_empty(&zbpg->bud_list)) {
339 /* ignore zombie page... see zbud_evict_pages() */
340 spin_unlock(&zbpg->lock);
341 spin_unlock(&zbud_budlists_spinlock);
342 return;
343 }
344 size = zbud_free(zh);
345 ASSERT_SPINLOCK(&zbpg->lock);
346 zh_other = &zbpg->buddy[(budnum == 0) ? 1 : 0];
347 if (zh_other->size == 0) { /* was unbuddied: unlist and free */
348 chunks = zbud_size_to_chunks(size) ;
349 BUG_ON(list_empty(&zbud_unbuddied[chunks].list));
350 list_del_init(&zbpg->bud_list);
351 zbud_unbuddied[chunks].count--;
352 spin_unlock(&zbud_budlists_spinlock);
353 zbud_free_raw_page(zbpg);
354 } else { /* was buddied: move remaining buddy to unbuddied list */
355 chunks = zbud_size_to_chunks(zh_other->size) ;
356 list_del_init(&zbpg->bud_list);
357 zcache_zbud_buddied_count--;
358 list_add_tail(&zbpg->bud_list, &zbud_unbuddied[chunks].list);
359 zbud_unbuddied[chunks].count++;
360 spin_unlock(&zbud_budlists_spinlock);
361 spin_unlock(&zbpg->lock);
362 }
363}
364
365static struct zbud_hdr *zbud_create(uint16_t client_id, uint16_t pool_id,
366 struct tmem_oid *oid,
367 uint32_t index, struct page *page,
368 void *cdata, unsigned size)
369{
370 struct zbud_hdr *zh0, *zh1, *zh = NULL;
371 struct zbud_page *zbpg = NULL, *ztmp;
372 unsigned nchunks;
373 char *to;
374 int i, found_good_buddy = 0;
375
376 nchunks = zbud_size_to_chunks(size) ;
377 for (i = MAX_CHUNK - nchunks + 1; i > 0; i--) {
378 spin_lock(&zbud_budlists_spinlock);
379 if (!list_empty(&zbud_unbuddied[i].list)) {
380 list_for_each_entry_safe(zbpg, ztmp,
381 &zbud_unbuddied[i].list, bud_list) {
382 if (spin_trylock(&zbpg->lock)) {
383 found_good_buddy = i;
384 goto found_unbuddied;
385 }
386 }
387 }
388 spin_unlock(&zbud_budlists_spinlock);
389 }
390 /* didn't find a good buddy, try allocating a new page */
391 zbpg = zbud_alloc_raw_page();
392 if (unlikely(zbpg == NULL))
393 goto out;
394 /* ok, have a page, now compress the data before taking locks */
395 spin_lock(&zbud_budlists_spinlock);
396 spin_lock(&zbpg->lock);
397 list_add_tail(&zbpg->bud_list, &zbud_unbuddied[nchunks].list);
398 zbud_unbuddied[nchunks].count++;
399 zh = &zbpg->buddy[0];
400 goto init_zh;
401
402found_unbuddied:
403 ASSERT_SPINLOCK(&zbpg->lock);
404 zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
405 BUG_ON(!((zh0->size == 0) ^ (zh1->size == 0)));
406 if (zh0->size != 0) { /* buddy0 in use, buddy1 is vacant */
407 ASSERT_SENTINEL(zh0, ZBH);
408 zh = zh1;
409 } else if (zh1->size != 0) { /* buddy1 in use, buddy0 is vacant */
410 ASSERT_SENTINEL(zh1, ZBH);
411 zh = zh0;
412 } else
413 BUG();
414 list_del_init(&zbpg->bud_list);
415 zbud_unbuddied[found_good_buddy].count--;
416 list_add_tail(&zbpg->bud_list, &zbud_buddied_list);
417 zcache_zbud_buddied_count++;
418
419init_zh:
420 SET_SENTINEL(zh, ZBH);
421 zh->size = size;
422 zh->index = index;
423 zh->oid = *oid;
424 zh->pool_id = pool_id;
425 zh->client_id = client_id;
426 to = zbud_data(zh, size);
427 memcpy(to, cdata, size);
428 spin_unlock(&zbpg->lock);
429 spin_unlock(&zbud_budlists_spinlock);
430
431 zbud_cumul_chunk_counts[nchunks]++;
432 atomic_inc(&zcache_zbud_curr_zpages);
433 zcache_zbud_cumul_zpages++;
434 zcache_zbud_curr_zbytes += size;
435 zcache_zbud_cumul_zbytes += size;
436out:
437 return zh;
438}
439
440static int zbud_decompress(struct page *page, struct zbud_hdr *zh)
441{
442 struct zbud_page *zbpg;
443 unsigned budnum = zbud_budnum(zh);
444 unsigned int out_len = PAGE_SIZE;
445 char *to_va, *from_va;
446 unsigned size;
447 int ret = 0;
448
449 zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
450 spin_lock(&zbpg->lock);
451 if (list_empty(&zbpg->bud_list)) {
452 /* ignore zombie page... see zbud_evict_pages() */
453 ret = -EINVAL;
454 goto out;
455 }
456 ASSERT_SENTINEL(zh, ZBH);
457 BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
458 to_va = kmap_atomic(page);
459 size = zh->size;
460 from_va = zbud_data(zh, size);
461 ret = zcache_comp_op(ZCACHE_COMPOP_DECOMPRESS, from_va, size,
462 to_va, &out_len);
463 BUG_ON(ret);
464 BUG_ON(out_len != PAGE_SIZE);
465 kunmap_atomic(to_va);
466out:
467 spin_unlock(&zbpg->lock);
468 return ret;
469}
470
471/*
472 * The following routines handle shrinking of ephemeral pages by evicting
473 * pages "least valuable" first.
474 */
475
476static unsigned long zcache_evicted_raw_pages;
477static unsigned long zcache_evicted_buddied_pages;
478static unsigned long zcache_evicted_unbuddied_pages;
479
480static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id,
481 uint16_t poolid);
482static void zcache_put_pool(struct tmem_pool *pool);
483
484/*
485 * Flush and free all zbuds in a zbpg, then free the pageframe
486 */
487static void zbud_evict_zbpg(struct zbud_page *zbpg)
488{
489 struct zbud_hdr *zh;
490 int i, j;
491 uint32_t pool_id[ZBUD_MAX_BUDS], client_id[ZBUD_MAX_BUDS];
492 uint32_t index[ZBUD_MAX_BUDS];
493 struct tmem_oid oid[ZBUD_MAX_BUDS];
494 struct tmem_pool *pool;
495
496 ASSERT_SPINLOCK(&zbpg->lock);
497 BUG_ON(!list_empty(&zbpg->bud_list));
498 for (i = 0, j = 0; i < ZBUD_MAX_BUDS; i++) {
499 zh = &zbpg->buddy[i];
500 if (zh->size) {
501 client_id[j] = zh->client_id;
502 pool_id[j] = zh->pool_id;
503 oid[j] = zh->oid;
504 index[j] = zh->index;
505 j++;
506 zbud_free(zh);
507 }
508 }
509 spin_unlock(&zbpg->lock);
510 for (i = 0; i < j; i++) {
511 pool = zcache_get_pool_by_id(client_id[i], pool_id[i]);
512 if (pool != NULL) {
513 tmem_flush_page(pool, &oid[i], index[i]);
514 zcache_put_pool(pool);
515 }
516 }
517 ASSERT_SENTINEL(zbpg, ZBPG);
518 spin_lock(&zbpg->lock);
519 zbud_free_raw_page(zbpg);
520}
521
522/*
523 * Free nr pages. This code is funky because we want to hold the locks
524 * protecting various lists for as short a time as possible, and in some
525 * circumstances the list may change asynchronously when the list lock is
526 * not held. In some cases we also trylock not only to avoid waiting on a
527 * page in use by another cpu, but also to avoid potential deadlock due to
528 * lock inversion.
529 */
530static void zbud_evict_pages(int nr)
531{
532 struct zbud_page *zbpg;
533 int i;
534
535 /* first try freeing any pages on unused list */
536retry_unused_list:
537 spin_lock_bh(&zbpg_unused_list_spinlock);
538 if (!list_empty(&zbpg_unused_list)) {
539 /* can't walk list here, since it may change when unlocked */
540 zbpg = list_first_entry(&zbpg_unused_list,
541 struct zbud_page, bud_list);
542 list_del_init(&zbpg->bud_list);
543 zcache_zbpg_unused_list_count--;
544 atomic_dec(&zcache_zbud_curr_raw_pages);
545 spin_unlock_bh(&zbpg_unused_list_spinlock);
546 zcache_free_page(zbpg);
547 zcache_evicted_raw_pages++;
548 if (--nr <= 0)
549 goto out;
550 goto retry_unused_list;
551 }
552 spin_unlock_bh(&zbpg_unused_list_spinlock);
553
554 /* now try freeing unbuddied pages, starting with least space avail */
555 for (i = 0; i < MAX_CHUNK; i++) {
556retry_unbud_list_i:
557 spin_lock_bh(&zbud_budlists_spinlock);
558 if (list_empty(&zbud_unbuddied[i].list)) {
559 spin_unlock_bh(&zbud_budlists_spinlock);
560 continue;
561 }
562 list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) {
563 if (unlikely(!spin_trylock(&zbpg->lock)))
564 continue;
565 list_del_init(&zbpg->bud_list);
566 zbud_unbuddied[i].count--;
567 spin_unlock(&zbud_budlists_spinlock);
568 zcache_evicted_unbuddied_pages++;
569 /* want budlists unlocked when doing zbpg eviction */
570 zbud_evict_zbpg(zbpg);
571 local_bh_enable();
572 if (--nr <= 0)
573 goto out;
574 goto retry_unbud_list_i;
575 }
576 spin_unlock_bh(&zbud_budlists_spinlock);
577 }
578
579 /* as a last resort, free buddied pages */
580retry_bud_list:
581 spin_lock_bh(&zbud_budlists_spinlock);
582 if (list_empty(&zbud_buddied_list)) {
583 spin_unlock_bh(&zbud_budlists_spinlock);
584 goto out;
585 }
586 list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) {
587 if (unlikely(!spin_trylock(&zbpg->lock)))
588 continue;
589 list_del_init(&zbpg->bud_list);
590 zcache_zbud_buddied_count--;
591 spin_unlock(&zbud_budlists_spinlock);
592 zcache_evicted_buddied_pages++;
593 /* want budlists unlocked when doing zbpg eviction */
594 zbud_evict_zbpg(zbpg);
595 local_bh_enable();
596 if (--nr <= 0)
597 goto out;
598 goto retry_bud_list;
599 }
600 spin_unlock_bh(&zbud_budlists_spinlock);
601out:
602 return;
603}
604
605static void zbud_init(void)
606{
607 int i;
608
609 INIT_LIST_HEAD(&zbud_buddied_list);
610 zcache_zbud_buddied_count = 0;
611 for (i = 0; i < NCHUNKS; i++) {
612 INIT_LIST_HEAD(&zbud_unbuddied[i].list);
613 zbud_unbuddied[i].count = 0;
614 }
615}
616
617#ifdef CONFIG_SYSFS
618/*
619 * These sysfs routines show a nice distribution of how many zbpg's are
620 * currently (and have ever been placed) in each unbuddied list. It's fun
621 * to watch but can probably go away before final merge.
622 */
623static int zbud_show_unbuddied_list_counts(char *buf)
624{
625 int i;
626 char *p = buf;
627
628 for (i = 0; i < NCHUNKS; i++)
629 p += sprintf(p, "%u ", zbud_unbuddied[i].count);
630 return p - buf;
631}
632
633static int zbud_show_cumul_chunk_counts(char *buf)
634{
635 unsigned long i, chunks = 0, total_chunks = 0, sum_total_chunks = 0;
636 unsigned long total_chunks_lte_21 = 0, total_chunks_lte_32 = 0;
637 unsigned long total_chunks_lte_42 = 0;
638 char *p = buf;
639
640 for (i = 0; i < NCHUNKS; i++) {
641 p += sprintf(p, "%lu ", zbud_cumul_chunk_counts[i]);
642 chunks += zbud_cumul_chunk_counts[i];
643 total_chunks += zbud_cumul_chunk_counts[i];
644 sum_total_chunks += i * zbud_cumul_chunk_counts[i];
645 if (i == 21)
646 total_chunks_lte_21 = total_chunks;
647 if (i == 32)
648 total_chunks_lte_32 = total_chunks;
649 if (i == 42)
650 total_chunks_lte_42 = total_chunks;
651 }
652 p += sprintf(p, "<=21:%lu <=32:%lu <=42:%lu, mean:%lu\n",
653 total_chunks_lte_21, total_chunks_lte_32, total_chunks_lte_42,
654 chunks == 0 ? 0 : sum_total_chunks / chunks);
655 return p - buf;
656}
657#endif
658
659/**********
660 * This "zv" PAM implementation combines the slab-based zsmalloc
661 * with the crypto compression API to maximize the amount of data that can
662 * be packed into a physical page.
663 *
664 * Zv represents a PAM page with the index and object (plus a "size" value
665 * necessary for decompression) immediately preceding the compressed data.
666 */
667
668#define ZVH_SENTINEL 0x43214321
669
670struct zv_hdr {
671 uint32_t pool_id;
672 struct tmem_oid oid;
673 uint32_t index;
674 size_t size;
675 DECL_SENTINEL
676};
677
678/* rudimentary policy limits */
679/* total number of persistent pages may not exceed this percentage */
680static unsigned int zv_page_count_policy_percent = 75;
681/*
682 * byte count defining poor compression; pages with greater zsize will be
683 * rejected
684 */
685static unsigned int zv_max_zsize = (PAGE_SIZE / 8) * 7;
686/*
687 * byte count defining poor *mean* compression; pages with greater zsize
688 * will be rejected until sufficient better-compressed pages are accepted
689 * driving the mean below this threshold
690 */
691static unsigned int zv_max_mean_zsize = (PAGE_SIZE / 8) * 5;
692
693static atomic_t zv_curr_dist_counts[NCHUNKS];
694static atomic_t zv_cumul_dist_counts[NCHUNKS];
695
696static struct zv_hdr *zv_create(struct zs_pool *pool, uint32_t pool_id,
697 struct tmem_oid *oid, uint32_t index,
698 void *cdata, unsigned clen)
699{
700 struct zv_hdr *zv;
701 u32 size = clen + sizeof(struct zv_hdr);
702 int chunks = (size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
703 void *handle = NULL;
704
705 BUG_ON(!irqs_disabled());
706 BUG_ON(chunks >= NCHUNKS);
707 handle = zs_malloc(pool, size);
708 if (!handle)
709 goto out;
710 atomic_inc(&zv_curr_dist_counts[chunks]);
711 atomic_inc(&zv_cumul_dist_counts[chunks]);
712 zv = zs_map_object(pool, handle);
713 zv->index = index;
714 zv->oid = *oid;
715 zv->pool_id = pool_id;
716 zv->size = clen;
717 SET_SENTINEL(zv, ZVH);
718 memcpy((char *)zv + sizeof(struct zv_hdr), cdata, clen);
719 zs_unmap_object(pool, handle);
720out:
721 return handle;
722}
723
724static void zv_free(struct zs_pool *pool, void *handle)
725{
726 unsigned long flags;
727 struct zv_hdr *zv;
728 uint16_t size;
729 int chunks;
730
731 zv = zs_map_object(pool, handle);
732 ASSERT_SENTINEL(zv, ZVH);
733 size = zv->size + sizeof(struct zv_hdr);
734 INVERT_SENTINEL(zv, ZVH);
735 zs_unmap_object(pool, handle);
736
737 chunks = (size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
738 BUG_ON(chunks >= NCHUNKS);
739 atomic_dec(&zv_curr_dist_counts[chunks]);
740
741 local_irq_save(flags);
742 zs_free(pool, handle);
743 local_irq_restore(flags);
744}
745
746static void zv_decompress(struct page *page, void *handle)
747{
748 unsigned int clen = PAGE_SIZE;
749 char *to_va;
750 int ret;
751 struct zv_hdr *zv;
752
753 zv = zs_map_object(zcache_host.zspool, handle);
754 BUG_ON(zv->size == 0);
755 ASSERT_SENTINEL(zv, ZVH);
756 to_va = kmap_atomic(page);
757 ret = zcache_comp_op(ZCACHE_COMPOP_DECOMPRESS, (char *)zv + sizeof(*zv),
758 zv->size, to_va, &clen);
759 kunmap_atomic(to_va);
760 zs_unmap_object(zcache_host.zspool, handle);
761 BUG_ON(ret);
762 BUG_ON(clen != PAGE_SIZE);
763}
764
765#ifdef CONFIG_SYSFS
766/*
767 * show a distribution of compression stats for zv pages.
768 */
769
770static int zv_curr_dist_counts_show(char *buf)
771{
772 unsigned long i, n, chunks = 0, sum_total_chunks = 0;
773 char *p = buf;
774
775 for (i = 0; i < NCHUNKS; i++) {
776 n = atomic_read(&zv_curr_dist_counts[i]);
777 p += sprintf(p, "%lu ", n);
778 chunks += n;
779 sum_total_chunks += i * n;
780 }
781 p += sprintf(p, "mean:%lu\n",
782 chunks == 0 ? 0 : sum_total_chunks / chunks);
783 return p - buf;
784}
785
786static int zv_cumul_dist_counts_show(char *buf)
787{
788 unsigned long i, n, chunks = 0, sum_total_chunks = 0;
789 char *p = buf;
790
791 for (i = 0; i < NCHUNKS; i++) {
792 n = atomic_read(&zv_cumul_dist_counts[i]);
793 p += sprintf(p, "%lu ", n);
794 chunks += n;
795 sum_total_chunks += i * n;
796 }
797 p += sprintf(p, "mean:%lu\n",
798 chunks == 0 ? 0 : sum_total_chunks / chunks);
799 return p - buf;
800}
801
802/*
803 * setting zv_max_zsize via sysfs causes all persistent (e.g. swap)
804 * pages that don't compress to less than this value (including metadata
805 * overhead) to be rejected. We don't allow the value to get too close
806 * to PAGE_SIZE.
807 */
808static ssize_t zv_max_zsize_show(struct kobject *kobj,
809 struct kobj_attribute *attr,
810 char *buf)
811{
812 return sprintf(buf, "%u\n", zv_max_zsize);
813}
814
815static ssize_t zv_max_zsize_store(struct kobject *kobj,
816 struct kobj_attribute *attr,
817 const char *buf, size_t count)
818{
819 unsigned long val;
820 int err;
821
822 if (!capable(CAP_SYS_ADMIN))
823 return -EPERM;
824
825 err = kstrtoul(buf, 10, &val);
826 if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
827 return -EINVAL;
828 zv_max_zsize = val;
829 return count;
830}
831
832/*
833 * setting zv_max_mean_zsize via sysfs causes all persistent (e.g. swap)
834 * pages that don't compress to less than this value (including metadata
835 * overhead) to be rejected UNLESS the mean compression is also smaller
836 * than this value. In other words, we are load-balancing-by-zsize the
837 * accepted pages. Again, we don't allow the value to get too close
838 * to PAGE_SIZE.
839 */
840static ssize_t zv_max_mean_zsize_show(struct kobject *kobj,
841 struct kobj_attribute *attr,
842 char *buf)
843{
844 return sprintf(buf, "%u\n", zv_max_mean_zsize);
845}
846
847static ssize_t zv_max_mean_zsize_store(struct kobject *kobj,
848 struct kobj_attribute *attr,
849 const char *buf, size_t count)
850{
851 unsigned long val;
852 int err;
853
854 if (!capable(CAP_SYS_ADMIN))
855 return -EPERM;
856
857 err = kstrtoul(buf, 10, &val);
858 if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
859 return -EINVAL;
860 zv_max_mean_zsize = val;
861 return count;
862}
863
864/*
865 * setting zv_page_count_policy_percent via sysfs sets an upper bound of
866 * persistent (e.g. swap) pages that will be retained according to:
867 * (zv_page_count_policy_percent * totalram_pages) / 100)
868 * when that limit is reached, further puts will be rejected (until
869 * some pages have been flushed). Note that, due to compression,
870 * this number may exceed 100; it defaults to 75 and we set an
871 * arbitary limit of 150. A poor choice will almost certainly result
872 * in OOM's, so this value should only be changed prudently.
873 */
874static ssize_t zv_page_count_policy_percent_show(struct kobject *kobj,
875 struct kobj_attribute *attr,
876 char *buf)
877{
878 return sprintf(buf, "%u\n", zv_page_count_policy_percent);
879}
880
881static ssize_t zv_page_count_policy_percent_store(struct kobject *kobj,
882 struct kobj_attribute *attr,
883 const char *buf, size_t count)
884{
885 unsigned long val;
886 int err;
887
888 if (!capable(CAP_SYS_ADMIN))
889 return -EPERM;
890
891 err = kstrtoul(buf, 10, &val);
892 if (err || (val == 0) || (val > 150))
893 return -EINVAL;
894 zv_page_count_policy_percent = val;
895 return count;
896}
897
898static struct kobj_attribute zcache_zv_max_zsize_attr = {
899 .attr = { .name = "zv_max_zsize", .mode = 0644 },
900 .show = zv_max_zsize_show,
901 .store = zv_max_zsize_store,
902};
903
904static struct kobj_attribute zcache_zv_max_mean_zsize_attr = {
905 .attr = { .name = "zv_max_mean_zsize", .mode = 0644 },
906 .show = zv_max_mean_zsize_show,
907 .store = zv_max_mean_zsize_store,
908};
909
910static struct kobj_attribute zcache_zv_page_count_policy_percent_attr = {
911 .attr = { .name = "zv_page_count_policy_percent",
912 .mode = 0644 },
913 .show = zv_page_count_policy_percent_show,
914 .store = zv_page_count_policy_percent_store,
915};
916#endif
917
918/*
919 * zcache core code starts here
920 */
921
922/* useful stats not collected by cleancache or frontswap */
923static unsigned long zcache_flush_total;
924static unsigned long zcache_flush_found;
925static unsigned long zcache_flobj_total;
926static unsigned long zcache_flobj_found;
927static unsigned long zcache_failed_eph_puts;
928static unsigned long zcache_failed_pers_puts;
929
930/*
931 * Tmem operations assume the poolid implies the invoking client.
932 * Zcache only has one client (the kernel itself): LOCAL_CLIENT.
933 * RAMster has each client numbered by cluster node, and a KVM version
934 * of zcache would have one client per guest and each client might
935 * have a poolid==N.
936 */
937static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id, uint16_t poolid)
938{
939 struct tmem_pool *pool = NULL;
940 struct zcache_client *cli = NULL;
941
942 if (cli_id == LOCAL_CLIENT)
943 cli = &zcache_host;
944 else {
945 if (cli_id >= MAX_CLIENTS)
946 goto out;
947 cli = &zcache_clients[cli_id];
948 if (cli == NULL)
949 goto out;
950 atomic_inc(&cli->refcount);
951 }
952 if (poolid < MAX_POOLS_PER_CLIENT) {
953 pool = cli->tmem_pools[poolid];
954 if (pool != NULL)
955 atomic_inc(&pool->refcount);
956 }
957out:
958 return pool;
959}
960
961static void zcache_put_pool(struct tmem_pool *pool)
962{
963 struct zcache_client *cli = NULL;
964
965 if (pool == NULL)
966 BUG();
967 cli = pool->client;
968 atomic_dec(&pool->refcount);
969 atomic_dec(&cli->refcount);
970}
971
972int zcache_new_client(uint16_t cli_id)
973{
974 struct zcache_client *cli = NULL;
975 int ret = -1;
976
977 if (cli_id == LOCAL_CLIENT)
978 cli = &zcache_host;
979 else if ((unsigned int)cli_id < MAX_CLIENTS)
980 cli = &zcache_clients[cli_id];
981 if (cli == NULL)
982 goto out;
983 if (cli->allocated)
984 goto out;
985 cli->allocated = 1;
986#ifdef CONFIG_FRONTSWAP
987 cli->zspool = zs_create_pool("zcache", ZCACHE_GFP_MASK);
988 if (cli->zspool == NULL)
989 goto out;
990#endif
991 ret = 0;
992out:
993 return ret;
994}
995
996/* counters for debugging */
997static unsigned long zcache_failed_get_free_pages;
998static unsigned long zcache_failed_alloc;
999static unsigned long zcache_put_to_flush;
1000
1001/*
1002 * for now, used named slabs so can easily track usage; later can
1003 * either just use kmalloc, or perhaps add a slab-like allocator
1004 * to more carefully manage total memory utilization
1005 */
1006static struct kmem_cache *zcache_objnode_cache;
1007static struct kmem_cache *zcache_obj_cache;
1008static atomic_t zcache_curr_obj_count = ATOMIC_INIT(0);
1009static unsigned long zcache_curr_obj_count_max;
1010static atomic_t zcache_curr_objnode_count = ATOMIC_INIT(0);
1011static unsigned long zcache_curr_objnode_count_max;
1012
1013/*
1014 * to avoid memory allocation recursion (e.g. due to direct reclaim), we
1015 * preload all necessary data structures so the hostops callbacks never
1016 * actually do a malloc
1017 */
1018struct zcache_preload {
1019 void *page;
1020 struct tmem_obj *obj;
1021 int nr;
1022 struct tmem_objnode *objnodes[OBJNODE_TREE_MAX_PATH];
1023};
1024static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, };
1025
1026static int zcache_do_preload(struct tmem_pool *pool)
1027{
1028 struct zcache_preload *kp;
1029 struct tmem_objnode *objnode;
1030 struct tmem_obj *obj;
1031 void *page;
1032 int ret = -ENOMEM;
1033
1034 if (unlikely(zcache_objnode_cache == NULL))
1035 goto out;
1036 if (unlikely(zcache_obj_cache == NULL))
1037 goto out;
1038 preempt_disable();
1039 kp = &__get_cpu_var(zcache_preloads);
1040 while (kp->nr < ARRAY_SIZE(kp->objnodes)) {
1041 preempt_enable_no_resched();
1042 objnode = kmem_cache_alloc(zcache_objnode_cache,
1043 ZCACHE_GFP_MASK);
1044 if (unlikely(objnode == NULL)) {
1045 zcache_failed_alloc++;
1046 goto out;
1047 }
1048 preempt_disable();
1049 kp = &__get_cpu_var(zcache_preloads);
1050 if (kp->nr < ARRAY_SIZE(kp->objnodes))
1051 kp->objnodes[kp->nr++] = objnode;
1052 else
1053 kmem_cache_free(zcache_objnode_cache, objnode);
1054 }
1055 preempt_enable_no_resched();
1056 obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK);
1057 if (unlikely(obj == NULL)) {
1058 zcache_failed_alloc++;
1059 goto out;
1060 }
1061 page = (void *)__get_free_page(ZCACHE_GFP_MASK);
1062 if (unlikely(page == NULL)) {
1063 zcache_failed_get_free_pages++;
1064 kmem_cache_free(zcache_obj_cache, obj);
1065 goto out;
1066 }
1067 preempt_disable();
1068 kp = &__get_cpu_var(zcache_preloads);
1069 if (kp->obj == NULL)
1070 kp->obj = obj;
1071 else
1072 kmem_cache_free(zcache_obj_cache, obj);
1073 if (kp->page == NULL)
1074 kp->page = page;
1075 else
1076 free_page((unsigned long)page);
1077 ret = 0;
1078out:
1079 return ret;
1080}
1081
1082static void *zcache_get_free_page(void)
1083{
1084 struct zcache_preload *kp;
1085 void *page;
1086
1087 kp = &__get_cpu_var(zcache_preloads);
1088 page = kp->page;
1089 BUG_ON(page == NULL);
1090 kp->page = NULL;
1091 return page;
1092}
1093
1094static void zcache_free_page(void *p)
1095{
1096 free_page((unsigned long)p);
1097}
1098
1099/*
1100 * zcache implementation for tmem host ops
1101 */
1102
1103static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool)
1104{
1105 struct tmem_objnode *objnode = NULL;
1106 unsigned long count;
1107 struct zcache_preload *kp;
1108
1109 kp = &__get_cpu_var(zcache_preloads);
1110 if (kp->nr <= 0)
1111 goto out;
1112 objnode = kp->objnodes[kp->nr - 1];
1113 BUG_ON(objnode == NULL);
1114 kp->objnodes[kp->nr - 1] = NULL;
1115 kp->nr--;
1116 count = atomic_inc_return(&zcache_curr_objnode_count);
1117 if (count > zcache_curr_objnode_count_max)
1118 zcache_curr_objnode_count_max = count;
1119out:
1120 return objnode;
1121}
1122
1123static void zcache_objnode_free(struct tmem_objnode *objnode,
1124 struct tmem_pool *pool)
1125{
1126 atomic_dec(&zcache_curr_objnode_count);
1127 BUG_ON(atomic_read(&zcache_curr_objnode_count) < 0);
1128 kmem_cache_free(zcache_objnode_cache, objnode);
1129}
1130
1131static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool)
1132{
1133 struct tmem_obj *obj = NULL;
1134 unsigned long count;
1135 struct zcache_preload *kp;
1136
1137 kp = &__get_cpu_var(zcache_preloads);
1138 obj = kp->obj;
1139 BUG_ON(obj == NULL);
1140 kp->obj = NULL;
1141 count = atomic_inc_return(&zcache_curr_obj_count);
1142 if (count > zcache_curr_obj_count_max)
1143 zcache_curr_obj_count_max = count;
1144 return obj;
1145}
1146
1147static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool)
1148{
1149 atomic_dec(&zcache_curr_obj_count);
1150 BUG_ON(atomic_read(&zcache_curr_obj_count) < 0);
1151 kmem_cache_free(zcache_obj_cache, obj);
1152}
1153
1154static struct tmem_hostops zcache_hostops = {
1155 .obj_alloc = zcache_obj_alloc,
1156 .obj_free = zcache_obj_free,
1157 .objnode_alloc = zcache_objnode_alloc,
1158 .objnode_free = zcache_objnode_free,
1159};
1160
1161/*
1162 * zcache implementations for PAM page descriptor ops
1163 */
1164
1165static atomic_t zcache_curr_eph_pampd_count = ATOMIC_INIT(0);
1166static unsigned long zcache_curr_eph_pampd_count_max;
1167static atomic_t zcache_curr_pers_pampd_count = ATOMIC_INIT(0);
1168static unsigned long zcache_curr_pers_pampd_count_max;
1169
1170/* forward reference */
1171static int zcache_compress(struct page *from, void **out_va, unsigned *out_len);
1172
1173static void *zcache_pampd_create(char *data, size_t size, bool raw, int eph,
1174 struct tmem_pool *pool, struct tmem_oid *oid,
1175 uint32_t index)
1176{
1177 void *pampd = NULL, *cdata;
1178 unsigned clen;
1179 int ret;
1180 unsigned long count;
1181 struct page *page = (struct page *)(data);
1182 struct zcache_client *cli = pool->client;
1183 uint16_t client_id = get_client_id_from_client(cli);
1184 unsigned long zv_mean_zsize;
1185 unsigned long curr_pers_pampd_count;
1186 u64 total_zsize;
1187
1188 if (eph) {
1189 ret = zcache_compress(page, &cdata, &clen);
1190 if (ret == 0)
1191 goto out;
1192 if (clen == 0 || clen > zbud_max_buddy_size()) {
1193 zcache_compress_poor++;
1194 goto out;
1195 }
1196 pampd = (void *)zbud_create(client_id, pool->pool_id, oid,
1197 index, page, cdata, clen);
1198 if (pampd != NULL) {
1199 count = atomic_inc_return(&zcache_curr_eph_pampd_count);
1200 if (count > zcache_curr_eph_pampd_count_max)
1201 zcache_curr_eph_pampd_count_max = count;
1202 }
1203 } else {
1204 curr_pers_pampd_count =
1205 atomic_read(&zcache_curr_pers_pampd_count);
1206 if (curr_pers_pampd_count >
1207 (zv_page_count_policy_percent * totalram_pages) / 100)
1208 goto out;
1209 ret = zcache_compress(page, &cdata, &clen);
1210 if (ret == 0)
1211 goto out;
1212 /* reject if compression is too poor */
1213 if (clen > zv_max_zsize) {
1214 zcache_compress_poor++;
1215 goto out;
1216 }
1217 /* reject if mean compression is too poor */
1218 if ((clen > zv_max_mean_zsize) && (curr_pers_pampd_count > 0)) {
1219 total_zsize = zs_get_total_size_bytes(cli->zspool);
1220 zv_mean_zsize = div_u64(total_zsize,
1221 curr_pers_pampd_count);
1222 if (zv_mean_zsize > zv_max_mean_zsize) {
1223 zcache_mean_compress_poor++;
1224 goto out;
1225 }
1226 }
1227 pampd = (void *)zv_create(cli->zspool, pool->pool_id,
1228 oid, index, cdata, clen);
1229 if (pampd == NULL)
1230 goto out;
1231 count = atomic_inc_return(&zcache_curr_pers_pampd_count);
1232 if (count > zcache_curr_pers_pampd_count_max)
1233 zcache_curr_pers_pampd_count_max = count;
1234 }
1235out:
1236 return pampd;
1237}
1238
1239/*
1240 * fill the pageframe corresponding to the struct page with the data
1241 * from the passed pampd
1242 */
1243static int zcache_pampd_get_data(char *data, size_t *bufsize, bool raw,
1244 void *pampd, struct tmem_pool *pool,
1245 struct tmem_oid *oid, uint32_t index)
1246{
1247 int ret = 0;
1248
1249 BUG_ON(is_ephemeral(pool));
1250 zv_decompress((struct page *)(data), pampd);
1251 return ret;
1252}
1253
1254/*
1255 * fill the pageframe corresponding to the struct page with the data
1256 * from the passed pampd
1257 */
1258static int zcache_pampd_get_data_and_free(char *data, size_t *bufsize, bool raw,
1259 void *pampd, struct tmem_pool *pool,
1260 struct tmem_oid *oid, uint32_t index)
1261{
1262 BUG_ON(!is_ephemeral(pool));
1263 if (zbud_decompress((struct page *)(data), pampd) < 0)
1264 return -EINVAL;
1265 zbud_free_and_delist((struct zbud_hdr *)pampd);
1266 atomic_dec(&zcache_curr_eph_pampd_count);
1267 return 0;
1268}
1269
1270/*
1271 * free the pampd and remove it from any zcache lists
1272 * pampd must no longer be pointed to from any tmem data structures!
1273 */
1274static void zcache_pampd_free(void *pampd, struct tmem_pool *pool,
1275 struct tmem_oid *oid, uint32_t index)
1276{
1277 struct zcache_client *cli = pool->client;
1278
1279 if (is_ephemeral(pool)) {
1280 zbud_free_and_delist((struct zbud_hdr *)pampd);
1281 atomic_dec(&zcache_curr_eph_pampd_count);
1282 BUG_ON(atomic_read(&zcache_curr_eph_pampd_count) < 0);
1283 } else {
1284 zv_free(cli->zspool, pampd);
1285 atomic_dec(&zcache_curr_pers_pampd_count);
1286 BUG_ON(atomic_read(&zcache_curr_pers_pampd_count) < 0);
1287 }
1288}
1289
1290static void zcache_pampd_free_obj(struct tmem_pool *pool, struct tmem_obj *obj)
1291{
1292}
1293
1294static void zcache_pampd_new_obj(struct tmem_obj *obj)
1295{
1296}
1297
1298static int zcache_pampd_replace_in_obj(void *pampd, struct tmem_obj *obj)
1299{
1300 return -1;
1301}
1302
1303static bool zcache_pampd_is_remote(void *pampd)
1304{
1305 return 0;
1306}
1307
1308static struct tmem_pamops zcache_pamops = {
1309 .create = zcache_pampd_create,
1310 .get_data = zcache_pampd_get_data,
1311 .get_data_and_free = zcache_pampd_get_data_and_free,
1312 .free = zcache_pampd_free,
1313 .free_obj = zcache_pampd_free_obj,
1314 .new_obj = zcache_pampd_new_obj,
1315 .replace_in_obj = zcache_pampd_replace_in_obj,
1316 .is_remote = zcache_pampd_is_remote,
1317};
1318
1319/*
1320 * zcache compression/decompression and related per-cpu stuff
1321 */
1322
1323static DEFINE_PER_CPU(unsigned char *, zcache_dstmem);
1324#define ZCACHE_DSTMEM_ORDER 1
1325
1326static int zcache_compress(struct page *from, void **out_va, unsigned *out_len)
1327{
1328 int ret = 0;
1329 unsigned char *dmem = __get_cpu_var(zcache_dstmem);
1330 char *from_va;
1331
1332 BUG_ON(!irqs_disabled());
1333 if (unlikely(dmem == NULL))
1334 goto out; /* no buffer or no compressor so can't compress */
1335 *out_len = PAGE_SIZE << ZCACHE_DSTMEM_ORDER;
1336 from_va = kmap_atomic(from);
1337 mb();
1338 ret = zcache_comp_op(ZCACHE_COMPOP_COMPRESS, from_va, PAGE_SIZE, dmem,
1339 out_len);
1340 BUG_ON(ret);
1341 *out_va = dmem;
1342 kunmap_atomic(from_va);
1343 ret = 1;
1344out:
1345 return ret;
1346}
1347
1348static int zcache_comp_cpu_up(int cpu)
1349{
1350 struct crypto_comp *tfm;
1351
1352 tfm = crypto_alloc_comp(zcache_comp_name, 0, 0);
1353 if (IS_ERR(tfm))
1354 return NOTIFY_BAD;
1355 *per_cpu_ptr(zcache_comp_pcpu_tfms, cpu) = tfm;
1356 return NOTIFY_OK;
1357}
1358
1359static void zcache_comp_cpu_down(int cpu)
1360{
1361 struct crypto_comp *tfm;
1362
1363 tfm = *per_cpu_ptr(zcache_comp_pcpu_tfms, cpu);
1364 crypto_free_comp(tfm);
1365 *per_cpu_ptr(zcache_comp_pcpu_tfms, cpu) = NULL;
1366}
1367
1368static int zcache_cpu_notifier(struct notifier_block *nb,
1369 unsigned long action, void *pcpu)
1370{
1371 int ret, cpu = (long)pcpu;
1372 struct zcache_preload *kp;
1373
1374 switch (action) {
1375 case CPU_UP_PREPARE:
1376 ret = zcache_comp_cpu_up(cpu);
1377 if (ret != NOTIFY_OK) {
1378 pr_err("zcache: can't allocate compressor transform\n");
1379 return ret;
1380 }
1381 per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages(
1382 GFP_KERNEL | __GFP_REPEAT, ZCACHE_DSTMEM_ORDER);
1383 break;
1384 case CPU_DEAD:
1385 case CPU_UP_CANCELED:
1386 zcache_comp_cpu_down(cpu);
1387 free_pages((unsigned long)per_cpu(zcache_dstmem, cpu),
1388 ZCACHE_DSTMEM_ORDER);
1389 per_cpu(zcache_dstmem, cpu) = NULL;
1390 kp = &per_cpu(zcache_preloads, cpu);
1391 while (kp->nr) {
1392 kmem_cache_free(zcache_objnode_cache,
1393 kp->objnodes[kp->nr - 1]);
1394 kp->objnodes[kp->nr - 1] = NULL;
1395 kp->nr--;
1396 }
1397 if (kp->obj) {
1398 kmem_cache_free(zcache_obj_cache, kp->obj);
1399 kp->obj = NULL;
1400 }
1401 if (kp->page) {
1402 free_page((unsigned long)kp->page);
1403 kp->page = NULL;
1404 }
1405 break;
1406 default:
1407 break;
1408 }
1409 return NOTIFY_OK;
1410}
1411
1412static struct notifier_block zcache_cpu_notifier_block = {
1413 .notifier_call = zcache_cpu_notifier
1414};
1415
1416#ifdef CONFIG_SYSFS
1417#define ZCACHE_SYSFS_RO(_name) \
1418 static ssize_t zcache_##_name##_show(struct kobject *kobj, \
1419 struct kobj_attribute *attr, char *buf) \
1420 { \
1421 return sprintf(buf, "%lu\n", zcache_##_name); \
1422 } \
1423 static struct kobj_attribute zcache_##_name##_attr = { \
1424 .attr = { .name = __stringify(_name), .mode = 0444 }, \
1425 .show = zcache_##_name##_show, \
1426 }
1427
1428#define ZCACHE_SYSFS_RO_ATOMIC(_name) \
1429 static ssize_t zcache_##_name##_show(struct kobject *kobj, \
1430 struct kobj_attribute *attr, char *buf) \
1431 { \
1432 return sprintf(buf, "%d\n", atomic_read(&zcache_##_name)); \
1433 } \
1434 static struct kobj_attribute zcache_##_name##_attr = { \
1435 .attr = { .name = __stringify(_name), .mode = 0444 }, \
1436 .show = zcache_##_name##_show, \
1437 }
1438
1439#define ZCACHE_SYSFS_RO_CUSTOM(_name, _func) \
1440 static ssize_t zcache_##_name##_show(struct kobject *kobj, \
1441 struct kobj_attribute *attr, char *buf) \
1442 { \
1443 return _func(buf); \
1444 } \
1445 static struct kobj_attribute zcache_##_name##_attr = { \
1446 .attr = { .name = __stringify(_name), .mode = 0444 }, \
1447 .show = zcache_##_name##_show, \
1448 }
1449
1450ZCACHE_SYSFS_RO(curr_obj_count_max);
1451ZCACHE_SYSFS_RO(curr_objnode_count_max);
1452ZCACHE_SYSFS_RO(flush_total);
1453ZCACHE_SYSFS_RO(flush_found);
1454ZCACHE_SYSFS_RO(flobj_total);
1455ZCACHE_SYSFS_RO(flobj_found);
1456ZCACHE_SYSFS_RO(failed_eph_puts);
1457ZCACHE_SYSFS_RO(failed_pers_puts);
1458ZCACHE_SYSFS_RO(zbud_curr_zbytes);
1459ZCACHE_SYSFS_RO(zbud_cumul_zpages);
1460ZCACHE_SYSFS_RO(zbud_cumul_zbytes);
1461ZCACHE_SYSFS_RO(zbud_buddied_count);
1462ZCACHE_SYSFS_RO(zbpg_unused_list_count);
1463ZCACHE_SYSFS_RO(evicted_raw_pages);
1464ZCACHE_SYSFS_RO(evicted_unbuddied_pages);
1465ZCACHE_SYSFS_RO(evicted_buddied_pages);
1466ZCACHE_SYSFS_RO(failed_get_free_pages);
1467ZCACHE_SYSFS_RO(failed_alloc);
1468ZCACHE_SYSFS_RO(put_to_flush);
1469ZCACHE_SYSFS_RO(compress_poor);
1470ZCACHE_SYSFS_RO(mean_compress_poor);
1471ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_raw_pages);
1472ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_zpages);
1473ZCACHE_SYSFS_RO_ATOMIC(curr_obj_count);
1474ZCACHE_SYSFS_RO_ATOMIC(curr_objnode_count);
1475ZCACHE_SYSFS_RO_CUSTOM(zbud_unbuddied_list_counts,
1476 zbud_show_unbuddied_list_counts);
1477ZCACHE_SYSFS_RO_CUSTOM(zbud_cumul_chunk_counts,
1478 zbud_show_cumul_chunk_counts);
1479ZCACHE_SYSFS_RO_CUSTOM(zv_curr_dist_counts,
1480 zv_curr_dist_counts_show);
1481ZCACHE_SYSFS_RO_CUSTOM(zv_cumul_dist_counts,
1482 zv_cumul_dist_counts_show);
1483
1484static struct attribute *zcache_attrs[] = {
1485 &zcache_curr_obj_count_attr.attr,
1486 &zcache_curr_obj_count_max_attr.attr,
1487 &zcache_curr_objnode_count_attr.attr,
1488 &zcache_curr_objnode_count_max_attr.attr,
1489 &zcache_flush_total_attr.attr,
1490 &zcache_flobj_total_attr.attr,
1491 &zcache_flush_found_attr.attr,
1492 &zcache_flobj_found_attr.attr,
1493 &zcache_failed_eph_puts_attr.attr,
1494 &zcache_failed_pers_puts_attr.attr,
1495 &zcache_compress_poor_attr.attr,
1496 &zcache_mean_compress_poor_attr.attr,
1497 &zcache_zbud_curr_raw_pages_attr.attr,
1498 &zcache_zbud_curr_zpages_attr.attr,
1499 &zcache_zbud_curr_zbytes_attr.attr,
1500 &zcache_zbud_cumul_zpages_attr.attr,
1501 &zcache_zbud_cumul_zbytes_attr.attr,
1502 &zcache_zbud_buddied_count_attr.attr,
1503 &zcache_zbpg_unused_list_count_attr.attr,
1504 &zcache_evicted_raw_pages_attr.attr,
1505 &zcache_evicted_unbuddied_pages_attr.attr,
1506 &zcache_evicted_buddied_pages_attr.attr,
1507 &zcache_failed_get_free_pages_attr.attr,
1508 &zcache_failed_alloc_attr.attr,
1509 &zcache_put_to_flush_attr.attr,
1510 &zcache_zbud_unbuddied_list_counts_attr.attr,
1511 &zcache_zbud_cumul_chunk_counts_attr.attr,
1512 &zcache_zv_curr_dist_counts_attr.attr,
1513 &zcache_zv_cumul_dist_counts_attr.attr,
1514 &zcache_zv_max_zsize_attr.attr,
1515 &zcache_zv_max_mean_zsize_attr.attr,
1516 &zcache_zv_page_count_policy_percent_attr.attr,
1517 NULL,
1518};
1519
1520static struct attribute_group zcache_attr_group = {
1521 .attrs = zcache_attrs,
1522 .name = "zcache",
1523};
1524
1525#endif /* CONFIG_SYSFS */
1526/*
1527 * When zcache is disabled ("frozen"), pools can be created and destroyed,
1528 * but all puts (and thus all other operations that require memory allocation)
1529 * must fail. If zcache is unfrozen, accepts puts, then frozen again,
1530 * data consistency requires all puts while frozen to be converted into
1531 * flushes.
1532 */
1533static bool zcache_freeze;
1534
1535/*
1536 * zcache shrinker interface (only useful for ephemeral pages, so zbud only)
1537 */
1538static int shrink_zcache_memory(struct shrinker *shrink,
1539 struct shrink_control *sc)
1540{
1541 int ret = -1;
1542 int nr = sc->nr_to_scan;
1543 gfp_t gfp_mask = sc->gfp_mask;
1544
1545 if (nr >= 0) {
1546 if (!(gfp_mask & __GFP_FS))
1547 /* does this case really need to be skipped? */
1548 goto out;
1549 zbud_evict_pages(nr);
1550 }
1551 ret = (int)atomic_read(&zcache_zbud_curr_raw_pages);
1552out:
1553 return ret;
1554}
1555
1556static struct shrinker zcache_shrinker = {
1557 .shrink = shrink_zcache_memory,
1558 .seeks = DEFAULT_SEEKS,
1559};
1560
1561/*
1562 * zcache shims between cleancache/frontswap ops and tmem
1563 */
1564
1565static int zcache_put_page(int cli_id, int pool_id, struct tmem_oid *oidp,
1566 uint32_t index, struct page *page)
1567{
1568 struct tmem_pool *pool;
1569 int ret = -1;
1570
1571 BUG_ON(!irqs_disabled());
1572 pool = zcache_get_pool_by_id(cli_id, pool_id);
1573 if (unlikely(pool == NULL))
1574 goto out;
1575 if (!zcache_freeze && zcache_do_preload(pool) == 0) {
1576 /* preload does preempt_disable on success */
1577 ret = tmem_put(pool, oidp, index, (char *)(page),
1578 PAGE_SIZE, 0, is_ephemeral(pool));
1579 if (ret < 0) {
1580 if (is_ephemeral(pool))
1581 zcache_failed_eph_puts++;
1582 else
1583 zcache_failed_pers_puts++;
1584 }
1585 zcache_put_pool(pool);
1586 preempt_enable_no_resched();
1587 } else {
1588 zcache_put_to_flush++;
1589 if (atomic_read(&pool->obj_count) > 0)
1590 /* the put fails whether the flush succeeds or not */
1591 (void)tmem_flush_page(pool, oidp, index);
1592 zcache_put_pool(pool);
1593 }
1594out:
1595 return ret;
1596}
1597
1598static int zcache_get_page(int cli_id, int pool_id, struct tmem_oid *oidp,
1599 uint32_t index, struct page *page)
1600{
1601 struct tmem_pool *pool;
1602 int ret = -1;
1603 unsigned long flags;
1604 size_t size = PAGE_SIZE;
1605
1606 local_irq_save(flags);
1607 pool = zcache_get_pool_by_id(cli_id, pool_id);
1608 if (likely(pool != NULL)) {
1609 if (atomic_read(&pool->obj_count) > 0)
1610 ret = tmem_get(pool, oidp, index, (char *)(page),
1611 &size, 0, is_ephemeral(pool));
1612 zcache_put_pool(pool);
1613 }
1614 local_irq_restore(flags);
1615 return ret;
1616}
1617
1618static int zcache_flush_page(int cli_id, int pool_id,
1619 struct tmem_oid *oidp, uint32_t index)
1620{
1621 struct tmem_pool *pool;
1622 int ret = -1;
1623 unsigned long flags;
1624
1625 local_irq_save(flags);
1626 zcache_flush_total++;
1627 pool = zcache_get_pool_by_id(cli_id, pool_id);
1628 if (likely(pool != NULL)) {
1629 if (atomic_read(&pool->obj_count) > 0)
1630 ret = tmem_flush_page(pool, oidp, index);
1631 zcache_put_pool(pool);
1632 }
1633 if (ret >= 0)
1634 zcache_flush_found++;
1635 local_irq_restore(flags);
1636 return ret;
1637}
1638
1639static int zcache_flush_object(int cli_id, int pool_id,
1640 struct tmem_oid *oidp)
1641{
1642 struct tmem_pool *pool;
1643 int ret = -1;
1644 unsigned long flags;
1645
1646 local_irq_save(flags);
1647 zcache_flobj_total++;
1648 pool = zcache_get_pool_by_id(cli_id, pool_id);
1649 if (likely(pool != NULL)) {
1650 if (atomic_read(&pool->obj_count) > 0)
1651 ret = tmem_flush_object(pool, oidp);
1652 zcache_put_pool(pool);
1653 }
1654 if (ret >= 0)
1655 zcache_flobj_found++;
1656 local_irq_restore(flags);
1657 return ret;
1658}
1659
1660static int zcache_destroy_pool(int cli_id, int pool_id)
1661{
1662 struct tmem_pool *pool = NULL;
1663 struct zcache_client *cli = NULL;
1664 int ret = -1;
1665
1666 if (pool_id < 0)
1667 goto out;
1668 if (cli_id == LOCAL_CLIENT)
1669 cli = &zcache_host;
1670 else if ((unsigned int)cli_id < MAX_CLIENTS)
1671 cli = &zcache_clients[cli_id];
1672 if (cli == NULL)
1673 goto out;
1674 atomic_inc(&cli->refcount);
1675 pool = cli->tmem_pools[pool_id];
1676 if (pool == NULL)
1677 goto out;
1678 cli->tmem_pools[pool_id] = NULL;
1679 /* wait for pool activity on other cpus to quiesce */
1680 while (atomic_read(&pool->refcount) != 0)
1681 ;
1682 atomic_dec(&cli->refcount);
1683 local_bh_disable();
1684 ret = tmem_destroy_pool(pool);
1685 local_bh_enable();
1686 kfree(pool);
1687 pr_info("zcache: destroyed pool id=%d, cli_id=%d\n",
1688 pool_id, cli_id);
1689out:
1690 return ret;
1691}
1692
1693static int zcache_new_pool(uint16_t cli_id, uint32_t flags)
1694{
1695 int poolid = -1;
1696 struct tmem_pool *pool;
1697 struct zcache_client *cli = NULL;
1698
1699 if (cli_id == LOCAL_CLIENT)
1700 cli = &zcache_host;
1701 else if ((unsigned int)cli_id < MAX_CLIENTS)
1702 cli = &zcache_clients[cli_id];
1703 if (cli == NULL)
1704 goto out;
1705 atomic_inc(&cli->refcount);
1706 pool = kmalloc(sizeof(struct tmem_pool), GFP_ATOMIC);
1707 if (pool == NULL) {
1708 pr_info("zcache: pool creation failed: out of memory\n");
1709 goto out;
1710 }
1711
1712 for (poolid = 0; poolid < MAX_POOLS_PER_CLIENT; poolid++)
1713 if (cli->tmem_pools[poolid] == NULL)
1714 break;
1715 if (poolid >= MAX_POOLS_PER_CLIENT) {
1716 pr_info("zcache: pool creation failed: max exceeded\n");
1717 kfree(pool);
1718 poolid = -1;
1719 goto out;
1720 }
1721 atomic_set(&pool->refcount, 0);
1722 pool->client = cli;
1723 pool->pool_id = poolid;
1724 tmem_new_pool(pool, flags);
1725 cli->tmem_pools[poolid] = pool;
1726 pr_info("zcache: created %s tmem pool, id=%d, client=%d\n",
1727 flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
1728 poolid, cli_id);
1729out:
1730 if (cli != NULL)
1731 atomic_dec(&cli->refcount);
1732 return poolid;
1733}
1734
1735/**********
1736 * Two kernel functionalities currently can be layered on top of tmem.
1737 * These are "cleancache" which is used as a second-chance cache for clean
1738 * page cache pages; and "frontswap" which is used for swap pages
1739 * to avoid writes to disk. A generic "shim" is provided here for each
1740 * to translate in-kernel semantics to zcache semantics.
1741 */
1742
1743#ifdef CONFIG_CLEANCACHE
1744static void zcache_cleancache_put_page(int pool_id,
1745 struct cleancache_filekey key,
1746 pgoff_t index, struct page *page)
1747{
1748 u32 ind = (u32) index;
1749 struct tmem_oid oid = *(struct tmem_oid *)&key;
1750
1751 if (likely(ind == index))
1752 (void)zcache_put_page(LOCAL_CLIENT, pool_id, &oid, index, page);
1753}
1754
1755static int zcache_cleancache_get_page(int pool_id,
1756 struct cleancache_filekey key,
1757 pgoff_t index, struct page *page)
1758{
1759 u32 ind = (u32) index;
1760 struct tmem_oid oid = *(struct tmem_oid *)&key;
1761 int ret = -1;
1762
1763 if (likely(ind == index))
1764 ret = zcache_get_page(LOCAL_CLIENT, pool_id, &oid, index, page);
1765 return ret;
1766}
1767
1768static void zcache_cleancache_flush_page(int pool_id,
1769 struct cleancache_filekey key,
1770 pgoff_t index)
1771{
1772 u32 ind = (u32) index;
1773 struct tmem_oid oid = *(struct tmem_oid *)&key;
1774
1775 if (likely(ind == index))
1776 (void)zcache_flush_page(LOCAL_CLIENT, pool_id, &oid, ind);
1777}
1778
1779static void zcache_cleancache_flush_inode(int pool_id,
1780 struct cleancache_filekey key)
1781{
1782 struct tmem_oid oid = *(struct tmem_oid *)&key;
1783
1784 (void)zcache_flush_object(LOCAL_CLIENT, pool_id, &oid);
1785}
1786
1787static void zcache_cleancache_flush_fs(int pool_id)
1788{
1789 if (pool_id >= 0)
1790 (void)zcache_destroy_pool(LOCAL_CLIENT, pool_id);
1791}
1792
1793static int zcache_cleancache_init_fs(size_t pagesize)
1794{
1795 BUG_ON(sizeof(struct cleancache_filekey) !=
1796 sizeof(struct tmem_oid));
1797 BUG_ON(pagesize != PAGE_SIZE);
1798 return zcache_new_pool(LOCAL_CLIENT, 0);
1799}
1800
1801static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize)
1802{
1803 /* shared pools are unsupported and map to private */
1804 BUG_ON(sizeof(struct cleancache_filekey) !=
1805 sizeof(struct tmem_oid));
1806 BUG_ON(pagesize != PAGE_SIZE);
1807 return zcache_new_pool(LOCAL_CLIENT, 0);
1808}
1809
1810static struct cleancache_ops zcache_cleancache_ops = {
1811 .put_page = zcache_cleancache_put_page,
1812 .get_page = zcache_cleancache_get_page,
1813 .invalidate_page = zcache_cleancache_flush_page,
1814 .invalidate_inode = zcache_cleancache_flush_inode,
1815 .invalidate_fs = zcache_cleancache_flush_fs,
1816 .init_shared_fs = zcache_cleancache_init_shared_fs,
1817 .init_fs = zcache_cleancache_init_fs
1818};
1819
1820struct cleancache_ops zcache_cleancache_register_ops(void)
1821{
1822 struct cleancache_ops old_ops =
1823 cleancache_register_ops(&zcache_cleancache_ops);
1824
1825 return old_ops;
1826}
1827#endif
1828
1829#ifdef CONFIG_FRONTSWAP
1830/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
1831static int zcache_frontswap_poolid = -1;
1832
1833/*
1834 * Swizzling increases objects per swaptype, increasing tmem concurrency
1835 * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
1836 * Setting SWIZ_BITS to 27 basically reconstructs the swap entry from
1837 * frontswap_load(), but has side-effects. Hence using 8.
1838 */
1839#define SWIZ_BITS 8
1840#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
1841#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
1842#define iswiz(_ind) (_ind >> SWIZ_BITS)
1843
1844static inline struct tmem_oid oswiz(unsigned type, u32 ind)
1845{
1846 struct tmem_oid oid = { .oid = { 0 } };
1847 oid.oid[0] = _oswiz(type, ind);
1848 return oid;
1849}
1850
1851static int zcache_frontswap_store(unsigned type, pgoff_t offset,
1852 struct page *page)
1853{
1854 u64 ind64 = (u64)offset;
1855 u32 ind = (u32)offset;
1856 struct tmem_oid oid = oswiz(type, ind);
1857 int ret = -1;
1858 unsigned long flags;
1859
1860 BUG_ON(!PageLocked(page));
1861 if (likely(ind64 == ind)) {
1862 local_irq_save(flags);
1863 ret = zcache_put_page(LOCAL_CLIENT, zcache_frontswap_poolid,
1864 &oid, iswiz(ind), page);
1865 local_irq_restore(flags);
1866 }
1867 return ret;
1868}
1869
1870/* returns 0 if the page was successfully gotten from frontswap, -1 if
1871 * was not present (should never happen!) */
1872static int zcache_frontswap_load(unsigned type, pgoff_t offset,
1873 struct page *page)
1874{
1875 u64 ind64 = (u64)offset;
1876 u32 ind = (u32)offset;
1877 struct tmem_oid oid = oswiz(type, ind);
1878 int ret = -1;
1879
1880 BUG_ON(!PageLocked(page));
1881 if (likely(ind64 == ind))
1882 ret = zcache_get_page(LOCAL_CLIENT, zcache_frontswap_poolid,
1883 &oid, iswiz(ind), page);
1884 return ret;
1885}
1886
1887/* flush a single page from frontswap */
1888static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset)
1889{
1890 u64 ind64 = (u64)offset;
1891 u32 ind = (u32)offset;
1892 struct tmem_oid oid = oswiz(type, ind);
1893
1894 if (likely(ind64 == ind))
1895 (void)zcache_flush_page(LOCAL_CLIENT, zcache_frontswap_poolid,
1896 &oid, iswiz(ind));
1897}
1898
1899/* flush all pages from the passed swaptype */
1900static void zcache_frontswap_flush_area(unsigned type)
1901{
1902 struct tmem_oid oid;
1903 int ind;
1904
1905 for (ind = SWIZ_MASK; ind >= 0; ind--) {
1906 oid = oswiz(type, ind);
1907 (void)zcache_flush_object(LOCAL_CLIENT,
1908 zcache_frontswap_poolid, &oid);
1909 }
1910}
1911
1912static void zcache_frontswap_init(unsigned ignored)
1913{
1914 /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
1915 if (zcache_frontswap_poolid < 0)
1916 zcache_frontswap_poolid =
1917 zcache_new_pool(LOCAL_CLIENT, TMEM_POOL_PERSIST);
1918}
1919
1920static struct frontswap_ops zcache_frontswap_ops = {
1921 .store = zcache_frontswap_store,
1922 .load = zcache_frontswap_load,
1923 .invalidate_page = zcache_frontswap_flush_page,
1924 .invalidate_area = zcache_frontswap_flush_area,
1925 .init = zcache_frontswap_init
1926};
1927
1928struct frontswap_ops zcache_frontswap_register_ops(void)
1929{
1930 struct frontswap_ops old_ops =
1931 frontswap_register_ops(&zcache_frontswap_ops);
1932
1933 return old_ops;
1934}
1935#endif
1936
1937/*
1938 * zcache initialization
1939 * NOTE FOR NOW zcache MUST BE PROVIDED AS A KERNEL BOOT PARAMETER OR
1940 * NOTHING HAPPENS!
1941 */
1942
1943static int zcache_enabled;
1944
1945static int __init enable_zcache(char *s)
1946{
1947 zcache_enabled = 1;
1948 return 1;
1949}
1950__setup("zcache", enable_zcache);
1951
1952/* allow independent dynamic disabling of cleancache and frontswap */
1953
1954static int use_cleancache = 1;
1955
1956static int __init no_cleancache(char *s)
1957{
1958 use_cleancache = 0;
1959 return 1;
1960}
1961
1962__setup("nocleancache", no_cleancache);
1963
1964static int use_frontswap = 1;
1965
1966static int __init no_frontswap(char *s)
1967{
1968 use_frontswap = 0;
1969 return 1;
1970}
1971
1972__setup("nofrontswap", no_frontswap);
1973
1974static int __init enable_zcache_compressor(char *s)
1975{
1976 strncpy(zcache_comp_name, s, ZCACHE_COMP_NAME_SZ);
1977 zcache_enabled = 1;
1978 return 1;
1979}
1980__setup("zcache=", enable_zcache_compressor);
1981
1982
1983static int zcache_comp_init(void)
1984{
1985 int ret = 0;
1986
1987 /* check crypto algorithm */
1988 if (*zcache_comp_name != '\0') {
1989 ret = crypto_has_comp(zcache_comp_name, 0, 0);
1990 if (!ret)
1991 pr_info("zcache: %s not supported\n",
1992 zcache_comp_name);
1993 }
1994 if (!ret)
1995 strcpy(zcache_comp_name, "lzo");
1996 ret = crypto_has_comp(zcache_comp_name, 0, 0);
1997 if (!ret) {
1998 ret = 1;
1999 goto out;
2000 }
2001 pr_info("zcache: using %s compressor\n", zcache_comp_name);
2002
2003 /* alloc percpu transforms */
2004 ret = 0;
2005 zcache_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
2006 if (!zcache_comp_pcpu_tfms)
2007 ret = 1;
2008out:
2009 return ret;
2010}
2011
2012static int __init zcache_init(void)
2013{
2014 int ret = 0;
2015
2016#ifdef CONFIG_SYSFS
2017 ret = sysfs_create_group(mm_kobj, &zcache_attr_group);
2018 if (ret) {
2019 pr_err("zcache: can't create sysfs\n");
2020 goto out;
2021 }
2022#endif /* CONFIG_SYSFS */
2023#if defined(CONFIG_CLEANCACHE) || defined(CONFIG_FRONTSWAP)
2024 if (zcache_enabled) {
2025 unsigned int cpu;
2026
2027 tmem_register_hostops(&zcache_hostops);
2028 tmem_register_pamops(&zcache_pamops);
2029 ret = register_cpu_notifier(&zcache_cpu_notifier_block);
2030 if (ret) {
2031 pr_err("zcache: can't register cpu notifier\n");
2032 goto out;
2033 }
2034 ret = zcache_comp_init();
2035 if (ret) {
2036 pr_err("zcache: compressor initialization failed\n");
2037 goto out;
2038 }
2039 for_each_online_cpu(cpu) {
2040 void *pcpu = (void *)(long)cpu;
2041 zcache_cpu_notifier(&zcache_cpu_notifier_block,
2042 CPU_UP_PREPARE, pcpu);
2043 }
2044 }
2045 zcache_objnode_cache = kmem_cache_create("zcache_objnode",
2046 sizeof(struct tmem_objnode), 0, 0, NULL);
2047 zcache_obj_cache = kmem_cache_create("zcache_obj",
2048 sizeof(struct tmem_obj), 0, 0, NULL);
2049 ret = zcache_new_client(LOCAL_CLIENT);
2050 if (ret) {
2051 pr_err("zcache: can't create client\n");
2052 goto out;
2053 }
2054#endif
2055#ifdef CONFIG_CLEANCACHE
2056 if (zcache_enabled && use_cleancache) {
2057 struct cleancache_ops old_ops;
2058
2059 zbud_init();
2060 register_shrinker(&zcache_shrinker);
2061 old_ops = zcache_cleancache_register_ops();
2062 pr_info("zcache: cleancache enabled using kernel "
2063 "transcendent memory and compression buddies\n");
2064 if (old_ops.init_fs != NULL)
2065 pr_warning("zcache: cleancache_ops overridden");
2066 }
2067#endif
2068#ifdef CONFIG_FRONTSWAP
2069 if (zcache_enabled && use_frontswap) {
2070 struct frontswap_ops old_ops;
2071
2072 old_ops = zcache_frontswap_register_ops();
2073 pr_info("zcache: frontswap enabled using kernel "
2074 "transcendent memory and zsmalloc\n");
2075 if (old_ops.init != NULL)
2076 pr_warning("zcache: frontswap_ops overridden");
2077 }
2078#endif
2079out:
2080 return ret;
2081}
2082
2083module_init(zcache_init)