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27 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
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33 * This file is part of Lustre, http://www.lustre.org/
34 * Lustre is a trademark of Sun Microsystems, Inc.
36 * Implementation of cl_page for OSC layer.
38 * Author: Nikita Danilov <nikita.danilov@sun.com>
39 * Author: Jinshan Xiong <jinshan.xiong@intel.com>
42 #define DEBUG_SUBSYSTEM S_OSC
44 #include "osc_cl_internal.h"
46 static void osc_lru_del(struct client_obd *cli, struct osc_page *opg);
47 static void osc_lru_use(struct client_obd *cli, struct osc_page *opg);
48 static int osc_lru_alloc(const struct lu_env *env, struct client_obd *cli,
49 struct osc_page *opg);
58 static void osc_page_transfer_get(struct osc_page *opg, const char *label)
60 struct cl_page *page = opg->ops_cl.cpl_page;
62 LASSERT(!opg->ops_transfer_pinned);
64 lu_ref_add_atomic(&page->cp_reference, label, page);
65 opg->ops_transfer_pinned = 1;
68 static void osc_page_transfer_put(const struct lu_env *env,
71 struct cl_page *page = opg->ops_cl.cpl_page;
73 if (opg->ops_transfer_pinned) {
74 opg->ops_transfer_pinned = 0;
75 lu_ref_del(&page->cp_reference, "transfer", page);
76 cl_page_put(env, page);
81 * This is called once for every page when it is submitted for a transfer
82 * either opportunistic (osc_page_cache_add()), or immediate
83 * (osc_page_submit()).
85 static void osc_page_transfer_add(const struct lu_env *env,
86 struct osc_page *opg, enum cl_req_type crt)
88 struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj);
90 /* ops_lru and ops_inflight share the same field, so take it from LRU
91 * first and then use it as inflight. */
92 osc_lru_use(osc_cli(obj), opg);
95 int osc_page_cache_add(const struct lu_env *env,
96 const struct cl_page_slice *slice, struct cl_io *io)
98 struct osc_page *opg = cl2osc_page(slice);
102 osc_page_transfer_get(opg, "transfer\0cache");
103 result = osc_queue_async_io(env, io, opg);
105 osc_page_transfer_put(env, opg);
107 osc_page_transfer_add(env, opg, CRT_WRITE);
112 void osc_index2policy(union ldlm_policy_data *policy,
113 const struct cl_object *obj, pgoff_t start, pgoff_t end)
115 memset(policy, 0, sizeof *policy);
116 policy->l_extent.start = cl_offset(obj, start);
117 policy->l_extent.end = cl_offset(obj, end + 1) - 1;
120 static const char *osc_list(struct list_head *head)
122 return list_empty(head) ? "-" : "+";
125 static inline cfs_time_t osc_submit_duration(struct osc_page *opg)
127 if (opg->ops_submit_time == 0)
130 return (cfs_time_current() - opg->ops_submit_time);
133 static int osc_page_print(const struct lu_env *env,
134 const struct cl_page_slice *slice,
135 void *cookie, lu_printer_t printer)
137 struct osc_page *opg = cl2osc_page(slice);
138 struct osc_async_page *oap = &opg->ops_oap;
139 struct osc_object *obj = cl2osc(slice->cpl_obj);
140 struct client_obd *cli = &osc_export(obj)->exp_obd->u.cli;
142 return (*printer)(env, cookie, LUSTRE_OSC_NAME"-page@%p %lu: "
143 "1< %#x %d %u %s %s > "
144 "2< %lld %u %u %#x %#x | %p %p %p > "
146 "4< %d %d %d %lu %s | %s %s %s %s > "
147 "5< %s %s %s %s | %d %s | %d %s %s>\n",
150 oap->oap_magic, oap->oap_cmd,
151 oap->oap_interrupted,
152 osc_list(&oap->oap_pending_item),
153 osc_list(&oap->oap_rpc_item),
155 oap->oap_obj_off, oap->oap_page_off, oap->oap_count,
156 oap->oap_async_flags, oap->oap_brw_flags,
157 oap->oap_request, oap->oap_cli, obj,
159 opg->ops_transfer_pinned,
160 osc_submit_duration(opg), opg->ops_srvlock,
162 cli->cl_r_in_flight, cli->cl_w_in_flight,
163 cli->cl_max_rpcs_in_flight,
165 osc_list(&cli->cl_cache_waiters),
166 osc_list(&cli->cl_loi_ready_list),
167 osc_list(&cli->cl_loi_hp_ready_list),
168 osc_list(&cli->cl_loi_write_list),
169 osc_list(&cli->cl_loi_read_list),
171 osc_list(&obj->oo_ready_item),
172 osc_list(&obj->oo_hp_ready_item),
173 osc_list(&obj->oo_write_item),
174 osc_list(&obj->oo_read_item),
175 atomic_read(&obj->oo_nr_reads),
176 osc_list(&obj->oo_reading_exts),
177 atomic_read(&obj->oo_nr_writes),
178 osc_list(&obj->oo_hp_exts),
179 osc_list(&obj->oo_urgent_exts));
182 static void osc_page_delete(const struct lu_env *env,
183 const struct cl_page_slice *slice)
185 struct osc_page *opg = cl2osc_page(slice);
186 struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj);
190 CDEBUG(D_TRACE, "%p\n", opg);
191 osc_page_transfer_put(env, opg);
192 rc = osc_teardown_async_page(env, obj, opg);
194 CL_PAGE_DEBUG(D_ERROR, env, slice->cpl_page,
195 "Trying to teardown failed: %d\n", rc);
199 osc_lru_del(osc_cli(obj), opg);
201 if (slice->cpl_page->cp_type == CPT_CACHEABLE) {
204 spin_lock(&obj->oo_tree_lock);
205 value = radix_tree_delete(&obj->oo_tree, osc_index(opg));
208 spin_unlock(&obj->oo_tree_lock);
210 LASSERT(ergo(value != NULL, value == opg));
216 static void osc_page_clip(const struct lu_env *env,
217 const struct cl_page_slice *slice,
220 struct osc_page *opg = cl2osc_page(slice);
221 struct osc_async_page *oap = &opg->ops_oap;
223 opg->ops_from = from;
225 spin_lock(&oap->oap_lock);
226 oap->oap_async_flags |= ASYNC_COUNT_STABLE;
227 spin_unlock(&oap->oap_lock);
230 static int osc_page_cancel(const struct lu_env *env,
231 const struct cl_page_slice *slice)
233 struct osc_page *opg = cl2osc_page(slice);
236 /* Check if the transferring against this page
237 * is completed, or not even queued. */
238 if (opg->ops_transfer_pinned)
239 /* FIXME: may not be interrupted.. */
240 rc = osc_cancel_async_page(env, opg);
241 LASSERT(ergo(rc == 0, opg->ops_transfer_pinned == 0));
245 static int osc_page_flush(const struct lu_env *env,
246 const struct cl_page_slice *slice,
249 struct osc_page *opg = cl2osc_page(slice);
252 rc = osc_flush_async_page(env, io, opg);
256 static const struct cl_page_operations osc_page_ops = {
257 .cpo_print = osc_page_print,
258 .cpo_delete = osc_page_delete,
259 .cpo_clip = osc_page_clip,
260 .cpo_cancel = osc_page_cancel,
261 .cpo_flush = osc_page_flush
264 int osc_page_init(const struct lu_env *env, struct cl_object *obj,
265 struct cl_page *page, pgoff_t index)
267 struct osc_object *osc = cl2osc(obj);
268 struct osc_page *opg = cl_object_page_slice(obj, page);
272 opg->ops_to = PAGE_SIZE;
274 result = osc_prep_async_page(osc, opg, page->cp_vmpage,
275 cl_offset(obj, index));
277 struct osc_io *oio = osc_env_io(env);
278 opg->ops_srvlock = osc_io_srvlock(oio);
279 cl_page_slice_add(page, &opg->ops_cl, obj, index,
282 INIT_LIST_HEAD(&opg->ops_lru);
284 /* reserve an LRU space for this page */
285 if (page->cp_type == CPT_CACHEABLE && result == 0) {
286 result = osc_lru_alloc(env, osc_cli(osc), opg);
288 spin_lock(&osc->oo_tree_lock);
289 result = radix_tree_insert(&osc->oo_tree, index, opg);
292 spin_unlock(&osc->oo_tree_lock);
293 LASSERT(result == 0);
301 * Helper function called by osc_io_submit() for every page in an immediate
302 * transfer (i.e., transferred synchronously).
304 void osc_page_submit(const struct lu_env *env, struct osc_page *opg,
305 enum cl_req_type crt, int brw_flags)
307 struct osc_async_page *oap = &opg->ops_oap;
309 LASSERTF(oap->oap_magic == OAP_MAGIC, "Bad oap magic: oap %p, "
310 "magic 0x%x\n", oap, oap->oap_magic);
311 LASSERT(oap->oap_async_flags & ASYNC_READY);
312 LASSERT(oap->oap_async_flags & ASYNC_COUNT_STABLE);
314 oap->oap_cmd = crt == CRT_WRITE ? OBD_BRW_WRITE : OBD_BRW_READ;
315 oap->oap_page_off = opg->ops_from;
316 oap->oap_count = opg->ops_to - opg->ops_from;
317 oap->oap_brw_flags = OBD_BRW_SYNC | brw_flags;
319 if (cfs_capable(CFS_CAP_SYS_RESOURCE)) {
320 oap->oap_brw_flags |= OBD_BRW_NOQUOTA;
321 oap->oap_cmd |= OBD_BRW_NOQUOTA;
324 opg->ops_submit_time = cfs_time_current();
325 osc_page_transfer_get(opg, "transfer\0imm");
326 osc_page_transfer_add(env, opg, crt);
329 /* --------------- LRU page management ------------------ */
331 /* OSC is a natural place to manage LRU pages as applications are specialized
332 * to write OSC by OSC. Ideally, if one OSC is used more frequently it should
333 * occupy more LRU slots. On the other hand, we should avoid using up all LRU
334 * slots (client_obd::cl_lru_left) otherwise process has to be put into sleep
335 * for free LRU slots - this will be very bad so the algorithm requires each
336 * OSC to free slots voluntarily to maintain a reasonable number of free slots
340 static DECLARE_WAIT_QUEUE_HEAD(osc_lru_waitq);
343 * LRU pages are freed in batch mode. OSC should at least free this
344 * number of pages to avoid running out of LRU slots.
346 static inline int lru_shrink_min(struct client_obd *cli)
348 return cli->cl_max_pages_per_rpc * 2;
352 * free this number at most otherwise it will take too long time to finsih.
354 static inline int lru_shrink_max(struct client_obd *cli)
356 return cli->cl_max_pages_per_rpc * cli->cl_max_rpcs_in_flight;
360 * Check if we can free LRU slots from this OSC. If there exists LRU waiters,
361 * we should free slots aggressively. In this way, slots are freed in a steady
362 * step to maintain fairness among OSCs.
364 * Return how many LRU pages should be freed.
366 static int osc_cache_too_much(struct client_obd *cli)
368 struct cl_client_cache *cache = cli->cl_cache;
369 long pages = atomic_long_read(&cli->cl_lru_in_list);
370 unsigned long budget;
372 LASSERT(cache != NULL);
373 budget = cache->ccc_lru_max / (atomic_read(&cache->ccc_users) - 2);
375 /* if it's going to run out LRU slots, we should free some, but not
376 * too much to maintain faireness among OSCs. */
377 if (atomic_long_read(cli->cl_lru_left) < cache->ccc_lru_max >> 2) {
379 return lru_shrink_max(cli);
380 else if (pages >= budget / 2)
381 return lru_shrink_min(cli);
383 int duration = cfs_time_current_sec() - cli->cl_lru_last_used;
385 /* knock out pages by duration of no IO activity */
386 duration >>= 6; /* approximately 1 minute */
387 if (duration > 0 && pages >= budget / duration)
388 return lru_shrink_min(cli);
393 int lru_queue_work(const struct lu_env *env, void *data)
395 struct client_obd *cli = data;
398 CDEBUG(D_CACHE, "%s: run LRU work for client obd\n", cli_name(cli));
399 count = osc_cache_too_much(cli);
401 int rc = osc_lru_shrink(env, cli, count, false);
403 CDEBUG(D_CACHE, "%s: shrank %d/%d pages from client obd\n",
404 cli_name(cli), rc, count);
406 CDEBUG(D_CACHE, "%s: queue again\n", cli_name(cli));
407 ptlrpcd_queue_work(cli->cl_lru_work);
414 void osc_lru_add_batch(struct client_obd *cli, struct list_head *plist)
416 struct list_head lru = LIST_HEAD_INIT(lru);
417 struct osc_async_page *oap;
420 list_for_each_entry(oap, plist, oap_pending_item) {
421 struct osc_page *opg = oap2osc_page(oap);
423 if (!opg->ops_in_lru)
427 LASSERT(list_empty(&opg->ops_lru));
428 list_add(&opg->ops_lru, &lru);
432 spin_lock(&cli->cl_lru_list_lock);
433 list_splice_tail(&lru, &cli->cl_lru_list);
434 atomic_long_sub(npages, &cli->cl_lru_busy);
435 atomic_long_add(npages, &cli->cl_lru_in_list);
436 cli->cl_lru_last_used = cfs_time_current_sec();
437 spin_unlock(&cli->cl_lru_list_lock);
439 if (waitqueue_active(&osc_lru_waitq))
440 (void)ptlrpcd_queue_work(cli->cl_lru_work);
444 static void __osc_lru_del(struct client_obd *cli, struct osc_page *opg)
446 LASSERT(atomic_long_read(&cli->cl_lru_in_list) > 0);
447 list_del_init(&opg->ops_lru);
448 atomic_long_dec(&cli->cl_lru_in_list);
452 * Page is being destroyed. The page may be not in LRU list, if the transfer
453 * has never finished(error occurred).
455 static void osc_lru_del(struct client_obd *cli, struct osc_page *opg)
457 if (opg->ops_in_lru) {
458 spin_lock(&cli->cl_lru_list_lock);
459 if (!list_empty(&opg->ops_lru)) {
460 __osc_lru_del(cli, opg);
462 LASSERT(atomic_long_read(&cli->cl_lru_busy) > 0);
463 atomic_long_dec(&cli->cl_lru_busy);
465 spin_unlock(&cli->cl_lru_list_lock);
467 atomic_long_inc(cli->cl_lru_left);
468 /* this is a great place to release more LRU pages if
469 * this osc occupies too many LRU pages and kernel is
470 * stealing one of them. */
471 if (osc_cache_too_much(cli)) {
472 CDEBUG(D_CACHE, "%s: queue LRU work\n", cli_name(cli));
473 (void)ptlrpcd_queue_work(cli->cl_lru_work);
475 wake_up(&osc_lru_waitq);
477 LASSERT(list_empty(&opg->ops_lru));
482 * Delete page from LRUlist for redirty.
484 static void osc_lru_use(struct client_obd *cli, struct osc_page *opg)
486 /* If page is being transferred for the first time,
487 * ops_lru should be empty */
488 if (opg->ops_in_lru && !list_empty(&opg->ops_lru)) {
489 spin_lock(&cli->cl_lru_list_lock);
490 __osc_lru_del(cli, opg);
491 spin_unlock(&cli->cl_lru_list_lock);
492 atomic_long_inc(&cli->cl_lru_busy);
496 static void discard_pagevec(const struct lu_env *env, struct cl_io *io,
497 struct cl_page **pvec, int max_index)
501 for (i = 0; i < max_index; i++) {
502 struct cl_page *page = pvec[i];
504 LASSERT(cl_page_is_owned(page, io));
505 cl_page_delete(env, page);
506 cl_page_discard(env, io, page);
507 cl_page_disown(env, io, page);
508 cl_page_put(env, page);
515 * Check if a cl_page can be released, i.e, it's not being used.
517 * If unstable account is turned on, bulk transfer may hold one refcount
518 * for recovery so we need to check vmpage refcount as well; otherwise,
519 * even we can destroy cl_page but the corresponding vmpage can't be reused.
521 static inline bool lru_page_busy(struct client_obd *cli, struct cl_page *page)
523 if (cl_page_in_use_noref(page))
526 if (cli->cl_cache->ccc_unstable_check) {
527 struct page *vmpage = cl_page_vmpage(page);
529 /* vmpage have two known users: cl_page and VM page cache */
530 if (page_count(vmpage) - page_mapcount(vmpage) > 2)
537 * Drop @target of pages from LRU at most.
539 long osc_lru_shrink(const struct lu_env *env, struct client_obd *cli,
540 long target, bool force)
543 struct cl_object *clobj = NULL;
544 struct cl_page **pvec;
545 struct osc_page *opg;
552 LASSERT(atomic_long_read(&cli->cl_lru_in_list) >= 0);
553 if (atomic_long_read(&cli->cl_lru_in_list) == 0 || target <= 0)
556 CDEBUG(D_CACHE, "%s: shrinkers: %d, force: %d\n",
557 cli_name(cli), atomic_read(&cli->cl_lru_shrinkers), force);
559 if (atomic_read(&cli->cl_lru_shrinkers) > 0)
562 if (atomic_inc_return(&cli->cl_lru_shrinkers) > 1) {
563 atomic_dec(&cli->cl_lru_shrinkers);
567 atomic_inc(&cli->cl_lru_shrinkers);
570 pvec = (struct cl_page **)osc_env_info(env)->oti_pvec;
571 io = &osc_env_info(env)->oti_io;
573 spin_lock(&cli->cl_lru_list_lock);
575 cli->cl_lru_reclaim++;
576 maxscan = min(target << 1, atomic_long_read(&cli->cl_lru_in_list));
577 while (!list_empty(&cli->cl_lru_list)) {
578 struct cl_page *page;
579 bool will_free = false;
581 if (!force && atomic_read(&cli->cl_lru_shrinkers) > 1)
587 opg = list_entry(cli->cl_lru_list.next, struct osc_page,
589 page = opg->ops_cl.cpl_page;
590 if (lru_page_busy(cli, page)) {
591 list_move_tail(&opg->ops_lru, &cli->cl_lru_list);
595 LASSERT(page->cp_obj != NULL);
596 if (clobj != page->cp_obj) {
597 struct cl_object *tmp = page->cp_obj;
600 spin_unlock(&cli->cl_lru_list_lock);
603 discard_pagevec(env, io, pvec, index);
607 cl_object_put(env, clobj);
613 io->ci_ignore_layout = 1;
614 rc = cl_io_init(env, io, CIT_MISC, clobj);
616 spin_lock(&cli->cl_lru_list_lock);
625 if (cl_page_own_try(env, io, page) == 0) {
626 if (!lru_page_busy(cli, page)) {
627 /* remove it from lru list earlier to avoid
629 __osc_lru_del(cli, opg);
630 opg->ops_in_lru = 0; /* will be discarded */
635 cl_page_disown(env, io, page);
640 list_move_tail(&opg->ops_lru, &cli->cl_lru_list);
644 /* Don't discard and free the page with cl_lru_list held */
645 pvec[index++] = page;
646 if (unlikely(index == OTI_PVEC_SIZE)) {
647 spin_unlock(&cli->cl_lru_list_lock);
648 discard_pagevec(env, io, pvec, index);
651 spin_lock(&cli->cl_lru_list_lock);
654 if (++count >= target)
657 spin_unlock(&cli->cl_lru_list_lock);
660 discard_pagevec(env, io, pvec, index);
663 cl_object_put(env, clobj);
666 atomic_dec(&cli->cl_lru_shrinkers);
668 atomic_long_add(count, cli->cl_lru_left);
669 wake_up_all(&osc_lru_waitq);
671 RETURN(count > 0 ? count : rc);
675 * Reclaim LRU pages by an IO thread. The caller wants to reclaim at least
676 * \@npages of LRU slots. For performance consideration, it's better to drop
677 * LRU pages in batch. Therefore, the actual number is adjusted at least
680 static long osc_lru_reclaim(struct client_obd *cli, unsigned long npages)
683 struct cl_client_cache *cache = cli->cl_cache;
689 LASSERT(cache != NULL);
691 env = cl_env_get(&refcheck);
695 npages = max_t(int, npages, cli->cl_max_pages_per_rpc);
696 CDEBUG(D_CACHE, "%s: start to reclaim %ld pages from LRU\n",
697 cli_name(cli), npages);
698 rc = osc_lru_shrink(env, cli, npages, true);
700 CDEBUG(D_CACHE, "%s: reclaimed %ld/%ld pages from LRU\n",
701 cli_name(cli), rc, npages);
702 if (osc_cache_too_much(cli) > 0)
703 ptlrpcd_queue_work(cli->cl_lru_work);
709 CDEBUG(D_CACHE, "%s: cli %p no free slots, pages: %ld/%ld, want: %ld\n",
710 cli_name(cli), cli, atomic_long_read(&cli->cl_lru_in_list),
711 atomic_long_read(&cli->cl_lru_busy), npages);
713 /* Reclaim LRU slots from other client_obd as it can't free enough
714 * from its own. This should rarely happen. */
715 spin_lock(&cache->ccc_lru_lock);
716 LASSERT(!list_empty(&cache->ccc_lru));
718 cache->ccc_lru_shrinkers++;
719 list_move_tail(&cli->cl_lru_osc, &cache->ccc_lru);
721 max_scans = atomic_read(&cache->ccc_users) - 2;
722 while (--max_scans > 0 && !list_empty(&cache->ccc_lru)) {
723 cli = list_entry(cache->ccc_lru.next, struct client_obd,
726 CDEBUG(D_CACHE, "%s: cli %p LRU pages: %ld, busy: %ld.\n",
728 atomic_long_read(&cli->cl_lru_in_list),
729 atomic_long_read(&cli->cl_lru_busy));
731 list_move_tail(&cli->cl_lru_osc, &cache->ccc_lru);
732 if (osc_cache_too_much(cli) > 0) {
733 spin_unlock(&cache->ccc_lru_lock);
735 rc = osc_lru_shrink(env, cli, npages, true);
736 spin_lock(&cache->ccc_lru_lock);
743 spin_unlock(&cache->ccc_lru_lock);
746 cl_env_put(env, &refcheck);
747 CDEBUG(D_CACHE, "%s: cli %p freed %ld pages.\n",
748 cli_name(cli), cli, rc);
753 * osc_lru_alloc() is called to allocate an LRU slot for a cl_page.
755 * Usually the LRU slots are reserved in osc_io_iter_rw_init().
756 * Only in the case that the LRU slots are in extreme shortage, it should
757 * have reserved enough slots for an IO.
759 static int osc_lru_alloc(const struct lu_env *env, struct client_obd *cli,
760 struct osc_page *opg)
762 struct l_wait_info lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
763 struct osc_io *oio = osc_env_io(env);
767 if (cli->cl_cache == NULL) /* shall not be in LRU */
770 if (oio->oi_lru_reserved > 0) {
771 --oio->oi_lru_reserved;
775 LASSERT(atomic_long_read(cli->cl_lru_left) >= 0);
776 while (!atomic_long_add_unless(cli->cl_lru_left, -1, 0)) {
777 /* run out of LRU spaces, try to drop some by itself */
778 rc = osc_lru_reclaim(cli, 1);
785 rc = l_wait_event(osc_lru_waitq,
786 atomic_long_read(cli->cl_lru_left) > 0,
794 atomic_long_inc(&cli->cl_lru_busy);
803 * osc_lru_reserve() is called to reserve enough LRU slots for I/O.
805 * The benefit of doing this is to reduce contention against atomic counter
806 * cl_lru_left by changing it from per-page access to per-IO access.
808 unsigned long osc_lru_reserve(struct client_obd *cli, unsigned long npages)
810 unsigned long reserved = 0;
811 unsigned long max_pages;
814 /* reserve a full RPC window at most to avoid that a thread accidentally
815 * consumes too many LRU slots */
816 max_pages = cli->cl_max_pages_per_rpc * cli->cl_max_rpcs_in_flight;
817 if (npages > max_pages)
820 c = atomic_long_read(cli->cl_lru_left);
821 if (c < npages && osc_lru_reclaim(cli, npages) > 0)
822 c = atomic_long_read(cli->cl_lru_left);
823 while (c >= npages) {
824 if (c == atomic_long_cmpxchg(cli->cl_lru_left, c, c - npages)) {
828 c = atomic_long_read(cli->cl_lru_left);
830 if (atomic_long_read(cli->cl_lru_left) < max_pages) {
831 /* If there aren't enough pages in the per-OSC LRU then
832 * wake up the LRU thread to try and clear out space, so
833 * we don't block if pages are being dirtied quickly. */
834 CDEBUG(D_CACHE, "%s: queue LRU, left: %lu/%ld.\n",
835 cli_name(cli), atomic_long_read(cli->cl_lru_left),
837 (void)ptlrpcd_queue_work(cli->cl_lru_work);
844 * osc_lru_unreserve() is called to unreserve LRU slots.
846 * LRU slots reserved by osc_lru_reserve() may have entries left due to several
847 * reasons such as page already existing or I/O error. Those reserved slots
848 * should be freed by calling this function.
850 void osc_lru_unreserve(struct client_obd *cli, unsigned long npages)
852 atomic_long_add(npages, cli->cl_lru_left);
853 wake_up_all(&osc_lru_waitq);
857 * Atomic operations are expensive. We accumulate the accounting for the
858 * same page zone to get better performance.
859 * In practice this can work pretty good because the pages in the same RPC
860 * are likely from the same page zone.
862 static inline void unstable_page_accounting(struct ptlrpc_bulk_desc *desc,
865 int page_count = desc->bd_iov_count;
870 LASSERT(ptlrpc_is_bulk_desc_kiov(desc->bd_type));
872 for (i = 0; i < page_count; i++) {
873 void *pz = page_zone(BD_GET_KIOV(desc, i).kiov_page);
875 if (likely(pz == zone)) {
881 mod_zone_page_state(zone, NR_UNSTABLE_NFS,
889 mod_zone_page_state(zone, NR_UNSTABLE_NFS, factor * count);
892 static inline void add_unstable_page_accounting(struct ptlrpc_bulk_desc *desc)
894 unstable_page_accounting(desc, 1);
897 static inline void dec_unstable_page_accounting(struct ptlrpc_bulk_desc *desc)
899 unstable_page_accounting(desc, -1);
903 * Performs "unstable" page accounting. This function balances the
904 * increment operations performed in osc_inc_unstable_pages. It is
905 * registered as the RPC request callback, and is executed when the
906 * bulk RPC is committed on the server. Thus at this point, the pages
907 * involved in the bulk transfer are no longer considered unstable.
909 * If this function is called, the request should have been committed
910 * or req:rq_unstable must have been set; it implies that the unstable
911 * statistic have been added.
913 void osc_dec_unstable_pages(struct ptlrpc_request *req)
915 struct ptlrpc_bulk_desc *desc = req->rq_bulk;
916 struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
917 int page_count = desc->bd_iov_count;
920 LASSERT(page_count >= 0);
921 dec_unstable_page_accounting(desc);
923 unstable_count = atomic_long_sub_return(page_count,
924 &cli->cl_unstable_count);
925 LASSERT(unstable_count >= 0);
927 unstable_count = atomic_long_sub_return(page_count,
928 &cli->cl_cache->ccc_unstable_nr);
929 LASSERT(unstable_count >= 0);
930 if (unstable_count == 0)
931 wake_up_all(&cli->cl_cache->ccc_unstable_waitq);
933 if (waitqueue_active(&osc_lru_waitq))
934 (void)ptlrpcd_queue_work(cli->cl_lru_work);
938 * "unstable" page accounting. See: osc_dec_unstable_pages.
940 void osc_inc_unstable_pages(struct ptlrpc_request *req)
942 struct ptlrpc_bulk_desc *desc = req->rq_bulk;
943 struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
944 long page_count = desc->bd_iov_count;
946 /* No unstable page tracking */
947 if (cli->cl_cache == NULL || !cli->cl_cache->ccc_unstable_check)
950 add_unstable_page_accounting(desc);
951 atomic_long_add(page_count, &cli->cl_unstable_count);
952 atomic_long_add(page_count, &cli->cl_cache->ccc_unstable_nr);
954 /* If the request has already been committed (i.e. brw_commit
955 * called via rq_commit_cb), we need to undo the unstable page
956 * increments we just performed because rq_commit_cb wont be
958 spin_lock(&req->rq_lock);
959 if (unlikely(req->rq_committed)) {
960 spin_unlock(&req->rq_lock);
962 osc_dec_unstable_pages(req);
964 req->rq_unstable = 1;
965 spin_unlock(&req->rq_lock);
970 * Check if it piggybacks SOFT_SYNC flag to OST from this OSC.
971 * This function will be called by every BRW RPC so it's critical
972 * to make this function fast.
974 bool osc_over_unstable_soft_limit(struct client_obd *cli)
976 long unstable_nr, osc_unstable_count;
978 /* Can't check cli->cl_unstable_count, therefore, no soft limit */
979 if (cli->cl_cache == NULL || !cli->cl_cache->ccc_unstable_check)
982 osc_unstable_count = atomic_long_read(&cli->cl_unstable_count);
983 unstable_nr = atomic_long_read(&cli->cl_cache->ccc_unstable_nr);
986 "%s: cli: %p unstable pages: %lu, osc unstable pages: %lu\n",
987 cli_name(cli), cli, unstable_nr, osc_unstable_count);
989 /* If the LRU slots are in shortage - 25% remaining AND this OSC
990 * has one full RPC window of unstable pages, it's a good chance
991 * to piggyback a SOFT_SYNC flag.
992 * Please notice that the OST won't take immediate response for the
993 * SOFT_SYNC request so active OSCs will have more chance to carry
994 * the flag, this is reasonable. */
995 return unstable_nr > cli->cl_cache->ccc_lru_max >> 2 &&
996 osc_unstable_count > cli->cl_max_pages_per_rpc *
997 cli->cl_max_rpcs_in_flight;
1001 * Return how many LRU pages in the cache of all OSC devices
1003 * \retval return # of cached LRU pages times reclaimation tendency
1004 * \retval SHRINK_STOP if it cannot do any scanning in this time
1006 unsigned long osc_cache_shrink_count(struct shrinker *sk,
1007 struct shrink_control *sc)
1009 struct client_obd *cli;
1010 unsigned long cached = 0;
1012 spin_lock(&osc_shrink_lock);
1013 list_for_each_entry(cli, &osc_shrink_list, cl_shrink_list)
1014 cached += atomic_long_read(&cli->cl_lru_in_list);
1015 spin_unlock(&osc_shrink_lock);
1017 return (cached * sysctl_vfs_cache_pressure) / 100;
1021 * Scan and try to reclaim sc->nr_to_scan cached LRU pages
1023 * \retval number of cached LRU pages reclaimed
1024 * \retval SHRINK_STOP if it cannot do any scanning in this time
1026 * Linux kernel will loop calling this shrinker scan routine with
1027 * sc->nr_to_scan = SHRINK_BATCH(128 for now) until kernel got enough memory.
1029 * If sc->nr_to_scan is 0, the VM is querying the cache size, we don't need
1030 * to scan and try to reclaim LRU pages, just return 0 and
1031 * osc_cache_shrink_count() will report the LRU page number.
1033 unsigned long osc_cache_shrink_scan(struct shrinker *sk,
1034 struct shrink_control *sc)
1036 struct client_obd *cli;
1037 struct client_obd *stop_anchor = NULL;
1043 if (sc->nr_to_scan == 0)
1046 if (!(sc->gfp_mask & __GFP_FS))
1049 env = cl_env_get(&refcheck);
1053 spin_lock(&osc_shrink_lock);
1054 while (!list_empty(&osc_shrink_list)) {
1055 cli = list_entry(osc_shrink_list.next, struct client_obd,
1058 if (stop_anchor == NULL)
1060 else if (cli == stop_anchor)
1063 list_move_tail(&cli->cl_shrink_list, &osc_shrink_list);
1064 spin_unlock(&osc_shrink_lock);
1066 /* shrink no more than max_pages_per_rpc for an OSC */
1067 rc = osc_lru_shrink(env, cli, (sc->nr_to_scan - shrank) >
1068 cli->cl_max_pages_per_rpc ?
1069 cli->cl_max_pages_per_rpc :
1070 sc->nr_to_scan - shrank, true);
1074 if (shrank >= sc->nr_to_scan)
1077 spin_lock(&osc_shrink_lock);
1079 spin_unlock(&osc_shrink_lock);
1082 cl_env_put(env, &refcheck);