4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
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17 * version 2 along with this program; If not, see
18 * http://www.gnu.org/licenses/gpl-2.0.html
23 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
24 * Use is subject to license terms.
26 * Copyright (c) 2011, 2016, Intel Corporation.
29 * This file is part of Lustre, http://www.lustre.org/
30 * Lustre is a trademark of Sun Microsystems, Inc.
32 * Implementation of cl_page for OSC layer.
34 * Author: Nikita Danilov <nikita.danilov@sun.com>
35 * Author: Jinshan Xiong <jinshan.xiong@intel.com>
38 #define DEBUG_SUBSYSTEM S_OSC
39 #include <lustre_osc.h>
41 #include "osc_internal.h"
43 static void osc_lru_del(struct client_obd *cli, struct osc_page *opg);
44 static void osc_lru_use(struct client_obd *cli, struct osc_page *opg);
45 static int osc_lru_alloc(const struct lu_env *env, struct client_obd *cli,
46 struct osc_page *opg);
55 static void osc_page_transfer_get(struct osc_page *opg, const char *label)
57 struct cl_page *page = opg->ops_cl.cpl_page;
59 LASSERT(!opg->ops_transfer_pinned);
61 lu_ref_add_atomic(&page->cp_reference, label, page);
62 opg->ops_transfer_pinned = 1;
65 static void osc_page_transfer_put(const struct lu_env *env,
68 struct cl_page *page = opg->ops_cl.cpl_page;
70 if (opg->ops_transfer_pinned) {
71 opg->ops_transfer_pinned = 0;
72 lu_ref_del(&page->cp_reference, "transfer", page);
73 cl_page_put(env, page);
78 * This is called once for every page when it is submitted for a transfer
79 * either opportunistic (osc_page_cache_add()), or immediate
80 * (osc_page_submit()).
82 static void osc_page_transfer_add(const struct lu_env *env,
83 struct osc_page *opg, enum cl_req_type crt)
85 struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj);
87 /* ops_lru and ops_inflight share the same field, so take it from LRU
88 * first and then use it as inflight. */
89 osc_lru_use(osc_cli(obj), opg);
92 int osc_page_cache_add(const struct lu_env *env,
93 const struct cl_page_slice *slice, struct cl_io *io)
95 struct osc_page *opg = cl2osc_page(slice);
99 osc_page_transfer_get(opg, "transfer\0cache");
100 result = osc_queue_async_io(env, io, opg);
102 osc_page_transfer_put(env, opg);
104 osc_page_transfer_add(env, opg, CRT_WRITE);
109 void osc_index2policy(union ldlm_policy_data *policy,
110 const struct cl_object *obj, pgoff_t start, pgoff_t end)
112 memset(policy, 0, sizeof *policy);
113 policy->l_extent.start = cl_offset(obj, start);
114 policy->l_extent.end = cl_offset(obj, end + 1) - 1;
117 static const char *osc_list(struct list_head *head)
119 return list_empty(head) ? "-" : "+";
122 static inline cfs_time_t osc_submit_duration(struct osc_page *opg)
124 if (opg->ops_submit_time == 0)
127 return (cfs_time_current() - opg->ops_submit_time);
130 static int osc_page_print(const struct lu_env *env,
131 const struct cl_page_slice *slice,
132 void *cookie, lu_printer_t printer)
134 struct osc_page *opg = cl2osc_page(slice);
135 struct osc_async_page *oap = &opg->ops_oap;
136 struct osc_object *obj = cl2osc(slice->cpl_obj);
137 struct client_obd *cli = &osc_export(obj)->exp_obd->u.cli;
139 return (*printer)(env, cookie, LUSTRE_OSC_NAME"-page@%p %lu: "
140 "1< %#x %d %u %s %s > "
141 "2< %lld %u %u %#x %#x | %p %p %p > "
143 "4< %d %d %d %lu %s | %s %s %s %s > "
144 "5< %s %s %s %s | %d %s | %d %s %s>\n",
147 oap->oap_magic, oap->oap_cmd,
148 oap->oap_interrupted,
149 osc_list(&oap->oap_pending_item),
150 osc_list(&oap->oap_rpc_item),
152 oap->oap_obj_off, oap->oap_page_off, oap->oap_count,
153 oap->oap_async_flags, oap->oap_brw_flags,
154 oap->oap_request, oap->oap_cli, obj,
156 opg->ops_transfer_pinned,
157 osc_submit_duration(opg), opg->ops_srvlock,
159 cli->cl_r_in_flight, cli->cl_w_in_flight,
160 cli->cl_max_rpcs_in_flight,
162 osc_list(&cli->cl_cache_waiters),
163 osc_list(&cli->cl_loi_ready_list),
164 osc_list(&cli->cl_loi_hp_ready_list),
165 osc_list(&cli->cl_loi_write_list),
166 osc_list(&cli->cl_loi_read_list),
168 osc_list(&obj->oo_ready_item),
169 osc_list(&obj->oo_hp_ready_item),
170 osc_list(&obj->oo_write_item),
171 osc_list(&obj->oo_read_item),
172 atomic_read(&obj->oo_nr_reads),
173 osc_list(&obj->oo_reading_exts),
174 atomic_read(&obj->oo_nr_writes),
175 osc_list(&obj->oo_hp_exts),
176 osc_list(&obj->oo_urgent_exts));
179 static void osc_page_delete(const struct lu_env *env,
180 const struct cl_page_slice *slice)
182 struct osc_page *opg = cl2osc_page(slice);
183 struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj);
187 CDEBUG(D_TRACE, "%p\n", opg);
188 osc_page_transfer_put(env, opg);
189 rc = osc_teardown_async_page(env, obj, opg);
191 CL_PAGE_DEBUG(D_ERROR, env, slice->cpl_page,
192 "Trying to teardown failed: %d\n", rc);
196 osc_lru_del(osc_cli(obj), opg);
198 if (slice->cpl_page->cp_type == CPT_CACHEABLE) {
201 spin_lock(&obj->oo_tree_lock);
202 value = radix_tree_delete(&obj->oo_tree, osc_index(opg));
205 spin_unlock(&obj->oo_tree_lock);
207 LASSERT(ergo(value != NULL, value == opg));
213 static void osc_page_clip(const struct lu_env *env,
214 const struct cl_page_slice *slice,
217 struct osc_page *opg = cl2osc_page(slice);
218 struct osc_async_page *oap = &opg->ops_oap;
220 opg->ops_from = from;
222 spin_lock(&oap->oap_lock);
223 oap->oap_async_flags |= ASYNC_COUNT_STABLE;
224 spin_unlock(&oap->oap_lock);
227 static int osc_page_cancel(const struct lu_env *env,
228 const struct cl_page_slice *slice)
230 struct osc_page *opg = cl2osc_page(slice);
233 /* Check if the transferring against this page
234 * is completed, or not even queued. */
235 if (opg->ops_transfer_pinned)
236 /* FIXME: may not be interrupted.. */
237 rc = osc_cancel_async_page(env, opg);
238 LASSERT(ergo(rc == 0, opg->ops_transfer_pinned == 0));
242 static int osc_page_flush(const struct lu_env *env,
243 const struct cl_page_slice *slice,
246 struct osc_page *opg = cl2osc_page(slice);
249 rc = osc_flush_async_page(env, io, opg);
253 static const struct cl_page_operations osc_page_ops = {
254 .cpo_print = osc_page_print,
255 .cpo_delete = osc_page_delete,
256 .cpo_clip = osc_page_clip,
257 .cpo_cancel = osc_page_cancel,
258 .cpo_flush = osc_page_flush
261 int osc_page_init(const struct lu_env *env, struct cl_object *obj,
262 struct cl_page *page, pgoff_t index)
264 struct osc_object *osc = cl2osc(obj);
265 struct osc_page *opg = cl_object_page_slice(obj, page);
266 struct osc_io *oio = osc_env_io(env);
270 opg->ops_to = PAGE_SIZE;
272 INIT_LIST_HEAD(&opg->ops_lru);
274 result = osc_prep_async_page(osc, opg, page->cp_vmpage,
275 cl_offset(obj, index));
279 opg->ops_srvlock = osc_io_srvlock(oio);
280 cl_page_slice_add(page, &opg->ops_cl, obj, index,
284 /* reserve an LRU space for this page */
285 if (page->cp_type == CPT_CACHEABLE) {
286 result = osc_lru_alloc(env, osc_cli(osc), opg);
288 result = radix_tree_preload(GFP_NOFS);
290 spin_lock(&osc->oo_tree_lock);
291 result = radix_tree_insert(&osc->oo_tree,
295 spin_unlock(&osc->oo_tree_lock);
297 radix_tree_preload_end();
304 EXPORT_SYMBOL(osc_page_init);
307 * Helper function called by osc_io_submit() for every page in an immediate
308 * transfer (i.e., transferred synchronously).
310 void osc_page_submit(const struct lu_env *env, struct osc_page *opg,
311 enum cl_req_type crt, int brw_flags)
313 struct osc_async_page *oap = &opg->ops_oap;
315 LASSERTF(oap->oap_magic == OAP_MAGIC, "Bad oap magic: oap %p, "
316 "magic 0x%x\n", oap, oap->oap_magic);
317 LASSERT(oap->oap_async_flags & ASYNC_READY);
318 LASSERT(oap->oap_async_flags & ASYNC_COUNT_STABLE);
320 oap->oap_cmd = crt == CRT_WRITE ? OBD_BRW_WRITE : OBD_BRW_READ;
321 oap->oap_page_off = opg->ops_from;
322 oap->oap_count = opg->ops_to - opg->ops_from;
323 oap->oap_brw_flags = OBD_BRW_SYNC | brw_flags;
325 if (cfs_capable(CFS_CAP_SYS_RESOURCE)) {
326 oap->oap_brw_flags |= OBD_BRW_NOQUOTA;
327 oap->oap_cmd |= OBD_BRW_NOQUOTA;
330 opg->ops_submit_time = cfs_time_current();
331 osc_page_transfer_get(opg, "transfer\0imm");
332 osc_page_transfer_add(env, opg, crt);
335 /* --------------- LRU page management ------------------ */
337 /* OSC is a natural place to manage LRU pages as applications are specialized
338 * to write OSC by OSC. Ideally, if one OSC is used more frequently it should
339 * occupy more LRU slots. On the other hand, we should avoid using up all LRU
340 * slots (client_obd::cl_lru_left) otherwise process has to be put into sleep
341 * for free LRU slots - this will be very bad so the algorithm requires each
342 * OSC to free slots voluntarily to maintain a reasonable number of free slots
346 static DECLARE_WAIT_QUEUE_HEAD(osc_lru_waitq);
349 * LRU pages are freed in batch mode. OSC should at least free this
350 * number of pages to avoid running out of LRU slots.
352 static inline int lru_shrink_min(struct client_obd *cli)
354 return cli->cl_max_pages_per_rpc * 2;
358 * free this number at most otherwise it will take too long time to finsih.
360 static inline int lru_shrink_max(struct client_obd *cli)
362 return cli->cl_max_pages_per_rpc * cli->cl_max_rpcs_in_flight;
366 * Check if we can free LRU slots from this OSC. If there exists LRU waiters,
367 * we should free slots aggressively. In this way, slots are freed in a steady
368 * step to maintain fairness among OSCs.
370 * Return how many LRU pages should be freed.
372 static int osc_cache_too_much(struct client_obd *cli)
374 struct cl_client_cache *cache = cli->cl_cache;
375 long pages = atomic_long_read(&cli->cl_lru_in_list);
376 unsigned long budget;
378 LASSERT(cache != NULL);
379 budget = cache->ccc_lru_max / (atomic_read(&cache->ccc_users) - 2);
381 /* if it's going to run out LRU slots, we should free some, but not
382 * too much to maintain faireness among OSCs. */
383 if (atomic_long_read(cli->cl_lru_left) < cache->ccc_lru_max >> 2) {
385 return lru_shrink_max(cli);
386 else if (pages >= budget / 2)
387 return lru_shrink_min(cli);
389 time64_t duration = ktime_get_real_seconds();
392 /* knock out pages by duration of no IO activity */
393 duration -= cli->cl_lru_last_used;
395 * The difference shouldn't be more than 70 years
396 * so we can safely case to a long. Round to
397 * approximately 1 minute.
399 timediff = (long)(duration >> 6);
400 if (timediff > 0 && pages >= budget / timediff)
401 return lru_shrink_min(cli);
406 int lru_queue_work(const struct lu_env *env, void *data)
408 struct client_obd *cli = data;
411 CDEBUG(D_CACHE, "%s: run LRU work for client obd\n", cli_name(cli));
412 count = osc_cache_too_much(cli);
414 int rc = osc_lru_shrink(env, cli, count, false);
416 CDEBUG(D_CACHE, "%s: shrank %d/%d pages from client obd\n",
417 cli_name(cli), rc, count);
419 CDEBUG(D_CACHE, "%s: queue again\n", cli_name(cli));
420 ptlrpcd_queue_work(cli->cl_lru_work);
427 void osc_lru_add_batch(struct client_obd *cli, struct list_head *plist)
429 struct list_head lru = LIST_HEAD_INIT(lru);
430 struct osc_async_page *oap;
433 list_for_each_entry(oap, plist, oap_pending_item) {
434 struct osc_page *opg = oap2osc_page(oap);
436 if (!opg->ops_in_lru)
440 LASSERT(list_empty(&opg->ops_lru));
441 list_add(&opg->ops_lru, &lru);
445 spin_lock(&cli->cl_lru_list_lock);
446 list_splice_tail(&lru, &cli->cl_lru_list);
447 atomic_long_sub(npages, &cli->cl_lru_busy);
448 atomic_long_add(npages, &cli->cl_lru_in_list);
449 cli->cl_lru_last_used = ktime_get_real_seconds();
450 spin_unlock(&cli->cl_lru_list_lock);
452 if (waitqueue_active(&osc_lru_waitq))
453 (void)ptlrpcd_queue_work(cli->cl_lru_work);
457 static void __osc_lru_del(struct client_obd *cli, struct osc_page *opg)
459 LASSERT(atomic_long_read(&cli->cl_lru_in_list) > 0);
460 list_del_init(&opg->ops_lru);
461 atomic_long_dec(&cli->cl_lru_in_list);
465 * Page is being destroyed. The page may be not in LRU list, if the transfer
466 * has never finished(error occurred).
468 static void osc_lru_del(struct client_obd *cli, struct osc_page *opg)
470 if (opg->ops_in_lru) {
471 spin_lock(&cli->cl_lru_list_lock);
472 if (!list_empty(&opg->ops_lru)) {
473 __osc_lru_del(cli, opg);
475 LASSERT(atomic_long_read(&cli->cl_lru_busy) > 0);
476 atomic_long_dec(&cli->cl_lru_busy);
478 spin_unlock(&cli->cl_lru_list_lock);
480 atomic_long_inc(cli->cl_lru_left);
481 /* this is a great place to release more LRU pages if
482 * this osc occupies too many LRU pages and kernel is
483 * stealing one of them. */
484 if (osc_cache_too_much(cli)) {
485 CDEBUG(D_CACHE, "%s: queue LRU work\n", cli_name(cli));
486 (void)ptlrpcd_queue_work(cli->cl_lru_work);
488 wake_up(&osc_lru_waitq);
490 LASSERT(list_empty(&opg->ops_lru));
495 * Delete page from LRU list for redirty.
497 static void osc_lru_use(struct client_obd *cli, struct osc_page *opg)
499 /* If page is being transferred for the first time,
500 * ops_lru should be empty */
501 if (opg->ops_in_lru) {
502 spin_lock(&cli->cl_lru_list_lock);
503 if (!list_empty(&opg->ops_lru)) {
504 __osc_lru_del(cli, opg);
505 atomic_long_inc(&cli->cl_lru_busy);
507 spin_unlock(&cli->cl_lru_list_lock);
511 static void discard_pagevec(const struct lu_env *env, struct cl_io *io,
512 struct cl_page **pvec, int max_index)
516 for (i = 0; i < max_index; i++) {
517 struct cl_page *page = pvec[i];
519 LASSERT(cl_page_is_owned(page, io));
520 cl_page_delete(env, page);
521 cl_page_discard(env, io, page);
522 cl_page_disown(env, io, page);
523 cl_page_put(env, page);
530 * Check if a cl_page can be released, i.e, it's not being used.
532 * If unstable account is turned on, bulk transfer may hold one refcount
533 * for recovery so we need to check vmpage refcount as well; otherwise,
534 * even we can destroy cl_page but the corresponding vmpage can't be reused.
536 static inline bool lru_page_busy(struct client_obd *cli, struct cl_page *page)
538 if (cl_page_in_use_noref(page))
541 if (cli->cl_cache->ccc_unstable_check) {
542 struct page *vmpage = cl_page_vmpage(page);
544 /* vmpage have two known users: cl_page and VM page cache */
545 if (page_count(vmpage) - page_mapcount(vmpage) > 2)
552 * Drop @target of pages from LRU at most.
554 long osc_lru_shrink(const struct lu_env *env, struct client_obd *cli,
555 long target, bool force)
558 struct cl_object *clobj = NULL;
559 struct cl_page **pvec;
560 struct osc_page *opg;
567 LASSERT(atomic_long_read(&cli->cl_lru_in_list) >= 0);
568 if (atomic_long_read(&cli->cl_lru_in_list) == 0 || target <= 0)
571 CDEBUG(D_CACHE, "%s: shrinkers: %d, force: %d\n",
572 cli_name(cli), atomic_read(&cli->cl_lru_shrinkers), force);
574 if (atomic_read(&cli->cl_lru_shrinkers) > 0)
577 if (atomic_inc_return(&cli->cl_lru_shrinkers) > 1) {
578 atomic_dec(&cli->cl_lru_shrinkers);
582 atomic_inc(&cli->cl_lru_shrinkers);
585 pvec = (struct cl_page **)osc_env_info(env)->oti_pvec;
586 io = osc_env_thread_io(env);
588 spin_lock(&cli->cl_lru_list_lock);
590 cli->cl_lru_reclaim++;
591 maxscan = min(target << 1, atomic_long_read(&cli->cl_lru_in_list));
592 while (!list_empty(&cli->cl_lru_list)) {
593 struct cl_page *page;
594 bool will_free = false;
596 if (!force && atomic_read(&cli->cl_lru_shrinkers) > 1)
602 opg = list_entry(cli->cl_lru_list.next, struct osc_page,
604 page = opg->ops_cl.cpl_page;
605 if (lru_page_busy(cli, page)) {
606 list_move_tail(&opg->ops_lru, &cli->cl_lru_list);
610 LASSERT(page->cp_obj != NULL);
611 if (clobj != page->cp_obj) {
612 struct cl_object *tmp = page->cp_obj;
615 spin_unlock(&cli->cl_lru_list_lock);
618 discard_pagevec(env, io, pvec, index);
622 cl_object_put(env, clobj);
628 io->ci_ignore_layout = 1;
629 rc = cl_io_init(env, io, CIT_MISC, clobj);
631 spin_lock(&cli->cl_lru_list_lock);
640 if (cl_page_own_try(env, io, page) == 0) {
641 if (!lru_page_busy(cli, page)) {
642 /* remove it from lru list earlier to avoid
644 __osc_lru_del(cli, opg);
645 opg->ops_in_lru = 0; /* will be discarded */
650 cl_page_disown(env, io, page);
655 list_move_tail(&opg->ops_lru, &cli->cl_lru_list);
659 /* Don't discard and free the page with cl_lru_list held */
660 pvec[index++] = page;
661 if (unlikely(index == OTI_PVEC_SIZE)) {
662 spin_unlock(&cli->cl_lru_list_lock);
663 discard_pagevec(env, io, pvec, index);
666 spin_lock(&cli->cl_lru_list_lock);
669 if (++count >= target)
672 spin_unlock(&cli->cl_lru_list_lock);
675 discard_pagevec(env, io, pvec, index);
678 cl_object_put(env, clobj);
681 atomic_dec(&cli->cl_lru_shrinkers);
683 atomic_long_add(count, cli->cl_lru_left);
684 wake_up_all(&osc_lru_waitq);
686 RETURN(count > 0 ? count : rc);
688 EXPORT_SYMBOL(osc_lru_shrink);
691 * Reclaim LRU pages by an IO thread. The caller wants to reclaim at least
692 * \@npages of LRU slots. For performance consideration, it's better to drop
693 * LRU pages in batch. Therefore, the actual number is adjusted at least
696 static long osc_lru_reclaim(struct client_obd *cli, unsigned long npages)
699 struct cl_client_cache *cache = cli->cl_cache;
705 LASSERT(cache != NULL);
707 env = cl_env_get(&refcheck);
711 npages = max_t(int, npages, cli->cl_max_pages_per_rpc);
712 CDEBUG(D_CACHE, "%s: start to reclaim %ld pages from LRU\n",
713 cli_name(cli), npages);
714 rc = osc_lru_shrink(env, cli, npages, true);
716 CDEBUG(D_CACHE, "%s: reclaimed %ld/%ld pages from LRU\n",
717 cli_name(cli), rc, npages);
718 if (osc_cache_too_much(cli) > 0)
719 ptlrpcd_queue_work(cli->cl_lru_work);
725 CDEBUG(D_CACHE, "%s: cli %p no free slots, pages: %ld/%ld, want: %ld\n",
726 cli_name(cli), cli, atomic_long_read(&cli->cl_lru_in_list),
727 atomic_long_read(&cli->cl_lru_busy), npages);
729 /* Reclaim LRU slots from other client_obd as it can't free enough
730 * from its own. This should rarely happen. */
731 spin_lock(&cache->ccc_lru_lock);
732 LASSERT(!list_empty(&cache->ccc_lru));
734 cache->ccc_lru_shrinkers++;
735 list_move_tail(&cli->cl_lru_osc, &cache->ccc_lru);
737 max_scans = atomic_read(&cache->ccc_users) - 2;
738 while (--max_scans > 0 && !list_empty(&cache->ccc_lru)) {
739 cli = list_entry(cache->ccc_lru.next, struct client_obd,
742 CDEBUG(D_CACHE, "%s: cli %p LRU pages: %ld, busy: %ld.\n",
744 atomic_long_read(&cli->cl_lru_in_list),
745 atomic_long_read(&cli->cl_lru_busy));
747 list_move_tail(&cli->cl_lru_osc, &cache->ccc_lru);
748 if (osc_cache_too_much(cli) > 0) {
749 spin_unlock(&cache->ccc_lru_lock);
751 rc = osc_lru_shrink(env, cli, npages, true);
752 spin_lock(&cache->ccc_lru_lock);
759 spin_unlock(&cache->ccc_lru_lock);
762 cl_env_put(env, &refcheck);
763 CDEBUG(D_CACHE, "%s: cli %p freed %ld pages.\n",
764 cli_name(cli), cli, rc);
769 * osc_lru_alloc() is called to allocate an LRU slot for a cl_page.
771 * Usually the LRU slots are reserved in osc_io_iter_rw_init().
772 * Only in the case that the LRU slots are in extreme shortage, it should
773 * have reserved enough slots for an IO.
775 static int osc_lru_alloc(const struct lu_env *env, struct client_obd *cli,
776 struct osc_page *opg)
778 struct l_wait_info lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
779 struct osc_io *oio = osc_env_io(env);
784 if (cli->cl_cache == NULL) /* shall not be in LRU */
787 if (oio->oi_lru_reserved > 0) {
788 --oio->oi_lru_reserved;
792 LASSERT(atomic_long_read(cli->cl_lru_left) >= 0);
793 while (!atomic_long_add_unless(cli->cl_lru_left, -1, 0)) {
794 /* run out of LRU spaces, try to drop some by itself */
795 rc = osc_lru_reclaim(cli, 1);
802 rc = l_wait_event(osc_lru_waitq,
803 atomic_long_read(cli->cl_lru_left) > 0,
811 atomic_long_inc(&cli->cl_lru_busy);
820 * osc_lru_reserve() is called to reserve enough LRU slots for I/O.
822 * The benefit of doing this is to reduce contention against atomic counter
823 * cl_lru_left by changing it from per-page access to per-IO access.
825 unsigned long osc_lru_reserve(struct client_obd *cli, unsigned long npages)
827 unsigned long reserved = 0;
828 unsigned long max_pages;
831 /* reserve a full RPC window at most to avoid that a thread accidentally
832 * consumes too many LRU slots */
833 max_pages = cli->cl_max_pages_per_rpc * cli->cl_max_rpcs_in_flight;
834 if (npages > max_pages)
837 c = atomic_long_read(cli->cl_lru_left);
838 if (c < npages && osc_lru_reclaim(cli, npages) > 0)
839 c = atomic_long_read(cli->cl_lru_left);
840 while (c >= npages) {
841 if (c == atomic_long_cmpxchg(cli->cl_lru_left, c, c - npages)) {
845 c = atomic_long_read(cli->cl_lru_left);
847 if (atomic_long_read(cli->cl_lru_left) < max_pages) {
848 /* If there aren't enough pages in the per-OSC LRU then
849 * wake up the LRU thread to try and clear out space, so
850 * we don't block if pages are being dirtied quickly. */
851 CDEBUG(D_CACHE, "%s: queue LRU, left: %lu/%ld.\n",
852 cli_name(cli), atomic_long_read(cli->cl_lru_left),
854 (void)ptlrpcd_queue_work(cli->cl_lru_work);
861 * osc_lru_unreserve() is called to unreserve LRU slots.
863 * LRU slots reserved by osc_lru_reserve() may have entries left due to several
864 * reasons such as page already existing or I/O error. Those reserved slots
865 * should be freed by calling this function.
867 void osc_lru_unreserve(struct client_obd *cli, unsigned long npages)
869 atomic_long_add(npages, cli->cl_lru_left);
870 wake_up_all(&osc_lru_waitq);
874 * Atomic operations are expensive. We accumulate the accounting for the
875 * same page zone to get better performance.
876 * In practice this can work pretty good because the pages in the same RPC
877 * are likely from the same page zone.
879 static inline void unstable_page_accounting(struct ptlrpc_bulk_desc *desc,
880 struct osc_brw_async_args *aa,
889 LASSERT(ptlrpc_is_bulk_desc_kiov(desc->bd_type));
890 page_count = desc->bd_iov_count;
892 page_count = aa->aa_page_count;
895 for (i = 0; i < page_count; i++) {
898 pz = page_zone(BD_GET_KIOV(desc, i).kiov_page);
900 pz = page_zone(aa->aa_ppga[i]->pg);
902 if (likely(pz == zone)) {
908 mod_zone_page_state(zone, NR_UNSTABLE_NFS,
916 mod_zone_page_state(zone, NR_UNSTABLE_NFS, factor * count);
919 static inline void add_unstable_page_accounting(struct ptlrpc_bulk_desc *desc,
920 struct osc_brw_async_args *aa)
922 unstable_page_accounting(desc, aa, 1);
925 static inline void dec_unstable_page_accounting(struct ptlrpc_bulk_desc *desc,
926 struct osc_brw_async_args *aa)
928 unstable_page_accounting(desc, aa, -1);
932 * Performs "unstable" page accounting. This function balances the
933 * increment operations performed in osc_inc_unstable_pages. It is
934 * registered as the RPC request callback, and is executed when the
935 * bulk RPC is committed on the server. Thus at this point, the pages
936 * involved in the bulk transfer are no longer considered unstable.
938 * If this function is called, the request should have been committed
939 * or req:rq_unstable must have been set; it implies that the unstable
940 * statistic have been added.
942 void osc_dec_unstable_pages(struct ptlrpc_request *req)
944 struct ptlrpc_bulk_desc *desc = req->rq_bulk;
945 struct osc_brw_async_args *aa = (void *)&req->rq_async_args;
946 struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
951 page_count = desc->bd_iov_count;
953 page_count = aa->aa_page_count;
955 LASSERT(page_count >= 0);
957 dec_unstable_page_accounting(desc, aa);
959 unstable_count = atomic_long_sub_return(page_count,
960 &cli->cl_unstable_count);
961 LASSERT(unstable_count >= 0);
963 unstable_count = atomic_long_sub_return(page_count,
964 &cli->cl_cache->ccc_unstable_nr);
965 LASSERT(unstable_count >= 0);
966 if (unstable_count == 0)
967 wake_up_all(&cli->cl_cache->ccc_unstable_waitq);
969 if (waitqueue_active(&osc_lru_waitq))
970 (void)ptlrpcd_queue_work(cli->cl_lru_work);
974 * "unstable" page accounting. See: osc_dec_unstable_pages.
976 void osc_inc_unstable_pages(struct ptlrpc_request *req)
978 struct ptlrpc_bulk_desc *desc = req->rq_bulk;
979 struct osc_brw_async_args *aa = (void *)&req->rq_async_args;
980 struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
983 /* No unstable page tracking */
984 if (cli->cl_cache == NULL || !cli->cl_cache->ccc_unstable_check)
988 page_count = desc->bd_iov_count;
990 page_count = aa->aa_page_count;
992 add_unstable_page_accounting(desc, aa);
993 atomic_long_add(page_count, &cli->cl_unstable_count);
994 atomic_long_add(page_count, &cli->cl_cache->ccc_unstable_nr);
996 /* If the request has already been committed (i.e. brw_commit
997 * called via rq_commit_cb), we need to undo the unstable page
998 * increments we just performed because rq_commit_cb wont be
1000 spin_lock(&req->rq_lock);
1001 if (unlikely(req->rq_committed)) {
1002 spin_unlock(&req->rq_lock);
1004 osc_dec_unstable_pages(req);
1006 req->rq_unstable = 1;
1007 spin_unlock(&req->rq_lock);
1012 * Check if it piggybacks SOFT_SYNC flag to OST from this OSC.
1013 * This function will be called by every BRW RPC so it's critical
1014 * to make this function fast.
1016 bool osc_over_unstable_soft_limit(struct client_obd *cli)
1018 long unstable_nr, osc_unstable_count;
1020 /* Can't check cli->cl_unstable_count, therefore, no soft limit */
1021 if (cli->cl_cache == NULL || !cli->cl_cache->ccc_unstable_check)
1024 osc_unstable_count = atomic_long_read(&cli->cl_unstable_count);
1025 unstable_nr = atomic_long_read(&cli->cl_cache->ccc_unstable_nr);
1028 "%s: cli: %p unstable pages: %lu, osc unstable pages: %lu\n",
1029 cli_name(cli), cli, unstable_nr, osc_unstable_count);
1031 /* If the LRU slots are in shortage - 25% remaining AND this OSC
1032 * has one full RPC window of unstable pages, it's a good chance
1033 * to piggyback a SOFT_SYNC flag.
1034 * Please notice that the OST won't take immediate response for the
1035 * SOFT_SYNC request so active OSCs will have more chance to carry
1036 * the flag, this is reasonable. */
1037 return unstable_nr > cli->cl_cache->ccc_lru_max >> 2 &&
1038 osc_unstable_count > cli->cl_max_pages_per_rpc *
1039 cli->cl_max_rpcs_in_flight;
1043 * Return how many LRU pages in the cache of all OSC devices
1045 * \retval return # of cached LRU pages times reclaimation tendency
1046 * \retval SHRINK_STOP if it cannot do any scanning in this time
1048 unsigned long osc_cache_shrink_count(struct shrinker *sk,
1049 struct shrink_control *sc)
1051 struct client_obd *cli;
1052 unsigned long cached = 0;
1054 spin_lock(&osc_shrink_lock);
1055 list_for_each_entry(cli, &osc_shrink_list, cl_shrink_list)
1056 cached += atomic_long_read(&cli->cl_lru_in_list);
1057 spin_unlock(&osc_shrink_lock);
1059 return (cached * sysctl_vfs_cache_pressure) / 100;
1063 * Scan and try to reclaim sc->nr_to_scan cached LRU pages
1065 * \retval number of cached LRU pages reclaimed
1066 * \retval SHRINK_STOP if it cannot do any scanning in this time
1068 * Linux kernel will loop calling this shrinker scan routine with
1069 * sc->nr_to_scan = SHRINK_BATCH(128 for now) until kernel got enough memory.
1071 * If sc->nr_to_scan is 0, the VM is querying the cache size, we don't need
1072 * to scan and try to reclaim LRU pages, just return 0 and
1073 * osc_cache_shrink_count() will report the LRU page number.
1075 unsigned long osc_cache_shrink_scan(struct shrinker *sk,
1076 struct shrink_control *sc)
1078 struct client_obd *cli;
1079 struct client_obd *stop_anchor = NULL;
1085 if (sc->nr_to_scan == 0)
1088 if (!(sc->gfp_mask & __GFP_FS))
1091 env = cl_env_get(&refcheck);
1095 spin_lock(&osc_shrink_lock);
1096 while (!list_empty(&osc_shrink_list)) {
1097 cli = list_entry(osc_shrink_list.next, struct client_obd,
1100 if (stop_anchor == NULL)
1102 else if (cli == stop_anchor)
1105 list_move_tail(&cli->cl_shrink_list, &osc_shrink_list);
1106 spin_unlock(&osc_shrink_lock);
1108 /* shrink no more than max_pages_per_rpc for an OSC */
1109 rc = osc_lru_shrink(env, cli, (sc->nr_to_scan - shrank) >
1110 cli->cl_max_pages_per_rpc ?
1111 cli->cl_max_pages_per_rpc :
1112 sc->nr_to_scan - shrank, true);
1116 if (shrank >= sc->nr_to_scan)
1119 spin_lock(&osc_shrink_lock);
1121 spin_unlock(&osc_shrink_lock);
1124 cl_env_put(env, &refcheck);