833 lines
22 KiB
C
833 lines
22 KiB
C
/*
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* GPL HEADER START
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*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 only,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License version 2 for more details (a copy is included
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* in the LICENSE file that accompanied this code).
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*
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* You should have received a copy of the GNU General Public License
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* version 2 along with this program; If not, see
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* http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*
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* GPL HEADER END
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*/
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/*
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* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
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* Use is subject to license terms.
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*
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* Copyright (c) 2011, 2015, Intel Corporation.
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*/
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/*
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* This file is part of Lustre, http://www.lustre.org/
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* Lustre is a trademark of Sun Microsystems, Inc.
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*
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* Implementation of cl_page for OSC layer.
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*
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* Author: Nikita Danilov <nikita.danilov@sun.com>
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*/
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#define DEBUG_SUBSYSTEM S_OSC
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#include "osc_cl_internal.h"
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static void osc_lru_del(struct client_obd *cli, struct osc_page *opg, bool del);
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static void osc_lru_add(struct client_obd *cli, struct osc_page *opg);
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static int osc_lru_reserve(const struct lu_env *env, struct osc_object *obj,
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struct osc_page *opg);
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/** \addtogroup osc
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* @{
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*/
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static int osc_page_protected(const struct lu_env *env,
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const struct osc_page *opg,
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enum cl_lock_mode mode, int unref)
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{
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return 1;
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}
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/*****************************************************************************
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*
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* Page operations.
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*
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*/
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static void osc_page_fini(const struct lu_env *env,
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struct cl_page_slice *slice)
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{
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struct osc_page *opg = cl2osc_page(slice);
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CDEBUG(D_TRACE, "%p\n", opg);
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LASSERT(!opg->ops_lock);
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}
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static void osc_page_transfer_get(struct osc_page *opg, const char *label)
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{
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struct cl_page *page = cl_page_top(opg->ops_cl.cpl_page);
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LASSERT(!opg->ops_transfer_pinned);
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cl_page_get(page);
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lu_ref_add_atomic(&page->cp_reference, label, page);
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opg->ops_transfer_pinned = 1;
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}
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static void osc_page_transfer_put(const struct lu_env *env,
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struct osc_page *opg)
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{
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struct cl_page *page = cl_page_top(opg->ops_cl.cpl_page);
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if (opg->ops_transfer_pinned) {
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lu_ref_del(&page->cp_reference, "transfer", page);
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opg->ops_transfer_pinned = 0;
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cl_page_put(env, page);
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}
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}
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/**
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* This is called once for every page when it is submitted for a transfer
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* either opportunistic (osc_page_cache_add()), or immediate
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* (osc_page_submit()).
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*/
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static void osc_page_transfer_add(const struct lu_env *env,
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struct osc_page *opg, enum cl_req_type crt)
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{
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struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj);
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/* ops_lru and ops_inflight share the same field, so take it from LRU
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* first and then use it as inflight.
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*/
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osc_lru_del(osc_cli(obj), opg, false);
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spin_lock(&obj->oo_seatbelt);
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list_add(&opg->ops_inflight, &obj->oo_inflight[crt]);
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opg->ops_submitter = current;
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spin_unlock(&obj->oo_seatbelt);
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}
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static int osc_page_cache_add(const struct lu_env *env,
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const struct cl_page_slice *slice,
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struct cl_io *io)
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{
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struct osc_io *oio = osc_env_io(env);
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struct osc_page *opg = cl2osc_page(slice);
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int result;
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LINVRNT(osc_page_protected(env, opg, CLM_WRITE, 0));
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osc_page_transfer_get(opg, "transfer\0cache");
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result = osc_queue_async_io(env, io, opg);
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if (result != 0)
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osc_page_transfer_put(env, opg);
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else
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osc_page_transfer_add(env, opg, CRT_WRITE);
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/* for sync write, kernel will wait for this page to be flushed before
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* osc_io_end() is called, so release it earlier.
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* for mkwrite(), it's known there is no further pages.
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*/
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if (cl_io_is_sync_write(io) || cl_io_is_mkwrite(io)) {
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if (oio->oi_active) {
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osc_extent_release(env, oio->oi_active);
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oio->oi_active = NULL;
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}
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}
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return result;
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}
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void osc_index2policy(ldlm_policy_data_t *policy, const struct cl_object *obj,
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pgoff_t start, pgoff_t end)
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{
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memset(policy, 0, sizeof(*policy));
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policy->l_extent.start = cl_offset(obj, start);
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policy->l_extent.end = cl_offset(obj, end + 1) - 1;
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}
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static int osc_page_addref_lock(const struct lu_env *env,
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struct osc_page *opg,
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struct cl_lock *lock)
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{
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struct osc_lock *olock;
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int rc;
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LASSERT(!opg->ops_lock);
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olock = osc_lock_at(lock);
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if (atomic_inc_return(&olock->ols_pageref) <= 0) {
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atomic_dec(&olock->ols_pageref);
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rc = -ENODATA;
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} else {
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cl_lock_get(lock);
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opg->ops_lock = lock;
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rc = 0;
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}
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return rc;
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}
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static void osc_page_putref_lock(const struct lu_env *env,
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struct osc_page *opg)
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{
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struct cl_lock *lock = opg->ops_lock;
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struct osc_lock *olock;
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LASSERT(lock);
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olock = osc_lock_at(lock);
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atomic_dec(&olock->ols_pageref);
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opg->ops_lock = NULL;
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cl_lock_put(env, lock);
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}
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static int osc_page_is_under_lock(const struct lu_env *env,
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const struct cl_page_slice *slice,
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struct cl_io *unused)
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{
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struct cl_lock *lock;
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int result = -ENODATA;
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lock = cl_lock_at_page(env, slice->cpl_obj, slice->cpl_page,
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NULL, 1, 0);
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if (lock) {
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if (osc_page_addref_lock(env, cl2osc_page(slice), lock) == 0)
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result = -EBUSY;
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cl_lock_put(env, lock);
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}
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return result;
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}
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static void osc_page_disown(const struct lu_env *env,
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const struct cl_page_slice *slice,
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struct cl_io *io)
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{
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struct osc_page *opg = cl2osc_page(slice);
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if (unlikely(opg->ops_lock))
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osc_page_putref_lock(env, opg);
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}
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static void osc_page_completion_read(const struct lu_env *env,
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const struct cl_page_slice *slice,
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int ioret)
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{
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struct osc_page *opg = cl2osc_page(slice);
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struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj);
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if (likely(opg->ops_lock))
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osc_page_putref_lock(env, opg);
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osc_lru_add(osc_cli(obj), opg);
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}
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static void osc_page_completion_write(const struct lu_env *env,
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const struct cl_page_slice *slice,
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int ioret)
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{
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struct osc_page *opg = cl2osc_page(slice);
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struct osc_object *obj = cl2osc(slice->cpl_obj);
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osc_lru_add(osc_cli(obj), opg);
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}
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static int osc_page_fail(const struct lu_env *env,
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const struct cl_page_slice *slice,
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struct cl_io *unused)
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{
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/*
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* Cached read?
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*/
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LBUG();
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return 0;
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}
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static const char *osc_list(struct list_head *head)
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{
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return list_empty(head) ? "-" : "+";
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}
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static inline unsigned long osc_submit_duration(struct osc_page *opg)
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{
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if (opg->ops_submit_time == 0)
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return 0;
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return (cfs_time_current() - opg->ops_submit_time);
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}
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static int osc_page_print(const struct lu_env *env,
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const struct cl_page_slice *slice,
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void *cookie, lu_printer_t printer)
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{
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struct osc_page *opg = cl2osc_page(slice);
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struct osc_async_page *oap = &opg->ops_oap;
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struct osc_object *obj = cl2osc(slice->cpl_obj);
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struct client_obd *cli = &osc_export(obj)->exp_obd->u.cli;
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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",
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opg,
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/* 1 */
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oap->oap_magic, oap->oap_cmd,
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oap->oap_interrupted,
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osc_list(&oap->oap_pending_item),
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osc_list(&oap->oap_rpc_item),
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/* 2 */
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oap->oap_obj_off, oap->oap_page_off, oap->oap_count,
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oap->oap_async_flags, oap->oap_brw_flags,
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oap->oap_request, oap->oap_cli, obj,
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/* 3 */
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osc_list(&opg->ops_inflight),
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opg->ops_submitter, opg->ops_transfer_pinned,
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osc_submit_duration(opg), opg->ops_srvlock,
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/* 4 */
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cli->cl_r_in_flight, cli->cl_w_in_flight,
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cli->cl_max_rpcs_in_flight,
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cli->cl_avail_grant,
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osc_list(&cli->cl_cache_waiters),
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osc_list(&cli->cl_loi_ready_list),
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osc_list(&cli->cl_loi_hp_ready_list),
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osc_list(&cli->cl_loi_write_list),
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osc_list(&cli->cl_loi_read_list),
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/* 5 */
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osc_list(&obj->oo_ready_item),
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osc_list(&obj->oo_hp_ready_item),
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osc_list(&obj->oo_write_item),
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osc_list(&obj->oo_read_item),
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atomic_read(&obj->oo_nr_reads),
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osc_list(&obj->oo_reading_exts),
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atomic_read(&obj->oo_nr_writes),
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osc_list(&obj->oo_hp_exts),
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osc_list(&obj->oo_urgent_exts));
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}
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static void osc_page_delete(const struct lu_env *env,
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const struct cl_page_slice *slice)
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{
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struct osc_page *opg = cl2osc_page(slice);
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struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj);
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int rc;
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LINVRNT(opg->ops_temp || osc_page_protected(env, opg, CLM_READ, 1));
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CDEBUG(D_TRACE, "%p\n", opg);
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osc_page_transfer_put(env, opg);
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rc = osc_teardown_async_page(env, obj, opg);
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if (rc) {
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CL_PAGE_DEBUG(D_ERROR, env, cl_page_top(slice->cpl_page),
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"Trying to teardown failed: %d\n", rc);
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LASSERT(0);
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}
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spin_lock(&obj->oo_seatbelt);
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if (opg->ops_submitter) {
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LASSERT(!list_empty(&opg->ops_inflight));
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list_del_init(&opg->ops_inflight);
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opg->ops_submitter = NULL;
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}
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spin_unlock(&obj->oo_seatbelt);
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osc_lru_del(osc_cli(obj), opg, true);
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}
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static void osc_page_clip(const struct lu_env *env,
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const struct cl_page_slice *slice, int from, int to)
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{
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struct osc_page *opg = cl2osc_page(slice);
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struct osc_async_page *oap = &opg->ops_oap;
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LINVRNT(osc_page_protected(env, opg, CLM_READ, 0));
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opg->ops_from = from;
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opg->ops_to = to;
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spin_lock(&oap->oap_lock);
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oap->oap_async_flags |= ASYNC_COUNT_STABLE;
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spin_unlock(&oap->oap_lock);
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}
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static int osc_page_cancel(const struct lu_env *env,
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const struct cl_page_slice *slice)
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{
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struct osc_page *opg = cl2osc_page(slice);
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int rc = 0;
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LINVRNT(osc_page_protected(env, opg, CLM_READ, 0));
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/* Check if the transferring against this page
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* is completed, or not even queued.
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*/
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if (opg->ops_transfer_pinned)
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/* FIXME: may not be interrupted.. */
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rc = osc_cancel_async_page(env, opg);
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LASSERT(ergo(rc == 0, opg->ops_transfer_pinned == 0));
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return rc;
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}
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static int osc_page_flush(const struct lu_env *env,
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const struct cl_page_slice *slice,
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struct cl_io *io)
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{
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struct osc_page *opg = cl2osc_page(slice);
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int rc;
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rc = osc_flush_async_page(env, io, opg);
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return rc;
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}
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static const struct cl_page_operations osc_page_ops = {
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.cpo_fini = osc_page_fini,
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.cpo_print = osc_page_print,
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.cpo_delete = osc_page_delete,
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.cpo_is_under_lock = osc_page_is_under_lock,
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.cpo_disown = osc_page_disown,
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.io = {
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[CRT_READ] = {
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.cpo_cache_add = osc_page_fail,
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.cpo_completion = osc_page_completion_read
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},
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[CRT_WRITE] = {
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.cpo_cache_add = osc_page_cache_add,
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.cpo_completion = osc_page_completion_write
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}
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},
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.cpo_clip = osc_page_clip,
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.cpo_cancel = osc_page_cancel,
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.cpo_flush = osc_page_flush
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};
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int osc_page_init(const struct lu_env *env, struct cl_object *obj,
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struct cl_page *page, struct page *vmpage)
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{
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struct osc_object *osc = cl2osc(obj);
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struct osc_page *opg = cl_object_page_slice(obj, page);
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int result;
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opg->ops_from = 0;
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opg->ops_to = PAGE_SIZE;
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result = osc_prep_async_page(osc, opg, vmpage,
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cl_offset(obj, page->cp_index));
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if (result == 0) {
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struct osc_io *oio = osc_env_io(env);
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opg->ops_srvlock = osc_io_srvlock(oio);
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cl_page_slice_add(page, &opg->ops_cl, obj, &osc_page_ops);
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}
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/*
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* Cannot assert osc_page_protected() here as read-ahead
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* creates temporary pages outside of a lock.
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*/
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/* ops_inflight and ops_lru are the same field, but it doesn't
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* hurt to initialize it twice :-)
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*/
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INIT_LIST_HEAD(&opg->ops_inflight);
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INIT_LIST_HEAD(&opg->ops_lru);
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/* reserve an LRU space for this page */
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if (page->cp_type == CPT_CACHEABLE && result == 0)
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result = osc_lru_reserve(env, osc, opg);
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return result;
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}
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/**
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* Helper function called by osc_io_submit() for every page in an immediate
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* transfer (i.e., transferred synchronously).
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*/
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void osc_page_submit(const struct lu_env *env, struct osc_page *opg,
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enum cl_req_type crt, int brw_flags)
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{
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struct osc_async_page *oap = &opg->ops_oap;
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struct osc_object *obj = oap->oap_obj;
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LINVRNT(osc_page_protected(env, opg,
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crt == CRT_WRITE ? CLM_WRITE : CLM_READ, 1));
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LASSERTF(oap->oap_magic == OAP_MAGIC, "Bad oap magic: oap %p, magic 0x%x\n",
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oap, oap->oap_magic);
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LASSERT(oap->oap_async_flags & ASYNC_READY);
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LASSERT(oap->oap_async_flags & ASYNC_COUNT_STABLE);
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oap->oap_cmd = crt == CRT_WRITE ? OBD_BRW_WRITE : OBD_BRW_READ;
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oap->oap_page_off = opg->ops_from;
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oap->oap_count = opg->ops_to - opg->ops_from;
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oap->oap_brw_flags = brw_flags | OBD_BRW_SYNC;
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if (!client_is_remote(osc_export(obj)) &&
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capable(CFS_CAP_SYS_RESOURCE)) {
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oap->oap_brw_flags |= OBD_BRW_NOQUOTA;
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oap->oap_cmd |= OBD_BRW_NOQUOTA;
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}
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opg->ops_submit_time = cfs_time_current();
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osc_page_transfer_get(opg, "transfer\0imm");
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osc_page_transfer_add(env, opg, crt);
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}
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/* --------------- LRU page management ------------------ */
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/* OSC is a natural place to manage LRU pages as applications are specialized
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* to write OSC by OSC. Ideally, if one OSC is used more frequently it should
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* occupy more LRU slots. On the other hand, we should avoid using up all LRU
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* slots (client_obd::cl_lru_left) otherwise process has to be put into sleep
|
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* for free LRU slots - this will be very bad so the algorithm requires each
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* OSC to free slots voluntarily to maintain a reasonable number of free slots
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* at any time.
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*/
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static DECLARE_WAIT_QUEUE_HEAD(osc_lru_waitq);
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static atomic_t osc_lru_waiters = ATOMIC_INIT(0);
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/* LRU pages are freed in batch mode. OSC should at least free this
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* number of pages to avoid running out of LRU budget, and..
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*/
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static const int lru_shrink_min = 2 << (20 - PAGE_SHIFT); /* 2M */
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/* free this number at most otherwise it will take too long time to finish. */
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static const int lru_shrink_max = 32 << (20 - PAGE_SHIFT); /* 32M */
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/* Check if we can free LRU slots from this OSC. If there exists LRU waiters,
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* we should free slots aggressively. In this way, slots are freed in a steady
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* step to maintain fairness among OSCs.
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*
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* Return how many LRU pages should be freed.
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*/
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static int osc_cache_too_much(struct client_obd *cli)
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|
{
|
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struct cl_client_cache *cache = cli->cl_cache;
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int pages = atomic_read(&cli->cl_lru_in_list) >> 1;
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if (atomic_read(&osc_lru_waiters) > 0 &&
|
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atomic_read(cli->cl_lru_left) < lru_shrink_max)
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/* drop lru pages aggressively */
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return min(pages, lru_shrink_max);
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/* if it's going to run out LRU slots, we should free some, but not
|
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* too much to maintain fairness among OSCs.
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*/
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if (atomic_read(cli->cl_lru_left) < cache->ccc_lru_max >> 4) {
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unsigned long tmp;
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|
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tmp = cache->ccc_lru_max / atomic_read(&cache->ccc_users);
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if (pages > tmp)
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return min(pages, lru_shrink_max);
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return pages > lru_shrink_min ? lru_shrink_min : 0;
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}
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return 0;
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}
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/* Return how many pages are not discarded in @pvec. */
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static int discard_pagevec(const struct lu_env *env, struct cl_io *io,
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struct cl_page **pvec, int max_index)
|
|
{
|
|
int count;
|
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int i;
|
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|
|
for (count = 0, i = 0; i < max_index; i++) {
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struct cl_page *page = pvec[i];
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|
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if (cl_page_own_try(env, io, page) == 0) {
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/* free LRU page only if nobody is using it.
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* This check is necessary to avoid freeing the pages
|
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* having already been removed from LRU and pinned
|
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* for IO.
|
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*/
|
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if (!cl_page_in_use(page)) {
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cl_page_unmap(env, io, page);
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cl_page_discard(env, io, page);
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++count;
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}
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cl_page_disown(env, io, page);
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}
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|
cl_page_put(env, page);
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pvec[i] = NULL;
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}
|
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return max_index - count;
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}
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|
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/**
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* Drop @target of pages from LRU at most.
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|
*/
|
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int osc_lru_shrink(struct client_obd *cli, int target)
|
|
{
|
|
struct cl_env_nest nest;
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struct lu_env *env;
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struct cl_io *io;
|
|
struct cl_object *clobj = NULL;
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struct cl_page **pvec;
|
|
struct osc_page *opg;
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|
struct osc_page *temp;
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|
int maxscan = 0;
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|
int count = 0;
|
|
int index = 0;
|
|
int rc = 0;
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|
|
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LASSERT(atomic_read(&cli->cl_lru_in_list) >= 0);
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|
if (atomic_read(&cli->cl_lru_in_list) == 0 || target <= 0)
|
|
return 0;
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|
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env = cl_env_nested_get(&nest);
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if (IS_ERR(env))
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return PTR_ERR(env);
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|
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pvec = osc_env_info(env)->oti_pvec;
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io = &osc_env_info(env)->oti_io;
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|
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client_obd_list_lock(&cli->cl_lru_list_lock);
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atomic_inc(&cli->cl_lru_shrinkers);
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maxscan = min(target << 1, atomic_read(&cli->cl_lru_in_list));
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list_for_each_entry_safe(opg, temp, &cli->cl_lru_list, ops_lru) {
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struct cl_page *page;
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|
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if (--maxscan < 0)
|
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break;
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|
|
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page = cl_page_top(opg->ops_cl.cpl_page);
|
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if (cl_page_in_use_noref(page)) {
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list_move_tail(&opg->ops_lru, &cli->cl_lru_list);
|
|
continue;
|
|
}
|
|
|
|
LASSERT(page->cp_obj);
|
|
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) {
|
|
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) {
|
|
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);
|
|
|
|
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);
|
|
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);
|
|
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) /* 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 */
|