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* 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.gnu.org/licenses/gpl-2.0.html
*
* GPL HEADER END
*/
/*
* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
*
* Copyright (c) 2011, 2015, 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>
* Author: Jinshan Xiong <jinshan.xiong@intel.com>
*/
#define DEBUG_SUBSYSTEM S_OSC
#include "osc_cl_internal.h"
static void osc_lru_del(struct client_obd *cli, struct osc_page *opg);
static void osc_lru_use(struct client_obd *cli, struct osc_page *opg);
static int osc_lru_reserve(const struct lu_env *env, struct osc_object *obj,
struct osc_page *opg);
/** \addtogroup osc
* @{
*/
/*****************************************************************************
*
* Page operations.
*
*/
static void osc_page_transfer_get(struct osc_page *opg, const char *label)
{
struct cl_page *page = opg->ops_cl.cpl_page;
LASSERT(!opg->ops_transfer_pinned);
cl_page_get(page);
lu_ref_add_atomic(&page->cp_reference, label, page);
opg->ops_transfer_pinned = 1;
}
static void osc_page_transfer_put(const struct lu_env *env,
struct osc_page *opg)
{
struct cl_page *page = opg->ops_cl.cpl_page;
if (opg->ops_transfer_pinned) {
opg->ops_transfer_pinned = 0;
lu_ref_del(&page->cp_reference, "transfer", page);
cl_page_put(env, page);
}
}
/**
* This is called once for every page when it is submitted for a transfer
* either opportunistic (osc_page_cache_add()), or immediate
* (osc_page_submit()).
*/
static void osc_page_transfer_add(const struct lu_env *env,
struct osc_page *opg, enum cl_req_type crt)
{
struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj);
osc_lru_use(osc_cli(obj), opg);
spin_lock(&obj->oo_seatbelt);
list_add(&opg->ops_inflight, &obj->oo_inflight[crt]);
opg->ops_submitter = current;
spin_unlock(&obj->oo_seatbelt);
}
int osc_page_cache_add(const struct lu_env *env,
const struct cl_page_slice *slice, struct cl_io *io)
{
struct osc_page *opg = cl2osc_page(slice);
int result;
osc_page_transfer_get(opg, "transfer\0cache");
result = osc_queue_async_io(env, io, opg);
if (result != 0)
osc_page_transfer_put(env, opg);
else
osc_page_transfer_add(env, opg, CRT_WRITE);
return result;
}
void osc_index2policy(ldlm_policy_data_t *policy, const struct cl_object *obj,
pgoff_t start, pgoff_t end)
{
memset(policy, 0, sizeof(*policy));
policy->l_extent.start = cl_offset(obj, start);
policy->l_extent.end = cl_offset(obj, end + 1) - 1;
}
static int osc_page_is_under_lock(const struct lu_env *env,
const struct cl_page_slice *slice,
struct cl_io *unused, pgoff_t *max_index)
{
struct osc_page *opg = cl2osc_page(slice);
struct ldlm_lock *dlmlock;
int result = -ENODATA;
dlmlock = osc_dlmlock_at_pgoff(env, cl2osc(slice->cpl_obj),
osc_index(opg), 1, 0);
if (dlmlock) {
*max_index = cl_index(slice->cpl_obj,
dlmlock->l_policy_data.l_extent.end);
LDLM_LOCK_PUT(dlmlock);
result = 0;
}
return result;
}
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 %lu: 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, osc_index(opg),
/* 1 */
oap->oap_magic, oap->oap_cmd,
oap->oap_interrupted,
osc_list(&oap->oap_pending_item),
osc_list(&oap->oap_rpc_item),
/* 2 */
oap->oap_obj_off, oap->oap_page_off, oap->oap_count,
oap->oap_async_flags, oap->oap_brw_flags,
oap->oap_request, oap->oap_cli, obj,
/* 3 */
osc_list(&opg->ops_inflight),
opg->ops_submitter, opg->ops_transfer_pinned,
osc_submit_duration(opg), opg->ops_srvlock,
/* 4 */
cli->cl_r_in_flight, cli->cl_w_in_flight,
cli->cl_max_rpcs_in_flight,
cli->cl_avail_grant,
osc_list(&cli->cl_cache_waiters),
osc_list(&cli->cl_loi_ready_list),
osc_list(&cli->cl_loi_hp_ready_list),
osc_list(&cli->cl_loi_write_list),
osc_list(&cli->cl_loi_read_list),
/* 5 */
osc_list(&obj->oo_ready_item),
osc_list(&obj->oo_hp_ready_item),
osc_list(&obj->oo_write_item),
osc_list(&obj->oo_read_item),
atomic_read(&obj->oo_nr_reads),
osc_list(&obj->oo_reading_exts),
atomic_read(&obj->oo_nr_writes),
osc_list(&obj->oo_hp_exts),
osc_list(&obj->oo_urgent_exts));
}
static void osc_page_delete(const struct lu_env *env,
const struct cl_page_slice *slice)
{
struct osc_page *opg = cl2osc_page(slice);
struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj);
int rc;
CDEBUG(D_TRACE, "%p\n", opg);
osc_page_transfer_put(env, opg);
rc = osc_teardown_async_page(env, obj, opg);
if (rc) {
CL_PAGE_DEBUG(D_ERROR, env, slice->cpl_page,
"Trying to teardown failed: %d\n", rc);
LASSERT(0);
}
spin_lock(&obj->oo_seatbelt);
if (opg->ops_submitter) {
LASSERT(!list_empty(&opg->ops_inflight));
list_del_init(&opg->ops_inflight);
opg->ops_submitter = NULL;
}
spin_unlock(&obj->oo_seatbelt);
osc_lru_del(osc_cli(obj), opg);
if (slice->cpl_page->cp_type == CPT_CACHEABLE) {
void *value;
spin_lock(&obj->oo_tree_lock);
value = radix_tree_delete(&obj->oo_tree, osc_index(opg));
if (value)
--obj->oo_npages;
spin_unlock(&obj->oo_tree_lock);
LASSERT(ergo(value, value == opg));
}
}
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;
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;
/* 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;
rc = osc_flush_async_page(env, io, opg);
return rc;
}
static const struct cl_page_operations osc_page_ops = {
.cpo_print = osc_page_print,
.cpo_delete = osc_page_delete,
.cpo_is_under_lock = osc_page_is_under_lock,
.cpo_clip = osc_page_clip,
.cpo_cancel = osc_page_cancel,
.cpo_flush = osc_page_flush
};
int osc_page_init(const struct lu_env *env, struct cl_object *obj,
struct cl_page *page, pgoff_t index)
{
struct osc_object *osc = cl2osc(obj);
struct osc_page *opg = cl_object_page_slice(obj, page);
int result;
opg->ops_from = 0;
opg->ops_to = PAGE_SIZE;
result = osc_prep_async_page(osc, opg, page->cp_vmpage,
cl_offset(obj, index));
if (result == 0) {
struct osc_io *oio = osc_env_io(env);
opg->ops_srvlock = osc_io_srvlock(oio);
cl_page_slice_add(page, &opg->ops_cl, obj, index,
&osc_page_ops);
}
/* ops_inflight and ops_lru are the same field, but it doesn't
* hurt to initialize it twice :-)
*/
INIT_LIST_HEAD(&opg->ops_inflight);
INIT_LIST_HEAD(&opg->ops_lru);
/* reserve an LRU space for this page */
if (page->cp_type == CPT_CACHEABLE && result == 0) {
result = osc_lru_reserve(env, osc, opg);
if (result == 0) {
spin_lock(&osc->oo_tree_lock);
result = radix_tree_insert(&osc->oo_tree, index, opg);
if (result == 0)
++osc->oo_npages;
spin_unlock(&osc->oo_tree_lock);
LASSERT(result == 0);
}
}
return result;
}
/**
* Helper function called by osc_io_submit() for every page in an immediate
* transfer (i.e., transferred synchronously).
*/
void osc_page_submit(const struct lu_env *env, struct osc_page *opg,
enum cl_req_type crt, int brw_flags)
{
struct osc_async_page *oap = &opg->ops_oap;
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 = brw_flags | OBD_BRW_SYNC;
if (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);
/* 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_SHIFT); /* 2M */
/* free this number at most otherwise it will take too long time to finish. */
static const int lru_shrink_max = 8 << (20 - PAGE_SHIFT); /* 8M */
/* Check if we can free LRU slots from this OSC. If there exists LRU waiters,
* we should free slots aggressively. In this way, slots are freed in a steady
* step to maintain fairness among OSCs.
*
* Return how many LRU pages should be freed.
*/
static int osc_cache_too_much(struct client_obd *cli)
{
struct cl_client_cache *cache = cli->cl_cache;
long pages = atomic_long_read(&cli->cl_lru_in_list);
unsigned long budget;
budget = cache->ccc_lru_max / (atomic_read(&cache->ccc_users) - 2);
/* if it's going to run out LRU slots, we should free some, but not
* too much to maintain fairness among OSCs.
*/
if (atomic_long_read(cli->cl_lru_left) < cache->ccc_lru_max >> 4) {
if (pages >= budget)
return lru_shrink_max;
else if (pages >= budget / 2)
return lru_shrink_min;
} else if (pages >= budget * 2) {
return lru_shrink_min;
}
return 0;
}
int lru_queue_work(const struct lu_env *env, void *data)
{
struct client_obd *cli = data;
CDEBUG(D_CACHE, "Run LRU work for client obd %p.\n", cli);
if (osc_cache_too_much(cli))
osc_lru_shrink(env, cli, lru_shrink_max, true);
return 0;
}
void osc_lru_add_batch(struct client_obd *cli, struct list_head *plist)
{
LIST_HEAD(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);
spin_unlock(&cli->cl_lru_list_lock);
/* XXX: May set force to be true for better performance */
if (osc_cache_too_much(cli))
(void)ptlrpcd_queue_work(cli->cl_lru_work);
}
}
static void __osc_lru_del(struct client_obd *cli, struct osc_page *opg)
{
LASSERT(atomic_long_read(&cli->cl_lru_in_list) > 0);
list_del_init(&opg->ops_lru);
atomic_long_dec(&cli->cl_lru_in_list);
}
/**
* Page is being destroyed. The page may be not in LRU list, if the transfer
* has never finished(error occurred).
*/
static void osc_lru_del(struct client_obd *cli, struct osc_page *opg)
{
if (opg->ops_in_lru) {
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 (!memory_pressure_get())
(void)ptlrpcd_queue_work(cli->cl_lru_work);
wake_up(&osc_lru_waitq);
} else {
LASSERT(list_empty(&opg->ops_lru));
}
}
/**
* Delete page from LRUlist for redirty.
*/
static void osc_lru_use(struct client_obd *cli, struct osc_page *opg)
{
/* If page is being transferred for the first time,
* ops_lru should be empty
*/
if (opg->ops_in_lru && !list_empty(&opg->ops_lru)) {
spin_lock(&cli->cl_lru_list_lock);
__osc_lru_del(cli, opg);
spin_unlock(&cli->cl_lru_list_lock);
atomic_long_inc(&cli->cl_lru_busy);
}
}
static void discard_pagevec(const struct lu_env *env, struct cl_io *io,
struct cl_page **pvec, int max_index)
{
int i;
for (i = 0; i < max_index; i++) {
struct cl_page *page = pvec[i];
LASSERT(cl_page_is_owned(page, io));
cl_page_discard(env, io, page);
cl_page_disown(env, io, page);
cl_page_put(env, page);
pvec[i] = NULL;
}
}
/**
* Check if a cl_page can be released, i.e, it's not being used.
*
* If unstable account is turned on, bulk transfer may hold one refcount
* for recovery so we need to check vmpage refcount as well; otherwise,
* even we can destroy cl_page but the corresponding vmpage can't be reused.
*/
static inline bool lru_page_busy(struct client_obd *cli, struct cl_page *page)
{
if (cl_page_in_use_noref(page))
return true;
if (cli->cl_cache->ccc_unstable_check) {
struct page *vmpage = cl_page_vmpage(page);
/* vmpage have two known users: cl_page and VM page cache */
if (page_count(vmpage) - page_mapcount(vmpage) > 2)
return true;
}
return false;
}
/**
* Drop @target of pages from LRU at most.
*/
long osc_lru_shrink(const struct lu_env *env, struct client_obd *cli,
long target, bool force)
{
struct cl_io *io;
struct cl_object *clobj = NULL;
struct cl_page **pvec;
struct osc_page *opg;
int maxscan = 0;
long count = 0;
int index = 0;
int rc = 0;
LASSERT(atomic_long_read(&cli->cl_lru_in_list) >= 0);
if (atomic_long_read(&cli->cl_lru_in_list) == 0 || target <= 0)
return 0;
if (!force) {
if (atomic_read(&cli->cl_lru_shrinkers) > 0)
return -EBUSY;
if (atomic_inc_return(&cli->cl_lru_shrinkers) > 1) {
atomic_dec(&cli->cl_lru_shrinkers);
return -EBUSY;
}
} else {
atomic_inc(&cli->cl_lru_shrinkers);
}
pvec = (struct cl_page **)osc_env_info(env)->oti_pvec;
io = &osc_env_info(env)->oti_io;
spin_lock(&cli->cl_lru_list_lock);
maxscan = min(target << 1, atomic_long_read(&cli->cl_lru_in_list));
while (!list_empty(&cli->cl_lru_list)) {
struct cl_page *page;
bool will_free = false;
if (--maxscan < 0)
break;
opg = list_entry(cli->cl_lru_list.next, struct osc_page,
ops_lru);
page = opg->ops_cl.cpl_page;
if (lru_page_busy(cli, page)) {
list_move_tail(&opg->ops_lru, &cli->cl_lru_list);
continue;
}
LASSERT(page->cp_obj);
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) {
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) {
discard_pagevec(env, io, pvec, index);
cl_io_fini(env, io);
cl_object_put(env, clobj);
}
atomic_dec(&cli->cl_lru_shrinkers);
if (count > 0) {
atomic_long_add(count, cli->cl_lru_left);
wake_up_all(&osc_lru_waitq);
}
return count > 0 ? count : rc;
}
long osc_lru_reclaim(struct client_obd *cli)
{
struct cl_env_nest nest;
struct lu_env *env;
struct cl_client_cache *cache = cli->cl_cache;
int max_scans;
long rc = 0;
LASSERT(cache);
env = cl_env_nested_get(&nest);
if (IS_ERR(env))
return 0;
rc = osc_lru_shrink(env, cli, osc_cache_too_much(cli), false);
if (rc != 0) {
if (rc == -EBUSY)
rc = 0;
CDEBUG(D_CACHE, "%s: Free %ld pages from own LRU: %p.\n",
cli->cl_import->imp_obd->obd_name, rc, cli);
goto out;
}
CDEBUG(D_CACHE, "%s: cli %p no free slots, pages: %ld, busy: %ld.\n",
cli->cl_import->imp_obd->obd_name, cli,
atomic_long_read(&cli->cl_lru_in_list),
atomic_long_read(&cli->cl_lru_busy));
/* Reclaim LRU slots from other client_obd as it can't free enough
* from its own. This should rarely happen.
*/
spin_lock(&cache->ccc_lru_lock);
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->cl_import->imp_obd->obd_name, cli,
atomic_long_read(&cli->cl_lru_in_list),
atomic_long_read(&cli->cl_lru_busy));
list_move_tail(&cli->cl_lru_osc, &cache->ccc_lru);
if (osc_cache_too_much(cli) > 0) {
spin_unlock(&cache->ccc_lru_lock);
rc = osc_lru_shrink(env, cli, osc_cache_too_much(cli),
true);
spin_lock(&cache->ccc_lru_lock);
if (rc != 0)
break;
}
}
spin_unlock(&cache->ccc_lru_lock);
out:
cl_env_nested_put(&nest, env);
CDEBUG(D_CACHE, "%s: cli %p freed %ld pages.\n",
cli->cl_import->imp_obd->obd_name, cli, rc);
return rc;
}
/**
* osc_lru_reserve() is called to reserve an LRU slot for a cl_page.
*
* Usually the LRU slots are reserved in osc_io_iter_rw_init().
* Only in the case that the LRU slots are in extreme shortage, it should
* have reserved enough slots for an IO.
*/
static int osc_lru_reserve(const struct lu_env *env, struct osc_object *obj,
struct osc_page *opg)
{
struct l_wait_info lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
struct osc_io *oio = osc_env_io(env);
struct client_obd *cli = osc_cli(obj);
int rc = 0;
if (!cli->cl_cache) /* shall not be in LRU */
return 0;
if (oio->oi_lru_reserved > 0) {
--oio->oi_lru_reserved;
goto out;
}
LASSERT(atomic_long_read(cli->cl_lru_left) >= 0);
while (!atomic_long_add_unless(cli->cl_lru_left, -1, 0)) {
/* run out of LRU spaces, try to drop some by itself */
rc = osc_lru_reclaim(cli);
if (rc < 0)
break;
if (rc > 0)
continue;
cond_resched();
rc = l_wait_event(osc_lru_waitq,
atomic_long_read(cli->cl_lru_left) > 0,
&lwi);
if (rc < 0)
break;
}
out:
if (rc >= 0) {
atomic_long_inc(&cli->cl_lru_busy);
opg->ops_in_lru = 1;
rc = 0;
}
return rc;
}
/**
* Atomic operations are expensive. We accumulate the accounting for the
* same page pgdat to get better performance.
* In practice this can work pretty good because the pages in the same RPC
* are likely from the same page zone.
*/
static inline void unstable_page_accounting(struct ptlrpc_bulk_desc *desc,
int factor)
{
int page_count = desc->bd_iov_count;
pg_data_t *last = NULL;
int count = 0;
int i;
for (i = 0; i < page_count; i++) {
pg_data_t *pgdat = page_pgdat(desc->bd_iov[i].bv_page);
if (likely(pgdat == last)) {
++count;
continue;
}
if (count > 0) {
mod_node_page_state(pgdat, NR_UNSTABLE_NFS,
factor * count);
count = 0;
}
last = pgdat;
++count;
}
if (count > 0)
mod_node_page_state(last, NR_UNSTABLE_NFS, factor * count);
}
static inline void add_unstable_page_accounting(struct ptlrpc_bulk_desc *desc)
{
unstable_page_accounting(desc, 1);
}
static inline void dec_unstable_page_accounting(struct ptlrpc_bulk_desc *desc)
{
unstable_page_accounting(desc, -1);
}
/**
* Performs "unstable" page accounting. This function balances the
* increment operations performed in osc_inc_unstable_pages. It is
* registered as the RPC request callback, and is executed when the
* bulk RPC is committed on the server. Thus at this point, the pages
* involved in the bulk transfer are no longer considered unstable.
*
* If this function is called, the request should have been committed
* or req:rq_unstable must have been set; it implies that the unstable
* statistic have been added.
*/
void osc_dec_unstable_pages(struct ptlrpc_request *req)
{
struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
struct ptlrpc_bulk_desc *desc = req->rq_bulk;
int page_count = desc->bd_iov_count;
long unstable_count;
LASSERT(page_count >= 0);
dec_unstable_page_accounting(desc);
unstable_count = atomic_long_sub_return(page_count,
&cli->cl_unstable_count);
LASSERT(unstable_count >= 0);
unstable_count = atomic_long_sub_return(page_count,
&cli->cl_cache->ccc_unstable_nr);
LASSERT(unstable_count >= 0);
if (!unstable_count)
wake_up_all(&cli->cl_cache->ccc_unstable_waitq);
if (osc_cache_too_much(cli))
(void)ptlrpcd_queue_work(cli->cl_lru_work);
}
/**
* "unstable" page accounting. See: osc_dec_unstable_pages.
*/
void osc_inc_unstable_pages(struct ptlrpc_request *req)
{
struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
struct ptlrpc_bulk_desc *desc = req->rq_bulk;
long page_count = desc->bd_iov_count;
/* No unstable page tracking */
if (!cli->cl_cache || !cli->cl_cache->ccc_unstable_check)
return;
add_unstable_page_accounting(desc);
atomic_long_add(page_count, &cli->cl_unstable_count);
atomic_long_add(page_count, &cli->cl_cache->ccc_unstable_nr);
/*
* If the request has already been committed (i.e. brw_commit
* called via rq_commit_cb), we need to undo the unstable page
* increments we just performed because rq_commit_cb wont be
* called again.
*/
spin_lock(&req->rq_lock);
if (unlikely(req->rq_committed)) {
spin_unlock(&req->rq_lock);
osc_dec_unstable_pages(req);
} else {
req->rq_unstable = 1;
spin_unlock(&req->rq_lock);
}
}
/**
* Check if it piggybacks SOFT_SYNC flag to OST from this OSC.
* This function will be called by every BRW RPC so it's critical
* to make this function fast.
*/
bool osc_over_unstable_soft_limit(struct client_obd *cli)
{
long unstable_nr, osc_unstable_count;
/* Can't check cli->cl_unstable_count, therefore, no soft limit */
if (!cli->cl_cache || !cli->cl_cache->ccc_unstable_check)
return false;
osc_unstable_count = atomic_long_read(&cli->cl_unstable_count);
unstable_nr = atomic_long_read(&cli->cl_cache->ccc_unstable_nr);
CDEBUG(D_CACHE,
"%s: cli: %p unstable pages: %lu, osc unstable pages: %lu\n",
cli->cl_import->imp_obd->obd_name, cli,
unstable_nr, osc_unstable_count);
/*
* If the LRU slots are in shortage - 25% remaining AND this OSC
* has one full RPC window of unstable pages, it's a good chance
* to piggyback a SOFT_SYNC flag.
* Please notice that the OST won't take immediate response for the
* SOFT_SYNC request so active OSCs will have more chance to carry
* the flag, this is reasonable.
*/
return unstable_nr > cli->cl_cache->ccc_lru_max >> 2 &&
osc_unstable_count > cli->cl_max_pages_per_rpc *
cli->cl_max_rpcs_in_flight;
}
/** @} osc */
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