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,
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10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
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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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21 * CA 95054 USA or visit www.sun.com if you need additional information or
27 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
28 * Use is subject to license terms.
30 * Copyright (c) 2011, 2014, Intel Corporation.
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_reserve(const struct lu_env *env, struct osc_object *obj,
49 struct osc_page *opg);
56 * Comment out osc_page_protected because it may sleep inside the
57 * the client_obd_list_lock.
58 * client_obd_list_lock -> osc_ap_completion -> osc_completion ->
59 * -> osc_page_protected -> osc_page_is_dlocked -> osc_match_base
60 * -> ldlm_lock_match -> sptlrpc_import_check_ctx -> sleep.
63 static int osc_page_is_dlocked(const struct lu_env *env,
64 const struct osc_page *opg,
65 enum cl_lock_mode mode, int pending, int unref)
68 struct osc_object *obj;
69 struct osc_thread_info *info;
70 struct ldlm_res_id *resname;
71 struct lustre_handle *lockh;
72 ldlm_policy_data_t *policy;
78 info = osc_env_info(env);
79 resname = &info->oti_resname;
80 policy = &info->oti_policy;
81 lockh = &info->oti_handle;
82 page = opg->ops_cl.cpl_page;
83 obj = cl2osc(opg->ops_cl.cpl_obj);
85 flags = LDLM_FL_TEST_LOCK | LDLM_FL_BLOCK_GRANTED;
87 flags |= LDLM_FL_CBPENDING;
89 dlmmode = osc_cl_lock2ldlm(mode) | LCK_PW;
90 osc_lock_build_res(env, obj, resname);
91 osc_index2policy(policy, page->cp_obj, osc_index(opg), osc_index(opg));
92 return osc_match_base(osc_export(obj), resname, LDLM_EXTENT, policy,
93 dlmmode, &flags, NULL, lockh, unref);
97 * Checks an invariant that a page in the cache is covered by a lock, as
100 static int osc_page_protected(const struct lu_env *env,
101 const struct osc_page *opg,
102 enum cl_lock_mode mode, int unref)
104 struct cl_object_header *hdr;
105 struct cl_lock *scan;
106 struct cl_page *page;
107 struct cl_lock_descr *descr;
110 LINVRNT(!opg->ops_temp);
112 page = opg->ops_cl.cpl_page;
113 if (page->cp_owner != NULL &&
114 cl_io_top(page->cp_owner)->ci_lockreq == CILR_NEVER)
116 * If IO is done without locks (liblustre, or lloop), lock is
121 /* otherwise check for a DLM lock */
122 result = osc_page_is_dlocked(env, opg, mode, 1, unref);
124 /* maybe this page is a part of a lockless io? */
125 hdr = cl_object_header(opg->ops_cl.cpl_obj);
126 descr = &osc_env_info(env)->oti_descr;
127 descr->cld_mode = mode;
128 descr->cld_start = osc_index(opg);
129 descr->cld_end = osc_index(opg);
130 spin_lock(&hdr->coh_lock_guard);
131 list_for_each_entry(scan, &hdr->coh_locks, cll_linkage) {
133 * Lock-less sub-lock has to be either in HELD state
134 * (when io is actively going on), or in CACHED state,
135 * when top-lock is being unlocked:
136 * cl_io_unlock()->cl_unuse()->...->lov_lock_unuse().
138 if ((scan->cll_state == CLS_HELD ||
139 scan->cll_state == CLS_CACHED) &&
140 cl_lock_ext_match(&scan->cll_descr, descr)) {
141 struct osc_lock *olck;
143 olck = osc_lock_at(scan);
144 result = osc_lock_is_lockless(olck);
148 spin_unlock(&hdr->coh_lock_guard);
153 static int osc_page_protected(const struct lu_env *env,
154 const struct osc_page *opg,
155 enum cl_lock_mode mode, int unref)
161 /*****************************************************************************
166 static void osc_page_transfer_get(struct osc_page *opg, const char *label)
168 struct cl_page *page = opg->ops_cl.cpl_page;
170 LASSERT(!opg->ops_transfer_pinned);
172 lu_ref_add_atomic(&page->cp_reference, label, page);
173 opg->ops_transfer_pinned = 1;
176 static void osc_page_transfer_put(const struct lu_env *env,
177 struct osc_page *opg)
179 struct cl_page *page = opg->ops_cl.cpl_page;
181 if (opg->ops_transfer_pinned) {
182 opg->ops_transfer_pinned = 0;
183 lu_ref_del(&page->cp_reference, "transfer", page);
184 cl_page_put(env, page);
189 * This is called once for every page when it is submitted for a transfer
190 * either opportunistic (osc_page_cache_add()), or immediate
191 * (osc_page_submit()).
193 static void osc_page_transfer_add(const struct lu_env *env,
194 struct osc_page *opg, enum cl_req_type crt)
196 struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj);
198 /* ops_lru and ops_inflight share the same field, so take it from LRU
199 * first and then use it as inflight. */
200 osc_lru_use(osc_cli(obj), opg);
202 spin_lock(&obj->oo_seatbelt);
203 list_add(&opg->ops_inflight, &obj->oo_inflight[crt]);
204 opg->ops_submitter = current;
205 spin_unlock(&obj->oo_seatbelt);
208 int osc_page_cache_add(const struct lu_env *env,
209 const struct cl_page_slice *slice, struct cl_io *io)
211 struct osc_page *opg = cl2osc_page(slice);
215 LINVRNT(osc_page_protected(env, opg, CLM_WRITE, 0));
217 osc_page_transfer_get(opg, "transfer\0cache");
218 result = osc_queue_async_io(env, io, opg);
220 osc_page_transfer_put(env, opg);
222 osc_page_transfer_add(env, opg, CRT_WRITE);
227 void osc_index2policy(ldlm_policy_data_t *policy, const struct cl_object *obj,
228 pgoff_t start, pgoff_t end)
230 memset(policy, 0, sizeof *policy);
231 policy->l_extent.start = cl_offset(obj, start);
232 policy->l_extent.end = cl_offset(obj, end + 1) - 1;
235 static const char *osc_list(struct list_head *head)
237 return list_empty(head) ? "-" : "+";
240 static inline cfs_time_t osc_submit_duration(struct osc_page *opg)
242 if (opg->ops_submit_time == 0)
245 return (cfs_time_current() - opg->ops_submit_time);
248 static int osc_page_print(const struct lu_env *env,
249 const struct cl_page_slice *slice,
250 void *cookie, lu_printer_t printer)
252 struct osc_page *opg = cl2osc_page(slice);
253 struct osc_async_page *oap = &opg->ops_oap;
254 struct osc_object *obj = cl2osc(slice->cpl_obj);
255 struct client_obd *cli = &osc_export(obj)->exp_obd->u.cli;
257 return (*printer)(env, cookie, LUSTRE_OSC_NAME"-page@%p %lu: "
258 "1< %#x %d %u %s %s > "
259 "2< "LPD64" %u %u %#x %#x | %p %p %p > "
260 "3< %s %p %d %lu %d > "
261 "4< %d %d %d %lu %s | %s %s %s %s > "
262 "5< %s %s %s %s | %d %s | %d %s %s>\n",
265 oap->oap_magic, oap->oap_cmd,
266 oap->oap_interrupted,
267 osc_list(&oap->oap_pending_item),
268 osc_list(&oap->oap_rpc_item),
270 oap->oap_obj_off, oap->oap_page_off, oap->oap_count,
271 oap->oap_async_flags, oap->oap_brw_flags,
272 oap->oap_request, oap->oap_cli, obj,
274 osc_list(&opg->ops_inflight),
275 opg->ops_submitter, opg->ops_transfer_pinned,
276 osc_submit_duration(opg), opg->ops_srvlock,
278 cli->cl_r_in_flight, cli->cl_w_in_flight,
279 cli->cl_max_rpcs_in_flight,
281 osc_list(&cli->cl_cache_waiters),
282 osc_list(&cli->cl_loi_ready_list),
283 osc_list(&cli->cl_loi_hp_ready_list),
284 osc_list(&cli->cl_loi_write_list),
285 osc_list(&cli->cl_loi_read_list),
287 osc_list(&obj->oo_ready_item),
288 osc_list(&obj->oo_hp_ready_item),
289 osc_list(&obj->oo_write_item),
290 osc_list(&obj->oo_read_item),
291 atomic_read(&obj->oo_nr_reads),
292 osc_list(&obj->oo_reading_exts),
293 atomic_read(&obj->oo_nr_writes),
294 osc_list(&obj->oo_hp_exts),
295 osc_list(&obj->oo_urgent_exts));
298 static void osc_page_delete(const struct lu_env *env,
299 const struct cl_page_slice *slice)
301 struct osc_page *opg = cl2osc_page(slice);
302 struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj);
305 LINVRNT(opg->ops_temp || osc_page_protected(env, opg, CLM_READ, 1));
308 CDEBUG(D_TRACE, "%p\n", opg);
309 osc_page_transfer_put(env, opg);
310 rc = osc_teardown_async_page(env, obj, opg);
312 CL_PAGE_DEBUG(D_ERROR, env, slice->cpl_page,
313 "Trying to teardown failed: %d\n", rc);
317 spin_lock(&obj->oo_seatbelt);
318 if (opg->ops_submitter != NULL) {
319 LASSERT(!list_empty(&opg->ops_inflight));
320 list_del_init(&opg->ops_inflight);
321 opg->ops_submitter = NULL;
323 spin_unlock(&obj->oo_seatbelt);
325 osc_lru_del(osc_cli(obj), opg);
327 if (slice->cpl_page->cp_type == CPT_CACHEABLE) {
330 spin_lock(&obj->oo_tree_lock);
331 value = radix_tree_delete(&obj->oo_tree, osc_index(opg));
334 spin_unlock(&obj->oo_tree_lock);
336 LASSERT(ergo(value != NULL, value == opg));
342 static void osc_page_clip(const struct lu_env *env,
343 const struct cl_page_slice *slice,
346 struct osc_page *opg = cl2osc_page(slice);
347 struct osc_async_page *oap = &opg->ops_oap;
349 LINVRNT(osc_page_protected(env, opg, CLM_READ, 0));
351 opg->ops_from = from;
353 spin_lock(&oap->oap_lock);
354 oap->oap_async_flags |= ASYNC_COUNT_STABLE;
355 spin_unlock(&oap->oap_lock);
358 static int osc_page_cancel(const struct lu_env *env,
359 const struct cl_page_slice *slice)
361 struct osc_page *opg = cl2osc_page(slice);
364 LINVRNT(osc_page_protected(env, opg, CLM_READ, 0));
366 /* Check if the transferring against this page
367 * is completed, or not even queued. */
368 if (opg->ops_transfer_pinned)
369 /* FIXME: may not be interrupted.. */
370 rc = osc_cancel_async_page(env, opg);
371 LASSERT(ergo(rc == 0, opg->ops_transfer_pinned == 0));
375 static int osc_page_flush(const struct lu_env *env,
376 const struct cl_page_slice *slice,
379 struct osc_page *opg = cl2osc_page(slice);
382 rc = osc_flush_async_page(env, io, opg);
386 static const struct cl_page_operations osc_page_ops = {
387 .cpo_print = osc_page_print,
388 .cpo_delete = osc_page_delete,
389 .cpo_clip = osc_page_clip,
390 .cpo_cancel = osc_page_cancel,
391 .cpo_flush = osc_page_flush
394 int osc_page_init(const struct lu_env *env, struct cl_object *obj,
395 struct cl_page *page, pgoff_t index)
397 struct osc_object *osc = cl2osc(obj);
398 struct osc_page *opg = cl_object_page_slice(obj, page);
402 opg->ops_to = PAGE_CACHE_SIZE;
404 result = osc_prep_async_page(osc, opg, page->cp_vmpage,
405 cl_offset(obj, index));
407 struct osc_io *oio = osc_env_io(env);
408 opg->ops_srvlock = osc_io_srvlock(oio);
409 cl_page_slice_add(page, &opg->ops_cl, obj, index,
413 * Cannot assert osc_page_protected() here as read-ahead
414 * creates temporary pages outside of a lock.
416 #ifdef CONFIG_LUSTRE_DEBUG_EXPENSIVE_CHECK
417 opg->ops_temp = !osc_page_protected(env, opg, CLM_READ, 1);
419 /* ops_inflight and ops_lru are the same field, but it doesn't
420 * hurt to initialize it twice :-) */
421 INIT_LIST_HEAD(&opg->ops_inflight);
422 INIT_LIST_HEAD(&opg->ops_lru);
424 /* reserve an LRU space for this page */
425 if (page->cp_type == CPT_CACHEABLE && result == 0) {
426 result = osc_lru_reserve(env, osc, opg);
428 spin_lock(&osc->oo_tree_lock);
429 result = radix_tree_insert(&osc->oo_tree, index, opg);
432 spin_unlock(&osc->oo_tree_lock);
433 LASSERT(result == 0);
441 * Helper function called by osc_io_submit() for every page in an immediate
442 * transfer (i.e., transferred synchronously).
444 void osc_page_submit(const struct lu_env *env, struct osc_page *opg,
445 enum cl_req_type crt, int brw_flags)
447 struct osc_async_page *oap = &opg->ops_oap;
448 struct osc_object *obj = oap->oap_obj;
450 LINVRNT(osc_page_protected(env, opg,
451 crt == CRT_WRITE ? CLM_WRITE : CLM_READ, 1));
453 LASSERTF(oap->oap_magic == OAP_MAGIC, "Bad oap magic: oap %p, "
454 "magic 0x%x\n", oap, oap->oap_magic);
455 LASSERT(oap->oap_async_flags & ASYNC_READY);
456 LASSERT(oap->oap_async_flags & ASYNC_COUNT_STABLE);
458 oap->oap_cmd = crt == CRT_WRITE ? OBD_BRW_WRITE : OBD_BRW_READ;
459 oap->oap_page_off = opg->ops_from;
460 oap->oap_count = opg->ops_to - opg->ops_from;
461 oap->oap_brw_flags = OBD_BRW_SYNC | brw_flags;
463 if (!client_is_remote(osc_export(obj)) &&
464 cfs_capable(CFS_CAP_SYS_RESOURCE)) {
465 oap->oap_brw_flags |= OBD_BRW_NOQUOTA;
466 oap->oap_cmd |= OBD_BRW_NOQUOTA;
469 opg->ops_submit_time = cfs_time_current();
470 osc_page_transfer_get(opg, "transfer\0imm");
471 osc_page_transfer_add(env, opg, crt);
474 /* --------------- LRU page management ------------------ */
476 /* OSC is a natural place to manage LRU pages as applications are specialized
477 * to write OSC by OSC. Ideally, if one OSC is used more frequently it should
478 * occupy more LRU slots. On the other hand, we should avoid using up all LRU
479 * slots (client_obd::cl_lru_left) otherwise process has to be put into sleep
480 * for free LRU slots - this will be very bad so the algorithm requires each
481 * OSC to free slots voluntarily to maintain a reasonable number of free slots
485 static CFS_DECL_WAITQ(osc_lru_waitq);
486 /* LRU pages are freed in batch mode. OSC should at least free this
487 * number of pages to avoid running out of LRU budget, and.. */
488 static const int lru_shrink_min = 2 << (20 - PAGE_CACHE_SHIFT); /* 2M */
489 /* free this number at most otherwise it will take too long time to finsih. */
490 static const int lru_shrink_max = 8 << (20 - PAGE_CACHE_SHIFT); /* 8M */
492 /* Check if we can free LRU slots from this OSC. If there exists LRU waiters,
493 * we should free slots aggressively. In this way, slots are freed in a steady
494 * step to maintain fairness among OSCs.
496 * Return how many LRU pages should be freed. */
497 static int osc_cache_too_much(struct client_obd *cli)
499 struct cl_client_cache *cache = cli->cl_cache;
500 long pages = atomic_long_read(&cli->cl_lru_in_list);
501 unsigned long budget;
503 LASSERT(cache != NULL);
504 budget = cache->ccc_lru_max / (atomic_read(&cache->ccc_users) - 2);
506 /* if it's going to run out LRU slots, we should free some, but not
507 * too much to maintain faireness among OSCs. */
508 if (atomic_long_read(cli->cl_lru_left) < cache->ccc_lru_max >> 4) {
510 return lru_shrink_max;
511 else if (pages >= budget / 2)
512 return lru_shrink_min;
514 } else if (pages >= budget * 2)
515 return lru_shrink_min;
521 int lru_queue_work(const struct lu_env *env, void *data)
523 struct client_obd *cli = data;
525 CDEBUG(D_CACHE, "Run LRU work for client obd %p.\n", cli);
527 if (osc_cache_too_much(cli))
528 osc_lru_shrink(env, cli, lru_shrink_max, true);
533 void osc_lru_add_batch(struct client_obd *cli, struct list_head *plist)
535 struct list_head lru = LIST_HEAD_INIT(lru);
536 struct osc_async_page *oap;
539 list_for_each_entry(oap, plist, oap_pending_item) {
540 struct osc_page *opg = oap2osc_page(oap);
542 if (!opg->ops_in_lru)
546 LASSERT(list_empty(&opg->ops_lru));
547 list_add(&opg->ops_lru, &lru);
551 spin_lock(&cli->cl_lru_list_lock);
552 list_splice_tail(&lru, &cli->cl_lru_list);
553 atomic_long_sub(npages, &cli->cl_lru_busy);
554 atomic_long_add(npages, &cli->cl_lru_in_list);
555 spin_unlock(&cli->cl_lru_list_lock);
557 /* XXX: May set force to be true for better performance */
558 if (osc_cache_too_much(cli))
559 (void)ptlrpcd_queue_work(cli->cl_lru_work);
563 static void __osc_lru_del(struct client_obd *cli, struct osc_page *opg)
565 LASSERT(atomic_long_read(&cli->cl_lru_in_list) > 0);
566 list_del_init(&opg->ops_lru);
567 atomic_long_dec(&cli->cl_lru_in_list);
571 * Page is being destroyed. The page may be not in LRU list, if the transfer
572 * has never finished(error occurred).
574 static void osc_lru_del(struct client_obd *cli, struct osc_page *opg)
576 if (opg->ops_in_lru) {
577 spin_lock(&cli->cl_lru_list_lock);
578 if (!list_empty(&opg->ops_lru)) {
579 __osc_lru_del(cli, opg);
581 LASSERT(atomic_long_read(&cli->cl_lru_busy) > 0);
582 atomic_long_dec(&cli->cl_lru_busy);
584 spin_unlock(&cli->cl_lru_list_lock);
586 atomic_long_inc(cli->cl_lru_left);
587 /* this is a great place to release more LRU pages if
588 * this osc occupies too many LRU pages and kernel is
589 * stealing one of them. */
590 if (!memory_pressure_get())
591 (void)ptlrpcd_queue_work(cli->cl_lru_work);
592 wake_up(&osc_lru_waitq);
594 LASSERT(list_empty(&opg->ops_lru));
599 * Delete page from LRUlist for redirty.
601 static void osc_lru_use(struct client_obd *cli, struct osc_page *opg)
603 /* If page is being transferred for the first time,
604 * ops_lru should be empty */
605 if (opg->ops_in_lru && !list_empty(&opg->ops_lru)) {
606 spin_lock(&cli->cl_lru_list_lock);
607 __osc_lru_del(cli, opg);
608 spin_unlock(&cli->cl_lru_list_lock);
609 atomic_long_inc(&cli->cl_lru_busy);
613 static void discard_pagevec(const struct lu_env *env, struct cl_io *io,
614 struct cl_page **pvec, int max_index)
618 for (i = 0; i < max_index; i++) {
619 struct cl_page *page = pvec[i];
621 LASSERT(cl_page_is_owned(page, io));
622 cl_page_discard(env, io, page);
623 cl_page_disown(env, io, page);
624 cl_page_put(env, page);
631 * Check if a cl_page can be released, i.e, it's not being used.
633 * If unstable account is turned on, bulk transfer may hold one refcount
634 * for recovery so we need to check vmpage refcount as well; otherwise,
635 * even we can destroy cl_page but the corresponding vmpage can't be reused.
637 static inline bool lru_page_busy(struct client_obd *cli, struct cl_page *page)
639 if (cl_page_in_use_noref(page))
642 if (cli->cl_cache->ccc_unstable_check) {
643 struct page *vmpage = cl_page_vmpage(page);
645 /* vmpage have two known users: cl_page and VM page cache */
646 if (page_count(vmpage) - page_mapcount(vmpage) > 2)
653 * Drop @target of pages from LRU at most.
655 long osc_lru_shrink(const struct lu_env *env, struct client_obd *cli,
656 long target, bool force)
659 struct cl_object *clobj = NULL;
660 struct cl_page **pvec;
661 struct osc_page *opg;
668 LASSERT(atomic_long_read(&cli->cl_lru_in_list) >= 0);
669 if (atomic_long_read(&cli->cl_lru_in_list) == 0 || target <= 0)
673 if (atomic_read(&cli->cl_lru_shrinkers) > 0)
676 if (atomic_inc_return(&cli->cl_lru_shrinkers) > 1) {
677 atomic_dec(&cli->cl_lru_shrinkers);
681 atomic_inc(&cli->cl_lru_shrinkers);
684 pvec = (struct cl_page **)osc_env_info(env)->oti_pvec;
685 io = &osc_env_info(env)->oti_io;
687 spin_lock(&cli->cl_lru_list_lock);
688 maxscan = min(target << 1, atomic_long_read(&cli->cl_lru_in_list));
689 while (!list_empty(&cli->cl_lru_list)) {
690 struct cl_page *page;
691 bool will_free = false;
696 opg = list_entry(cli->cl_lru_list.next, struct osc_page,
698 page = opg->ops_cl.cpl_page;
699 if (lru_page_busy(cli, page)) {
700 list_move_tail(&opg->ops_lru, &cli->cl_lru_list);
704 LASSERT(page->cp_obj != NULL);
705 if (clobj != page->cp_obj) {
706 struct cl_object *tmp = page->cp_obj;
709 spin_unlock(&cli->cl_lru_list_lock);
712 discard_pagevec(env, io, pvec, index);
716 cl_object_put(env, clobj);
722 io->ci_ignore_layout = 1;
723 rc = cl_io_init(env, io, CIT_MISC, clobj);
725 spin_lock(&cli->cl_lru_list_lock);
734 if (cl_page_own_try(env, io, page) == 0) {
735 if (!lru_page_busy(cli, page)) {
736 /* remove it from lru list earlier to avoid
738 __osc_lru_del(cli, opg);
739 opg->ops_in_lru = 0; /* will be discarded */
744 cl_page_disown(env, io, page);
749 list_move_tail(&opg->ops_lru, &cli->cl_lru_list);
753 /* Don't discard and free the page with cl_lru_list held */
754 pvec[index++] = page;
755 if (unlikely(index == OTI_PVEC_SIZE)) {
756 spin_unlock(&cli->cl_lru_list_lock);
757 discard_pagevec(env, io, pvec, index);
760 spin_lock(&cli->cl_lru_list_lock);
763 if (++count >= target)
766 spin_unlock(&cli->cl_lru_list_lock);
769 discard_pagevec(env, io, pvec, index);
772 cl_object_put(env, clobj);
775 atomic_dec(&cli->cl_lru_shrinkers);
777 atomic_long_add(count, cli->cl_lru_left);
778 wake_up_all(&osc_lru_waitq);
780 RETURN(count > 0 ? count : rc);
783 long osc_lru_reclaim(struct client_obd *cli)
785 struct cl_env_nest nest;
787 struct cl_client_cache *cache = cli->cl_cache;
792 LASSERT(cache != NULL);
793 LASSERT(!list_empty(&cache->ccc_lru));
795 env = cl_env_nested_get(&nest);
799 rc = osc_lru_shrink(env, cli, osc_cache_too_much(cli), false);
804 CDEBUG(D_CACHE, "%s: Free %ld pages from own LRU: %p.\n",
805 cli->cl_import->imp_obd->obd_name, rc, cli);
809 CDEBUG(D_CACHE, "%s: cli %p no free slots, pages: %ld, busy: %ld.\n",
810 cli->cl_import->imp_obd->obd_name, cli,
811 atomic_long_read(&cli->cl_lru_in_list),
812 atomic_long_read(&cli->cl_lru_busy));
814 /* Reclaim LRU slots from other client_obd as it can't free enough
815 * from its own. This should rarely happen. */
816 spin_lock(&cache->ccc_lru_lock);
817 cache->ccc_lru_shrinkers++;
818 list_move_tail(&cli->cl_lru_osc, &cache->ccc_lru);
820 max_scans = atomic_read(&cache->ccc_users) - 2;
821 while (--max_scans > 0 && !list_empty(&cache->ccc_lru)) {
822 cli = list_entry(cache->ccc_lru.next, struct client_obd,
825 CDEBUG(D_CACHE, "%s: cli %p LRU pages: %ld, busy: %ld.\n",
826 cli->cl_import->imp_obd->obd_name, cli,
827 atomic_long_read(&cli->cl_lru_in_list),
828 atomic_long_read(&cli->cl_lru_busy));
830 list_move_tail(&cli->cl_lru_osc, &cache->ccc_lru);
831 if (osc_cache_too_much(cli) > 0) {
832 spin_unlock(&cache->ccc_lru_lock);
834 rc = osc_lru_shrink(env, cli, osc_cache_too_much(cli),
836 spin_lock(&cache->ccc_lru_lock);
841 spin_unlock(&cache->ccc_lru_lock);
844 cl_env_nested_put(&nest, env);
845 CDEBUG(D_CACHE, "%s: cli %p freed %ld pages.\n",
846 cli->cl_import->imp_obd->obd_name, cli, rc);
851 * osc_lru_reserve() is called to reserve an LRU slot for a cl_page.
853 * Usually the LRU slots are reserved in osc_io_iter_rw_init().
854 * Only in the case that the LRU slots are in extreme shortage, it should
855 * have reserved enough slots for an IO.
857 static int osc_lru_reserve(const struct lu_env *env, struct osc_object *obj,
858 struct osc_page *opg)
860 struct l_wait_info lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
861 struct osc_io *oio = osc_env_io(env);
862 struct client_obd *cli = osc_cli(obj);
866 if (cli->cl_cache == NULL) /* shall not be in LRU */
869 if (oio->oi_lru_reserved > 0) {
870 --oio->oi_lru_reserved;
874 LASSERT(atomic_long_read(cli->cl_lru_left) >= 0);
875 while (!atomic_long_add_unless(cli->cl_lru_left, -1, 0)) {
877 /* run out of LRU spaces, try to drop some by itself */
878 rc = osc_lru_reclaim(cli);
885 rc = l_wait_event(osc_lru_waitq,
886 atomic_long_read(cli->cl_lru_left) > 0,
894 atomic_long_inc(&cli->cl_lru_busy);
903 * Atomic operations are expensive. We accumulate the accounting for the
904 * same page zone to get better performance.
905 * In practice this can work pretty good because the pages in the same RPC
906 * are likely from the same page zone.
908 static inline void unstable_page_accounting(struct ptlrpc_bulk_desc *desc,
911 int page_count = desc->bd_iov_count;
916 for (i = 0; i < page_count; i++) {
917 void *pz = page_zone(desc->bd_iov[i].kiov_page);
919 if (likely(pz == zone)) {
925 mod_zone_page_state(zone, NR_UNSTABLE_NFS,
933 mod_zone_page_state(zone, NR_UNSTABLE_NFS, factor * count);
936 static inline void add_unstable_page_accounting(struct ptlrpc_bulk_desc *desc)
938 unstable_page_accounting(desc, 1);
941 static inline void dec_unstable_page_accounting(struct ptlrpc_bulk_desc *desc)
943 unstable_page_accounting(desc, -1);
947 * Performs "unstable" page accounting. This function balances the
948 * increment operations performed in osc_inc_unstable_pages. It is
949 * registered as the RPC request callback, and is executed when the
950 * bulk RPC is committed on the server. Thus at this point, the pages
951 * involved in the bulk transfer are no longer considered unstable.
953 * If this function is called, the request should have been committed
954 * or req:rq_unstable must have been set; it implies that the unstable
955 * statistic have been added.
957 void osc_dec_unstable_pages(struct ptlrpc_request *req)
959 struct ptlrpc_bulk_desc *desc = req->rq_bulk;
960 struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
961 int page_count = desc->bd_iov_count;
964 LASSERT(page_count >= 0);
965 dec_unstable_page_accounting(desc);
967 unstable_count = atomic_long_sub_return(page_count,
968 &cli->cl_unstable_count);
969 LASSERT(unstable_count >= 0);
971 unstable_count = atomic_long_sub_return(page_count,
972 &cli->cl_cache->ccc_unstable_nr);
973 LASSERT(unstable_count >= 0);
974 if (unstable_count == 0)
975 wake_up_all(&cli->cl_cache->ccc_unstable_waitq);
977 if (osc_cache_too_much(cli))
978 (void)ptlrpcd_queue_work(cli->cl_lru_work);
982 * "unstable" page accounting. See: osc_dec_unstable_pages.
984 void osc_inc_unstable_pages(struct ptlrpc_request *req)
986 struct ptlrpc_bulk_desc *desc = req->rq_bulk;
987 struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
988 long page_count = desc->bd_iov_count;
990 /* No unstable page tracking */
991 if (cli->cl_cache == NULL || !cli->cl_cache->ccc_unstable_check)
994 add_unstable_page_accounting(desc);
995 atomic_long_add(page_count, &cli->cl_unstable_count);
996 atomic_long_add(page_count, &cli->cl_cache->ccc_unstable_nr);
998 /* If the request has already been committed (i.e. brw_commit
999 * called via rq_commit_cb), we need to undo the unstable page
1000 * increments we just performed because rq_commit_cb wont be
1002 spin_lock(&req->rq_lock);
1003 if (unlikely(req->rq_committed)) {
1004 spin_unlock(&req->rq_lock);
1006 osc_dec_unstable_pages(req);
1008 req->rq_unstable = 1;
1009 spin_unlock(&req->rq_lock);
1014 * Check if it piggybacks SOFT_SYNC flag to OST from this OSC.
1015 * This function will be called by every BRW RPC so it's critical
1016 * to make this function fast.
1018 bool osc_over_unstable_soft_limit(struct client_obd *cli)
1020 long unstable_nr, osc_unstable_count;
1022 /* Can't check cli->cl_unstable_count, therefore, no soft limit */
1023 if (cli->cl_cache == NULL || !cli->cl_cache->ccc_unstable_check)
1026 osc_unstable_count = atomic_long_read(&cli->cl_unstable_count);
1027 unstable_nr = atomic_long_read(&cli->cl_cache->ccc_unstable_nr);
1030 "%s: cli: %p unstable pages: %lu, osc unstable pages: %lu\n",
1031 cli->cl_import->imp_obd->obd_name, cli,
1032 unstable_nr, osc_unstable_count);
1034 /* If the LRU slots are in shortage - 25% remaining AND this OSC
1035 * has one full RPC window of unstable pages, it's a good chance
1036 * to piggyback a SOFT_SYNC flag.
1037 * Please notice that the OST won't take immediate response for the
1038 * SOFT_SYNC request so active OSCs will have more chance to carry
1039 * the flag, this is reasonable. */
1040 return unstable_nr > cli->cl_cache->ccc_lru_max >> 2 &&
1041 osc_unstable_count > cli->cl_max_pages_per_rpc *
1042 cli->cl_max_rpcs_in_flight;