/* * GPL HEADER START * * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 only, * as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License version 2 for more details (a copy is included * in the LICENSE file that accompanied this code). * * You should have received a copy of the GNU General Public License * version 2 along with this program; If not, see * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf * * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, * CA 95054 USA or visit www.sun.com if you need additional information or * have any questions. * * GPL HEADER END */ /* * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved. * Use is subject to license terms. * * Copyright (c) 2011, 2013, Intel Corporation. */ /* * This file is part of Lustre, http://www.lustre.org/ * Lustre is a trademark of Sun Microsystems, Inc. * * Implementation of cl_page for OSC layer. * * Author: Nikita Danilov * Author: Jinshan Xiong */ #define DEBUG_SUBSYSTEM S_OSC #include "osc_cl_internal.h" static void osc_lru_del(struct client_obd *cli, struct osc_page *opg); static void osc_lru_use(struct client_obd *cli, struct osc_page *opg); static int osc_lru_reserve(const struct lu_env *env, struct osc_object *obj, struct osc_page *opg); /** \addtogroup osc * @{ */ /* * Comment out osc_page_protected because it may sleep inside the * the client_obd_list_lock. * client_obd_list_lock -> osc_ap_completion -> osc_completion -> * -> osc_page_protected -> osc_page_is_dlocked -> osc_match_base * -> ldlm_lock_match -> sptlrpc_import_check_ctx -> sleep. */ #if 0 static int osc_page_is_dlocked(const struct lu_env *env, const struct osc_page *opg, enum cl_lock_mode mode, int pending, int unref) { struct cl_page *page; struct osc_object *obj; struct osc_thread_info *info; struct ldlm_res_id *resname; struct lustre_handle *lockh; ldlm_policy_data_t *policy; ldlm_mode_t dlmmode; __u64 flags; might_sleep(); info = osc_env_info(env); resname = &info->oti_resname; policy = &info->oti_policy; lockh = &info->oti_handle; page = opg->ops_cl.cpl_page; obj = cl2osc(opg->ops_cl.cpl_obj); flags = LDLM_FL_TEST_LOCK | LDLM_FL_BLOCK_GRANTED; if (pending) flags |= LDLM_FL_CBPENDING; dlmmode = osc_cl_lock2ldlm(mode) | LCK_PW; osc_lock_build_res(env, obj, resname); osc_index2policy(policy, page->cp_obj, osc_index(opg), osc_index(opg)); return osc_match_base(osc_export(obj), resname, LDLM_EXTENT, policy, dlmmode, &flags, NULL, lockh, unref); } /** * Checks an invariant that a page in the cache is covered by a lock, as * needed. */ static int osc_page_protected(const struct lu_env *env, const struct osc_page *opg, enum cl_lock_mode mode, int unref) { struct cl_object_header *hdr; struct cl_lock *scan; struct cl_page *page; struct cl_lock_descr *descr; int result; LINVRNT(!opg->ops_temp); page = opg->ops_cl.cpl_page; if (page->cp_owner != NULL && cl_io_top(page->cp_owner)->ci_lockreq == CILR_NEVER) /* * If IO is done without locks (liblustre, or lloop), lock is * not required. */ result = 1; else /* otherwise check for a DLM lock */ result = osc_page_is_dlocked(env, opg, mode, 1, unref); if (result == 0) { /* maybe this page is a part of a lockless io? */ hdr = cl_object_header(opg->ops_cl.cpl_obj); descr = &osc_env_info(env)->oti_descr; descr->cld_mode = mode; descr->cld_start = osc_index(opg); descr->cld_end = osc_index(opg); spin_lock(&hdr->coh_lock_guard); list_for_each_entry(scan, &hdr->coh_locks, cll_linkage) { /* * Lock-less sub-lock has to be either in HELD state * (when io is actively going on), or in CACHED state, * when top-lock is being unlocked: * cl_io_unlock()->cl_unuse()->...->lov_lock_unuse(). */ if ((scan->cll_state == CLS_HELD || scan->cll_state == CLS_CACHED) && cl_lock_ext_match(&scan->cll_descr, descr)) { struct osc_lock *olck; olck = osc_lock_at(scan); result = osc_lock_is_lockless(olck); break; } } spin_unlock(&hdr->coh_lock_guard); } return result; } #else static int osc_page_protected(const struct lu_env *env, const struct osc_page *opg, enum cl_lock_mode mode, int unref) { return 1; } #endif /***************************************************************************** * * Page operations. * */ static void osc_page_transfer_get(struct osc_page *opg, const char *label) { struct cl_page *page = opg->ops_cl.cpl_page; LASSERT(!opg->ops_transfer_pinned); cl_page_get(page); lu_ref_add_atomic(&page->cp_reference, label, page); opg->ops_transfer_pinned = 1; } static void osc_page_transfer_put(const struct lu_env *env, struct osc_page *opg) { struct cl_page *page = opg->ops_cl.cpl_page; if (opg->ops_transfer_pinned) { opg->ops_transfer_pinned = 0; lu_ref_del(&page->cp_reference, "transfer", page); cl_page_put(env, page); } } /** * This is called once for every page when it is submitted for a transfer * either opportunistic (osc_page_cache_add()), or immediate * (osc_page_submit()). */ static void osc_page_transfer_add(const struct lu_env *env, struct osc_page *opg, enum cl_req_type crt) { struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj); /* ops_lru and ops_inflight share the same field, so take it from LRU * first and then use it as inflight. */ osc_lru_use(osc_cli(obj), opg); spin_lock(&obj->oo_seatbelt); list_add(&opg->ops_inflight, &obj->oo_inflight[crt]); opg->ops_submitter = current; spin_unlock(&obj->oo_seatbelt); } int osc_page_cache_add(const struct lu_env *env, const struct cl_page_slice *slice, struct cl_io *io) { struct osc_page *opg = cl2osc_page(slice); int result; ENTRY; LINVRNT(osc_page_protected(env, opg, CLM_WRITE, 0)); osc_page_transfer_get(opg, "transfer\0cache"); result = osc_queue_async_io(env, io, opg); if (result != 0) osc_page_transfer_put(env, opg); else osc_page_transfer_add(env, opg, CRT_WRITE); RETURN(result); } void osc_index2policy(ldlm_policy_data_t *policy, const struct cl_object *obj, pgoff_t start, pgoff_t end) { memset(policy, 0, sizeof *policy); policy->l_extent.start = cl_offset(obj, start); policy->l_extent.end = cl_offset(obj, end + 1) - 1; } static int osc_page_is_under_lock(const struct lu_env *env, const struct cl_page_slice *slice, struct cl_io *unused, pgoff_t *max_index) { struct osc_page *opg = cl2osc_page(slice); struct cl_lock *lock; int result = -ENODATA; ENTRY; *max_index = 0; lock = cl_lock_at_pgoff(env, slice->cpl_obj, osc_index(opg), NULL, 1, 0); if (lock != NULL) { *max_index = lock->cll_descr.cld_end; cl_lock_put(env, lock); result = 0; } RETURN(result); } static const char *osc_list(struct list_head *head) { return list_empty(head) ? "-" : "+"; } static inline cfs_time_t osc_submit_duration(struct osc_page *opg) { if (opg->ops_submit_time == 0) return 0; return (cfs_time_current() - opg->ops_submit_time); } static int osc_page_print(const struct lu_env *env, const struct cl_page_slice *slice, void *cookie, lu_printer_t printer) { struct osc_page *opg = cl2osc_page(slice); struct osc_async_page *oap = &opg->ops_oap; struct osc_object *obj = cl2osc(slice->cpl_obj); struct client_obd *cli = &osc_export(obj)->exp_obd->u.cli; return (*printer)(env, cookie, LUSTRE_OSC_NAME"-page@%p %lu: " "1< %#x %d %u %s %s > " "2< "LPU64" %u %u %#x %#x | %p %p %p > " "3< %s %p %d %lu %d > " "4< %d %d %d %lu %s | %s %s %s %s > " "5< %s %s %s %s | %d %s | %d %s %s>\n", opg, osc_index(opg), /* 1 */ oap->oap_magic, oap->oap_cmd, oap->oap_interrupted, osc_list(&oap->oap_pending_item), osc_list(&oap->oap_rpc_item), /* 2 */ oap->oap_obj_off, oap->oap_page_off, oap->oap_count, oap->oap_async_flags, oap->oap_brw_flags, oap->oap_request, oap->oap_cli, obj, /* 3 */ osc_list(&opg->ops_inflight), opg->ops_submitter, opg->ops_transfer_pinned, osc_submit_duration(opg), opg->ops_srvlock, /* 4 */ cli->cl_r_in_flight, cli->cl_w_in_flight, cli->cl_max_rpcs_in_flight, cli->cl_avail_grant, osc_list(&cli->cl_cache_waiters), osc_list(&cli->cl_loi_ready_list), osc_list(&cli->cl_loi_hp_ready_list), osc_list(&cli->cl_loi_write_list), osc_list(&cli->cl_loi_read_list), /* 5 */ osc_list(&obj->oo_ready_item), osc_list(&obj->oo_hp_ready_item), osc_list(&obj->oo_write_item), osc_list(&obj->oo_read_item), atomic_read(&obj->oo_nr_reads), osc_list(&obj->oo_reading_exts), atomic_read(&obj->oo_nr_writes), osc_list(&obj->oo_hp_exts), osc_list(&obj->oo_urgent_exts)); } static void osc_page_delete(const struct lu_env *env, const struct cl_page_slice *slice) { struct osc_page *opg = cl2osc_page(slice); struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj); int rc; LINVRNT(opg->ops_temp || osc_page_protected(env, opg, CLM_READ, 1)); ENTRY; CDEBUG(D_TRACE, "%p\n", opg); osc_page_transfer_put(env, opg); rc = osc_teardown_async_page(env, obj, opg); if (rc) { CL_PAGE_DEBUG(D_ERROR, env, slice->cpl_page, "Trying to teardown failed: %d\n", rc); LASSERT(0); } spin_lock(&obj->oo_seatbelt); if (opg->ops_submitter != NULL) { LASSERT(!list_empty(&opg->ops_inflight)); list_del_init(&opg->ops_inflight); opg->ops_submitter = NULL; } spin_unlock(&obj->oo_seatbelt); osc_lru_del(osc_cli(obj), opg); if (slice->cpl_page->cp_type == CPT_CACHEABLE) { void *value; spin_lock(&obj->oo_tree_lock); value = radix_tree_delete(&obj->oo_tree, osc_index(opg)); if (value != NULL) --obj->oo_npages; spin_unlock(&obj->oo_tree_lock); LASSERT(ergo(value != NULL, value == opg)); } EXIT; } void osc_page_clip(const struct lu_env *env, const struct cl_page_slice *slice, int from, int to) { struct osc_page *opg = cl2osc_page(slice); struct osc_async_page *oap = &opg->ops_oap; LINVRNT(osc_page_protected(env, opg, CLM_READ, 0)); opg->ops_from = from; opg->ops_to = to; spin_lock(&oap->oap_lock); oap->oap_async_flags |= ASYNC_COUNT_STABLE; spin_unlock(&oap->oap_lock); } static int osc_page_cancel(const struct lu_env *env, const struct cl_page_slice *slice) { struct osc_page *opg = cl2osc_page(slice); int rc = 0; LINVRNT(osc_page_protected(env, opg, CLM_READ, 0)); /* Check if the transferring against this page * is completed, or not even queued. */ if (opg->ops_transfer_pinned) /* FIXME: may not be interrupted.. */ rc = osc_cancel_async_page(env, opg); LASSERT(ergo(rc == 0, opg->ops_transfer_pinned == 0)); return rc; } static int osc_page_flush(const struct lu_env *env, const struct cl_page_slice *slice, struct cl_io *io) { struct osc_page *opg = cl2osc_page(slice); int rc = 0; ENTRY; rc = osc_flush_async_page(env, io, opg); RETURN(rc); } static const struct cl_page_operations osc_page_ops = { .cpo_print = osc_page_print, .cpo_delete = osc_page_delete, .cpo_is_under_lock = osc_page_is_under_lock, .cpo_clip = osc_page_clip, .cpo_cancel = osc_page_cancel, .cpo_flush = osc_page_flush }; int osc_page_init(const struct lu_env *env, struct cl_object *obj, struct cl_page *page, pgoff_t index) { struct osc_object *osc = cl2osc(obj); struct osc_page *opg = cl_object_page_slice(obj, page); int result; opg->ops_from = 0; opg->ops_to = PAGE_CACHE_SIZE; result = osc_prep_async_page(osc, opg, page->cp_vmpage, cl_offset(obj, index)); if (result == 0) { struct osc_io *oio = osc_env_io(env); opg->ops_srvlock = osc_io_srvlock(oio); cl_page_slice_add(page, &opg->ops_cl, obj, index, &osc_page_ops); } /* * Cannot assert osc_page_protected() here as read-ahead * creates temporary pages outside of a lock. */ #ifdef CONFIG_LUSTRE_DEBUG_EXPENSIVE_CHECK opg->ops_temp = !osc_page_protected(env, opg, CLM_READ, 1); #endif /* ops_inflight and ops_lru are the same field, but it doesn't * hurt to initialize it twice :-) */ INIT_LIST_HEAD(&opg->ops_inflight); INIT_LIST_HEAD(&opg->ops_lru); /* reserve an LRU space for this page */ if (page->cp_type == CPT_CACHEABLE && result == 0) { result = osc_lru_reserve(env, osc, opg); if (result == 0) { spin_lock(&osc->oo_tree_lock); result = radix_tree_insert(&osc->oo_tree, index, opg); if (result == 0) ++osc->oo_npages; spin_unlock(&osc->oo_tree_lock); LASSERT(result == 0); } } return result; } /** * Helper function called by osc_io_submit() for every page in an immediate * transfer (i.e., transferred synchronously). */ void osc_page_submit(const struct lu_env *env, struct osc_page *opg, enum cl_req_type crt, int brw_flags) { struct osc_async_page *oap = &opg->ops_oap; struct osc_object *obj = oap->oap_obj; LINVRNT(osc_page_protected(env, opg, crt == CRT_WRITE ? CLM_WRITE : CLM_READ, 1)); LASSERTF(oap->oap_magic == OAP_MAGIC, "Bad oap magic: oap %p, " "magic 0x%x\n", oap, oap->oap_magic); LASSERT(oap->oap_async_flags & ASYNC_READY); LASSERT(oap->oap_async_flags & ASYNC_COUNT_STABLE); oap->oap_cmd = crt == CRT_WRITE ? OBD_BRW_WRITE : OBD_BRW_READ; oap->oap_page_off = opg->ops_from; oap->oap_count = opg->ops_to - opg->ops_from; oap->oap_brw_flags = OBD_BRW_SYNC | brw_flags; if (!client_is_remote(osc_export(obj)) && cfs_capable(CFS_CAP_SYS_RESOURCE)) { oap->oap_brw_flags |= OBD_BRW_NOQUOTA; oap->oap_cmd |= OBD_BRW_NOQUOTA; } opg->ops_submit_time = cfs_time_current(); osc_page_transfer_get(opg, "transfer\0imm"); osc_page_transfer_add(env, opg, crt); } /* --------------- LRU page management ------------------ */ /* OSC is a natural place to manage LRU pages as applications are specialized * to write OSC by OSC. Ideally, if one OSC is used more frequently it should * occupy more LRU slots. On the other hand, we should avoid using up all LRU * slots (client_obd::cl_lru_left) otherwise process has to be put into sleep * for free LRU slots - this will be very bad so the algorithm requires each * OSC to free slots voluntarily to maintain a reasonable number of free slots * at any time. */ static CFS_DECL_WAITQ(osc_lru_waitq); /* LRU pages are freed in batch mode. OSC should at least free this * number of pages to avoid running out of LRU budget, and.. */ static const int lru_shrink_min = 2 << (20 - PAGE_CACHE_SHIFT); /* 2M */ /* free this number at most otherwise it will take too long time to finsih. */ static const int lru_shrink_max = 8 << (20 - PAGE_CACHE_SHIFT); /* 8M */ /* Check if we can free LRU slots from this OSC. If there exists LRU waiters, * we should free slots aggressively. In this way, slots are freed in a steady * step to maintain fairness among OSCs. * * Return how many LRU pages should be freed. */ static int osc_cache_too_much(struct client_obd *cli) { struct cl_client_cache *cache = cli->cl_cache; long pages = atomic_long_read(&cli->cl_lru_in_list); unsigned long budget; budget = cache->ccc_lru_max / atomic_read(&cache->ccc_users); /* if it's going to run out LRU slots, we should free some, but not * too much to maintain faireness among OSCs. */ if (atomic_long_read(cli->cl_lru_left) < cache->ccc_lru_max >> 4) { if (pages >= budget) return lru_shrink_max; else if (pages >= budget / 2) return lru_shrink_min; } else if (pages >= budget * 2) return lru_shrink_min; return 0; } int lru_queue_work(const struct lu_env *env, void *data) { struct client_obd *cli = data; CDEBUG(D_CACHE, "Run LRU work for client obd %p.\n", cli); if (osc_cache_too_much(cli)) osc_lru_shrink(env, cli, lru_shrink_max, true); RETURN(0); } void osc_lru_add_batch(struct client_obd *cli, struct list_head *plist) { struct list_head lru = LIST_HEAD_INIT(lru); struct osc_async_page *oap; long npages = 0; list_for_each_entry(oap, plist, oap_pending_item) { struct osc_page *opg = oap2osc_page(oap); if (!opg->ops_in_lru) continue; ++npages; LASSERT(list_empty(&opg->ops_lru)); list_add(&opg->ops_lru, &lru); } if (npages > 0) { client_obd_list_lock(&cli->cl_lru_list_lock); list_splice_tail(&lru, &cli->cl_lru_list); atomic_long_sub(npages, &cli->cl_lru_busy); atomic_long_add(npages, &cli->cl_lru_in_list); client_obd_list_unlock(&cli->cl_lru_list_lock); /* XXX: May set force to be true for better performance */ if (osc_cache_too_much(cli)) (void)ptlrpcd_queue_work(cli->cl_lru_work); } } static void __osc_lru_del(struct client_obd *cli, struct osc_page *opg) { LASSERT(atomic_long_read(&cli->cl_lru_in_list) > 0); list_del_init(&opg->ops_lru); atomic_long_dec(&cli->cl_lru_in_list); } /** * Page is being destroyed. The page may be not in LRU list, if the transfer * has never finished(error occurred). */ static void osc_lru_del(struct client_obd *cli, struct osc_page *opg) { if (opg->ops_in_lru) { client_obd_list_lock(&cli->cl_lru_list_lock); if (!list_empty(&opg->ops_lru)) { __osc_lru_del(cli, opg); } else { LASSERT(atomic_long_read(&cli->cl_lru_busy) > 0); atomic_long_dec(&cli->cl_lru_busy); } client_obd_list_unlock(&cli->cl_lru_list_lock); atomic_long_inc(cli->cl_lru_left); /* this is a great place to release more LRU pages if * this osc occupies too many LRU pages and kernel is * stealing one of them. */ if (!memory_pressure_get()) (void)ptlrpcd_queue_work(cli->cl_lru_work); wake_up(&osc_lru_waitq); } else { LASSERT(list_empty(&opg->ops_lru)); } } /** * Delete page from LRUlist for redirty. */ static void osc_lru_use(struct client_obd *cli, struct osc_page *opg) { /* If page is being transfered for the first time, * ops_lru should be empty */ if (opg->ops_in_lru && !list_empty(&opg->ops_lru)) { client_obd_list_lock(&cli->cl_lru_list_lock); __osc_lru_del(cli, opg); client_obd_list_unlock(&cli->cl_lru_list_lock); atomic_long_inc(&cli->cl_lru_busy); } } static void discard_pagevec(const struct lu_env *env, struct cl_io *io, struct cl_page **pvec, int max_index) { int i; for (i = 0; i < max_index; i++) { struct cl_page *page = pvec[i]; LASSERT(cl_page_is_owned(page, io)); cl_page_discard(env, io, page); cl_page_disown(env, io, page); cl_page_put(env, page); pvec[i] = NULL; } } /** * Check if a cl_page can be released, i.e, it's not being used. * * If unstable account is turned on, bulk transfer may hold one refcount * for recovery so we need to check vmpage refcount as well; otherwise, * even we can destroy cl_page but the corresponding vmpage can't be reused. */ static inline bool lru_page_busy(struct client_obd *cli, struct cl_page *page) { if (cl_page_in_use_noref(page)) return true; if (cli->cl_cache->ccc_unstable_check) { struct page *vmpage = cl_page_vmpage(page); /* vmpage have two known users: cl_page and VM page cache */ if (page_count(vmpage) - page_mapcount(vmpage) > 2) return true; } return false; } /** * Drop @target of pages from LRU at most. */ long osc_lru_shrink(const struct lu_env *env, struct client_obd *cli, long target, bool force) { struct cl_io *io; struct cl_object *clobj = NULL; struct cl_page **pvec; struct osc_page *opg; long count = 0; int maxscan = 0; int index = 0; int rc = 0; ENTRY; LASSERT(atomic_long_read(&cli->cl_lru_in_list) >= 0); if (atomic_long_read(&cli->cl_lru_in_list) == 0 || target <= 0) RETURN(0); if (!force) { if (atomic_read(&cli->cl_lru_shrinkers) > 0) RETURN(-EBUSY); if (atomic_inc_return(&cli->cl_lru_shrinkers) > 1) { atomic_dec(&cli->cl_lru_shrinkers); RETURN(-EBUSY); } } else { atomic_inc(&cli->cl_lru_shrinkers); } pvec = (struct cl_page **)osc_env_info(env)->oti_pvec; io = &osc_env_info(env)->oti_io; client_obd_list_lock(&cli->cl_lru_list_lock); maxscan = min(target << 1, atomic_long_read(&cli->cl_lru_in_list)); while (!list_empty(&cli->cl_lru_list)) { struct cl_page *page; bool will_free = false; if (--maxscan < 0) break; opg = list_entry(cli->cl_lru_list.next, struct osc_page, ops_lru); page = opg->ops_cl.cpl_page; if (lru_page_busy(cli, page)) { list_move_tail(&opg->ops_lru, &cli->cl_lru_list); continue; } LASSERT(page->cp_obj != NULL); if (clobj != page->cp_obj) { struct cl_object *tmp = page->cp_obj; cl_object_get(tmp); client_obd_list_unlock(&cli->cl_lru_list_lock); if (clobj != NULL) { discard_pagevec(env, io, pvec, index); index = 0; cl_io_fini(env, io); cl_object_put(env, clobj); clobj = NULL; } clobj = tmp; io->ci_obj = clobj; io->ci_ignore_layout = 1; rc = cl_io_init(env, io, CIT_MISC, clobj); client_obd_list_lock(&cli->cl_lru_list_lock); if (rc != 0) break; ++maxscan; continue; } if (cl_page_own_try(env, io, page) == 0) { if (!lru_page_busy(cli, page)) { /* remove it from lru list earlier to avoid * lock contention */ __osc_lru_del(cli, opg); opg->ops_in_lru = 0; /* will be discarded */ cl_page_get(page); will_free = true; } else { cl_page_disown(env, io, page); } } if (!will_free) { list_move_tail(&opg->ops_lru, &cli->cl_lru_list); continue; } /* Don't discard and free the page with cl_lru_list held */ pvec[index++] = page; if (unlikely(index == OTI_PVEC_SIZE)) { client_obd_list_unlock(&cli->cl_lru_list_lock); discard_pagevec(env, io, pvec, index); index = 0; client_obd_list_lock(&cli->cl_lru_list_lock); } if (++count >= target) break; } client_obd_list_unlock(&cli->cl_lru_list_lock); if (clobj != NULL) { discard_pagevec(env, io, pvec, index); cl_io_fini(env, io); cl_object_put(env, clobj); } atomic_dec(&cli->cl_lru_shrinkers); if (count > 0) { atomic_long_add(count, cli->cl_lru_left); wake_up_all(&osc_lru_waitq); } RETURN(count > 0 ? count : rc); } long osc_lru_reclaim(struct client_obd *cli) { struct cl_env_nest nest; struct lu_env *env; struct cl_client_cache *cache = cli->cl_cache; long rc = 0; int max_scans; ENTRY; LASSERT(cache != NULL); LASSERT(!list_empty(&cache->ccc_lru)); env = cl_env_nested_get(&nest); if (IS_ERR(env)) RETURN(rc); rc = osc_lru_shrink(env, cli, osc_cache_too_much(cli), false); if (rc != 0) { if (rc == -EBUSY) rc = 0; CDEBUG(D_CACHE, "%s: Free %ld pages from own LRU: %p.\n", cli->cl_import->imp_obd->obd_name, rc, cli); GOTO(out, rc); } CDEBUG(D_CACHE, "%s: cli %p no free slots, pages: %ld, busy: %ld.\n", cli->cl_import->imp_obd->obd_name, cli, atomic_long_read(&cli->cl_lru_in_list), atomic_long_read(&cli->cl_lru_busy)); /* Reclaim LRU slots from other client_obd as it can't free enough * from its own. This should rarely happen. */ spin_lock(&cache->ccc_lru_lock); cache->ccc_lru_shrinkers++; list_move_tail(&cli->cl_lru_osc, &cache->ccc_lru); max_scans = atomic_read(&cache->ccc_users); while (--max_scans > 0 && !list_empty(&cache->ccc_lru)) { cli = list_entry(cache->ccc_lru.next, struct client_obd, cl_lru_osc); CDEBUG(D_CACHE, "%s: cli %p LRU pages: %ld, busy: %ld.\n", cli->cl_import->imp_obd->obd_name, cli, atomic_long_read(&cli->cl_lru_in_list), atomic_long_read(&cli->cl_lru_busy)); list_move_tail(&cli->cl_lru_osc, &cache->ccc_lru); if (osc_cache_too_much(cli) > 0) { spin_unlock(&cache->ccc_lru_lock); rc = osc_lru_shrink(env, cli, osc_cache_too_much(cli), true); spin_lock(&cache->ccc_lru_lock); if (rc != 0) break; } } spin_unlock(&cache->ccc_lru_lock); out: cl_env_nested_put(&nest, env); CDEBUG(D_CACHE, "%s: cli %p freed %ld pages.\n", cli->cl_import->imp_obd->obd_name, cli, rc); return rc; } /** * osc_lru_reserve() is called to reserve an LRU slot for a cl_page. * * Usually the LRU slots are reserved in osc_io_iter_rw_init(). * Only in the case that the LRU slots are in extreme shortage, it should * have reserved enough slots for an IO. */ static int osc_lru_reserve(const struct lu_env *env, struct osc_object *obj, struct osc_page *opg) { struct l_wait_info lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL); struct osc_io *oio = osc_env_io(env); struct client_obd *cli = osc_cli(obj); int rc = 0; ENTRY; if (cli->cl_cache == NULL) /* shall not be in LRU */ RETURN(0); if (oio->oi_lru_reserved > 0) { --oio->oi_lru_reserved; goto out; } LASSERT(atomic_long_read(cli->cl_lru_left) >= 0); while (!atomic_long_add_unless(cli->cl_lru_left, -1, 0)) { /* run out of LRU spaces, try to drop some by itself */ rc = osc_lru_reclaim(cli); if (rc < 0) break; if (rc > 0) continue; cond_resched(); rc = l_wait_event(osc_lru_waitq, atomic_long_read(cli->cl_lru_left) > 0, &lwi); if (rc < 0) break; } out: if (rc >= 0) { atomic_long_inc(&cli->cl_lru_busy); opg->ops_in_lru = 1; rc = 0; } RETURN(rc); } /** * Atomic operations are expensive. We accumulate the accounting for the * same page zone to get better performance. * In practice this can work pretty good because the pages in the same RPC * are likely from the same page zone. */ static inline void unstable_page_accounting(struct ptlrpc_bulk_desc *desc, int factor) { obd_count page_count = desc->bd_iov_count; void *zone = NULL; int count = 0; int i; for (i = 0; i < page_count; i++) { void *pz = page_zone(desc->bd_iov[i].kiov_page); if (likely(pz == zone)) { ++count; continue; } if (count > 0) { mod_zone_page_state(zone, NR_UNSTABLE_NFS, factor * count); count = 0; } zone = pz; ++count; } if (count > 0) mod_zone_page_state(zone, NR_UNSTABLE_NFS, factor * count); } static inline void add_unstable_page_accounting(struct ptlrpc_bulk_desc *desc) { unstable_page_accounting(desc, 1); } static inline void dec_unstable_page_accounting(struct ptlrpc_bulk_desc *desc) { unstable_page_accounting(desc, -1); } /** * Performs "unstable" page accounting. This function balances the * increment operations performed in osc_inc_unstable_pages. It is * registered as the RPC request callback, and is executed when the * bulk RPC is committed on the server. Thus at this point, the pages * involved in the bulk transfer are no longer considered unstable. * * If this function is called, the request should have been committed * or req:rq_unstable must have been set; it implies that the unstable * statistic have been added. */ void osc_dec_unstable_pages(struct ptlrpc_request *req) { struct ptlrpc_bulk_desc *desc = req->rq_bulk; struct client_obd *cli = &req->rq_import->imp_obd->u.cli; int page_count = desc->bd_iov_count; long unstable_count; LASSERT(page_count >= 0); dec_unstable_page_accounting(desc); unstable_count = atomic_long_sub_return(page_count, &cli->cl_unstable_count); LASSERT(unstable_count >= 0); unstable_count = atomic_long_sub_return(page_count, &cli->cl_cache->ccc_unstable_nr); LASSERT(unstable_count >= 0); if (unstable_count == 0) wake_up_all(&cli->cl_cache->ccc_unstable_waitq); if (osc_cache_too_much(cli)) (void)ptlrpcd_queue_work(cli->cl_lru_work); } /** * "unstable" page accounting. See: osc_dec_unstable_pages. */ void osc_inc_unstable_pages(struct ptlrpc_request *req) { struct ptlrpc_bulk_desc *desc = req->rq_bulk; struct client_obd *cli = &req->rq_import->imp_obd->u.cli; long page_count = desc->bd_iov_count; /* No unstable page tracking */ if (cli->cl_cache == NULL || !cli->cl_cache->ccc_unstable_check) return; add_unstable_page_accounting(desc); atomic_long_add(page_count, &cli->cl_unstable_count); atomic_long_add(page_count, &cli->cl_cache->ccc_unstable_nr); /* If the request has already been committed (i.e. brw_commit * called via rq_commit_cb), we need to undo the unstable page * increments we just performed because rq_commit_cb wont be * called again. */ spin_lock(&req->rq_lock); if (unlikely(req->rq_committed)) { spin_unlock(&req->rq_lock); osc_dec_unstable_pages(req); } else { req->rq_unstable = 1; spin_unlock(&req->rq_lock); } } /** * Check if it piggybacks SOFT_SYNC flag to OST from this OSC. * This function will be called by every BRW RPC so it's critical * to make this function fast. */ bool osc_over_unstable_soft_limit(struct client_obd *cli) { long unstable_nr, osc_unstable_count; /* Can't check cli->cl_unstable_count, therefore, no soft limit */ if (cli->cl_cache == NULL || !cli->cl_cache->ccc_unstable_check) return false; osc_unstable_count = atomic_long_read(&cli->cl_unstable_count); unstable_nr = atomic_long_read(&cli->cl_cache->ccc_unstable_nr); CDEBUG(D_CACHE, "%s: cli: %p unstable pages: %lu, osc unstable pages: %lu\n", cli->cl_import->imp_obd->obd_name, cli, unstable_nr, osc_unstable_count); /* If the LRU slots are in shortage - 25% remaining AND this OSC * has one full RPC window of unstable pages, it's a good chance * to piggyback a SOFT_SYNC flag. * Please notice that the OST won't take immediate response for the * SOFT_SYNC request so active OSCs will have more chance to carry * the flag, this is reasonable. */ return unstable_nr > cli->cl_cache->ccc_lru_max >> 2 && osc_unstable_count > cli->cl_max_pages_per_rpc * cli->cl_max_rpcs_in_flight; } /** @} osc */