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/
31 * Implementation of cl_page for OSC layer.
33 * Author: Nikita Danilov <nikita.danilov@sun.com>
34 * Author: Jinshan Xiong <jinshan.xiong@intel.com>
37 #define DEBUG_SUBSYSTEM S_OSC
38 #include <lustre_osc.h>
40 #include "osc_internal.h"
42 static void osc_lru_del(struct client_obd *cli, struct osc_page *opg);
43 static void osc_lru_use(struct client_obd *cli, struct osc_page *opg);
44 static int osc_lru_alloc(const struct lu_env *env, struct client_obd *cli,
45 struct osc_page *opg);
54 static void osc_page_transfer_get(struct osc_page *opg, const char *label)
56 struct cl_page *page = opg->ops_cl.cpl_page;
58 LASSERT(!opg->ops_transfer_pinned);
60 lu_ref_add_atomic(&page->cp_reference, label, page);
61 opg->ops_transfer_pinned = 1;
64 static void osc_page_transfer_put(const struct lu_env *env,
67 struct cl_page *page = opg->ops_cl.cpl_page;
69 if (opg->ops_transfer_pinned) {
70 opg->ops_transfer_pinned = 0;
71 lu_ref_del(&page->cp_reference, "transfer", page);
72 cl_page_put(env, page);
77 * This is called once for every page when it is submitted for a transfer
78 * either opportunistic (osc_page_cache_add()), or immediate
79 * (osc_page_submit()).
81 static void osc_page_transfer_add(const struct lu_env *env,
82 struct osc_page *opg, enum cl_req_type crt)
84 struct osc_object *obj = osc_page_object(opg);
86 osc_lru_use(osc_cli(obj), opg);
89 int osc_page_cache_add(const struct lu_env *env, struct osc_page *opg,
90 struct cl_io *io, cl_commit_cbt cb)
95 osc_page_transfer_get(opg, "transfer\0cache");
96 result = osc_queue_async_io(env, io, opg, cb);
98 osc_page_transfer_put(env, opg);
100 osc_page_transfer_add(env, opg, CRT_WRITE);
105 void osc_index2policy(union ldlm_policy_data *policy,
106 const struct cl_object *obj, pgoff_t start, pgoff_t end)
108 memset(policy, 0, sizeof *policy);
109 policy->l_extent.start = start << PAGE_SHIFT;
110 policy->l_extent.end = ((end + 1) << PAGE_SHIFT) - 1;
113 static int osc_page_print(const struct lu_env *env,
114 const struct cl_page_slice *slice,
115 void *cookie, lu_printer_t printer)
117 struct osc_page *opg = cl2osc_page(slice);
118 struct osc_async_page *oap = &opg->ops_oap;
119 struct osc_object *obj = osc_page_object(opg);
120 struct client_obd *cli = &osc_export(obj)->exp_obd->u.cli;
122 return (*printer)(env, cookie, LUSTRE_OSC_NAME"-page@%p %lu: "
124 "2< %lld %u %u %#x %#x | %p %p %p > "
126 "4< %d %d %d %lu %c | %c %c %c %c > "
127 "5< %c %c %c %c | %d %c | %d %c %c>\n",
131 list_empty_marker(&oap->oap_pending_item),
132 list_empty_marker(&oap->oap_rpc_item),
134 oap->oap_obj_off, oap->oap_page_off, oap->oap_count,
135 oap->oap_async_flags, oap->oap_brw_flags,
136 oap->oap_request, cli, obj,
138 opg->ops_transfer_pinned,
141 cli->cl_r_in_flight, cli->cl_w_in_flight,
142 cli->cl_max_rpcs_in_flight,
144 waitqueue_active(&cli->cl_cache_waiters) ? '+' : '-',
145 list_empty_marker(&cli->cl_loi_ready_list),
146 list_empty_marker(&cli->cl_loi_hp_ready_list),
147 list_empty_marker(&cli->cl_loi_write_list),
148 list_empty_marker(&cli->cl_loi_read_list),
150 list_empty_marker(&obj->oo_ready_item),
151 list_empty_marker(&obj->oo_hp_ready_item),
152 list_empty_marker(&obj->oo_write_item),
153 list_empty_marker(&obj->oo_read_item),
154 atomic_read(&obj->oo_nr_reads),
155 list_empty_marker(&obj->oo_reading_exts),
156 atomic_read(&obj->oo_nr_writes),
157 list_empty_marker(&obj->oo_hp_exts),
158 list_empty_marker(&obj->oo_urgent_exts));
161 static void osc_page_delete(const struct lu_env *env,
162 const struct cl_page_slice *slice)
164 struct osc_page *opg = cl2osc_page(slice);
165 struct osc_object *obj = osc_page_object(opg);
169 CDEBUG(D_TRACE, "%p\n", opg);
170 osc_page_transfer_put(env, opg);
171 rc = osc_teardown_async_page(env, obj, opg);
173 CL_PAGE_DEBUG(D_ERROR, env, slice->cpl_page,
174 "Trying to teardown failed: %d\n", rc);
178 osc_lru_del(osc_cli(obj), opg);
180 if (slice->cpl_page->cp_type == CPT_CACHEABLE) {
183 spin_lock(&obj->oo_tree_lock);
184 if (opg->ops_intree) {
185 value = radix_tree_delete(&obj->oo_tree,
192 spin_unlock(&obj->oo_tree_lock);
194 LASSERT(ergo(value != NULL, value == opg));
200 static void osc_page_clip(const struct lu_env *env,
201 const struct cl_page_slice *slice,
204 struct osc_page *opg = cl2osc_page(slice);
205 struct osc_async_page *oap = &opg->ops_oap;
207 CDEBUG(D_CACHE, "from %d, to %d\n", from, to);
209 opg->ops_from = from;
210 /* argument @to is exclusive, but @ops_to is inclusive */
211 opg->ops_to = to - 1;
212 oap->oap_async_flags |= ASYNC_COUNT_STABLE;
215 static int osc_page_flush(const struct lu_env *env,
216 const struct cl_page_slice *slice,
219 struct osc_page *opg = cl2osc_page(slice);
222 rc = osc_flush_async_page(env, io, opg);
226 static void osc_page_touch(const struct lu_env *env,
227 const struct cl_page_slice *slice, size_t to)
229 struct osc_page *opg = cl2osc_page(slice);
230 struct cl_object *obj = osc2cl(osc_page_object(opg));
232 osc_page_touch_at(env, obj, osc_index(opg), to);
235 static const struct cl_page_operations osc_page_ops = {
236 .cpo_print = osc_page_print,
237 .cpo_delete = osc_page_delete,
238 .cpo_clip = osc_page_clip,
239 .cpo_flush = osc_page_flush,
240 .cpo_page_touch = osc_page_touch,
243 int osc_page_init(const struct lu_env *env, struct cl_object *obj,
244 struct cl_page *cl_page, pgoff_t index)
246 struct osc_object *osc = cl2osc(obj);
247 struct osc_page *opg = cl_object_page_slice(obj, cl_page);
248 struct osc_io *oio = osc_env_io(env);
252 opg->ops_to = PAGE_SIZE - 1;
254 INIT_LIST_HEAD(&opg->ops_lru);
256 result = osc_prep_async_page(osc, opg, cl_page, index << PAGE_SHIFT);
260 opg->ops_srvlock = osc_io_srvlock(oio);
261 cl_page_slice_add(cl_page, &opg->ops_cl, obj, &osc_page_ops);
263 /* reserve an LRU space for this page */
264 if (cl_page->cp_type == CPT_CACHEABLE) {
265 result = osc_lru_alloc(env, osc_cli(osc), opg);
267 result = radix_tree_preload(GFP_NOFS);
269 spin_lock(&osc->oo_tree_lock);
270 result = radix_tree_insert(&osc->oo_tree,
276 spin_unlock(&osc->oo_tree_lock);
278 radix_tree_preload_end();
285 EXPORT_SYMBOL(osc_page_init);
288 * Helper function called by osc_io_submit() for every page in an immediate
289 * transfer (i.e., transferred synchronously).
291 void osc_page_submit(const struct lu_env *env, struct osc_page *opg,
292 enum cl_req_type crt, int brw_flags)
294 struct osc_io *oio = osc_env_io(env);
295 struct osc_async_page *oap = &opg->ops_oap;
297 LASSERT(oap->oap_async_flags & ASYNC_READY);
298 LASSERT(oap->oap_async_flags & ASYNC_COUNT_STABLE);
300 oap->oap_cmd = crt == CRT_WRITE ? OBD_BRW_WRITE : OBD_BRW_READ;
301 oap->oap_page_off = opg->ops_from;
302 oap->oap_count = opg->ops_to - opg->ops_from + 1;
303 oap->oap_brw_flags = OBD_BRW_SYNC | brw_flags;
305 if (oio->oi_cap_sys_resource)
306 oap->oap_brw_flags |= OBD_BRW_SYS_RESOURCE;
308 osc_page_transfer_get(opg, "transfer\0imm");
309 osc_page_transfer_add(env, opg, crt);
312 /* --------------- LRU page management ------------------ */
314 /* OSC is a natural place to manage LRU pages as applications are specialized
315 * to write OSC by OSC. Ideally, if one OSC is used more frequently it should
316 * occupy more LRU slots. On the other hand, we should avoid using up all LRU
317 * slots (client_obd::cl_lru_left) otherwise process has to be put into sleep
318 * for free LRU slots - this will be very bad so the algorithm requires each
319 * OSC to free slots voluntarily to maintain a reasonable number of free slots
323 static DECLARE_WAIT_QUEUE_HEAD(osc_lru_waitq);
326 * LRU pages are freed in batch mode. OSC should at least free this
327 * number of pages to avoid running out of LRU slots.
329 static inline int lru_shrink_min(struct client_obd *cli)
331 return cli->cl_max_pages_per_rpc * 2;
335 * free this number at most otherwise it will take too long time to finsih.
337 static inline int lru_shrink_max(struct client_obd *cli)
339 return cli->cl_max_pages_per_rpc * cli->cl_max_rpcs_in_flight;
343 * Check if we can free LRU slots from this OSC. If there exists LRU waiters,
344 * we should free slots aggressively. In this way, slots are freed in a steady
345 * step to maintain fairness among OSCs.
347 * Return how many LRU pages should be freed.
349 static int osc_cache_too_much(struct client_obd *cli)
351 struct cl_client_cache *cache = cli->cl_cache;
352 long pages = atomic_long_read(&cli->cl_lru_in_list);
353 unsigned long budget;
355 LASSERT(cache != NULL);
356 budget = cache->ccc_lru_max / (refcount_read(&cache->ccc_users) - 2);
358 /* if it's going to run out LRU slots, we should free some, but not
359 * too much to maintain faireness among OSCs. */
360 if (atomic_long_read(cli->cl_lru_left) < cache->ccc_lru_max >> 2) {
362 return lru_shrink_max(cli);
363 else if (pages >= budget / 2)
364 return lru_shrink_min(cli);
366 time64_t duration = ktime_get_real_seconds();
369 /* knock out pages by duration of no IO activity */
370 duration -= cli->cl_lru_last_used;
372 * The difference shouldn't be more than 70 years
373 * so we can safely case to a long. Round to
374 * approximately 1 minute.
376 timediff = (long)(duration >> 6);
377 if (timediff > 0 && pages >= budget / timediff)
378 return lru_shrink_min(cli);
383 int lru_queue_work(const struct lu_env *env, void *data)
385 struct client_obd *cli = data;
388 CDEBUG(D_CACHE, "%s: run LRU work for client obd\n", cli_name(cli));
389 count = osc_cache_too_much(cli);
391 int rc = osc_lru_shrink(env, cli, count, false);
393 CDEBUG(D_CACHE, "%s: shrank %d/%d pages from client obd\n",
394 cli_name(cli), rc, count);
396 CDEBUG(D_CACHE, "%s: queue again\n", cli_name(cli));
397 ptlrpcd_queue_work(cli->cl_lru_work);
404 void osc_lru_add_batch(struct client_obd *cli, struct list_head *plist)
407 struct osc_async_page *oap;
410 list_for_each_entry(oap, plist, oap_pending_item) {
411 struct osc_page *opg = oap2osc_page(oap);
413 if (!opg->ops_in_lru)
417 LASSERT(list_empty(&opg->ops_lru));
418 list_add(&opg->ops_lru, &lru);
422 spin_lock(&cli->cl_lru_list_lock);
423 list_splice_tail(&lru, &cli->cl_lru_list);
424 atomic_long_sub(npages, &cli->cl_lru_busy);
425 atomic_long_add(npages, &cli->cl_lru_in_list);
426 cli->cl_lru_last_used = ktime_get_real_seconds();
427 spin_unlock(&cli->cl_lru_list_lock);
429 if (waitqueue_active(&osc_lru_waitq))
430 (void)ptlrpcd_queue_work(cli->cl_lru_work);
434 static void __osc_lru_del(struct client_obd *cli, struct osc_page *opg)
436 LASSERT(atomic_long_read(&cli->cl_lru_in_list) > 0);
437 list_del_init(&opg->ops_lru);
438 atomic_long_dec(&cli->cl_lru_in_list);
442 * Page is being destroyed. The page may be not in LRU list, if the transfer
443 * has never finished(error occurred).
445 static void osc_lru_del(struct client_obd *cli, struct osc_page *opg)
447 if (opg->ops_in_lru) {
448 spin_lock(&cli->cl_lru_list_lock);
449 if (!list_empty(&opg->ops_lru)) {
450 __osc_lru_del(cli, opg);
452 LASSERT(atomic_long_read(&cli->cl_lru_busy) > 0);
453 atomic_long_dec(&cli->cl_lru_busy);
455 spin_unlock(&cli->cl_lru_list_lock);
457 atomic_long_inc(cli->cl_lru_left);
458 /* this is a great place to release more LRU pages if
459 * this osc occupies too many LRU pages and kernel is
460 * stealing one of them. */
461 if (osc_cache_too_much(cli)) {
462 CDEBUG(D_CACHE, "%s: queue LRU work\n", cli_name(cli));
463 (void)ptlrpcd_queue_work(cli->cl_lru_work);
465 wake_up(&osc_lru_waitq);
467 LASSERT(list_empty(&opg->ops_lru));
472 * Delete page from LRU list for redirty.
474 static void osc_lru_use(struct client_obd *cli, struct osc_page *opg)
476 /* If page is being transferred for the first time,
477 * ops_lru should be empty */
478 if (opg->ops_in_lru) {
479 if (list_empty(&opg->ops_lru))
481 spin_lock(&cli->cl_lru_list_lock);
482 if (!list_empty(&opg->ops_lru)) {
483 __osc_lru_del(cli, opg);
484 atomic_long_inc(&cli->cl_lru_busy);
486 spin_unlock(&cli->cl_lru_list_lock);
490 static void discard_pagevec(const struct lu_env *env, struct cl_io *io,
491 struct cl_page **pvec, int max_index)
493 struct pagevec *pagevec = &osc_env_info(env)->oti_pagevec;
496 ll_pagevec_init(pagevec, 0);
497 for (i = 0; i < max_index; i++) {
498 struct cl_page *page = pvec[i];
500 LASSERT(cl_page_is_owned(page, io));
501 cl_page_discard(env, io, page);
502 cl_page_disown(env, io, page);
503 cl_pagevec_put(env, page, pagevec);
507 pagevec_release(pagevec);
511 * Check if a cl_page can be released, i.e, it's not being used.
513 * If unstable account is turned on, bulk transfer may hold one refcount
514 * for recovery so we need to check vmpage refcount as well; otherwise,
515 * even we can destroy cl_page but the corresponding vmpage can't be reused.
517 static inline bool lru_page_busy(struct client_obd *cli, struct cl_page *page)
519 if (cl_page_in_use_noref(page))
522 if (cli->cl_cache->ccc_unstable_check) {
523 struct page *vmpage = cl_page_vmpage(page);
525 /* vmpage have two known users: cl_page and VM page cache */
526 if (page_count(vmpage) - page_mapcount(vmpage) > 2)
533 * Drop @target of pages from LRU at most.
535 long osc_lru_shrink(const struct lu_env *env, struct client_obd *cli,
536 long target, bool force)
539 struct cl_object *clobj = NULL;
540 struct cl_page **pvec;
541 struct osc_page *opg;
548 LASSERT(atomic_long_read(&cli->cl_lru_in_list) >= 0);
549 if (atomic_long_read(&cli->cl_lru_in_list) == 0 || target <= 0)
552 CDEBUG(D_CACHE, "%s: shrinkers: %d, force: %d\n",
553 cli_name(cli), atomic_read(&cli->cl_lru_shrinkers), force);
555 if (atomic_read(&cli->cl_lru_shrinkers) > 0)
558 if (atomic_inc_return(&cli->cl_lru_shrinkers) > 1) {
559 atomic_dec(&cli->cl_lru_shrinkers);
563 atomic_inc(&cli->cl_lru_shrinkers);
566 pvec = (struct cl_page **)osc_env_info(env)->oti_pvec;
567 io = osc_env_thread_io(env);
569 spin_lock(&cli->cl_lru_list_lock);
571 cli->cl_lru_reclaim++;
572 maxscan = min(target << 1, atomic_long_read(&cli->cl_lru_in_list));
573 while (!list_empty(&cli->cl_lru_list)) {
574 struct cl_page *page;
575 bool will_free = false;
577 if (!force && atomic_read(&cli->cl_lru_shrinkers) > 1)
583 opg = list_first_entry(&cli->cl_lru_list, struct osc_page,
585 page = opg->ops_cl.cpl_page;
586 if (lru_page_busy(cli, page)) {
587 list_move_tail(&opg->ops_lru, &cli->cl_lru_list);
591 LASSERT(page->cp_obj != NULL);
592 if (clobj != page->cp_obj) {
593 struct cl_object *tmp = page->cp_obj;
596 spin_unlock(&cli->cl_lru_list_lock);
599 discard_pagevec(env, io, pvec, index);
603 cl_object_put(env, clobj);
609 io->ci_ignore_layout = 1;
610 rc = cl_io_init(env, io, CIT_MISC, clobj);
612 spin_lock(&cli->cl_lru_list_lock);
621 if (cl_page_own_try(env, io, page) == 0) {
622 if (!lru_page_busy(cli, page)) {
623 /* remove it from lru list earlier to avoid
625 __osc_lru_del(cli, opg);
626 opg->ops_in_lru = 0; /* will be discarded */
631 cl_page_disown(env, io, page);
636 list_move_tail(&opg->ops_lru, &cli->cl_lru_list);
640 /* Don't discard and free the page with cl_lru_list held */
641 pvec[index++] = page;
642 if (unlikely(index == OTI_PVEC_SIZE)) {
643 spin_unlock(&cli->cl_lru_list_lock);
644 discard_pagevec(env, io, pvec, index);
647 spin_lock(&cli->cl_lru_list_lock);
650 if (++count >= target)
653 spin_unlock(&cli->cl_lru_list_lock);
656 discard_pagevec(env, io, pvec, index);
659 cl_object_put(env, clobj);
662 atomic_dec(&cli->cl_lru_shrinkers);
664 atomic_long_add(count, cli->cl_lru_left);
665 wake_up(&osc_lru_waitq);
667 RETURN(count > 0 ? count : rc);
669 EXPORT_SYMBOL(osc_lru_shrink);
672 * Reclaim LRU pages by an IO thread. The caller wants to reclaim at least
673 * \@npages of LRU slots. For performance consideration, it's better to drop
674 * LRU pages in batch. Therefore, the actual number is adjusted at least
677 static long osc_lru_reclaim(struct client_obd *cli, unsigned long npages)
680 struct cl_client_cache *cache = cli->cl_cache;
681 struct client_obd *scan;
687 LASSERT(cache != NULL);
689 env = cl_env_get(&refcheck);
693 npages = max_t(int, npages, cli->cl_max_pages_per_rpc);
694 CDEBUG(D_CACHE, "%s: start to reclaim %ld pages from LRU\n",
695 cli_name(cli), npages);
696 rc = osc_lru_shrink(env, cli, npages, true);
698 CDEBUG(D_CACHE, "%s: reclaimed %ld/%ld pages from LRU\n",
699 cli_name(cli), rc, npages);
700 if (osc_cache_too_much(cli) > 0)
701 ptlrpcd_queue_work(cli->cl_lru_work);
707 CDEBUG(D_CACHE, "%s: cli %p no free slots, pages: %ld/%ld, want: %ld\n",
708 cli_name(cli), cli, atomic_long_read(&cli->cl_lru_in_list),
709 atomic_long_read(&cli->cl_lru_busy), npages);
711 /* Reclaim LRU slots from other client_obd as it can't free enough
712 * from its own. This should rarely happen. */
713 spin_lock(&cache->ccc_lru_lock);
714 LASSERT(!list_empty(&cache->ccc_lru));
716 cache->ccc_lru_shrinkers++;
717 list_move_tail(&cli->cl_lru_osc, &cache->ccc_lru);
719 max_scans = refcount_read(&cache->ccc_users) - 2;
720 while (--max_scans > 0 &&
721 (scan = list_first_entry_or_null(&cache->ccc_lru,
723 cl_lru_osc)) != NULL) {
724 CDEBUG(D_CACHE, "%s: cli %p LRU pages: %ld, busy: %ld.\n",
725 cli_name(scan), scan,
726 atomic_long_read(&scan->cl_lru_in_list),
727 atomic_long_read(&scan->cl_lru_busy));
729 list_move_tail(&scan->cl_lru_osc, &cache->ccc_lru);
730 if (osc_cache_too_much(scan) > 0) {
731 spin_unlock(&cache->ccc_lru_lock);
733 rc = osc_lru_shrink(env, scan, npages, true);
734 spin_lock(&cache->ccc_lru_lock);
741 spin_unlock(&cache->ccc_lru_lock);
744 cl_env_put(env, &refcheck);
745 CDEBUG(D_CACHE, "%s: cli %p freed %ld pages.\n",
746 cli_name(cli), cli, rc);
751 * osc_lru_alloc() is called to allocate an LRU slot for a cl_page.
753 * Usually the LRU slots are reserved in osc_io_iter_rw_init().
754 * Only in the case that the LRU slots are in extreme shortage, it should
755 * have reserved enough slots for an IO.
757 static int osc_lru_alloc(const struct lu_env *env, struct client_obd *cli,
758 struct osc_page *opg)
760 struct osc_io *oio = osc_env_io(env);
765 if (cli->cl_cache == NULL) /* shall not be in LRU */
768 if (oio->oi_lru_reserved > 0) {
769 --oio->oi_lru_reserved;
773 LASSERT(atomic_long_read(cli->cl_lru_left) >= 0);
774 while (!atomic_long_add_unless(cli->cl_lru_left, -1, 0)) {
775 /* run out of LRU spaces, try to drop some by itself */
776 rc = osc_lru_reclaim(cli, 1);
781 /* IO issued by readahead, don't try hard */
782 if (oio->oi_is_readahead) {
783 if (atomic_long_read(cli->cl_lru_left) > 0)
790 rc = l_wait_event_abortable(
792 atomic_long_read(cli->cl_lru_left) > 0);
801 atomic_long_inc(&cli->cl_lru_busy);
810 * osc_lru_reserve() is called to reserve enough LRU slots for I/O.
812 * The benefit of doing this is to reduce contention against atomic counter
813 * cl_lru_left by changing it from per-page access to per-IO access.
815 unsigned long osc_lru_reserve(struct client_obd *cli, unsigned long npages)
817 unsigned long reserved = 0;
818 unsigned long max_pages;
823 c = atomic_long_read(cli->cl_lru_left);
824 if (c < npages && osc_lru_reclaim(cli, npages) > 0)
825 c = atomic_long_read(cli->cl_lru_left);
829 * Trigger writeback in the hope some LRU slot could
832 rc = ptlrpcd_queue_work(cli->cl_writeback_work);
837 while (c >= npages) {
838 if (c == atomic_long_cmpxchg(cli->cl_lru_left, c, c - npages)) {
842 c = atomic_long_read(cli->cl_lru_left);
845 if (reserved != npages) {
847 rc = l_wait_event_abortable(
849 atomic_long_read(cli->cl_lru_left) > 0);
853 max_pages = cli->cl_max_pages_per_rpc * cli->cl_max_rpcs_in_flight;
854 if (atomic_long_read(cli->cl_lru_left) < max_pages) {
855 /* If there aren't enough pages in the per-OSC LRU then
856 * wake up the LRU thread to try and clear out space, so
857 * we don't block if pages are being dirtied quickly. */
858 CDEBUG(D_CACHE, "%s: queue LRU, left: %lu/%ld.\n",
859 cli_name(cli), atomic_long_read(cli->cl_lru_left),
861 (void)ptlrpcd_queue_work(cli->cl_lru_work);
868 * osc_lru_unreserve() is called to unreserve LRU slots.
870 * LRU slots reserved by osc_lru_reserve() may have entries left due to several
871 * reasons such as page already existing or I/O error. Those reserved slots
872 * should be freed by calling this function.
874 void osc_lru_unreserve(struct client_obd *cli, unsigned long npages)
876 atomic_long_add(npages, cli->cl_lru_left);
877 wake_up(&osc_lru_waitq);
881 * Atomic operations are expensive. We accumulate the accounting for the
882 * same page zone to get better performance.
883 * In practice this can work pretty good because the pages in the same RPC
884 * are likely from the same page zone.
886 #ifdef HAVE_NR_UNSTABLE_NFS
887 /* Old kernels use a separate counter for unstable pages,
888 * newer kernels treat them like any other writeback.
889 * (see Linux commit: v5.7-467-g8d92890bd6b8)
891 #define NR_ZONE_WRITE_PENDING ((enum zone_stat_item)NR_UNSTABLE_NFS)
892 #elif !defined(HAVE_NR_ZONE_WRITE_PENDING)
893 #define NR_ZONE_WRITE_PENDING ((enum zone_stat_item)NR_WRITEBACK)
896 static inline void unstable_page_accounting(struct ptlrpc_bulk_desc *desc,
906 page_count = desc->bd_iov_count;
908 CDEBUG(D_PAGE, "%s %d unstable pages\n",
909 factor == 1 ? "adding" : "removing", page_count);
911 for (i = 0; i < page_count; i++) {
912 void *pz = page_zone(desc->bd_vec[i].bv_page);
914 if (likely(pz == zone)) {
920 mod_zone_page_state(zone, NR_ZONE_WRITE_PENDING,
928 mod_zone_page_state(zone, NR_ZONE_WRITE_PENDING,
934 static inline void add_unstable_pages(struct ptlrpc_bulk_desc *desc)
936 unstable_page_accounting(desc, 1);
939 static inline void dec_unstable_pages(struct ptlrpc_bulk_desc *desc)
941 unstable_page_accounting(desc, -1);
945 * Performs "unstable" page accounting. This function balances the
946 * increment operations performed in osc_inc_unstable_pages. It is
947 * registered as the RPC request callback, and is executed when the
948 * bulk RPC is committed on the server. Thus at this point, the pages
949 * involved in the bulk transfer are no longer considered unstable.
951 * If this function is called, the request should have been committed
952 * or req:rq_unstable must have been set; it implies that the unstable
953 * statistic have been added.
955 void osc_dec_unstable_pages(struct ptlrpc_request *req)
957 struct ptlrpc_bulk_desc *desc = req->rq_bulk;
958 struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
962 /* no desc means short io, which doesn't have separate unstable pages,
963 * it's just using space inside the RPC itself
968 page_count = desc->bd_iov_count;
970 LASSERT(page_count >= 0);
972 dec_unstable_pages(desc);
974 unstable_count = atomic_long_sub_return(page_count,
975 &cli->cl_unstable_count);
976 LASSERT(unstable_count >= 0);
978 unstable_count = atomic_long_sub_return(page_count,
979 &cli->cl_cache->ccc_unstable_nr);
980 LASSERT(unstable_count >= 0);
982 if (waitqueue_active(&osc_lru_waitq))
983 (void)ptlrpcd_queue_work(cli->cl_lru_work);
987 * "unstable" page accounting. See: osc_dec_unstable_pages.
989 void osc_inc_unstable_pages(struct ptlrpc_request *req)
991 struct ptlrpc_bulk_desc *desc = req->rq_bulk;
992 struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
995 /* No unstable page tracking */
996 if (cli->cl_cache == NULL || !cli->cl_cache->ccc_unstable_check)
999 /* no desc means short io, which doesn't have separate unstable pages,
1000 * it's just using space inside the RPC itself
1005 page_count = desc->bd_iov_count;
1007 add_unstable_pages(desc);
1008 atomic_long_add(page_count, &cli->cl_unstable_count);
1009 atomic_long_add(page_count, &cli->cl_cache->ccc_unstable_nr);
1011 /* If the request has already been committed (i.e. brw_commit
1012 * called via rq_commit_cb), we need to undo the unstable page
1013 * increments we just performed because rq_commit_cb wont be
1015 spin_lock(&req->rq_lock);
1016 if (unlikely(req->rq_committed)) {
1017 spin_unlock(&req->rq_lock);
1019 osc_dec_unstable_pages(req);
1021 req->rq_unstable = 1;
1022 spin_unlock(&req->rq_lock);
1027 * Check if it piggybacks SOFT_SYNC flag to OST from this OSC.
1028 * This function will be called by every BRW RPC so it's critical
1029 * to make this function fast.
1031 bool osc_over_unstable_soft_limit(struct client_obd *cli)
1033 long unstable_nr, osc_unstable_count;
1035 /* Can't check cli->cl_unstable_count, therefore, no soft limit */
1036 if (cli->cl_cache == NULL || !cli->cl_cache->ccc_unstable_check)
1039 osc_unstable_count = atomic_long_read(&cli->cl_unstable_count);
1040 unstable_nr = atomic_long_read(&cli->cl_cache->ccc_unstable_nr);
1043 "%s: cli: %p unstable pages: %lu, osc unstable pages: %lu\n",
1044 cli_name(cli), cli, unstable_nr, osc_unstable_count);
1046 /* If the LRU slots are in shortage - 25% remaining AND this OSC
1047 * has one full RPC window of unstable pages, it's a good chance
1048 * to piggyback a SOFT_SYNC flag.
1049 * Please notice that the OST won't take immediate response for the
1050 * SOFT_SYNC request so active OSCs will have more chance to carry
1051 * the flag, this is reasonable. */
1052 return unstable_nr > cli->cl_cache->ccc_lru_max >> 2 &&
1053 osc_unstable_count > cli->cl_max_pages_per_rpc *
1054 cli->cl_max_rpcs_in_flight;
1058 * Return how many LRU pages in the cache of all OSC devices
1060 * \retval return # of cached LRU pages times reclaimation tendency
1061 * \retval SHRINK_STOP if it cannot do any scanning in this time
1063 unsigned long osc_cache_shrink_count(struct shrinker *sk,
1064 struct shrink_control *sc)
1066 struct client_obd *cli;
1067 unsigned long cached = 0;
1069 spin_lock(&osc_shrink_lock);
1070 list_for_each_entry(cli, &osc_shrink_list, cl_shrink_list)
1071 cached += atomic_long_read(&cli->cl_lru_in_list);
1072 spin_unlock(&osc_shrink_lock);
1074 return (cached * sysctl_vfs_cache_pressure) / 100;
1078 * Scan and try to reclaim sc->nr_to_scan cached LRU pages
1080 * \retval number of cached LRU pages reclaimed
1081 * \retval SHRINK_STOP if it cannot do any scanning in this time
1083 * Linux kernel will loop calling this shrinker scan routine with
1084 * sc->nr_to_scan = SHRINK_BATCH(128 for now) until kernel got enough memory.
1086 * If sc->nr_to_scan is 0, the VM is querying the cache size, we don't need
1087 * to scan and try to reclaim LRU pages, just return 0 and
1088 * osc_cache_shrink_count() will report the LRU page number.
1090 unsigned long osc_cache_shrink_scan(struct shrinker *sk,
1091 struct shrink_control *sc)
1093 struct client_obd *cli;
1094 struct client_obd *stop_anchor = NULL;
1100 if (sc->nr_to_scan == 0)
1103 if (!(sc->gfp_mask & __GFP_FS))
1106 env = cl_env_get(&refcheck);
1110 spin_lock(&osc_shrink_lock);
1111 while ((cli = list_first_entry_or_null(&osc_shrink_list,
1113 cl_shrink_list)) != NULL) {
1114 if (stop_anchor == NULL)
1116 else if (cli == stop_anchor)
1119 list_move_tail(&cli->cl_shrink_list, &osc_shrink_list);
1120 spin_unlock(&osc_shrink_lock);
1122 /* shrink no more than max_pages_per_rpc for an OSC */
1123 rc = osc_lru_shrink(env, cli, (sc->nr_to_scan - shrank) >
1124 cli->cl_max_pages_per_rpc ?
1125 cli->cl_max_pages_per_rpc :
1126 sc->nr_to_scan - shrank, true);
1130 if (shrank >= sc->nr_to_scan)
1133 spin_lock(&osc_shrink_lock);
1135 spin_unlock(&osc_shrink_lock);
1138 cl_env_put(env, &refcheck);