1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Request reply cache. This is currently a global cache, but this may
4 * change in the future and be a per-client cache.
5 *
6 * This code is heavily inspired by the 44BSD implementation, although
7 * it does things a bit differently.
8 *
9 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
10 */
11
12 #include <linux/sunrpc/svc_xprt.h>
13 #include <linux/slab.h>
14 #include <linux/vmalloc.h>
15 #include <linux/sunrpc/addr.h>
16 #include <linux/highmem.h>
17 #include <linux/log2.h>
18 #include <linux/hash.h>
19 #include <net/checksum.h>
20
21 #include "nfsd.h"
22 #include "cache.h"
23 #include "trace.h"
24
25 /*
26 * We use this value to determine the number of hash buckets from the max
27 * cache size, the idea being that when the cache is at its maximum number
28 * of entries, then this should be the average number of entries per bucket.
29 */
30 #define TARGET_BUCKET_SIZE 64
31
32 struct nfsd_drc_bucket {
33 struct rb_root rb_head;
34 struct list_head lru_head;
35 spinlock_t cache_lock;
36 };
37
38 static struct kmem_cache *drc_slab;
39
40 static int nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *vec);
41 static unsigned long nfsd_reply_cache_count(struct shrinker *shrink,
42 struct shrink_control *sc);
43 static unsigned long nfsd_reply_cache_scan(struct shrinker *shrink,
44 struct shrink_control *sc);
45
46 /*
47 * Put a cap on the size of the DRC based on the amount of available
48 * low memory in the machine.
49 *
50 * 64MB: 8192
51 * 128MB: 11585
52 * 256MB: 16384
53 * 512MB: 23170
54 * 1GB: 32768
55 * 2GB: 46340
56 * 4GB: 65536
57 * 8GB: 92681
58 * 16GB: 131072
59 *
60 * ...with a hard cap of 256k entries. In the worst case, each entry will be
61 * ~1k, so the above numbers should give a rough max of the amount of memory
62 * used in k.
63 *
64 * XXX: these limits are per-container, so memory used will increase
65 * linearly with number of containers. Maybe that's OK.
66 */
67 static unsigned int
68 nfsd_cache_size_limit(void)
69 {
70 unsigned int limit;
71 unsigned long low_pages = totalram_pages() - totalhigh_pages();
72
73 limit = (16 * int_sqrt(low_pages)) << (PAGE_SHIFT-10);
74 return min_t(unsigned int, limit, 256*1024);
75 }
76
77 /*
78 * Compute the number of hash buckets we need. Divide the max cachesize by
79 * the "target" max bucket size, and round up to next power of two.
80 */
81 static unsigned int
82 nfsd_hashsize(unsigned int limit)
83 {
84 return roundup_pow_of_two(limit / TARGET_BUCKET_SIZE);
85 }
86
87 static struct nfsd_cacherep *
88 nfsd_cacherep_alloc(struct svc_rqst *rqstp, __wsum csum,
89 struct nfsd_net *nn)
90 {
91 struct nfsd_cacherep *rp;
92
93 rp = kmem_cache_alloc(drc_slab, GFP_KERNEL);
94 if (rp) {
95 rp->c_state = RC_UNUSED;
96 rp->c_type = RC_NOCACHE;
97 RB_CLEAR_NODE(&rp->c_node);
98 INIT_LIST_HEAD(&rp->c_lru);
99
100 memset(&rp->c_key, 0, sizeof(rp->c_key));
101 rp->c_key.k_xid = rqstp->rq_xid;
102 rp->c_key.k_proc = rqstp->rq_proc;
103 rpc_copy_addr((struct sockaddr *)&rp->c_key.k_addr, svc_addr(rqstp));
104 rpc_set_port((struct sockaddr *)&rp->c_key.k_addr, rpc_get_port(svc_addr(rqstp)));
105 rp->c_key.k_prot = rqstp->rq_prot;
106 rp->c_key.k_vers = rqstp->rq_vers;
107 rp->c_key.k_len = rqstp->rq_arg.len;
108 rp->c_key.k_csum = csum;
109 }
110 return rp;
111 }
112
113 static void nfsd_cacherep_free(struct nfsd_cacherep *rp)
114 {
115 if (rp->c_type == RC_REPLBUFF)
116 kfree(rp->c_replvec.iov_base);
117 kmem_cache_free(drc_slab, rp);
118 }
119
120 static unsigned long
121 nfsd_cacherep_dispose(struct list_head *dispose)
122 {
123 struct nfsd_cacherep *rp;
124 unsigned long freed = 0;
125
126 while (!list_empty(dispose)) {
127 rp = list_first_entry(dispose, struct nfsd_cacherep, c_lru);
128 list_del(&rp->c_lru);
129 nfsd_cacherep_free(rp);
130 freed++;
131 }
132 return freed;
133 }
134
135 static void
136 nfsd_cacherep_unlink_locked(struct nfsd_net *nn, struct nfsd_drc_bucket *b,
137 struct nfsd_cacherep *rp)
138 {
139 if (rp->c_type == RC_REPLBUFF && rp->c_replvec.iov_base)
140 nfsd_stats_drc_mem_usage_sub(nn, rp->c_replvec.iov_len);
141 if (rp->c_state != RC_UNUSED) {
142 rb_erase(&rp->c_node, &b->rb_head);
143 list_del(&rp->c_lru);
144 atomic_dec(&nn->num_drc_entries);
145 nfsd_stats_drc_mem_usage_sub(nn, sizeof(*rp));
146 }
147 }
148
149 static void
150 nfsd_reply_cache_free_locked(struct nfsd_drc_bucket *b, struct nfsd_cacherep *rp,
151 struct nfsd_net *nn)
152 {
153 nfsd_cacherep_unlink_locked(nn, b, rp);
154 nfsd_cacherep_free(rp);
155 }
156
157 static void
158 nfsd_reply_cache_free(struct nfsd_drc_bucket *b, struct nfsd_cacherep *rp,
159 struct nfsd_net *nn)
160 {
161 spin_lock(&b->cache_lock);
162 nfsd_cacherep_unlink_locked(nn, b, rp);
163 spin_unlock(&b->cache_lock);
164 nfsd_cacherep_free(rp);
165 }
166
167 int nfsd_drc_slab_create(void)
168 {
169 drc_slab = KMEM_CACHE(nfsd_cacherep, 0);
170 return drc_slab ? 0: -ENOMEM;
171 }
172
173 void nfsd_drc_slab_free(void)
174 {
175 kmem_cache_destroy(drc_slab);
176 }
177
178 int nfsd_reply_cache_init(struct nfsd_net *nn)
179 {
180 unsigned int hashsize;
181 unsigned int i;
182
183 nn->max_drc_entries = nfsd_cache_size_limit();
184 atomic_set(&nn->num_drc_entries, 0);
185 hashsize = nfsd_hashsize(nn->max_drc_entries);
186 nn->maskbits = ilog2(hashsize);
187
188 nn->drc_hashtbl = kvzalloc(array_size(hashsize,
189 sizeof(*nn->drc_hashtbl)), GFP_KERNEL);
190 if (!nn->drc_hashtbl)
191 return -ENOMEM;
192
193 nn->nfsd_reply_cache_shrinker = shrinker_alloc(0, "nfsd-reply:%s",
194 nn->nfsd_name);
195 if (!nn->nfsd_reply_cache_shrinker)
196 goto out_shrinker;
197
198 nn->nfsd_reply_cache_shrinker->scan_objects = nfsd_reply_cache_scan;
199 nn->nfsd_reply_cache_shrinker->count_objects = nfsd_reply_cache_count;
200 nn->nfsd_reply_cache_shrinker->seeks = 1;
201 nn->nfsd_reply_cache_shrinker->private_data = nn;
202
203 shrinker_register(nn->nfsd_reply_cache_shrinker);
204
205 for (i = 0; i < hashsize; i++) {
206 INIT_LIST_HEAD(&nn->drc_hashtbl[i].lru_head);
207 spin_lock_init(&nn->drc_hashtbl[i].cache_lock);
208 }
209 nn->drc_hashsize = hashsize;
210
211 return 0;
212 out_shrinker:
213 kvfree(nn->drc_hashtbl);
214 printk(KERN_ERR "nfsd: failed to allocate reply cache\n");
215 return -ENOMEM;
216 }
217
218 void nfsd_reply_cache_shutdown(struct nfsd_net *nn)
219 {
220 struct nfsd_cacherep *rp;
221 unsigned int i;
222
223 shrinker_free(nn->nfsd_reply_cache_shrinker);
224
225 for (i = 0; i < nn->drc_hashsize; i++) {
226 struct list_head *head = &nn->drc_hashtbl[i].lru_head;
227 while (!list_empty(head)) {
228 rp = list_first_entry(head, struct nfsd_cacherep, c_lru);
229 nfsd_reply_cache_free_locked(&nn->drc_hashtbl[i],
230 rp, nn);
231 }
232 }
233
234 kvfree(nn->drc_hashtbl);
235 nn->drc_hashtbl = NULL;
236 nn->drc_hashsize = 0;
237
238 }
239
240 /*
241 * Move cache entry to end of LRU list, and queue the cleaner to run if it's
242 * not already scheduled.
243 */
244 static void
245 lru_put_end(struct nfsd_drc_bucket *b, struct nfsd_cacherep *rp)
246 {
247 rp->c_timestamp = jiffies;
248 list_move_tail(&rp->c_lru, &b->lru_head);
249 }
250
251 static noinline struct nfsd_drc_bucket *
252 nfsd_cache_bucket_find(__be32 xid, struct nfsd_net *nn)
253 {
254 unsigned int hash = hash_32((__force u32)xid, nn->maskbits);
255
256 return &nn->drc_hashtbl[hash];
257 }
258
259 /*
260 * Remove and return no more than @max expired entries in bucket @b.
261 * If @max is zero, do not limit the number of removed entries.
262 */
263 static void
264 nfsd_prune_bucket_locked(struct nfsd_net *nn, struct nfsd_drc_bucket *b,
265 unsigned int max, struct list_head *dispose)
266 {
267 unsigned long expiry = jiffies - RC_EXPIRE;
268 struct nfsd_cacherep *rp, *tmp;
269 unsigned int freed = 0;
270
271 lockdep_assert_held(&b->cache_lock);
272
273 /* The bucket LRU is ordered oldest-first. */
274 list_for_each_entry_safe(rp, tmp, &b->lru_head, c_lru) {
275 /*
276 * Don't free entries attached to calls that are still
277 * in-progress, but do keep scanning the list.
278 */
279 if (rp->c_state == RC_INPROG)
280 continue;
281
282 if (atomic_read(&nn->num_drc_entries) <= nn->max_drc_entries &&
283 time_before(expiry, rp->c_timestamp))
284 break;
285
286 nfsd_cacherep_unlink_locked(nn, b, rp);
287 list_add(&rp->c_lru, dispose);
288
289 if (max && ++freed > max)
290 break;
291 }
292 }
293
294 /**
295 * nfsd_reply_cache_count - count_objects method for the DRC shrinker
296 * @shrink: our registered shrinker context
297 * @sc: garbage collection parameters
298 *
299 * Returns the total number of entries in the duplicate reply cache. To
300 * keep things simple and quick, this is not the number of expired entries
301 * in the cache (ie, the number that would be removed by a call to
302 * nfsd_reply_cache_scan).
303 */
304 static unsigned long
305 nfsd_reply_cache_count(struct shrinker *shrink, struct shrink_control *sc)
306 {
307 struct nfsd_net *nn = shrink->private_data;
308
309 return atomic_read(&nn->num_drc_entries);
310 }
311
312 /**
313 * nfsd_reply_cache_scan - scan_objects method for the DRC shrinker
314 * @shrink: our registered shrinker context
315 * @sc: garbage collection parameters
316 *
317 * Free expired entries on each bucket's LRU list until we've released
318 * nr_to_scan freed objects. Nothing will be released if the cache
319 * has not exceeded it's max_drc_entries limit.
320 *
321 * Returns the number of entries released by this call.
322 */
323 static unsigned long
324 nfsd_reply_cache_scan(struct shrinker *shrink, struct shrink_control *sc)
325 {
326 struct nfsd_net *nn = shrink->private_data;
327 unsigned long freed = 0;
328 LIST_HEAD(dispose);
329 unsigned int i;
330
331 for (i = 0; i < nn->drc_hashsize; i++) {
332 struct nfsd_drc_bucket *b = &nn->drc_hashtbl[i];
333
334 if (list_empty(&b->lru_head))
335 continue;
336
337 spin_lock(&b->cache_lock);
338 nfsd_prune_bucket_locked(nn, b, 0, &dispose);
339 spin_unlock(&b->cache_lock);
340
341 freed += nfsd_cacherep_dispose(&dispose);
342 if (freed > sc->nr_to_scan)
343 break;
344 }
345 return freed;
346 }
347
348 /**
349 * nfsd_cache_csum - Checksum incoming NFS Call arguments
350 * @buf: buffer containing a whole RPC Call message
351 * @start: starting byte of the NFS Call header
352 * @remaining: size of the NFS Call header, in bytes
353 *
354 * Compute a weak checksum of the leading bytes of an NFS procedure
355 * call header to help verify that a retransmitted Call matches an
356 * entry in the duplicate reply cache.
357 *
358 * To avoid assumptions about how the RPC message is laid out in
359 * @buf and what else it might contain (eg, a GSS MIC suffix), the
360 * caller passes us the exact location and length of the NFS Call
361 * header.
362 *
363 * Returns a 32-bit checksum value, as defined in RFC 793.
364 */
365 static __wsum nfsd_cache_csum(struct xdr_buf *buf, unsigned int start,
366 unsigned int remaining)
367 {
368 unsigned int base, len;
369 struct xdr_buf subbuf;
370 __wsum csum = 0;
371 void *p;
372 int idx;
373
374 if (remaining > RC_CSUMLEN)
375 remaining = RC_CSUMLEN;
376 if (xdr_buf_subsegment(buf, &subbuf, start, remaining))
377 return csum;
378
379 /* rq_arg.head first */
380 if (subbuf.head[0].iov_len) {
381 len = min_t(unsigned int, subbuf.head[0].iov_len, remaining);
382 csum = csum_partial(subbuf.head[0].iov_base, len, csum);
383 remaining -= len;
384 }
385
386 /* Continue into page array */
387 idx = subbuf.page_base / PAGE_SIZE;
388 base = subbuf.page_base & ~PAGE_MASK;
389 while (remaining) {
390 p = page_address(subbuf.pages[idx]) + base;
391 len = min_t(unsigned int, PAGE_SIZE - base, remaining);
392 csum = csum_partial(p, len, csum);
393 remaining -= len;
394 base = 0;
395 ++idx;
396 }
397 return csum;
398 }
399
400 static int
401 nfsd_cache_key_cmp(const struct nfsd_cacherep *key,
402 const struct nfsd_cacherep *rp, struct nfsd_net *nn)
403 {
404 if (key->c_key.k_xid == rp->c_key.k_xid &&
405 key->c_key.k_csum != rp->c_key.k_csum) {
406 nfsd_stats_payload_misses_inc(nn);
407 trace_nfsd_drc_mismatch(nn, key, rp);
408 }
409
410 return memcmp(&key->c_key, &rp->c_key, sizeof(key->c_key));
411 }
412
413 /*
414 * Search the request hash for an entry that matches the given rqstp.
415 * Must be called with cache_lock held. Returns the found entry or
416 * inserts an empty key on failure.
417 */
418 static struct nfsd_cacherep *
419 nfsd_cache_insert(struct nfsd_drc_bucket *b, struct nfsd_cacherep *key,
420 struct nfsd_net *nn)
421 {
422 struct nfsd_cacherep *rp, *ret = key;
423 struct rb_node **p = &b->rb_head.rb_node,
424 *parent = NULL;
425 unsigned int entries = 0;
426 int cmp;
427
428 while (*p != NULL) {
429 ++entries;
430 parent = *p;
431 rp = rb_entry(parent, struct nfsd_cacherep, c_node);
432
433 cmp = nfsd_cache_key_cmp(key, rp, nn);
434 if (cmp < 0)
435 p = &parent->rb_left;
436 else if (cmp > 0)
437 p = &parent->rb_right;
438 else {
439 ret = rp;
440 goto out;
441 }
442 }
443 rb_link_node(&key->c_node, parent, p);
444 rb_insert_color(&key->c_node, &b->rb_head);
445 out:
446 /* tally hash chain length stats */
447 if (entries > nn->longest_chain) {
448 nn->longest_chain = entries;
449 nn->longest_chain_cachesize = atomic_read(&nn->num_drc_entries);
450 } else if (entries == nn->longest_chain) {
451 /* prefer to keep the smallest cachesize possible here */
452 nn->longest_chain_cachesize = min_t(unsigned int,
453 nn->longest_chain_cachesize,
454 atomic_read(&nn->num_drc_entries));
455 }
456
457 lru_put_end(b, ret);
458 return ret;
459 }
460
461 /**
462 * nfsd_cache_lookup - Find an entry in the duplicate reply cache
463 * @rqstp: Incoming Call to find
464 * @start: starting byte in @rqstp->rq_arg of the NFS Call header
465 * @len: size of the NFS Call header, in bytes
466 * @cacherep: OUT: DRC entry for this request
467 *
468 * Try to find an entry matching the current call in the cache. When none
469 * is found, we try to grab the oldest expired entry off the LRU list. If
470 * a suitable one isn't there, then drop the cache_lock and allocate a
471 * new one, then search again in case one got inserted while this thread
472 * didn't hold the lock.
473 *
474 * Return values:
475 * %RC_DOIT: Process the request normally
476 * %RC_REPLY: Reply from cache
477 * %RC_DROPIT: Do not process the request further
478 */
479 int nfsd_cache_lookup(struct svc_rqst *rqstp, unsigned int start,
480 unsigned int len, struct nfsd_cacherep **cacherep)
481 {
482 struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
483 struct nfsd_cacherep *rp, *found;
484 __wsum csum;
485 struct nfsd_drc_bucket *b;
486 int type = rqstp->rq_cachetype;
487 LIST_HEAD(dispose);
488 int rtn = RC_DOIT;
489
490 if (type == RC_NOCACHE) {
491 nfsd_stats_rc_nocache_inc(nn);
492 goto out;
493 }
494
495 csum = nfsd_cache_csum(&rqstp->rq_arg, start, len);
496
497 /*
498 * Since the common case is a cache miss followed by an insert,
499 * preallocate an entry.
500 */
501 rp = nfsd_cacherep_alloc(rqstp, csum, nn);
502 if (!rp)
503 goto out;
504
505 b = nfsd_cache_bucket_find(rqstp->rq_xid, nn);
506 spin_lock(&b->cache_lock);
507 found = nfsd_cache_insert(b, rp, nn);
508 if (found != rp)
509 goto found_entry;
510 *cacherep = rp;
511 rp->c_state = RC_INPROG;
512 nfsd_prune_bucket_locked(nn, b, 3, &dispose);
513 spin_unlock(&b->cache_lock);
514
515 nfsd_cacherep_dispose(&dispose);
516
517 nfsd_stats_rc_misses_inc(nn);
518 atomic_inc(&nn->num_drc_entries);
519 nfsd_stats_drc_mem_usage_add(nn, sizeof(*rp));
520 goto out;
521
522 found_entry:
523 /* We found a matching entry which is either in progress or done. */
524 nfsd_reply_cache_free_locked(NULL, rp, nn);
525 nfsd_stats_rc_hits_inc(nn);
526 rtn = RC_DROPIT;
527 rp = found;
528
529 /* Request being processed */
530 if (rp->c_state == RC_INPROG)
531 goto out_trace;
532
533 /* From the hall of fame of impractical attacks:
534 * Is this a user who tries to snoop on the cache? */
535 rtn = RC_DOIT;
536 if (!test_bit(RQ_SECURE, &rqstp->rq_flags) && rp->c_secure)
537 goto out_trace;
538
539 /* Compose RPC reply header */
540 switch (rp->c_type) {
541 case RC_NOCACHE:
542 break;
543 case RC_REPLSTAT:
544 xdr_stream_encode_be32(&rqstp->rq_res_stream, rp->c_replstat);
545 rtn = RC_REPLY;
546 break;
547 case RC_REPLBUFF:
548 if (!nfsd_cache_append(rqstp, &rp->c_replvec))
549 goto out_unlock; /* should not happen */
550 rtn = RC_REPLY;
551 break;
552 default:
553 WARN_ONCE(1, "nfsd: bad repcache type %d\n", rp->c_type);
554 }
555
556 out_trace:
557 trace_nfsd_drc_found(nn, rqstp, rtn);
558 out_unlock:
559 spin_unlock(&b->cache_lock);
560 out:
561 return rtn;
562 }
563
564 /**
565 * nfsd_cache_update - Update an entry in the duplicate reply cache.
566 * @rqstp: svc_rqst with a finished Reply
567 * @rp: IN: DRC entry for this request
568 * @cachetype: which cache to update
569 * @statp: pointer to Reply's NFS status code, or NULL
570 *
571 * This is called from nfsd_dispatch when the procedure has been
572 * executed and the complete reply is in rqstp->rq_res.
573 *
574 * We're copying around data here rather than swapping buffers because
575 * the toplevel loop requires max-sized buffers, which would be a waste
576 * of memory for a cache with a max reply size of 100 bytes (diropokres).
577 *
578 * If we should start to use different types of cache entries tailored
579 * specifically for attrstat and fh's, we may save even more space.
580 *
581 * Also note that a cachetype of RC_NOCACHE can legally be passed when
582 * nfsd failed to encode a reply that otherwise would have been cached.
583 * In this case, nfsd_cache_update is called with statp == NULL.
584 */
585 void nfsd_cache_update(struct svc_rqst *rqstp, struct nfsd_cacherep *rp,
586 int cachetype, __be32 *statp)
587 {
588 struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
589 struct kvec *resv = &rqstp->rq_res.head[0], *cachv;
590 struct nfsd_drc_bucket *b;
591 int len;
592 size_t bufsize = 0;
593
594 if (!rp)
595 return;
596
597 b = nfsd_cache_bucket_find(rp->c_key.k_xid, nn);
598
599 len = resv->iov_len - ((char*)statp - (char*)resv->iov_base);
600 len >>= 2;
601
602 /* Don't cache excessive amounts of data and XDR failures */
603 if (!statp || len > (256 >> 2)) {
604 nfsd_reply_cache_free(b, rp, nn);
605 return;
606 }
607
608 switch (cachetype) {
609 case RC_REPLSTAT:
610 if (len != 1)
611 printk("nfsd: RC_REPLSTAT/reply len %d!\n",len);
612 rp->c_replstat = *statp;
613 break;
614 case RC_REPLBUFF:
615 cachv = &rp->c_replvec;
616 bufsize = len << 2;
617 cachv->iov_base = kmalloc(bufsize, GFP_KERNEL);
618 if (!cachv->iov_base) {
619 nfsd_reply_cache_free(b, rp, nn);
620 return;
621 }
622 cachv->iov_len = bufsize;
623 memcpy(cachv->iov_base, statp, bufsize);
624 break;
625 case RC_NOCACHE:
626 nfsd_reply_cache_free(b, rp, nn);
627 return;
628 }
629 spin_lock(&b->cache_lock);
630 nfsd_stats_drc_mem_usage_add(nn, bufsize);
631 lru_put_end(b, rp);
632 rp->c_secure = test_bit(RQ_SECURE, &rqstp->rq_flags);
633 rp->c_type = cachetype;
634 rp->c_state = RC_DONE;
635 spin_unlock(&b->cache_lock);
636 return;
637 }
638
639 static int
640 nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *data)
641 {
642 __be32 *p;
643
644 p = xdr_reserve_space(&rqstp->rq_res_stream, data->iov_len);
645 if (unlikely(!p))
646 return false;
647 memcpy(p, data->iov_base, data->iov_len);
648 xdr_commit_encode(&rqstp->rq_res_stream);
649 return true;
650 }
651
652 /*
653 * Note that fields may be added, removed or reordered in the future. Programs
654 * scraping this file for info should test the labels to ensure they're
655 * getting the correct field.
656 */
657 int nfsd_reply_cache_stats_show(struct seq_file *m, void *v)
658 {
659 struct nfsd_net *nn = net_generic(file_inode(m->file)->i_sb->s_fs_info,
660 nfsd_net_id);
661
662 seq_printf(m, "max entries: %u\n", nn->max_drc_entries);
663 seq_printf(m, "num entries: %u\n",
664 atomic_read(&nn->num_drc_entries));
665 seq_printf(m, "hash buckets: %u\n", 1 << nn->maskbits);
666 seq_printf(m, "mem usage: %lld\n",
667 percpu_counter_sum_positive(&nn->counter[NFSD_STATS_DRC_MEM_USAGE]));
668 seq_printf(m, "cache hits: %lld\n",
669 percpu_counter_sum_positive(&nn->counter[NFSD_STATS_RC_HITS]));
670 seq_printf(m, "cache misses: %lld\n",
671 percpu_counter_sum_positive(&nn->counter[NFSD_STATS_RC_MISSES]));
672 seq_printf(m, "not cached: %lld\n",
673 percpu_counter_sum_positive(&nn->counter[NFSD_STATS_RC_NOCACHE]));
674 seq_printf(m, "payload misses: %lld\n",
675 percpu_counter_sum_positive(&nn->counter[NFSD_STATS_PAYLOAD_MISSES]));
676 seq_printf(m, "longest chain len: %u\n", nn->longest_chain);
677 seq_printf(m, "cachesize at longest: %u\n", nn->longest_chain_cachesize);
678 return 0;
679 }
680
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