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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.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) 2003, 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.
*
* lustre/ptlrpc/ptlrpcd.c
*/
/** \defgroup ptlrpcd PortalRPC daemon
*
* ptlrpcd is a special thread with its own set where other user might add
* requests when they don't want to wait for their completion.
* PtlRPCD will take care of sending such requests and then processing their
* replies and calling completion callbacks as necessary.
* The callbacks are called directly from ptlrpcd context.
* It is important to never significantly block (esp. on RPCs!) within such
* completion handler or a deadlock might occur where ptlrpcd enters some
* callback that attempts to send another RPC and wait for it to return,
* during which time ptlrpcd is completely blocked, so e.g. if import
* fails, recovery cannot progress because connection requests are also
* sent by ptlrpcd.
*
* @{
*/
#define DEBUG_SUBSYSTEM S_RPC
# include <linux/libcfs/libcfs.h>
#include <lustre_net.h>
# include <lustre_lib.h>
#include <lustre_ha.h>
#include <obd_class.h> /* for obd_zombie */
#include <obd_support.h> /* for OBD_FAIL_CHECK */
#include <cl_object.h> /* cl_env_{get,put}() */
#include <lprocfs_status.h>
#include "ptlrpc_internal.h"
struct ptlrpcd {
int pd_size;
int pd_index;
int pd_nthreads;
struct ptlrpcd_ctl pd_thread_rcv;
struct ptlrpcd_ctl pd_threads[0];
};
static int max_ptlrpcds;
module_param(max_ptlrpcds, int, 0644);
MODULE_PARM_DESC(max_ptlrpcds, "Max ptlrpcd thread count to be started.");
static int ptlrpcd_bind_policy = PDB_POLICY_PAIR;
module_param(ptlrpcd_bind_policy, int, 0644);
MODULE_PARM_DESC(ptlrpcd_bind_policy, "Ptlrpcd threads binding mode.");
static struct ptlrpcd *ptlrpcds;
struct mutex ptlrpcd_mutex;
static int ptlrpcd_users = 0;
void ptlrpcd_wake(struct ptlrpc_request *req)
{
struct ptlrpc_request_set *rq_set = req->rq_set;
LASSERT(rq_set != NULL);
wake_up(&rq_set->set_waitq);
}
EXPORT_SYMBOL(ptlrpcd_wake);
static struct ptlrpcd_ctl *
ptlrpcd_select_pc(struct ptlrpc_request *req, pdl_policy_t policy, int index)
{
int idx = 0;
if (req != NULL && req->rq_send_state != LUSTRE_IMP_FULL)
return &ptlrpcds->pd_thread_rcv;
switch (policy) {
case PDL_POLICY_SAME:
idx = smp_processor_id() % ptlrpcds->pd_nthreads;
break;
case PDL_POLICY_LOCAL:
/* Before CPU partition patches available, process it the same
* as "PDL_POLICY_ROUND". */
# ifdef CFS_CPU_MODE_NUMA
# warning "fix this code to use new CPU partition APIs"
# endif
/* Fall through to PDL_POLICY_ROUND until the CPU
* CPU partition patches are available. */
index = -1;
case PDL_POLICY_PREFERRED:
if (index >= 0 && index < num_online_cpus()) {
idx = index % ptlrpcds->pd_nthreads;
break;
}
/* Fall through to PDL_POLICY_ROUND for bad index. */
default:
/* Fall through to PDL_POLICY_ROUND for unknown policy. */
case PDL_POLICY_ROUND:
/* We do not care whether it is strict load balance. */
idx = ptlrpcds->pd_index + 1;
if (idx == smp_processor_id())
idx++;
idx %= ptlrpcds->pd_nthreads;
ptlrpcds->pd_index = idx;
break;
}
return &ptlrpcds->pd_threads[idx];
}
/**
* Move all request from an existing request set to the ptlrpcd queue.
* All requests from the set must be in phase RQ_PHASE_NEW.
*/
void ptlrpcd_add_rqset(struct ptlrpc_request_set *set)
{
struct list_head *tmp, *pos;
struct ptlrpcd_ctl *pc;
struct ptlrpc_request_set *new;
int count, i;
pc = ptlrpcd_select_pc(NULL, PDL_POLICY_LOCAL, -1);
new = pc->pc_set;
list_for_each_safe(pos, tmp, &set->set_requests) {
struct ptlrpc_request *req =
list_entry(pos, struct ptlrpc_request,
rq_set_chain);
LASSERT(req->rq_phase == RQ_PHASE_NEW);
req->rq_set = new;
req->rq_queued_time = cfs_time_current();
}
spin_lock(&new->set_new_req_lock);
list_splice_init(&set->set_requests, &new->set_new_requests);
i = atomic_read(&set->set_remaining);
count = atomic_add_return(i, &new->set_new_count);
atomic_set(&set->set_remaining, 0);
spin_unlock(&new->set_new_req_lock);
if (count == i) {
wake_up(&new->set_waitq);
/* XXX: It maybe unnecessary to wakeup all the partners. But to
* guarantee the async RPC can be processed ASAP, we have
* no other better choice. It maybe fixed in future. */
for (i = 0; i < pc->pc_npartners; i++)
wake_up(&pc->pc_partners[i]->pc_set->set_waitq);
}
}
EXPORT_SYMBOL(ptlrpcd_add_rqset);
/**
* Return transferred RPCs count.
*/
static int ptlrpcd_steal_rqset(struct ptlrpc_request_set *des,
struct ptlrpc_request_set *src)
{
struct list_head *tmp, *pos;
struct ptlrpc_request *req;
int rc = 0;
spin_lock(&src->set_new_req_lock);
if (likely(!list_empty(&src->set_new_requests))) {
list_for_each_safe(pos, tmp, &src->set_new_requests) {
req = list_entry(pos, struct ptlrpc_request,
rq_set_chain);
req->rq_set = des;
}
list_splice_init(&src->set_new_requests,
&des->set_requests);
rc = atomic_read(&src->set_new_count);
atomic_add(rc, &des->set_remaining);
atomic_set(&src->set_new_count, 0);
}
spin_unlock(&src->set_new_req_lock);
return rc;
}
/**
* Requests that are added to the ptlrpcd queue are sent via
* ptlrpcd_check->ptlrpc_check_set().
*/
void ptlrpcd_add_req(struct ptlrpc_request *req, pdl_policy_t policy, int idx)
{
struct ptlrpcd_ctl *pc;
if (req->rq_reqmsg)
lustre_msg_set_jobid(req->rq_reqmsg, NULL);
spin_lock(&req->rq_lock);
if (req->rq_invalid_rqset) {
struct l_wait_info lwi = LWI_TIMEOUT(cfs_time_seconds(5),
back_to_sleep, NULL);
req->rq_invalid_rqset = 0;
spin_unlock(&req->rq_lock);
l_wait_event(req->rq_set_waitq, (req->rq_set == NULL), &lwi);
} else if (req->rq_set) {
/* If we have a valid "rq_set", just reuse it to avoid double
* linked. */
LASSERT(req->rq_phase == RQ_PHASE_NEW);
LASSERT(req->rq_send_state == LUSTRE_IMP_REPLAY);
/* ptlrpc_check_set will decrease the count */
atomic_inc(&req->rq_set->set_remaining);
spin_unlock(&req->rq_lock);
wake_up(&req->rq_set->set_waitq);
return;
} else {
spin_unlock(&req->rq_lock);
}
pc = ptlrpcd_select_pc(req, policy, idx);
DEBUG_REQ(D_INFO, req, "add req [%p] to pc [%s:%d]",
req, pc->pc_name, pc->pc_index);
ptlrpc_set_add_new_req(pc, req);
}
EXPORT_SYMBOL(ptlrpcd_add_req);
static inline void ptlrpc_reqset_get(struct ptlrpc_request_set *set)
{
atomic_inc(&set->set_refcount);
}
/**
* Check if there is more work to do on ptlrpcd set.
* Returns 1 if yes.
*/
static int ptlrpcd_check(struct lu_env *env, struct ptlrpcd_ctl *pc)
{
struct list_head *tmp, *pos;
struct ptlrpc_request *req;
struct ptlrpc_request_set *set = pc->pc_set;
int rc = 0;
int rc2;
if (atomic_read(&set->set_new_count)) {
spin_lock(&set->set_new_req_lock);
if (likely(!list_empty(&set->set_new_requests))) {
list_splice_init(&set->set_new_requests,
&set->set_requests);
atomic_add(atomic_read(&set->set_new_count),
&set->set_remaining);
atomic_set(&set->set_new_count, 0);
/*
* Need to calculate its timeout.
*/
rc = 1;
}
spin_unlock(&set->set_new_req_lock);
}
/* We should call lu_env_refill() before handling new requests to make
* sure that env key the requests depending on really exists.
*/
rc2 = lu_env_refill(env);
if (rc2 != 0) {
/*
* XXX This is very awkward situation, because
* execution can neither continue (request
* interpreters assume that env is set up), nor repeat
* the loop (as this potentially results in a tight
* loop of -ENOMEM's).
*
* Fortunately, refill only ever does something when
* new modules are loaded, i.e., early during boot up.
*/
CERROR("Failure to refill session: %d\n", rc2);
return rc;
}
if (atomic_read(&set->set_remaining))
rc |= ptlrpc_check_set(env, set);
if (!list_empty(&set->set_requests)) {
/*
* XXX: our set never completes, so we prune the completed
* reqs after each iteration. boy could this be smarter.
*/
list_for_each_safe(pos, tmp, &set->set_requests) {
req = list_entry(pos, struct ptlrpc_request,
rq_set_chain);
if (req->rq_phase != RQ_PHASE_COMPLETE)
continue;
list_del_init(&req->rq_set_chain);
req->rq_set = NULL;
ptlrpc_req_finished(req);
}
}
if (rc == 0) {
/*
* If new requests have been added, make sure to wake up.
*/
rc = atomic_read(&set->set_new_count);
/* If we have nothing to do, check whether we can take some
* work from our partner threads. */
if (rc == 0 && pc->pc_npartners > 0) {
struct ptlrpcd_ctl *partner;
struct ptlrpc_request_set *ps;
int first = pc->pc_cursor;
do {
partner = pc->pc_partners[pc->pc_cursor++];
if (pc->pc_cursor >= pc->pc_npartners)
pc->pc_cursor = 0;
if (partner == NULL)
continue;
spin_lock(&partner->pc_lock);
ps = partner->pc_set;
if (ps == NULL) {
spin_unlock(&partner->pc_lock);
continue;
}
ptlrpc_reqset_get(ps);
spin_unlock(&partner->pc_lock);
if (atomic_read(&ps->set_new_count)) {
rc = ptlrpcd_steal_rqset(set, ps);
if (rc > 0)
CDEBUG(D_RPCTRACE, "transfer %d"
" async RPCs [%d->%d]\n",
rc, partner->pc_index,
pc->pc_index);
}
ptlrpc_reqset_put(ps);
} while (rc == 0 && pc->pc_cursor != first);
}
}
return rc;
}
/**
* Main ptlrpcd thread.
* ptlrpc's code paths like to execute in process context, so we have this
* thread which spins on a set which contains the rpcs and sends them.
*
*/
static int ptlrpcd(void *arg)
{
struct ptlrpcd_ctl *pc = arg;
struct ptlrpc_request_set *set = pc->pc_set;
struct lu_env env = { .le_ses = NULL };
int rc, exit = 0;
unshare_fs_struct();
#if defined(CONFIG_SMP)
if (test_bit(LIOD_BIND, &pc->pc_flags)) {
int index = pc->pc_index;
if (index >= 0 && index < num_possible_cpus()) {
while (!cpu_online(index)) {
if (++index >= num_possible_cpus())
index = 0;
}
set_cpus_allowed_ptr(current,
cpumask_of_node(cpu_to_node(index)));
}
}
#endif
/*
* XXX So far only "client" ptlrpcd uses an environment. In
* the future, ptlrpcd thread (or a thread-set) has to given
* an argument, describing its "scope".
*/
rc = lu_context_init(&env.le_ctx,
LCT_CL_THREAD|LCT_REMEMBER|LCT_NOREF);
complete(&pc->pc_starting);
if (rc != 0)
return rc;
/*
* This mainloop strongly resembles ptlrpc_set_wait() except that our
* set never completes. ptlrpcd_check() calls ptlrpc_check_set() when
* there are requests in the set. New requests come in on the set's
* new_req_list and ptlrpcd_check() moves them into the set.
*/
do {
struct l_wait_info lwi;
int timeout;
timeout = ptlrpc_set_next_timeout(set);
lwi = LWI_TIMEOUT(cfs_time_seconds(timeout ? timeout : 1),
ptlrpc_expired_set, set);
lu_context_enter(&env.le_ctx);
l_wait_event(set->set_waitq,
ptlrpcd_check(&env, pc), &lwi);
lu_context_exit(&env.le_ctx);
/*
* Abort inflight rpcs for forced stop case.
*/
if (test_bit(LIOD_STOP, &pc->pc_flags)) {
if (test_bit(LIOD_FORCE, &pc->pc_flags))
ptlrpc_abort_set(set);
exit++;
}
/*
* Let's make one more loop to make sure that ptlrpcd_check()
* copied all raced new rpcs into the set so we can kill them.
*/
} while (exit < 2);
/*
* Wait for inflight requests to drain.
*/
if (!list_empty(&set->set_requests))
ptlrpc_set_wait(set);
lu_context_fini(&env.le_ctx);
complete(&pc->pc_finishing);
return 0;
}
/* XXX: We want multiple CPU cores to share the async RPC load. So we start many
* ptlrpcd threads. We also want to reduce the ptlrpcd overhead caused by
* data transfer cross-CPU cores. So we bind ptlrpcd thread to specified
* CPU core. But binding all ptlrpcd threads maybe cause response delay
* because of some CPU core(s) busy with other loads.
*
* For example: "ls -l", some async RPCs for statahead are assigned to
* ptlrpcd_0, and ptlrpcd_0 is bound to CPU_0, but CPU_0 may be quite busy
* with other non-ptlrpcd, like "ls -l" itself (we want to the "ls -l"
* thread, statahead thread, and ptlrpcd thread can run in parallel), under
* such case, the statahead async RPCs can not be processed in time, it is
* unexpected. If ptlrpcd_0 can be re-scheduled on other CPU core, it may
* be better. But it breaks former data transfer policy.
*
* So we shouldn't be blind for avoiding the data transfer. We make some
* compromise: divide the ptlrpcd threads pool into two parts. One part is
* for bound mode, each ptlrpcd thread in this part is bound to some CPU
* core. The other part is for free mode, all the ptlrpcd threads in the
* part can be scheduled on any CPU core. We specify some partnership
* between bound mode ptlrpcd thread(s) and free mode ptlrpcd thread(s),
* and the async RPC load within the partners are shared.
*
* It can partly avoid data transfer cross-CPU (if the bound mode ptlrpcd
* thread can be scheduled in time), and try to guarantee the async RPC
* processed ASAP (as long as the free mode ptlrpcd thread can be scheduled
* on any CPU core).
*
* As for how to specify the partnership between bound mode ptlrpcd
* thread(s) and free mode ptlrpcd thread(s), the simplest way is to use
* <free bound> pair. In future, we can specify some more complex
* partnership based on the patches for CPU partition. But before such
* patches are available, we prefer to use the simplest one.
*/
# ifdef CFS_CPU_MODE_NUMA
# warning "fix ptlrpcd_bind() to use new CPU partition APIs"
# endif
static int ptlrpcd_bind(int index, int max)
{
struct ptlrpcd_ctl *pc;
int rc = 0;
#if defined(CONFIG_NUMA)
cpumask_t mask;
#endif
LASSERT(index <= max - 1);
pc = &ptlrpcds->pd_threads[index];
switch (ptlrpcd_bind_policy) {
case PDB_POLICY_NONE:
pc->pc_npartners = -1;
break;
case PDB_POLICY_FULL:
pc->pc_npartners = 0;
set_bit(LIOD_BIND, &pc->pc_flags);
break;
case PDB_POLICY_PAIR:
LASSERT(max % 2 == 0);
pc->pc_npartners = 1;
break;
case PDB_POLICY_NEIGHBOR:
#if defined(CONFIG_NUMA)
{
int i;
mask = *cpumask_of_node(cpu_to_node(index));
for (i = max; i < num_online_cpus(); i++)
cpu_clear(i, mask);
pc->pc_npartners = cpus_weight(mask) - 1;
set_bit(LIOD_BIND, &pc->pc_flags);
}
#else
LASSERT(max >= 3);
pc->pc_npartners = 2;
#endif
break;
default:
CERROR("unknown ptlrpcd bind policy %d\n", ptlrpcd_bind_policy);
rc = -EINVAL;
}
if (rc == 0 && pc->pc_npartners > 0) {
OBD_ALLOC(pc->pc_partners,
sizeof(struct ptlrpcd_ctl *) * pc->pc_npartners);
if (pc->pc_partners == NULL) {
pc->pc_npartners = 0;
rc = -ENOMEM;
} else {
switch (ptlrpcd_bind_policy) {
case PDB_POLICY_PAIR:
if (index & 0x1) {
set_bit(LIOD_BIND, &pc->pc_flags);
pc->pc_partners[0] = &ptlrpcds->
pd_threads[index - 1];
ptlrpcds->pd_threads[index - 1].
pc_partners[0] = pc;
}
break;
case PDB_POLICY_NEIGHBOR:
#if defined(CONFIG_NUMA)
{
struct ptlrpcd_ctl *ppc;
int i, pidx;
/* partners are cores in the same NUMA node.
* setup partnership only with ptlrpcd threads
* that are already initialized
*/
for (pidx = 0, i = 0; i < index; i++) {
if (cpu_isset(i, mask)) {
ppc = &ptlrpcds->pd_threads[i];
pc->pc_partners[pidx++] = ppc;
ppc->pc_partners[ppc->
pc_npartners++] = pc;
}
}
/* adjust number of partners to the number
* of partnership really setup */
pc->pc_npartners = pidx;
}
#else
if (index & 0x1)
set_bit(LIOD_BIND, &pc->pc_flags);
if (index > 0) {
pc->pc_partners[0] = &ptlrpcds->
pd_threads[index - 1];
ptlrpcds->pd_threads[index - 1].
pc_partners[1] = pc;
if (index == max - 1) {
pc->pc_partners[1] =
&ptlrpcds->pd_threads[0];
ptlrpcds->pd_threads[0].
pc_partners[0] = pc;
}
}
#endif
break;
}
}
}
return rc;
}
int ptlrpcd_start(int index, int max, const char *name, struct ptlrpcd_ctl *pc)
{
int rc;
/*
* Do not allow start second thread for one pc.
*/
if (test_and_set_bit(LIOD_START, &pc->pc_flags)) {
CWARN("Starting second thread (%s) for same pc %p\n",
name, pc);
return 0;
}
pc->pc_index = index;
init_completion(&pc->pc_starting);
init_completion(&pc->pc_finishing);
spin_lock_init(&pc->pc_lock);
strlcpy(pc->pc_name, name, sizeof(pc->pc_name));
pc->pc_set = ptlrpc_prep_set();
if (pc->pc_set == NULL)
GOTO(out, rc = -ENOMEM);
/*
* So far only "client" ptlrpcd uses an environment. In the future,
* ptlrpcd thread (or a thread-set) has to be given an argument,
* describing its "scope".
*/
rc = lu_context_init(&pc->pc_env.le_ctx, LCT_CL_THREAD|LCT_REMEMBER);
if (rc != 0)
GOTO(out_set, rc);
{
struct task_struct *task;
if (index >= 0) {
rc = ptlrpcd_bind(index, max);
if (rc < 0)
GOTO(out_env, rc);
}
task = kthread_run(ptlrpcd, pc, "%s", pc->pc_name);
if (IS_ERR(task))
GOTO(out_env, rc = PTR_ERR(task));
wait_for_completion(&pc->pc_starting);
}
return 0;
out_env:
lu_context_fini(&pc->pc_env.le_ctx);
out_set:
if (pc->pc_set != NULL) {
struct ptlrpc_request_set *set = pc->pc_set;
spin_lock(&pc->pc_lock);
pc->pc_set = NULL;
spin_unlock(&pc->pc_lock);
ptlrpc_set_destroy(set);
}
clear_bit(LIOD_BIND, &pc->pc_flags);
out:
clear_bit(LIOD_START, &pc->pc_flags);
return rc;
}
void ptlrpcd_stop(struct ptlrpcd_ctl *pc, int force)
{
if (!test_bit(LIOD_START, &pc->pc_flags)) {
CWARN("Thread for pc %p was not started\n", pc);
return;
}
set_bit(LIOD_STOP, &pc->pc_flags);
if (force)
set_bit(LIOD_FORCE, &pc->pc_flags);
wake_up(&pc->pc_set->set_waitq);
}
void ptlrpcd_free(struct ptlrpcd_ctl *pc)
{
struct ptlrpc_request_set *set = pc->pc_set;
if (!test_bit(LIOD_START, &pc->pc_flags)) {
CWARN("Thread for pc %p was not started\n", pc);
goto out;
}
wait_for_completion(&pc->pc_finishing);
lu_context_fini(&pc->pc_env.le_ctx);
spin_lock(&pc->pc_lock);
pc->pc_set = NULL;
spin_unlock(&pc->pc_lock);
ptlrpc_set_destroy(set);
clear_bit(LIOD_START, &pc->pc_flags);
clear_bit(LIOD_STOP, &pc->pc_flags);
clear_bit(LIOD_FORCE, &pc->pc_flags);
clear_bit(LIOD_BIND, &pc->pc_flags);
out:
if (pc->pc_npartners > 0) {
LASSERT(pc->pc_partners != NULL);
OBD_FREE(pc->pc_partners,
sizeof(struct ptlrpcd_ctl *) * pc->pc_npartners);
pc->pc_partners = NULL;
}
pc->pc_npartners = 0;
}
static void ptlrpcd_fini(void)
{
int i;
if (ptlrpcds != NULL) {
for (i = 0; i < ptlrpcds->pd_nthreads; i++)
ptlrpcd_stop(&ptlrpcds->pd_threads[i], 0);
for (i = 0; i < ptlrpcds->pd_nthreads; i++)
ptlrpcd_free(&ptlrpcds->pd_threads[i]);
ptlrpcd_stop(&ptlrpcds->pd_thread_rcv, 0);
ptlrpcd_free(&ptlrpcds->pd_thread_rcv);
OBD_FREE(ptlrpcds, ptlrpcds->pd_size);
ptlrpcds = NULL;
}
}
static int ptlrpcd_init(void)
{
int nthreads = num_online_cpus();
char name[16];
int size, i = -1, j, rc = 0;
if (max_ptlrpcds > 0 && max_ptlrpcds < nthreads)
nthreads = max_ptlrpcds;
if (nthreads < 2)
nthreads = 2;
if (nthreads < 3 && ptlrpcd_bind_policy == PDB_POLICY_NEIGHBOR)
ptlrpcd_bind_policy = PDB_POLICY_PAIR;
else if (nthreads % 2 != 0 && ptlrpcd_bind_policy == PDB_POLICY_PAIR)
nthreads &= ~1; /* make sure it is even */
size = offsetof(struct ptlrpcd, pd_threads[nthreads]);
OBD_ALLOC(ptlrpcds, size);
if (ptlrpcds == NULL)
GOTO(out, rc = -ENOMEM);
snprintf(name, sizeof(name), "ptlrpcd_rcv");
set_bit(LIOD_RECOVERY, &ptlrpcds->pd_thread_rcv.pc_flags);
rc = ptlrpcd_start(-1, nthreads, name, &ptlrpcds->pd_thread_rcv);
if (rc < 0)
GOTO(out, rc);
/* XXX: We start nthreads ptlrpc daemons. Each of them can process any
* non-recovery async RPC to improve overall async RPC efficiency.
*
* But there are some issues with async I/O RPCs and async non-I/O
* RPCs processed in the same set under some cases. The ptlrpcd may
* be blocked by some async I/O RPC(s), then will cause other async
* non-I/O RPC(s) can not be processed in time.
*
* Maybe we should distinguish blocked async RPCs from non-blocked
* async RPCs, and process them in different ptlrpcd sets to avoid
* unnecessary dependency. But how to distribute async RPCs load
* among all the ptlrpc daemons becomes another trouble. */
for (i = 0; i < nthreads; i++) {
snprintf(name, sizeof(name), "ptlrpcd_%d", i);
rc = ptlrpcd_start(i, nthreads, name, &ptlrpcds->pd_threads[i]);
if (rc < 0)
GOTO(out, rc);
}
ptlrpcds->pd_size = size;
ptlrpcds->pd_index = 0;
ptlrpcds->pd_nthreads = nthreads;
out:
if (rc != 0 && ptlrpcds != NULL) {
for (j = 0; j <= i; j++)
ptlrpcd_stop(&ptlrpcds->pd_threads[j], 0);
for (j = 0; j <= i; j++)
ptlrpcd_free(&ptlrpcds->pd_threads[j]);
ptlrpcd_stop(&ptlrpcds->pd_thread_rcv, 0);
ptlrpcd_free(&ptlrpcds->pd_thread_rcv);
OBD_FREE(ptlrpcds, size);
ptlrpcds = NULL;
}
return 0;
}
int ptlrpcd_addref(void)
{
int rc = 0;
mutex_lock(&ptlrpcd_mutex);
if (++ptlrpcd_users == 1)
rc = ptlrpcd_init();
mutex_unlock(&ptlrpcd_mutex);
return rc;
}
EXPORT_SYMBOL(ptlrpcd_addref);
void ptlrpcd_decref(void)
{
mutex_lock(&ptlrpcd_mutex);
if (--ptlrpcd_users == 0)
ptlrpcd_fini();
mutex_unlock(&ptlrpcd_mutex);
}
EXPORT_SYMBOL(ptlrpcd_decref);
/** @} ptlrpcd */
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