--- /dev/null
+/*
+ * 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, 2012, 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 <nikita.danilov@sun.com>
+ */
+
+#define DEBUG_SUBSYSTEM S_OSC
+
+#include "osc_cl_internal.h"
+
+static void osc_lru_del(struct client_obd *cli, struct osc_page *opg, bool del);
+static void osc_lru_add(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, page->cp_index, page->cp_index);
+ 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 = page->cp_index;
+ descr->cld_end = page->cp_index;
+ 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_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);
+}
+
+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);
+
+ 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 = cl_page_top(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);
+ }
+}
+
+/**
+ * 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_del(osc_cli(obj), opg, false);
+
+ spin_lock(&obj->oo_seatbelt);
+ list_add(&opg->ops_inflight, &obj->oo_inflight[crt]);
+ opg->ops_submitter = current;
+ 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 *io)
+{
+ struct osc_io *oio = osc_env_io(env);
+ struct osc_page *opg = cl2osc_page(slice);
+ int result;
+
+ 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);
+
+ /* for sync write, kernel will wait for this page to be flushed before
+ * osc_io_end() is called, so release it earlier.
+ * for mkwrite(), it's known there is no further pages. */
+ if (cl_io_is_sync_write(io) || cl_io_is_mkwrite(io)) {
+ if (oio->oi_active != NULL) {
+ osc_extent_release(env, oio->oi_active);
+ oio->oi_active = NULL;
+ }
+ }
+
+ 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 (atomic_inc_return(&olock->ols_pageref) <= 0) {
+ atomic_dec(&olock->ols_pageref);
+ rc = -ENODATA;
+ } else {
+ cl_lock_get(lock);
+ 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);
+
+ atomic_dec(&olock->ols_pageref);
+ opg->ops_lock = NULL;
+
+ cl_lock_put(env, lock);
+}
+
+static int osc_page_is_under_lock(const struct lu_env *env,
+ const struct cl_page_slice *slice,
+ struct cl_io *unused)
+{
+ struct cl_lock *lock;
+ int result = -ENODATA;
+
+ lock = cl_lock_at_page(env, slice->cpl_obj, slice->cpl_page,
+ NULL, 1, 0);
+ if (lock != NULL) {
+ if (osc_page_addref_lock(env, cl2osc_page(slice), lock) == 0)
+ result = -EBUSY;
+ cl_lock_put(env, lock);
+ }
+ return result;
+}
+
+static void osc_page_disown(const struct lu_env *env,
+ const struct cl_page_slice *slice,
+ struct cl_io *io)
+{
+ struct osc_page *opg = cl2osc_page(slice);
+
+ if (unlikely(opg->ops_lock))
+ osc_page_putref_lock(env, opg);
+}
+
+static void osc_page_completion_read(const struct lu_env *env,
+ const struct cl_page_slice *slice,
+ int ioret)
+{
+ struct osc_page *opg = cl2osc_page(slice);
+ struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj);
+
+ if (likely(opg->ops_lock))
+ osc_page_putref_lock(env, opg);
+ osc_lru_add(osc_cli(obj), opg);
+}
+
+static void osc_page_completion_write(const struct lu_env *env,
+ const struct cl_page_slice *slice,
+ int ioret)
+{
+ struct osc_page *opg = cl2osc_page(slice);
+ struct osc_object *obj = cl2osc(slice->cpl_obj);
+
+ osc_lru_add(osc_cli(obj), 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(struct list_head *head)
+{
+ return list_empty(head) ? "-" : "+";
+}
+
+static inline unsigned long 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: 1< %#x %d %u %s %s > 2< %llu %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,
+ /* 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));
+
+ 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, cl_page_top(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, true);
+}
+
+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;
+
+ 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_completion = osc_page_completion_write
+ }
+ },
+ .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, struct page *vmpage)
+{
+ 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, vmpage,
+ cl_offset(obj, page->cp_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,
+ &osc_page_ops);
+ }
+ /*
+ * Cannot assert osc_page_protected() here as read-ahead
+ * creates temporary pages outside of a lock.
+ */
+ /* 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);
+
+ 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)) &&
+ 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 DECLARE_WAIT_QUEUE_HEAD(osc_lru_waitq);
+static atomic_t osc_lru_waiters = ATOMIC_INIT(0);
+/* 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 finish. */
+static const int lru_shrink_max = 32 << (20 - PAGE_CACHE_SHIFT); /* 32M */
+
+/* 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;
+ int pages = atomic_read(&cli->cl_lru_in_list) >> 1;
+
+ if (atomic_read(&osc_lru_waiters) > 0 &&
+ atomic_read(cli->cl_lru_left) < lru_shrink_max)
+ /* drop lru pages aggressively */
+ return min(pages, lru_shrink_max);
+
+ /* if it's going to run out LRU slots, we should free some, but not
+ * too much to maintain fairness among OSCs. */
+ if (atomic_read(cli->cl_lru_left) < cache->ccc_lru_max >> 4) {
+ unsigned long tmp;
+
+ tmp = cache->ccc_lru_max / atomic_read(&cache->ccc_users);
+ if (pages > tmp)
+ return min(pages, lru_shrink_max);
+
+ return pages > lru_shrink_min ? lru_shrink_min : 0;
+ }
+
+ return 0;
+}
+
+/* Return how many pages are not discarded in @pvec. */
+static int discard_pagevec(const struct lu_env *env, struct cl_io *io,
+ struct cl_page **pvec, int max_index)
+{
+ int count;
+ int i;
+
+ for (count = 0, i = 0; i < max_index; i++) {
+ struct cl_page *page = pvec[i];
+ if (cl_page_own_try(env, io, page) == 0) {
+ /* free LRU page only if nobody is using it.
+ * This check is necessary to avoid freeing the pages
+ * having already been removed from LRU and pinned
+ * for IO. */
+ if (!cl_page_in_use(page)) {
+ cl_page_unmap(env, io, page);
+ cl_page_discard(env, io, page);
+ ++count;
+ }
+ cl_page_disown(env, io, page);
+ }
+ cl_page_put(env, page);
+ pvec[i] = NULL;
+ }
+ return max_index - count;
+}
+
+/**
+ * Drop @target of pages from LRU at most.
+ */
+int osc_lru_shrink(struct client_obd *cli, int target)
+{
+ struct cl_env_nest nest;
+ struct lu_env *env;
+ struct cl_io *io;
+ struct cl_object *clobj = NULL;
+ struct cl_page **pvec;
+ struct osc_page *opg;
+ int maxscan = 0;
+ int count = 0;
+ int index = 0;
+ int rc = 0;
+
+ LASSERT(atomic_read(&cli->cl_lru_in_list) >= 0);
+ if (atomic_read(&cli->cl_lru_in_list) == 0 || target <= 0)
+ return 0;
+
+ env = cl_env_nested_get(&nest);
+ if (IS_ERR(env))
+ return PTR_ERR(env);
+
+ pvec = osc_env_info(env)->oti_pvec;
+ io = &osc_env_info(env)->oti_io;
+
+ client_obd_list_lock(&cli->cl_lru_list_lock);
+ atomic_inc(&cli->cl_lru_shrinkers);
+ maxscan = min(target << 1, atomic_read(&cli->cl_lru_in_list));
+ while (!list_empty(&cli->cl_lru_list)) {
+ struct cl_page *page;
+
+ if (--maxscan < 0)
+ break;
+
+ opg = list_entry(cli->cl_lru_list.next, struct osc_page,
+ ops_lru);
+ page = cl_page_top(opg->ops_cl.cpl_page);
+ if (cl_page_in_use_noref(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) {
+ count -= 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;
+ }
+
+ /* move this page to the end of list as it will be discarded
+ * soon. The page will be finally removed from LRU list in
+ * osc_page_delete(). */
+ list_move_tail(&opg->ops_lru, &cli->cl_lru_list);
+
+ /* it's okay to grab a refcount here w/o holding lock because
+ * it has to grab cl_lru_list_lock to delete the page. */
+ cl_page_get(page);
+ pvec[index++] = page;
+ if (++count >= target)
+ break;
+
+ if (unlikely(index == OTI_PVEC_SIZE)) {
+ client_obd_list_unlock(&cli->cl_lru_list_lock);
+ count -= discard_pagevec(env, io, pvec, index);
+ index = 0;
+
+ client_obd_list_lock(&cli->cl_lru_list_lock);
+ }
+ }
+ client_obd_list_unlock(&cli->cl_lru_list_lock);
+
+ if (clobj != NULL) {
+ count -= discard_pagevec(env, io, pvec, index);
+
+ cl_io_fini(env, io);
+ cl_object_put(env, clobj);
+ }
+ cl_env_nested_put(&nest, env);
+
+ atomic_dec(&cli->cl_lru_shrinkers);
+ return count > 0 ? count : rc;
+}
+
+static void osc_lru_add(struct client_obd *cli, struct osc_page *opg)
+{
+ bool wakeup = false;
+
+ if (!opg->ops_in_lru)
+ return;
+
+ atomic_dec(&cli->cl_lru_busy);
+ client_obd_list_lock(&cli->cl_lru_list_lock);
+ if (list_empty(&opg->ops_lru)) {
+ list_move_tail(&opg->ops_lru, &cli->cl_lru_list);
+ atomic_inc_return(&cli->cl_lru_in_list);
+ wakeup = atomic_read(&osc_lru_waiters) > 0;
+ }
+ client_obd_list_unlock(&cli->cl_lru_list_lock);
+
+ if (wakeup) {
+ osc_lru_shrink(cli, osc_cache_too_much(cli));
+ wake_up_all(&osc_lru_waitq);
+ }
+}
+
+/* delete page from LRUlist. The page can be deleted from LRUlist for two
+ * reasons: redirtied or deleted from page cache. */
+static void osc_lru_del(struct client_obd *cli, struct osc_page *opg, bool del)
+{
+ if (opg->ops_in_lru) {
+ client_obd_list_lock(&cli->cl_lru_list_lock);
+ if (!list_empty(&opg->ops_lru)) {
+ LASSERT(atomic_read(&cli->cl_lru_in_list) > 0);
+ list_del_init(&opg->ops_lru);
+ atomic_dec(&cli->cl_lru_in_list);
+ if (!del)
+ atomic_inc(&cli->cl_lru_busy);
+ } else if (del) {
+ LASSERT(atomic_read(&cli->cl_lru_busy) > 0);
+ atomic_dec(&cli->cl_lru_busy);
+ }
+ client_obd_list_unlock(&cli->cl_lru_list_lock);
+ if (del) {
+ atomic_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.
+ * cl_lru_shrinkers is to avoid recursive call in case
+ * we're already in the context of osc_lru_shrink(). */
+ if (atomic_read(&cli->cl_lru_shrinkers) == 0 &&
+ !memory_pressure_get())
+ osc_lru_shrink(cli, osc_cache_too_much(cli));
+ wake_up(&osc_lru_waitq);
+ }
+ } else {
+ LASSERT(list_empty(&opg->ops_lru));
+ }
+}
+
+static inline int max_to_shrink(struct client_obd *cli)
+{
+ return min(atomic_read(&cli->cl_lru_in_list) >> 1, lru_shrink_max);
+}
+
+static int osc_lru_reclaim(struct client_obd *cli)
+{
+ struct cl_client_cache *cache = cli->cl_cache;
+ int max_scans;
+ int rc;
+
+ LASSERT(cache != NULL);
+ LASSERT(!list_empty(&cache->ccc_lru));
+
+ rc = osc_lru_shrink(cli, lru_shrink_min);
+ if (rc != 0) {
+ CDEBUG(D_CACHE, "%s: Free %d pages from own LRU: %p.\n",
+ cli->cl_import->imp_obd->obd_name, rc, cli);
+ return rc;
+ }
+
+ CDEBUG(D_CACHE, "%s: cli %p no free slots, pages: %d, busy: %d.\n",
+ cli->cl_import->imp_obd->obd_name, cli,
+ atomic_read(&cli->cl_lru_in_list),
+ atomic_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: %d, busy: %d.\n",
+ cli->cl_import->imp_obd->obd_name, cli,
+ atomic_read(&cli->cl_lru_in_list),
+ atomic_read(&cli->cl_lru_busy));
+
+ list_move_tail(&cli->cl_lru_osc, &cache->ccc_lru);
+ if (atomic_read(&cli->cl_lru_in_list) > 0) {
+ spin_unlock(&cache->ccc_lru_lock);
+
+ rc = osc_lru_shrink(cli, max_to_shrink(cli));
+ spin_lock(&cache->ccc_lru_lock);
+ if (rc != 0)
+ break;
+ }
+ }
+ spin_unlock(&cache->ccc_lru_lock);
+
+ CDEBUG(D_CACHE, "%s: cli %p freed %d pages.\n",
+ cli->cl_import->imp_obd->obd_name, cli, rc);
+ return rc;
+}
+
+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 client_obd *cli = osc_cli(obj);
+ int rc = 0;
+
+ if (cli->cl_cache == NULL) /* shall not be in LRU */
+ return 0;
+
+ LASSERT(atomic_read(cli->cl_lru_left) >= 0);
+ while (!atomic_add_unless(cli->cl_lru_left, -1, 0)) {
+ int gen;
+
+ /* 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();
+
+ /* slowest case, all of caching pages are busy, notifying
+ * other OSCs that we're lack of LRU slots. */
+ atomic_inc(&osc_lru_waiters);
+
+ gen = atomic_read(&cli->cl_lru_in_list);
+ rc = l_wait_event(osc_lru_waitq,
+ atomic_read(cli->cl_lru_left) > 0 ||
+ (atomic_read(&cli->cl_lru_in_list) > 0 &&
+ gen != atomic_read(&cli->cl_lru_in_list)),
+ &lwi);
+
+ atomic_dec(&osc_lru_waiters);
+ if (rc < 0)
+ break;
+ }
+
+ if (rc >= 0) {
+ atomic_inc(&cli->cl_lru_busy);
+ opg->ops_in_lru = 1;
+ rc = 0;
+ }
+
+ return rc;
+}
+
+/** @} osc */
Code Review / kvmfornfv.git / blobdiff