X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=blobdiff_plain;f=lustre%2Fosc%2Fosc_page.c;h=e9292119f243b6f203d28474444084149cb07b2d;hp=55bb24c876dcf8358a6580aca57106d54a7b56e6;hb=70f092a0587866662735e1a6eaf27701a576370d;hpb=c5361360e51de22a59d4427327bddf9fd398f352 diff --git a/lustre/osc/osc_page.c b/lustre/osc/osc_page.c index 55bb24c..e929211 100644 --- a/lustre/osc/osc_page.c +++ b/lustre/osc/osc_page.c @@ -1,6 +1,4 @@ -/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*- - * vim:expandtab:shiftwidth=8:tabstop=8: - * +/* * GPL HEADER START * * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. @@ -17,11 +15,7 @@ * * 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. + * http://www.gnu.org/licenses/gpl-2.0.html * * GPL HEADER END */ @@ -29,8 +23,7 @@ * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved. * Use is subject to license terms. * - * Copyright (c) 2011 Whamcloud, Inc. - * + * Copyright (c) 2011, 2016, Intel Corporation. */ /* * This file is part of Lustre, http://www.lustre.org/ @@ -39,156 +32,46 @@ * Implementation of cl_page for OSC layer. * * Author: Nikita Danilov + * Author: Jinshan Xiong */ #define DEBUG_SUBSYSTEM S_OSC +#include -#include "osc_cl_internal.h" - -/** \addtogroup osc - * @{ - */ +#include "osc_internal.h" -/* - * 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; - int flags; - - cfs_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, page->cp_index, page->cp_index); - return osc_match_base(osc_export(obj), resname, LDLM_EXTENT, policy, - dlmmode, &flags, NULL, lockh, unref); -} +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_alloc(const struct lu_env *env, struct client_obd *cli, + struct osc_page *opg); -/** - * Checks an invariant that a page in the cache is covered by a lock, as - * needed. +/** \addtogroup osc + * @{ */ -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 = page->cp_index; - descr->cld_end = page->cp_index; - cfs_spin_lock(&hdr->coh_lock_guard); - cfs_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; - } - } - cfs_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_fini(const struct lu_env *env, - struct cl_page_slice *slice) -{ - struct osc_page *opg = cl2osc_page(slice); - CDEBUG(D_TRACE, "%p\n", opg); - LASSERT(opg->ops_lock == NULL); - OBD_SLAB_FREE_PTR(opg, osc_page_kmem); -} - static void osc_page_transfer_get(struct osc_page *opg, const char *label) { - struct cl_page *page = cl_page_top(opg->ops_cl.cpl_page); + 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; + 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 osc_page *opg) { - struct cl_page *page = cl_page_top(opg->ops_cl.cpl_page); + struct cl_page *page = opg->ops_cl.cpl_page; - if (opg->ops_transfer_pinned) { - lu_ref_del(&page->cp_reference, "transfer", page); - opg->ops_transfer_pinned = 0; - cl_page_put(env, page); - } + if (opg->ops_transfer_pinned) { + opg->ops_transfer_pinned = 0; + lu_ref_del(&page->cp_reference, "transfer", page); + cl_page_put(env, page); + } } /** @@ -199,152 +82,41 @@ static void osc_page_transfer_put(const struct lu_env *env, static void osc_page_transfer_add(const struct lu_env *env, struct osc_page *opg, enum cl_req_type crt) { - struct osc_object *obj; - - obj = cl2osc(opg->ops_cl.cpl_obj); - cfs_spin_lock(&obj->oo_seatbelt); - cfs_list_add(&opg->ops_inflight, &obj->oo_inflight[crt]); - opg->ops_submitter = cfs_current(); - cfs_spin_unlock(&obj->oo_seatbelt); -} - -static int osc_page_cache_add(const struct lu_env *env, - const struct cl_page_slice *slice, - struct cl_io *unused) -{ - struct osc_page *opg = cl2osc_page(slice); - struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj); - int result; - /* All cacheable IO is async-capable */ - int brw_flags = OBD_BRW_ASYNC; - int noquota = 0; - - LINVRNT(osc_page_protected(env, opg, CLM_WRITE, 0)); - ENTRY; - - /* Set the OBD_BRW_SRVLOCK before the page is queued. */ - brw_flags |= opg->ops_srvlock ? OBD_BRW_SRVLOCK : 0; - if (!client_is_remote(osc_export(obj)) && - cfs_capable(CFS_CAP_SYS_RESOURCE)) { - brw_flags |= OBD_BRW_NOQUOTA; - noquota = OBD_BRW_NOQUOTA; - } - - osc_page_transfer_get(opg, "transfer\0cache"); - result = osc_queue_async_io(env, osc_export(obj), NULL, obj->oo_oinfo, - &opg->ops_oap, OBD_BRW_WRITE | noquota, - opg->ops_from, opg->ops_to - opg->ops_from, - brw_flags, 0); - 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_addref_lock(const struct lu_env *env, - struct osc_page *opg, - struct cl_lock *lock) -{ - struct osc_lock *olock; - int rc; - - LASSERT(opg->ops_lock == NULL); - - olock = osc_lock_at(lock); - if (cfs_atomic_inc_return(&olock->ols_pageref) <= 0) { - cfs_atomic_dec(&olock->ols_pageref); - cl_lock_put(env, lock); - rc = 1; - } else { - opg->ops_lock = lock; - rc = 0; - } - return rc; -} - -static void osc_page_putref_lock(const struct lu_env *env, - struct osc_page *opg) -{ - struct cl_lock *lock = opg->ops_lock; - struct osc_lock *olock; - - LASSERT(lock != NULL); - olock = osc_lock_at(lock); + struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj); - cfs_atomic_dec(&olock->ols_pageref); - opg->ops_lock = NULL; - - /* - * Note: usually this won't be the last reference of the lock, but if - * it is, then all the lock_put do is at most just freeing some memory, - * so it would be OK that caller is holding spinlocks. - */ - LASSERT(cfs_atomic_read(&lock->cll_ref) > 1 || olock->ols_hold == 0); - cl_lock_put(env, lock); + /* 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); } -static int osc_page_is_under_lock(const struct lu_env *env, - const struct cl_page_slice *slice, - struct cl_io *unused) +int osc_page_cache_add(const struct lu_env *env, + const struct cl_page_slice *slice, struct cl_io *io) { - struct cl_lock *lock; - int result; - - ENTRY; - lock = cl_lock_at_page(env, slice->cpl_obj, slice->cpl_page, - NULL, 1, 0); - if (lock != NULL && - osc_page_addref_lock(env, cl2osc_page(slice), lock) == 0) - result = -EBUSY; - else - result = -ENODATA; - RETURN(result); + struct osc_page *opg = cl2osc_page(slice); + int result; + ENTRY; + + 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); } -static void osc_page_disown(const struct lu_env *env, - const struct cl_page_slice *slice, - struct cl_io *io) +void osc_index2policy(union ldlm_policy_data *policy, + const struct cl_object *obj, pgoff_t start, pgoff_t end) { - struct osc_page *opg = cl2osc_page(slice); - - if (unlikely(opg->ops_lock)) - osc_page_putref_lock(env, opg); + memset(policy, 0, sizeof *policy); + policy->l_extent.start = cl_offset(obj, start); + policy->l_extent.end = cl_offset(obj, end + 1) - 1; } -static void osc_page_completion_read(const struct lu_env *env, - const struct cl_page_slice *slice, - int ioret) +static const char *osc_list(struct list_head *head) { - struct osc_page *opg = cl2osc_page(slice); - - if (likely(opg->ops_lock)) - osc_page_putref_lock(env, opg); -} - -static int osc_page_fail(const struct lu_env *env, - const struct cl_page_slice *slice, - struct cl_io *unused) -{ - /* - * Cached read? - */ - LBUG(); - return 0; -} - - -static const char *osc_list(cfs_list_t *head) -{ - return cfs_list_empty(head) ? "-" : "+"; + return list_empty(head) ? "-" : "+"; } static inline cfs_time_t osc_submit_duration(struct osc_page *opg) @@ -363,31 +135,26 @@ static int osc_page_print(const struct lu_env *env, 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; - struct lov_oinfo *loi = obj->oo_oinfo; - - return (*printer)(env, cookie, LUSTRE_OSC_NAME"-page@%p: " - "1< %#x %d %u %s %s %s > " - "2< "LPU64" %u %u %#x %#x | %p %p %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 %s | %d %s %s>\n", - opg, + + return (*printer)(env, cookie, LUSTRE_OSC_NAME"-page@%p %lu: " + "1< %#x %d %u %s %s > " + "2< %lld %u %u %#x %#x | %p %p %p > " + "3< %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_urgent_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, oap->oap_loi, oap->oap_caller_ops, - oap->oap_caller_data, - /* 3 */ - osc_list(&opg->ops_inflight), - opg->ops_submitter, opg->ops_transfer_pinned, - osc_submit_duration(opg), opg->ops_srvlock, + oap->oap_request, oap->oap_cli, obj, + /* 3 */ + 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, @@ -398,309 +165,962 @@ static int osc_page_print(const struct lu_env *env, osc_list(&cli->cl_loi_write_list), osc_list(&cli->cl_loi_read_list), /* 5 */ - osc_list(&loi->loi_ready_item), - osc_list(&loi->loi_hp_ready_item), - osc_list(&loi->loi_write_item), - osc_list(&loi->loi_read_item), - loi->loi_read_lop.lop_num_pending, - osc_list(&loi->loi_read_lop.lop_pending), - osc_list(&loi->loi_read_lop.lop_urgent), - loi->loi_write_lop.lop_num_pending, - osc_list(&loi->loi_write_lop.lop_pending), - osc_list(&loi->loi_write_lop.lop_urgent)); + 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) + const struct cl_page_slice *slice) { - struct osc_page *opg = cl2osc_page(slice); - struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj); - struct osc_async_page *oap = &opg->ops_oap; - 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(osc_export(obj), NULL, obj->oo_oinfo, oap); - if (rc) { - CL_PAGE_DEBUG(D_ERROR, env, cl_page_top(slice->cpl_page), - "Trying to teardown failed: %d\n", rc); - LASSERT(0); - } - cfs_spin_lock(&obj->oo_seatbelt); - cfs_list_del_init(&opg->ops_inflight); - cfs_spin_unlock(&obj->oo_seatbelt); - EXIT; + struct osc_page *opg = cl2osc_page(slice); + struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj); + int rc; + + 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); + } + + 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) +static 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; - cfs_spin_lock(&oap->oap_lock); - oap->oap_async_flags |= ASYNC_COUNT_STABLE; - cfs_spin_unlock(&oap->oap_lock); + struct osc_page *opg = cl2osc_page(slice); + struct osc_async_page *oap = &opg->ops_oap; + + 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) + const struct cl_page_slice *slice) { - struct osc_page *opg = cl2osc_page(slice); - struct osc_async_page *oap = &opg->ops_oap; - int rc = 0; - - LINVRNT(osc_page_protected(env, opg, CLM_READ, 0)); + struct osc_page *opg = cl2osc_page(slice); + int rc = 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; +} - client_obd_list_lock(&oap->oap_cli->cl_loi_list_lock); - /* 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_oap_interrupted(env, oap); - LASSERT(ergo(rc == 0, opg->ops_transfer_pinned == 0)); - client_obd_list_unlock(&oap->oap_cli->cl_loi_list_lock); - 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_fini = osc_page_fini, - .cpo_print = osc_page_print, - .cpo_delete = osc_page_delete, - .cpo_is_under_lock = osc_page_is_under_lock, - .cpo_disown = osc_page_disown, - .io = { - [CRT_READ] = { - .cpo_cache_add = osc_page_fail, - .cpo_completion = osc_page_completion_read - }, - [CRT_WRITE] = { - .cpo_cache_add = osc_page_cache_add - } - }, - .cpo_clip = osc_page_clip, - .cpo_cancel = osc_page_cancel + .cpo_print = osc_page_print, + .cpo_delete = osc_page_delete, + .cpo_clip = osc_page_clip, + .cpo_cancel = osc_page_cancel, + .cpo_flush = osc_page_flush }; -static int osc_make_ready(const struct lu_env *env, void *data, int cmd) +int osc_page_init(const struct lu_env *env, struct cl_object *obj, + struct cl_page *page, pgoff_t index) { - struct osc_page *opg = data; - struct cl_page *page = cl_page_top(opg->ops_cl.cpl_page); - int result; + struct osc_object *osc = cl2osc(obj); + struct osc_page *opg = cl_object_page_slice(obj, page); + struct osc_io *oio = osc_env_io(env); + int result; + + opg->ops_from = 0; + opg->ops_to = PAGE_SIZE; + + INIT_LIST_HEAD(&opg->ops_lru); + + result = osc_prep_async_page(osc, opg, page->cp_vmpage, + cl_offset(obj, index)); + if (result != 0) + return result; + + opg->ops_srvlock = osc_io_srvlock(oio); + cl_page_slice_add(page, &opg->ops_cl, obj, index, + &osc_page_ops); + + + /* reserve an LRU space for this page */ + if (page->cp_type == CPT_CACHEABLE) { + result = osc_lru_alloc(env, osc_cli(osc), opg); + if (result == 0) { + result = radix_tree_preload(GFP_NOFS); + 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); + + radix_tree_preload_end(); + } + } + } + + return result; +} - LASSERT(cmd == OBD_BRW_WRITE); /* no cached reads */ - LINVRNT(osc_page_protected(env, opg, CLM_WRITE, 1)); +/** + * 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; + + 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 (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); +} - ENTRY; - result = cl_page_make_ready(env, page, CRT_WRITE); - if (result == 0) - opg->ops_submit_time = cfs_time_current(); - RETURN(result); +/* --------------- 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 DECLARE_WAIT_QUEUE_HEAD(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 slots. + */ +static inline int lru_shrink_min(struct client_obd *cli) +{ + return cli->cl_max_pages_per_rpc * 2; } -static int osc_refresh_count(const struct lu_env *env, void *data, int cmd) +/** + * free this number at most otherwise it will take too long time to finsih. + */ +static inline int lru_shrink_max(struct client_obd *cli) { - struct cl_page *page; - struct osc_page *osc = data; - struct cl_object *obj; - struct cl_attr *attr = &osc_env_info(env)->oti_attr; + return cli->cl_max_pages_per_rpc * cli->cl_max_rpcs_in_flight; +} - int result; - loff_t kms; +/** + * 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; + + LASSERT(cache != NULL); + budget = cache->ccc_lru_max / (atomic_read(&cache->ccc_users) - 2); + + /* 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 >> 2) { + if (pages >= budget) + return lru_shrink_max(cli); + else if (pages >= budget / 2) + return lru_shrink_min(cli); + } else { + time64_t duration = ktime_get_real_seconds(); + long timediff; + + /* knock out pages by duration of no IO activity */ + duration -= cli->cl_lru_last_used; + /* + * The difference shouldn't be more than 70 years + * so we can safely case to a long. Round to + * approximately 1 minute. + */ + timediff = (long)(duration >> 6); + if (timediff > 0 && pages >= budget / timediff) + return lru_shrink_min(cli); + } + return 0; +} - LINVRNT(osc_page_protected(env, osc, CLM_READ, 1)); +int lru_queue_work(const struct lu_env *env, void *data) +{ + struct client_obd *cli = data; + int count; + + CDEBUG(D_CACHE, "%s: run LRU work for client obd\n", cli_name(cli)); + count = osc_cache_too_much(cli); + if (count > 0) { + int rc = osc_lru_shrink(env, cli, count, false); + + CDEBUG(D_CACHE, "%s: shrank %d/%d pages from client obd\n", + cli_name(cli), rc, count); + if (rc >= count) { + CDEBUG(D_CACHE, "%s: queue again\n", cli_name(cli)); + ptlrpcd_queue_work(cli->cl_lru_work); + } + } + + RETURN(0); +} - /* readpage queues with _COUNT_STABLE, shouldn't get here. */ - LASSERT(!(cmd & OBD_BRW_READ)); - LASSERT(osc != NULL); - page = osc->ops_cl.cpl_page; - obj = osc->ops_cl.cpl_obj; +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) { + spin_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); + cli->cl_lru_last_used = ktime_get_real_seconds(); + spin_unlock(&cli->cl_lru_list_lock); + + if (waitqueue_active(&osc_lru_waitq)) + (void)ptlrpcd_queue_work(cli->cl_lru_work); + } +} - cl_object_attr_lock(obj); - result = cl_object_attr_get(env, obj, attr); - cl_object_attr_unlock(obj); - if (result < 0) - return result; - kms = attr->cat_kms; - if (cl_offset(obj, page->cp_index) >= kms) - /* catch race with truncate */ - return 0; - else if (cl_offset(obj, page->cp_index + 1) > kms) - /* catch sub-page write at end of file */ - return kms % CFS_PAGE_SIZE; - else - return CFS_PAGE_SIZE; -} - -static int osc_completion(const struct lu_env *env, - void *data, int cmd, struct obdo *oa, int rc) -{ - struct osc_page *opg = data; - struct osc_async_page *oap = &opg->ops_oap; - struct cl_page *page = cl_page_top(opg->ops_cl.cpl_page); - struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj); - enum cl_req_type crt; - int srvlock; - - LINVRNT(osc_page_protected(env, opg, CLM_READ, 1)); - - ENTRY; - - cmd &= ~OBD_BRW_NOQUOTA; - LASSERT(equi(page->cp_state == CPS_PAGEIN, cmd == OBD_BRW_READ)); - LASSERT(equi(page->cp_state == CPS_PAGEOUT, cmd == OBD_BRW_WRITE)); - LASSERT(opg->ops_transfer_pinned); - - /* - * page->cp_req can be NULL if io submission failed before - * cl_req was allocated. - */ - if (page->cp_req != NULL) - cl_req_page_done(env, page); - LASSERT(page->cp_req == NULL); - - /* As the transfer for this page is being done, clear the flags */ - cfs_spin_lock(&oap->oap_lock); - oap->oap_async_flags = 0; - cfs_spin_unlock(&oap->oap_lock); - - crt = cmd == OBD_BRW_READ ? CRT_READ : CRT_WRITE; - /* Clear opg->ops_transfer_pinned before VM lock is released. */ - opg->ops_transfer_pinned = 0; - - cfs_spin_lock(&obj->oo_seatbelt); - LASSERT(opg->ops_submitter != NULL); - LASSERT(!cfs_list_empty(&opg->ops_inflight)); - cfs_list_del_init(&opg->ops_inflight); - cfs_spin_unlock(&obj->oo_seatbelt); - - opg->ops_submit_time = 0; - srvlock = oap->oap_brw_flags & OBD_BRW_SRVLOCK; - - cl_page_completion(env, page, crt, rc); - - /* statistic */ - if (rc == 0 && srvlock) { - struct lu_device *ld = opg->ops_cl.cpl_obj->co_lu.lo_dev; - struct osc_stats *stats = &lu2osc_dev(ld)->od_stats; - int bytes = oap->oap_count; - - if (crt == CRT_READ) - stats->os_lockless_reads += bytes; - else - stats->os_lockless_writes += bytes; +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) { + spin_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); + } + spin_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 (osc_cache_too_much(cli)) { + CDEBUG(D_CACHE, "%s: queue LRU work\n", cli_name(cli)); + (void)ptlrpcd_queue_work(cli->cl_lru_work); + } + wake_up(&osc_lru_waitq); + } else { + LASSERT(list_empty(&opg->ops_lru)); + } +} + +/** + * Delete page from LRU list for redirty. + */ +static void osc_lru_use(struct client_obd *cli, struct osc_page *opg) +{ + /* If page is being transferred for the first time, + * ops_lru should be empty */ + if (opg->ops_in_lru) { + spin_lock(&cli->cl_lru_list_lock); + if (!list_empty(&opg->ops_lru)) { + __osc_lru_del(cli, opg); + atomic_long_inc(&cli->cl_lru_busy); + } + spin_unlock(&cli->cl_lru_list_lock); + } +} + +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_delete(env, page); + cl_page_discard(env, io, page); + cl_page_disown(env, io, page); + cl_page_put(env, page); + + pvec[i] = NULL; } +} - /* - * This has to be the last operation with the page, as locks are - * released in cl_page_completion() and nothing except for the - * reference counter protects page from concurrent reclaim. - */ - lu_ref_del(&page->cp_reference, "transfer", page); - /* - * As page->cp_obj is pinned by a reference from page->cp_req, it is - * safe to call cl_page_put() without risking object destruction in a - * non-blocking context. - */ - cl_page_put(env, page); - RETURN(0); -} - -const static struct obd_async_page_ops osc_async_page_ops = { - .ap_make_ready = osc_make_ready, - .ap_refresh_count = osc_refresh_count, - .ap_completion = osc_completion -}; +/** + * 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; -struct cl_page *osc_page_init(const struct lu_env *env, - struct cl_object *obj, - struct cl_page *page, cfs_page_t *vmpage) -{ - struct osc_object *osc = cl2osc(obj); - struct osc_page *opg; - int result; - - OBD_SLAB_ALLOC_PTR_GFP(opg, osc_page_kmem, CFS_ALLOC_IO); - if (opg != NULL) { - void *oap = &opg->ops_oap; - - opg->ops_from = 0; - opg->ops_to = CFS_PAGE_SIZE; - - result = osc_prep_async_page(osc_export(osc), - NULL, osc->oo_oinfo, vmpage, - cl_offset(obj, page->cp_index), - &osc_async_page_ops, - opg, (void **)&oap, 1, NULL); - 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, - &osc_page_ops); - } - /* - * Cannot assert osc_page_protected() here as read-ahead - * creates temporary pages outside of a lock. - */ -#ifdef INVARIANT_CHECK - opg->ops_temp = !osc_page_protected(env, opg, CLM_READ, 1); -#endif - CFS_INIT_LIST_HEAD(&opg->ops_inflight); - } else - result = -ENOMEM; - return ERR_PTR(result); + 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; } /** - * Helper function called by osc_io_submit() for every page in an immediate - * transfer (i.e., transferred synchronously). + * Drop @target of pages from LRU at most. */ -void osc_io_submit_page(const struct lu_env *env, - struct osc_io *oio, struct osc_page *opg, - enum cl_req_type crt) +long osc_lru_shrink(const struct lu_env *env, struct client_obd *cli, + long target, bool force) { - struct osc_async_page *oap = &opg->ops_oap; - struct client_obd *cli = oap->oap_cli; - int flags = 0; - - LINVRNT(osc_page_protected(env, opg, - crt == CRT_WRITE ? CLM_WRITE : CLM_READ, 1)); - - oap->oap_page_off = opg->ops_from; - oap->oap_count = opg->ops_to - opg->ops_from; - /* Give a hint to OST that requests are coming from kswapd - bug19529 */ - if (cfs_memory_pressure_get()) - oap->oap_brw_flags |= OBD_BRW_MEMALLOC; - oap->oap_brw_flags |= OBD_BRW_SYNC; - if (osc_io_srvlock(oio)) - oap->oap_brw_flags |= OBD_BRW_SRVLOCK; - - oap->oap_cmd = crt == CRT_WRITE ? OBD_BRW_WRITE : OBD_BRW_READ; - if (!client_is_remote(osc_export(cl2osc(opg->ops_cl.cpl_obj))) && - cfs_capable(CFS_CAP_SYS_RESOURCE)) { - oap->oap_brw_flags |= OBD_BRW_NOQUOTA; - oap->oap_cmd |= OBD_BRW_NOQUOTA; - } + 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); + + CDEBUG(D_CACHE, "%s: shrinkers: %d, force: %d\n", + cli_name(cli), atomic_read(&cli->cl_lru_shrinkers), force); + 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; + + spin_lock(&cli->cl_lru_list_lock); + if (force) + cli->cl_lru_reclaim++; + 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 (!force && atomic_read(&cli->cl_lru_shrinkers) > 1) + break; + + 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); + spin_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); + + spin_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)) { + spin_unlock(&cli->cl_lru_list_lock); + discard_pagevec(env, io, pvec, index); + index = 0; + + spin_lock(&cli->cl_lru_list_lock); + } + + if (++count >= target) + break; + } + spin_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); +} + +/** + * Reclaim LRU pages by an IO thread. The caller wants to reclaim at least + * \@npages of LRU slots. For performance consideration, it's better to drop + * LRU pages in batch. Therefore, the actual number is adjusted at least + * max_pages_per_rpc. + */ +static long osc_lru_reclaim(struct client_obd *cli, unsigned long npages) +{ + struct lu_env *env; + struct cl_client_cache *cache = cli->cl_cache; + int max_scans; + __u16 refcheck; + long rc = 0; + ENTRY; + + LASSERT(cache != NULL); + + env = cl_env_get(&refcheck); + if (IS_ERR(env)) + RETURN(rc); + + npages = max_t(int, npages, cli->cl_max_pages_per_rpc); + CDEBUG(D_CACHE, "%s: start to reclaim %ld pages from LRU\n", + cli_name(cli), npages); + rc = osc_lru_shrink(env, cli, npages, true); + if (rc >= npages) { + CDEBUG(D_CACHE, "%s: reclaimed %ld/%ld pages from LRU\n", + cli_name(cli), rc, npages); + if (osc_cache_too_much(cli) > 0) + ptlrpcd_queue_work(cli->cl_lru_work); + GOTO(out, rc); + } else if (rc > 0) { + npages -= rc; + } + + CDEBUG(D_CACHE, "%s: cli %p no free slots, pages: %ld/%ld, want: %ld\n", + cli_name(cli), cli, atomic_long_read(&cli->cl_lru_in_list), + atomic_long_read(&cli->cl_lru_busy), npages); + + /* 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); + LASSERT(!list_empty(&cache->ccc_lru)); + + cache->ccc_lru_shrinkers++; + list_move_tail(&cli->cl_lru_osc, &cache->ccc_lru); + + max_scans = atomic_read(&cache->ccc_users) - 2; + 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_name(cli), 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, npages, true); + spin_lock(&cache->ccc_lru_lock); + if (rc >= npages) + break; + if (rc > 0) + npages -= rc; + } + } + spin_unlock(&cache->ccc_lru_lock); + +out: + cl_env_put(env, &refcheck); + CDEBUG(D_CACHE, "%s: cli %p freed %ld pages.\n", + cli_name(cli), cli, rc); + return rc; +} + +/** + * osc_lru_alloc() is called to allocate 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_alloc(const struct lu_env *env, struct client_obd *cli, + struct osc_page *opg) +{ + struct l_wait_info lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL); + struct osc_io *oio = osc_env_io(env); + 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, 1); + 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); +} - if (oap->oap_cmd & OBD_BRW_READ) - flags = ASYNC_COUNT_STABLE; - else if (!(oap->oap_brw_page.flag & OBD_BRW_FROM_GRANT)) - osc_enter_cache_try(env, cli, oap->oap_loi, oap, 1); +/** + * osc_lru_reserve() is called to reserve enough LRU slots for I/O. + * + * The benefit of doing this is to reduce contention against atomic counter + * cl_lru_left by changing it from per-page access to per-IO access. + */ +unsigned long osc_lru_reserve(struct client_obd *cli, unsigned long npages) +{ + unsigned long reserved = 0; + unsigned long max_pages; + unsigned long c; + + /* reserve a full RPC window at most to avoid that a thread accidentally + * consumes too many LRU slots */ + max_pages = cli->cl_max_pages_per_rpc * cli->cl_max_rpcs_in_flight; + if (npages > max_pages) + npages = max_pages; + + c = atomic_long_read(cli->cl_lru_left); + if (c < npages && osc_lru_reclaim(cli, npages) > 0) + c = atomic_long_read(cli->cl_lru_left); + while (c >= npages) { + if (c == atomic_long_cmpxchg(cli->cl_lru_left, c, c - npages)) { + reserved = npages; + break; + } + c = atomic_long_read(cli->cl_lru_left); + } + if (atomic_long_read(cli->cl_lru_left) < max_pages) { + /* If there aren't enough pages in the per-OSC LRU then + * wake up the LRU thread to try and clear out space, so + * we don't block if pages are being dirtied quickly. */ + CDEBUG(D_CACHE, "%s: queue LRU, left: %lu/%ld.\n", + cli_name(cli), atomic_long_read(cli->cl_lru_left), + max_pages); + (void)ptlrpcd_queue_work(cli->cl_lru_work); + } + + return reserved; +} - cfs_spin_lock(&oap->oap_lock); - oap->oap_async_flags |= OSC_FLAGS | flags; - cfs_spin_unlock(&oap->oap_lock); +/** + * osc_lru_unreserve() is called to unreserve LRU slots. + * + * LRU slots reserved by osc_lru_reserve() may have entries left due to several + * reasons such as page already existing or I/O error. Those reserved slots + * should be freed by calling this function. + */ +void osc_lru_unreserve(struct client_obd *cli, unsigned long npages) +{ + atomic_long_add(npages, cli->cl_lru_left); + wake_up_all(&osc_lru_waitq); +} - osc_oap_to_pending(oap); - osc_page_transfer_get(opg, "transfer\0imm"); - osc_page_transfer_add(env, opg, crt); +/** + * 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, + struct osc_brw_async_args *aa, + int factor) +{ + int page_count; + void *zone = NULL; + int count = 0; + int i; + + if (desc != NULL) { + LASSERT(ptlrpc_is_bulk_desc_kiov(desc->bd_type)); + page_count = desc->bd_iov_count; + } else { + page_count = aa->aa_page_count; + } + + for (i = 0; i < page_count; i++) { + void *pz; + if (desc) + pz = page_zone(BD_GET_KIOV(desc, i).kiov_page); + else + pz = page_zone(aa->aa_ppga[i]->pg); + + 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, + struct osc_brw_async_args *aa) +{ + unstable_page_accounting(desc, aa, 1); +} + +static inline void dec_unstable_page_accounting(struct ptlrpc_bulk_desc *desc, + struct osc_brw_async_args *aa) +{ + unstable_page_accounting(desc, aa, -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 osc_brw_async_args *aa = (void *)&req->rq_async_args; + struct client_obd *cli = &req->rq_import->imp_obd->u.cli; + int page_count; + long unstable_count; + + if (desc) + page_count = desc->bd_iov_count; + else + page_count = aa->aa_page_count; + + LASSERT(page_count >= 0); + + dec_unstable_page_accounting(desc, aa); + + 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 (waitqueue_active(&osc_lru_waitq)) + (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 osc_brw_async_args *aa = (void *)&req->rq_async_args; + struct client_obd *cli = &req->rq_import->imp_obd->u.cli; + long page_count; + + /* No unstable page tracking */ + if (cli->cl_cache == NULL || !cli->cl_cache->ccc_unstable_check) + return; + + if (desc) + page_count = desc->bd_iov_count; + else + page_count = aa->aa_page_count; + + add_unstable_page_accounting(desc, aa); + 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_name(cli), 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; +} + +/** + * Return how many LRU pages in the cache of all OSC devices + * + * \retval return # of cached LRU pages times reclaimation tendency + * \retval SHRINK_STOP if it cannot do any scanning in this time + */ +unsigned long osc_cache_shrink_count(struct shrinker *sk, + struct shrink_control *sc) +{ + struct client_obd *cli; + unsigned long cached = 0; + + spin_lock(&osc_shrink_lock); + list_for_each_entry(cli, &osc_shrink_list, cl_shrink_list) + cached += atomic_long_read(&cli->cl_lru_in_list); + spin_unlock(&osc_shrink_lock); + + return (cached * sysctl_vfs_cache_pressure) / 100; +} + +/** + * Scan and try to reclaim sc->nr_to_scan cached LRU pages + * + * \retval number of cached LRU pages reclaimed + * \retval SHRINK_STOP if it cannot do any scanning in this time + * + * Linux kernel will loop calling this shrinker scan routine with + * sc->nr_to_scan = SHRINK_BATCH(128 for now) until kernel got enough memory. + * + * If sc->nr_to_scan is 0, the VM is querying the cache size, we don't need + * to scan and try to reclaim LRU pages, just return 0 and + * osc_cache_shrink_count() will report the LRU page number. + */ +unsigned long osc_cache_shrink_scan(struct shrinker *sk, + struct shrink_control *sc) +{ + struct client_obd *cli; + struct client_obd *stop_anchor = NULL; + struct lu_env *env; + long shrank = 0; + int rc; + __u16 refcheck; + + if (sc->nr_to_scan == 0) + return 0; + + if (!(sc->gfp_mask & __GFP_FS)) + return SHRINK_STOP; + + env = cl_env_get(&refcheck); + if (IS_ERR(env)) + return SHRINK_STOP; + + spin_lock(&osc_shrink_lock); + while (!list_empty(&osc_shrink_list)) { + cli = list_entry(osc_shrink_list.next, struct client_obd, + cl_shrink_list); + + if (stop_anchor == NULL) + stop_anchor = cli; + else if (cli == stop_anchor) + break; + + list_move_tail(&cli->cl_shrink_list, &osc_shrink_list); + spin_unlock(&osc_shrink_lock); + + /* shrink no more than max_pages_per_rpc for an OSC */ + rc = osc_lru_shrink(env, cli, (sc->nr_to_scan - shrank) > + cli->cl_max_pages_per_rpc ? + cli->cl_max_pages_per_rpc : + sc->nr_to_scan - shrank, true); + if (rc > 0) + shrank += rc; + + if (shrank >= sc->nr_to_scan) + goto out; + + spin_lock(&osc_shrink_lock); + } + spin_unlock(&osc_shrink_lock); + +out: + cl_env_put(env, &refcheck); + + return shrank; } /** @} osc */