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).
16 * You should have received a copy of the GNU General Public License
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, 2017, 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 s64 osc_submit_duration(struct osc_page *opg)
124 if (ktime_to_ns(opg->ops_submit_time) == 0)
127 return ktime_ms_delta(ktime_get(), 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 void osc_page_touch(const struct lu_env *env,
254 const struct cl_page_slice *slice, size_t to)
256 struct osc_page *opg = cl2osc_page(slice);
257 struct cl_object *obj = opg->ops_cl.cpl_obj;
259 osc_page_touch_at(env, obj, osc_index(opg), to);
262 static const struct cl_page_operations osc_page_ops = {
263 .cpo_print = osc_page_print,
264 .cpo_delete = osc_page_delete,
265 .cpo_clip = osc_page_clip,
266 .cpo_cancel = osc_page_cancel,
267 .cpo_flush = osc_page_flush,
268 .cpo_page_touch = osc_page_touch,
271 int osc_page_init(const struct lu_env *env, struct cl_object *obj,
272 struct cl_page *page, pgoff_t index)
274 struct osc_object *osc = cl2osc(obj);
275 struct osc_page *opg = cl_object_page_slice(obj, page);
276 struct osc_io *oio = osc_env_io(env);
280 opg->ops_to = PAGE_SIZE;
282 INIT_LIST_HEAD(&opg->ops_lru);
284 result = osc_prep_async_page(osc, opg, page->cp_vmpage,
285 cl_offset(obj, index));
289 opg->ops_srvlock = osc_io_srvlock(oio);
290 cl_page_slice_add(page, &opg->ops_cl, obj, index,
294 /* reserve an LRU space for this page */
295 if (page->cp_type == CPT_CACHEABLE) {
296 result = osc_lru_alloc(env, osc_cli(osc), opg);
298 result = radix_tree_preload(GFP_NOFS);
300 spin_lock(&osc->oo_tree_lock);
301 result = radix_tree_insert(&osc->oo_tree,
305 spin_unlock(&osc->oo_tree_lock);
307 radix_tree_preload_end();
314 EXPORT_SYMBOL(osc_page_init);
317 * Helper function called by osc_io_submit() for every page in an immediate
318 * transfer (i.e., transferred synchronously).
320 void osc_page_submit(const struct lu_env *env, struct osc_page *opg,
321 enum cl_req_type crt, int brw_flags)
323 struct osc_async_page *oap = &opg->ops_oap;
325 LASSERTF(oap->oap_magic == OAP_MAGIC, "Bad oap magic: oap %p, "
326 "magic 0x%x\n", oap, oap->oap_magic);
327 LASSERT(oap->oap_async_flags & ASYNC_READY);
328 LASSERT(oap->oap_async_flags & ASYNC_COUNT_STABLE);
330 oap->oap_cmd = crt == CRT_WRITE ? OBD_BRW_WRITE : OBD_BRW_READ;
331 oap->oap_page_off = opg->ops_from;
332 oap->oap_count = opg->ops_to - opg->ops_from;
333 oap->oap_brw_flags = OBD_BRW_SYNC | brw_flags;
335 if (cfs_capable(CFS_CAP_SYS_RESOURCE)) {
336 oap->oap_brw_flags |= OBD_BRW_NOQUOTA;
337 oap->oap_cmd |= OBD_BRW_NOQUOTA;
340 opg->ops_submit_time = ktime_get();
341 osc_page_transfer_get(opg, "transfer\0imm");
342 osc_page_transfer_add(env, opg, crt);
345 /* --------------- LRU page management ------------------ */
347 /* OSC is a natural place to manage LRU pages as applications are specialized
348 * to write OSC by OSC. Ideally, if one OSC is used more frequently it should
349 * occupy more LRU slots. On the other hand, we should avoid using up all LRU
350 * slots (client_obd::cl_lru_left) otherwise process has to be put into sleep
351 * for free LRU slots - this will be very bad so the algorithm requires each
352 * OSC to free slots voluntarily to maintain a reasonable number of free slots
356 static DECLARE_WAIT_QUEUE_HEAD(osc_lru_waitq);
359 * LRU pages are freed in batch mode. OSC should at least free this
360 * number of pages to avoid running out of LRU slots.
362 static inline int lru_shrink_min(struct client_obd *cli)
364 return cli->cl_max_pages_per_rpc * 2;
368 * free this number at most otherwise it will take too long time to finsih.
370 static inline int lru_shrink_max(struct client_obd *cli)
372 return cli->cl_max_pages_per_rpc * cli->cl_max_rpcs_in_flight;
376 * Check if we can free LRU slots from this OSC. If there exists LRU waiters,
377 * we should free slots aggressively. In this way, slots are freed in a steady
378 * step to maintain fairness among OSCs.
380 * Return how many LRU pages should be freed.
382 static int osc_cache_too_much(struct client_obd *cli)
384 struct cl_client_cache *cache = cli->cl_cache;
385 long pages = atomic_long_read(&cli->cl_lru_in_list);
386 unsigned long budget;
388 LASSERT(cache != NULL);
389 budget = cache->ccc_lru_max / (atomic_read(&cache->ccc_users) - 2);
391 /* if it's going to run out LRU slots, we should free some, but not
392 * too much to maintain faireness among OSCs. */
393 if (atomic_long_read(cli->cl_lru_left) < cache->ccc_lru_max >> 2) {
395 return lru_shrink_max(cli);
396 else if (pages >= budget / 2)
397 return lru_shrink_min(cli);
399 time64_t duration = ktime_get_real_seconds();
402 /* knock out pages by duration of no IO activity */
403 duration -= cli->cl_lru_last_used;
405 * The difference shouldn't be more than 70 years
406 * so we can safely case to a long. Round to
407 * approximately 1 minute.
409 timediff = (long)(duration >> 6);
410 if (timediff > 0 && pages >= budget / timediff)
411 return lru_shrink_min(cli);
416 int lru_queue_work(const struct lu_env *env, void *data)
418 struct client_obd *cli = data;
421 CDEBUG(D_CACHE, "%s: run LRU work for client obd\n", cli_name(cli));
422 count = osc_cache_too_much(cli);
424 int rc = osc_lru_shrink(env, cli, count, false);
426 CDEBUG(D_CACHE, "%s: shrank %d/%d pages from client obd\n",
427 cli_name(cli), rc, count);
429 CDEBUG(D_CACHE, "%s: queue again\n", cli_name(cli));
430 ptlrpcd_queue_work(cli->cl_lru_work);
437 void osc_lru_add_batch(struct client_obd *cli, struct list_head *plist)
439 struct list_head lru = LIST_HEAD_INIT(lru);
440 struct osc_async_page *oap;
443 list_for_each_entry(oap, plist, oap_pending_item) {
444 struct osc_page *opg = oap2osc_page(oap);
446 if (!opg->ops_in_lru)
450 LASSERT(list_empty(&opg->ops_lru));
451 list_add(&opg->ops_lru, &lru);
455 spin_lock(&cli->cl_lru_list_lock);
456 list_splice_tail(&lru, &cli->cl_lru_list);
457 atomic_long_sub(npages, &cli->cl_lru_busy);
458 atomic_long_add(npages, &cli->cl_lru_in_list);
459 cli->cl_lru_last_used = ktime_get_real_seconds();
460 spin_unlock(&cli->cl_lru_list_lock);
462 if (waitqueue_active(&osc_lru_waitq))
463 (void)ptlrpcd_queue_work(cli->cl_lru_work);
467 static void __osc_lru_del(struct client_obd *cli, struct osc_page *opg)
469 LASSERT(atomic_long_read(&cli->cl_lru_in_list) > 0);
470 list_del_init(&opg->ops_lru);
471 atomic_long_dec(&cli->cl_lru_in_list);
475 * Page is being destroyed. The page may be not in LRU list, if the transfer
476 * has never finished(error occurred).
478 static void osc_lru_del(struct client_obd *cli, struct osc_page *opg)
480 if (opg->ops_in_lru) {
481 spin_lock(&cli->cl_lru_list_lock);
482 if (!list_empty(&opg->ops_lru)) {
483 __osc_lru_del(cli, opg);
485 LASSERT(atomic_long_read(&cli->cl_lru_busy) > 0);
486 atomic_long_dec(&cli->cl_lru_busy);
488 spin_unlock(&cli->cl_lru_list_lock);
490 atomic_long_inc(cli->cl_lru_left);
491 /* this is a great place to release more LRU pages if
492 * this osc occupies too many LRU pages and kernel is
493 * stealing one of them. */
494 if (osc_cache_too_much(cli)) {
495 CDEBUG(D_CACHE, "%s: queue LRU work\n", cli_name(cli));
496 (void)ptlrpcd_queue_work(cli->cl_lru_work);
498 wake_up(&osc_lru_waitq);
500 LASSERT(list_empty(&opg->ops_lru));
505 * Delete page from LRU list for redirty.
507 static void osc_lru_use(struct client_obd *cli, struct osc_page *opg)
509 /* If page is being transferred for the first time,
510 * ops_lru should be empty */
511 if (opg->ops_in_lru) {
512 spin_lock(&cli->cl_lru_list_lock);
513 if (!list_empty(&opg->ops_lru)) {
514 __osc_lru_del(cli, opg);
515 atomic_long_inc(&cli->cl_lru_busy);
517 spin_unlock(&cli->cl_lru_list_lock);
521 static void discard_pagevec(const struct lu_env *env, struct cl_io *io,
522 struct cl_page **pvec, int max_index)
526 for (i = 0; i < max_index; i++) {
527 struct cl_page *page = pvec[i];
529 LASSERT(cl_page_is_owned(page, io));
530 cl_page_delete(env, page);
531 cl_page_discard(env, io, page);
532 cl_page_disown(env, io, page);
533 cl_page_put(env, page);
540 * Check if a cl_page can be released, i.e, it's not being used.
542 * If unstable account is turned on, bulk transfer may hold one refcount
543 * for recovery so we need to check vmpage refcount as well; otherwise,
544 * even we can destroy cl_page but the corresponding vmpage can't be reused.
546 static inline bool lru_page_busy(struct client_obd *cli, struct cl_page *page)
548 if (cl_page_in_use_noref(page))
551 if (cli->cl_cache->ccc_unstable_check) {
552 struct page *vmpage = cl_page_vmpage(page);
554 /* vmpage have two known users: cl_page and VM page cache */
555 if (page_count(vmpage) - page_mapcount(vmpage) > 2)
562 * Drop @target of pages from LRU at most.
564 long osc_lru_shrink(const struct lu_env *env, struct client_obd *cli,
565 long target, bool force)
568 struct cl_object *clobj = NULL;
569 struct cl_page **pvec;
570 struct osc_page *opg;
577 LASSERT(atomic_long_read(&cli->cl_lru_in_list) >= 0);
578 if (atomic_long_read(&cli->cl_lru_in_list) == 0 || target <= 0)
581 CDEBUG(D_CACHE, "%s: shrinkers: %d, force: %d\n",
582 cli_name(cli), atomic_read(&cli->cl_lru_shrinkers), force);
584 if (atomic_read(&cli->cl_lru_shrinkers) > 0)
587 if (atomic_inc_return(&cli->cl_lru_shrinkers) > 1) {
588 atomic_dec(&cli->cl_lru_shrinkers);
592 atomic_inc(&cli->cl_lru_shrinkers);
595 pvec = (struct cl_page **)osc_env_info(env)->oti_pvec;
596 io = osc_env_thread_io(env);
598 spin_lock(&cli->cl_lru_list_lock);
600 cli->cl_lru_reclaim++;
601 maxscan = min(target << 1, atomic_long_read(&cli->cl_lru_in_list));
602 while (!list_empty(&cli->cl_lru_list)) {
603 struct cl_page *page;
604 bool will_free = false;
606 if (!force && atomic_read(&cli->cl_lru_shrinkers) > 1)
612 opg = list_entry(cli->cl_lru_list.next, struct osc_page,
614 page = opg->ops_cl.cpl_page;
615 if (lru_page_busy(cli, page)) {
616 list_move_tail(&opg->ops_lru, &cli->cl_lru_list);
620 LASSERT(page->cp_obj != NULL);
621 if (clobj != page->cp_obj) {
622 struct cl_object *tmp = page->cp_obj;
625 spin_unlock(&cli->cl_lru_list_lock);
628 discard_pagevec(env, io, pvec, index);
632 cl_object_put(env, clobj);
638 io->ci_ignore_layout = 1;
639 rc = cl_io_init(env, io, CIT_MISC, clobj);
641 spin_lock(&cli->cl_lru_list_lock);
650 if (cl_page_own_try(env, io, page) == 0) {
651 if (!lru_page_busy(cli, page)) {
652 /* remove it from lru list earlier to avoid
654 __osc_lru_del(cli, opg);
655 opg->ops_in_lru = 0; /* will be discarded */
660 cl_page_disown(env, io, page);
665 list_move_tail(&opg->ops_lru, &cli->cl_lru_list);
669 /* Don't discard and free the page with cl_lru_list held */
670 pvec[index++] = page;
671 if (unlikely(index == OTI_PVEC_SIZE)) {
672 spin_unlock(&cli->cl_lru_list_lock);
673 discard_pagevec(env, io, pvec, index);
676 spin_lock(&cli->cl_lru_list_lock);
679 if (++count >= target)
682 spin_unlock(&cli->cl_lru_list_lock);
685 discard_pagevec(env, io, pvec, index);
688 cl_object_put(env, clobj);
691 atomic_dec(&cli->cl_lru_shrinkers);
693 atomic_long_add(count, cli->cl_lru_left);
694 wake_up_all(&osc_lru_waitq);
696 RETURN(count > 0 ? count : rc);
698 EXPORT_SYMBOL(osc_lru_shrink);
701 * Reclaim LRU pages by an IO thread. The caller wants to reclaim at least
702 * \@npages of LRU slots. For performance consideration, it's better to drop
703 * LRU pages in batch. Therefore, the actual number is adjusted at least
706 static long osc_lru_reclaim(struct client_obd *cli, unsigned long npages)
709 struct cl_client_cache *cache = cli->cl_cache;
715 LASSERT(cache != NULL);
717 env = cl_env_get(&refcheck);
721 npages = max_t(int, npages, cli->cl_max_pages_per_rpc);
722 CDEBUG(D_CACHE, "%s: start to reclaim %ld pages from LRU\n",
723 cli_name(cli), npages);
724 rc = osc_lru_shrink(env, cli, npages, true);
726 CDEBUG(D_CACHE, "%s: reclaimed %ld/%ld pages from LRU\n",
727 cli_name(cli), rc, npages);
728 if (osc_cache_too_much(cli) > 0)
729 ptlrpcd_queue_work(cli->cl_lru_work);
735 CDEBUG(D_CACHE, "%s: cli %p no free slots, pages: %ld/%ld, want: %ld\n",
736 cli_name(cli), cli, atomic_long_read(&cli->cl_lru_in_list),
737 atomic_long_read(&cli->cl_lru_busy), npages);
739 /* Reclaim LRU slots from other client_obd as it can't free enough
740 * from its own. This should rarely happen. */
741 spin_lock(&cache->ccc_lru_lock);
742 LASSERT(!list_empty(&cache->ccc_lru));
744 cache->ccc_lru_shrinkers++;
745 list_move_tail(&cli->cl_lru_osc, &cache->ccc_lru);
747 max_scans = atomic_read(&cache->ccc_users) - 2;
748 while (--max_scans > 0 && !list_empty(&cache->ccc_lru)) {
749 cli = list_entry(cache->ccc_lru.next, struct client_obd,
752 CDEBUG(D_CACHE, "%s: cli %p LRU pages: %ld, busy: %ld.\n",
754 atomic_long_read(&cli->cl_lru_in_list),
755 atomic_long_read(&cli->cl_lru_busy));
757 list_move_tail(&cli->cl_lru_osc, &cache->ccc_lru);
758 if (osc_cache_too_much(cli) > 0) {
759 spin_unlock(&cache->ccc_lru_lock);
761 rc = osc_lru_shrink(env, cli, npages, true);
762 spin_lock(&cache->ccc_lru_lock);
769 spin_unlock(&cache->ccc_lru_lock);
772 cl_env_put(env, &refcheck);
773 CDEBUG(D_CACHE, "%s: cli %p freed %ld pages.\n",
774 cli_name(cli), cli, rc);
779 * osc_lru_alloc() is called to allocate an LRU slot for a cl_page.
781 * Usually the LRU slots are reserved in osc_io_iter_rw_init().
782 * Only in the case that the LRU slots are in extreme shortage, it should
783 * have reserved enough slots for an IO.
785 static int osc_lru_alloc(const struct lu_env *env, struct client_obd *cli,
786 struct osc_page *opg)
788 struct l_wait_info lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
789 struct osc_io *oio = osc_env_io(env);
794 if (cli->cl_cache == NULL) /* shall not be in LRU */
797 if (oio->oi_lru_reserved > 0) {
798 --oio->oi_lru_reserved;
802 LASSERT(atomic_long_read(cli->cl_lru_left) >= 0);
803 while (!atomic_long_add_unless(cli->cl_lru_left, -1, 0)) {
804 /* run out of LRU spaces, try to drop some by itself */
805 rc = osc_lru_reclaim(cli, 1);
812 rc = l_wait_event(osc_lru_waitq,
813 atomic_long_read(cli->cl_lru_left) > 0,
821 atomic_long_inc(&cli->cl_lru_busy);
830 * osc_lru_reserve() is called to reserve enough LRU slots for I/O.
832 * The benefit of doing this is to reduce contention against atomic counter
833 * cl_lru_left by changing it from per-page access to per-IO access.
835 unsigned long osc_lru_reserve(struct client_obd *cli, unsigned long npages)
837 unsigned long reserved = 0;
838 unsigned long max_pages;
841 /* reserve a full RPC window at most to avoid that a thread accidentally
842 * consumes too many LRU slots */
843 max_pages = cli->cl_max_pages_per_rpc * cli->cl_max_rpcs_in_flight;
844 if (npages > max_pages)
847 c = atomic_long_read(cli->cl_lru_left);
848 if (c < npages && osc_lru_reclaim(cli, npages) > 0)
849 c = atomic_long_read(cli->cl_lru_left);
850 while (c >= npages) {
851 if (c == atomic_long_cmpxchg(cli->cl_lru_left, c, c - npages)) {
855 c = atomic_long_read(cli->cl_lru_left);
857 if (atomic_long_read(cli->cl_lru_left) < max_pages) {
858 /* If there aren't enough pages in the per-OSC LRU then
859 * wake up the LRU thread to try and clear out space, so
860 * we don't block if pages are being dirtied quickly. */
861 CDEBUG(D_CACHE, "%s: queue LRU, left: %lu/%ld.\n",
862 cli_name(cli), atomic_long_read(cli->cl_lru_left),
864 (void)ptlrpcd_queue_work(cli->cl_lru_work);
871 * osc_lru_unreserve() is called to unreserve LRU slots.
873 * LRU slots reserved by osc_lru_reserve() may have entries left due to several
874 * reasons such as page already existing or I/O error. Those reserved slots
875 * should be freed by calling this function.
877 void osc_lru_unreserve(struct client_obd *cli, unsigned long npages)
879 atomic_long_add(npages, cli->cl_lru_left);
880 wake_up_all(&osc_lru_waitq);
884 * Atomic operations are expensive. We accumulate the accounting for the
885 * same page zone to get better performance.
886 * In practice this can work pretty good because the pages in the same RPC
887 * are likely from the same page zone.
889 static inline void unstable_page_accounting(struct ptlrpc_bulk_desc *desc,
890 struct osc_brw_async_args *aa,
899 LASSERT(ptlrpc_is_bulk_desc_kiov(desc->bd_type));
900 page_count = desc->bd_iov_count;
902 page_count = aa->aa_page_count;
905 for (i = 0; i < page_count; i++) {
908 pz = page_zone(BD_GET_KIOV(desc, i).kiov_page);
910 pz = page_zone(aa->aa_ppga[i]->pg);
912 if (likely(pz == zone)) {
918 mod_zone_page_state(zone, NR_UNSTABLE_NFS,
926 mod_zone_page_state(zone, NR_UNSTABLE_NFS, factor * count);
929 static inline void add_unstable_page_accounting(struct ptlrpc_bulk_desc *desc,
930 struct osc_brw_async_args *aa)
932 unstable_page_accounting(desc, aa, 1);
935 static inline void dec_unstable_page_accounting(struct ptlrpc_bulk_desc *desc,
936 struct osc_brw_async_args *aa)
938 unstable_page_accounting(desc, aa, -1);
942 * Performs "unstable" page accounting. This function balances the
943 * increment operations performed in osc_inc_unstable_pages. It is
944 * registered as the RPC request callback, and is executed when the
945 * bulk RPC is committed on the server. Thus at this point, the pages
946 * involved in the bulk transfer are no longer considered unstable.
948 * If this function is called, the request should have been committed
949 * or req:rq_unstable must have been set; it implies that the unstable
950 * statistic have been added.
952 void osc_dec_unstable_pages(struct ptlrpc_request *req)
954 struct ptlrpc_bulk_desc *desc = req->rq_bulk;
955 struct osc_brw_async_args *aa = (void *)&req->rq_async_args;
956 struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
961 page_count = desc->bd_iov_count;
963 page_count = aa->aa_page_count;
965 LASSERT(page_count >= 0);
967 dec_unstable_page_accounting(desc, aa);
969 unstable_count = atomic_long_sub_return(page_count,
970 &cli->cl_unstable_count);
971 LASSERT(unstable_count >= 0);
973 unstable_count = atomic_long_sub_return(page_count,
974 &cli->cl_cache->ccc_unstable_nr);
975 LASSERT(unstable_count >= 0);
976 if (unstable_count == 0)
977 wake_up_all(&cli->cl_cache->ccc_unstable_waitq);
979 if (waitqueue_active(&osc_lru_waitq))
980 (void)ptlrpcd_queue_work(cli->cl_lru_work);
984 * "unstable" page accounting. See: osc_dec_unstable_pages.
986 void osc_inc_unstable_pages(struct ptlrpc_request *req)
988 struct ptlrpc_bulk_desc *desc = req->rq_bulk;
989 struct osc_brw_async_args *aa = (void *)&req->rq_async_args;
990 struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
993 /* No unstable page tracking */
994 if (cli->cl_cache == NULL || !cli->cl_cache->ccc_unstable_check)
998 page_count = desc->bd_iov_count;
1000 page_count = aa->aa_page_count;
1002 add_unstable_page_accounting(desc, aa);
1003 atomic_long_add(page_count, &cli->cl_unstable_count);
1004 atomic_long_add(page_count, &cli->cl_cache->ccc_unstable_nr);
1006 /* If the request has already been committed (i.e. brw_commit
1007 * called via rq_commit_cb), we need to undo the unstable page
1008 * increments we just performed because rq_commit_cb wont be
1010 spin_lock(&req->rq_lock);
1011 if (unlikely(req->rq_committed)) {
1012 spin_unlock(&req->rq_lock);
1014 osc_dec_unstable_pages(req);
1016 req->rq_unstable = 1;
1017 spin_unlock(&req->rq_lock);
1022 * Check if it piggybacks SOFT_SYNC flag to OST from this OSC.
1023 * This function will be called by every BRW RPC so it's critical
1024 * to make this function fast.
1026 bool osc_over_unstable_soft_limit(struct client_obd *cli)
1028 long unstable_nr, osc_unstable_count;
1030 /* Can't check cli->cl_unstable_count, therefore, no soft limit */
1031 if (cli->cl_cache == NULL || !cli->cl_cache->ccc_unstable_check)
1034 osc_unstable_count = atomic_long_read(&cli->cl_unstable_count);
1035 unstable_nr = atomic_long_read(&cli->cl_cache->ccc_unstable_nr);
1038 "%s: cli: %p unstable pages: %lu, osc unstable pages: %lu\n",
1039 cli_name(cli), cli, unstable_nr, osc_unstable_count);
1041 /* If the LRU slots are in shortage - 25% remaining AND this OSC
1042 * has one full RPC window of unstable pages, it's a good chance
1043 * to piggyback a SOFT_SYNC flag.
1044 * Please notice that the OST won't take immediate response for the
1045 * SOFT_SYNC request so active OSCs will have more chance to carry
1046 * the flag, this is reasonable. */
1047 return unstable_nr > cli->cl_cache->ccc_lru_max >> 2 &&
1048 osc_unstable_count > cli->cl_max_pages_per_rpc *
1049 cli->cl_max_rpcs_in_flight;
1053 * Return how many LRU pages in the cache of all OSC devices
1055 * \retval return # of cached LRU pages times reclaimation tendency
1056 * \retval SHRINK_STOP if it cannot do any scanning in this time
1058 unsigned long osc_cache_shrink_count(struct shrinker *sk,
1059 struct shrink_control *sc)
1061 struct client_obd *cli;
1062 unsigned long cached = 0;
1064 spin_lock(&osc_shrink_lock);
1065 list_for_each_entry(cli, &osc_shrink_list, cl_shrink_list)
1066 cached += atomic_long_read(&cli->cl_lru_in_list);
1067 spin_unlock(&osc_shrink_lock);
1069 return (cached * sysctl_vfs_cache_pressure) / 100;
1073 * Scan and try to reclaim sc->nr_to_scan cached LRU pages
1075 * \retval number of cached LRU pages reclaimed
1076 * \retval SHRINK_STOP if it cannot do any scanning in this time
1078 * Linux kernel will loop calling this shrinker scan routine with
1079 * sc->nr_to_scan = SHRINK_BATCH(128 for now) until kernel got enough memory.
1081 * If sc->nr_to_scan is 0, the VM is querying the cache size, we don't need
1082 * to scan and try to reclaim LRU pages, just return 0 and
1083 * osc_cache_shrink_count() will report the LRU page number.
1085 unsigned long osc_cache_shrink_scan(struct shrinker *sk,
1086 struct shrink_control *sc)
1088 struct client_obd *cli;
1089 struct client_obd *stop_anchor = NULL;
1095 if (sc->nr_to_scan == 0)
1098 if (!(sc->gfp_mask & __GFP_FS))
1101 env = cl_env_get(&refcheck);
1105 spin_lock(&osc_shrink_lock);
1106 while (!list_empty(&osc_shrink_list)) {
1107 cli = list_entry(osc_shrink_list.next, struct client_obd,
1110 if (stop_anchor == NULL)
1112 else if (cli == stop_anchor)
1115 list_move_tail(&cli->cl_shrink_list, &osc_shrink_list);
1116 spin_unlock(&osc_shrink_lock);
1118 /* shrink no more than max_pages_per_rpc for an OSC */
1119 rc = osc_lru_shrink(env, cli, (sc->nr_to_scan - shrank) >
1120 cli->cl_max_pages_per_rpc ?
1121 cli->cl_max_pages_per_rpc :
1122 sc->nr_to_scan - shrank, true);
1126 if (shrank >= sc->nr_to_scan)
1129 spin_lock(&osc_shrink_lock);
1131 spin_unlock(&osc_shrink_lock);
1134 cl_env_put(env, &refcheck);