lustre/ptlrpc/ptlrpcd.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2011, 2015, Intel Corporation.
  27  */
  28 /*
  29  * This file is part of Lustre, http://www.lustre.org/
  30  * Lustre is a trademark of Sun Microsystems, Inc.
  31  *
  32  * lustre/ptlrpc/ptlrpcd.c
  33  */
  34
  35 /** \defgroup ptlrpcd PortalRPC daemon
  36  *
  37  * ptlrpcd is a special thread with its own set where other user might add
  38  * requests when they don't want to wait for their completion.
  39  * PtlRPCD will take care of sending such requests and then processing their
  40  * replies and calling completion callbacks as necessary.
  41  * The callbacks are called directly from ptlrpcd context.
  42  * It is important to never significantly block (esp. on RPCs!) within such
  43  * completion handler or a deadlock might occur where ptlrpcd enters some
  44  * callback that attempts to send another RPC and wait for it to return,
  45  * during which time ptlrpcd is completely blocked, so e.g. if import
  46  * fails, recovery cannot progress because connection requests are also
  47  * sent by ptlrpcd.
  48  *
  49  * @{
  50  */
  51
  52 #define DEBUG_SUBSYSTEM S_RPC
  53
  54 #include <linux/kthread.h>
  55 #include <libcfs/libcfs.h>
  56 #include <lustre_net.h>
  57 #include <lustre_lib.h>
  58 #include <lustre_ha.h>
  59 #include <obd_class.h>   /* for obd_zombie */
  60 #include <obd_support.h> /* for OBD_FAIL_CHECK */
  61 #include <cl_object.h> /* cl_env_{get,put}() */
  62 #include <lprocfs_status.h>
  63
  64 #include "ptlrpc_internal.h"
  65
  66 /* One of these per CPT. */
  67 struct ptlrpcd {
  68         int                     pd_size;
  69         int                     pd_index;
  70         int                     pd_cpt;
  71         int                     pd_cursor;
  72         int                     pd_nthreads;
  73         int                     pd_groupsize;
  74         struct ptlrpcd_ctl      pd_threads[0];
  75 };
  76
  77 /*
  78  * max_ptlrpcds is obsolete, but retained to ensure that the kernel
  79  * module will load on a system where it has been tuned.
  80  * A value other than 0 implies it was tuned, in which case the value
  81  * is used to derive a setting for ptlrpcd_per_cpt_max.
  82  */
  83 static int max_ptlrpcds;
  84 module_param(max_ptlrpcds, int, 0644);
  85 MODULE_PARM_DESC(max_ptlrpcds, "Max ptlrpcd thread count to be started.");
  86
  87 /*
  88  * ptlrpcd_bind_policy is obsolete, but retained to ensure that
  89  * the kernel module will load on a system where it has been tuned.
  90  * A value other than 0 implies it was tuned, in which case the value
  91  * is used to derive a setting for ptlrpcd_partner_group_size.
  92  */
  93 static int ptlrpcd_bind_policy;
  94 module_param(ptlrpcd_bind_policy, int, 0644);
  95 MODULE_PARM_DESC(ptlrpcd_bind_policy,
  96                  "Ptlrpcd threads binding mode (obsolete).");
  97
  98 /*
  99  * ptlrpcd_per_cpt_max: The maximum number of ptlrpcd threads to run
 100  * in a CPT.
 101  */
 102 static int ptlrpcd_per_cpt_max;
 103 MODULE_PARM_DESC(ptlrpcd_per_cpt_max,
 104                  "Max ptlrpcd thread count to be started per cpt.");
 105
 106 /*
 107  * ptlrpcd_partner_group_size: The desired number of threads in each
 108  * ptlrpcd partner thread group. Default is 2, corresponding to the
 109  * old PDB_POLICY_PAIR. A negative value makes all ptlrpcd threads in
 110  * a CPT partners of each other.
 111  */
 112 static int ptlrpcd_partner_group_size;
 113 module_param(ptlrpcd_partner_group_size, int, 0644);
 114 MODULE_PARM_DESC(ptlrpcd_partner_group_size,
 115                  "Number of ptlrpcd threads in a partner group.");
 116
 117 /*
 118  * ptlrpcd_cpts: A CPT string describing the CPU partitions that
 119  * ptlrpcd threads should run on. Used to make ptlrpcd threads run on
 120  * a subset of all CPTs.
 121  *
 122  * ptlrpcd_cpts=2
 123  * ptlrpcd_cpts=[2]
 124  *   run ptlrpcd threads only on CPT 2.
 125  *
 126  * ptlrpcd_cpts=0-3
 127  * ptlrpcd_cpts=[0-3]
 128  *   run ptlrpcd threads on CPTs 0, 1, 2, and 3.
 129  *
 130  * ptlrpcd_cpts=[0-3,5,7]
 131  *   run ptlrpcd threads on CPTS 0, 1, 2, 3, 5, and 7.
 132  */
 133 static char *ptlrpcd_cpts;
 134 module_param(ptlrpcd_cpts, charp, 0644);
 135 MODULE_PARM_DESC(ptlrpcd_cpts,
 136                  "CPU partitions ptlrpcd threads should run in");
 137
 138 /* ptlrpcds_cpt_idx maps cpt numbers to an index in the ptlrpcds array. */
 139 static int              *ptlrpcds_cpt_idx;
 140
 141 /* ptlrpcds_num is the number of entries in the ptlrpcds array. */
 142 static int              ptlrpcds_num;
 143 static struct ptlrpcd   **ptlrpcds;
 144
 145 /*
 146  * In addition to the regular thread pool above, there is a single
 147  * global recovery thread. Recovery isn't critical for performance,
 148  * and doesn't block, but must always be able to proceed, and it is
 149  * possible that all normal ptlrpcd threads are blocked. Hence the
 150  * need for a dedicated thread.
 151  */
 152 static struct ptlrpcd_ctl ptlrpcd_rcv;
 153
 154 struct mutex ptlrpcd_mutex;
 155 static int ptlrpcd_users = 0;
 156
 157 void ptlrpcd_wake(struct ptlrpc_request *req)
 158 {
 159         struct ptlrpc_request_set *set = req->rq_set;
 160
 161         LASSERT(set != NULL);
 162         wake_up(&set->set_waitq);
 163 }
 164 EXPORT_SYMBOL(ptlrpcd_wake);
 165
 166 static struct ptlrpcd_ctl *
 167 ptlrpcd_select_pc(struct ptlrpc_request *req)
 168 {
 169         struct ptlrpcd  *pd;
 170         int             cpt;
 171         int             idx;
 172
 173         if (req != NULL && req->rq_send_state != LUSTRE_IMP_FULL)
 174                 return &ptlrpcd_rcv;
 175
 176         cpt = cfs_cpt_current(cfs_cpt_table, 1);
 177         if (ptlrpcds_cpt_idx == NULL)
 178                 idx = cpt;
 179         else
 180                 idx = ptlrpcds_cpt_idx[cpt];
 181         pd = ptlrpcds[idx];
 182
 183         /* We do not care whether it is strict load balance. */
 184         idx = pd->pd_cursor;
 185         if (++idx == pd->pd_nthreads)
 186                 idx = 0;
 187         pd->pd_cursor = idx;
 188
 189         return &pd->pd_threads[idx];
 190 }
 191
 192 /**
 193  * Move all request from an existing request set to the ptlrpcd queue.
 194  * All requests from the set must be in phase RQ_PHASE_NEW.
 195  */
 196 void ptlrpcd_add_rqset(struct ptlrpc_request_set *set)
 197 {
 198         struct list_head *tmp, *pos;
 199         struct ptlrpcd_ctl *pc;
 200         struct ptlrpc_request_set *new;
 201         int count, i;
 202
 203         pc = ptlrpcd_select_pc(NULL);
 204         new = pc->pc_set;
 205
 206         list_for_each_safe(pos, tmp, &set->set_requests) {
 207                 struct ptlrpc_request *req =
 208                         list_entry(pos, struct ptlrpc_request,
 209                                    rq_set_chain);
 210
 211                 LASSERT(req->rq_phase == RQ_PHASE_NEW);
 212                 req->rq_set = new;
 213                 req->rq_queued_time = cfs_time_current();
 214         }
 215
 216         spin_lock(&new->set_new_req_lock);
 217         list_splice_init(&set->set_requests, &new->set_new_requests);
 218         i = atomic_read(&set->set_remaining);
 219         count = atomic_add_return(i, &new->set_new_count);
 220         atomic_set(&set->set_remaining, 0);
 221         spin_unlock(&new->set_new_req_lock);
 222         if (count == i) {
 223                 wake_up(&new->set_waitq);
 224
 225                 /* XXX: It maybe unnecessary to wakeup all the partners. But to
 226                  *      guarantee the async RPC can be processed ASAP, we have
 227                  *      no other better choice. It maybe fixed in future. */
 228                 for (i = 0; i < pc->pc_npartners; i++)
 229                         wake_up(&pc->pc_partners[i]->pc_set->set_waitq);
 230         }
 231 }
 232
 233 /**
 234  * Return transferred RPCs count.
 235  */
 236 static int ptlrpcd_steal_rqset(struct ptlrpc_request_set *des,
 237                                struct ptlrpc_request_set *src)
 238 {
 239         struct list_head *tmp, *pos;
 240         struct ptlrpc_request *req;
 241         int rc = 0;
 242
 243         spin_lock(&src->set_new_req_lock);
 244         if (likely(!list_empty(&src->set_new_requests))) {
 245                 list_for_each_safe(pos, tmp, &src->set_new_requests) {
 246                         req = list_entry(pos, struct ptlrpc_request,
 247                                          rq_set_chain);
 248                         req->rq_set = des;
 249                 }
 250                 list_splice_init(&src->set_new_requests,
 251                                  &des->set_requests);
 252                 rc = atomic_read(&src->set_new_count);
 253                 atomic_add(rc, &des->set_remaining);
 254                 atomic_set(&src->set_new_count, 0);
 255         }
 256         spin_unlock(&src->set_new_req_lock);
 257         return rc;
 258 }
 259
 260 /**
 261  * Requests that are added to the ptlrpcd queue are sent via
 262  * ptlrpcd_check->ptlrpc_check_set().
 263  */
 264 void ptlrpcd_add_req(struct ptlrpc_request *req)
 265 {
 266         struct ptlrpcd_ctl *pc;
 267
 268         if (req->rq_reqmsg)
 269                 lustre_msg_set_jobid(req->rq_reqmsg, NULL);
 270
 271         spin_lock(&req->rq_lock);
 272         if (req->rq_invalid_rqset) {
 273                 struct l_wait_info lwi = LWI_TIMEOUT(cfs_time_seconds(5),
 274                                                      back_to_sleep, NULL);
 275
 276                 req->rq_invalid_rqset = 0;
 277                 spin_unlock(&req->rq_lock);
 278                 l_wait_event(req->rq_set_waitq, (req->rq_set == NULL), &lwi);
 279         } else if (req->rq_set) {
 280                 /* If we have a vaid "rq_set", just reuse it to avoid double
 281                  * linked. */
 282                 LASSERT(req->rq_phase == RQ_PHASE_NEW);
 283                 LASSERT(req->rq_send_state == LUSTRE_IMP_REPLAY);
 284
 285                 /* ptlrpc_check_set will decrease the count */
 286                 atomic_inc(&req->rq_set->set_remaining);
 287                 spin_unlock(&req->rq_lock);
 288                 wake_up(&req->rq_set->set_waitq);
 289                 return;
 290         } else {
 291                 spin_unlock(&req->rq_lock);
 292         }
 293
 294         pc = ptlrpcd_select_pc(req);
 295
 296         DEBUG_REQ(D_INFO, req, "add req [%p] to pc [%s:%d]",
 297                   req, pc->pc_name, pc->pc_index);
 298
 299         ptlrpc_set_add_new_req(pc, req);
 300 }
 301 EXPORT_SYMBOL(ptlrpcd_add_req);
 302
 303 static inline void ptlrpc_reqset_get(struct ptlrpc_request_set *set)
 304 {
 305         atomic_inc(&set->set_refcount);
 306 }
 307
 308 /**
 309  * Check if there is more work to do on ptlrpcd set.
 310  * Returns 1 if yes.
 311  */
 312 static int ptlrpcd_check(struct lu_env *env, struct ptlrpcd_ctl *pc)
 313 {
 314         struct list_head *tmp, *pos;
 315         struct ptlrpc_request *req;
 316         struct ptlrpc_request_set *set = pc->pc_set;
 317         int rc = 0;
 318         int rc2;
 319         ENTRY;
 320
 321         if (atomic_read(&set->set_new_count)) {
 322                 spin_lock(&set->set_new_req_lock);
 323                 if (likely(!list_empty(&set->set_new_requests))) {
 324                         list_splice_init(&set->set_new_requests,
 325                                              &set->set_requests);
 326                         atomic_add(atomic_read(&set->set_new_count),
 327                                    &set->set_remaining);
 328                         atomic_set(&set->set_new_count, 0);
 329                         /*
 330                          * Need to calculate its timeout.
 331                          */
 332                         rc = 1;
 333                 }
 334                 spin_unlock(&set->set_new_req_lock);
 335         }
 336
 337         /* We should call lu_env_refill() before handling new requests to make
 338          * sure that env key the requests depending on really exists.
 339          */
 340         rc2 = lu_env_refill(env);
 341         if (rc2 != 0) {
 342                 /*
 343                  * XXX This is very awkward situation, because
 344                  * execution can neither continue (request
 345                  * interpreters assume that env is set up), nor repeat
 346                  * the loop (as this potentially results in a tight
 347                  * loop of -ENOMEM's).
 348                  *
 349                  * Fortunately, refill only ever does something when
 350                  * new modules are loaded, i.e., early during boot up.
 351                  */
 352                 CERROR("Failure to refill session: %d\n", rc2);
 353                 RETURN(rc);
 354         }
 355
 356         if (atomic_read(&set->set_remaining))
 357                 rc |= ptlrpc_check_set(env, set);
 358
 359         /* NB: ptlrpc_check_set has already moved complted request at the
 360          * head of seq::set_requests */
 361         list_for_each_safe(pos, tmp, &set->set_requests) {
 362                 req = list_entry(pos, struct ptlrpc_request, rq_set_chain);
 363                 if (req->rq_phase != RQ_PHASE_COMPLETE)
 364                         break;
 365
 366                 list_del_init(&req->rq_set_chain);
 367                 req->rq_set = NULL;
 368                 ptlrpc_req_finished(req);
 369         }
 370
 371         if (rc == 0) {
 372                 /*
 373                  * If new requests have been added, make sure to wake up.
 374                  */
 375                 rc = atomic_read(&set->set_new_count);
 376
 377                 /* If we have nothing to do, check whether we can take some
 378                  * work from our partner threads. */
 379                 if (rc == 0 && pc->pc_npartners > 0) {
 380                         struct ptlrpcd_ctl *partner;
 381                         struct ptlrpc_request_set *ps;
 382                         int first = pc->pc_cursor;
 383
 384                         do {
 385                                 partner = pc->pc_partners[pc->pc_cursor++];
 386                                 if (pc->pc_cursor >= pc->pc_npartners)
 387                                         pc->pc_cursor = 0;
 388                                 if (partner == NULL)
 389                                         continue;
 390
 391                                 spin_lock(&partner->pc_lock);
 392                                 ps = partner->pc_set;
 393                                 if (ps == NULL) {
 394                                         spin_unlock(&partner->pc_lock);
 395                                         continue;
 396                                 }
 397
 398                                 ptlrpc_reqset_get(ps);
 399                                 spin_unlock(&partner->pc_lock);
 400
 401                                 if (atomic_read(&ps->set_new_count)) {
 402                                         rc = ptlrpcd_steal_rqset(set, ps);
 403                                         if (rc > 0)
 404                                                 CDEBUG(D_RPCTRACE, "transfer %d"
 405                                                        " async RPCs [%d->%d]\n",
 406                                                        rc, partner->pc_index,
 407                                                        pc->pc_index);
 408                                 }
 409                                 ptlrpc_reqset_put(ps);
 410                         } while (rc == 0 && pc->pc_cursor != first);
 411                 }
 412         }
 413
 414         RETURN(rc);
 415 }
 416
 417 /**
 418  * Main ptlrpcd thread.
 419  * ptlrpc's code paths like to execute in process context, so we have this
 420  * thread which spins on a set which contains the rpcs and sends them.
 421  *
 422  */
 423 static int ptlrpcd(void *arg)
 424 {
 425         struct ptlrpcd_ctl              *pc = arg;
 426         struct ptlrpc_request_set       *set;
 427         struct lu_context               ses = { 0 };
 428         struct lu_env                   env = { .le_ses = &ses };
 429         int                             rc = 0;
 430         int                             exit = 0;
 431         ENTRY;
 432
 433         unshare_fs_struct();
 434
 435         if (cfs_cpt_bind(cfs_cpt_table, pc->pc_cpt) != 0)
 436                 CWARN("Failed to bind %s on CPT %d\n", pc->pc_name, pc->pc_cpt);
 437
 438         /*
 439          * Allocate the request set after the thread has been bound
 440          * above. This is safe because no requests will be queued
 441          * until all ptlrpcd threads have confirmed that they have
 442          * successfully started.
 443          */
 444         set = ptlrpc_prep_set();
 445         if (set == NULL)
 446                 GOTO(failed, rc = -ENOMEM);
 447         spin_lock(&pc->pc_lock);
 448         pc->pc_set = set;
 449         spin_unlock(&pc->pc_lock);
 450
 451         /* Both client and server (MDT/OST) may use the environment. */
 452         rc = lu_context_init(&env.le_ctx, LCT_MD_THREAD |
 453                                           LCT_DT_THREAD |
 454                                           LCT_CL_THREAD |
 455                                           LCT_REMEMBER  |
 456                                           LCT_NOREF);
 457         if (rc != 0)
 458                 GOTO(failed, rc);
 459         rc = lu_context_init(env.le_ses, LCT_SESSION  |
 460                                          LCT_REMEMBER |
 461                                          LCT_NOREF);
 462         if (rc != 0) {
 463                 lu_context_fini(&env.le_ctx);
 464                 GOTO(failed, rc);
 465         }
 466
 467         complete(&pc->pc_starting);
 468
 469         /*
 470          * This mainloop strongly resembles ptlrpc_set_wait() except that our
 471          * set never completes.  ptlrpcd_check() calls ptlrpc_check_set() when
 472          * there are requests in the set. New requests come in on the set's
 473          * new_req_list and ptlrpcd_check() moves them into the set.
 474          */
 475         do {
 476                 struct l_wait_info lwi;
 477                 int timeout;
 478
 479                 timeout = ptlrpc_set_next_timeout(set);
 480                 lwi = LWI_TIMEOUT(cfs_time_seconds(timeout ? timeout : 1),
 481                                   ptlrpc_expired_set, set);
 482
 483                 lu_context_enter(&env.le_ctx);
 484                 lu_context_enter(env.le_ses);
 485                 l_wait_event(set->set_waitq, ptlrpcd_check(&env, pc), &lwi);
 486                 lu_context_exit(&env.le_ctx);
 487                 lu_context_exit(env.le_ses);
 488
 489                 /*
 490                  * Abort inflight rpcs for forced stop case.
 491                  */
 492                 if (test_bit(LIOD_STOP, &pc->pc_flags)) {
 493                         if (test_bit(LIOD_FORCE, &pc->pc_flags))
 494                                 ptlrpc_abort_set(set);
 495                         exit++;
 496                 }
 497
 498                 /*
 499                  * Let's make one more loop to make sure that ptlrpcd_check()
 500                  * copied all raced new rpcs into the set so we can kill them.
 501                  */
 502         } while (exit < 2);
 503
 504         /*
 505          * Wait for inflight requests to drain.
 506          */
 507         if (!list_empty(&set->set_requests))
 508                 ptlrpc_set_wait(set);
 509         lu_context_fini(&env.le_ctx);
 510         lu_context_fini(env.le_ses);
 511
 512         complete(&pc->pc_finishing);
 513
 514         return 0;
 515
 516 failed:
 517         pc->pc_error = rc;
 518         complete(&pc->pc_starting);
 519         RETURN(rc);
 520 }
 521
 522 static void ptlrpcd_ctl_init(struct ptlrpcd_ctl *pc, int index, int cpt)
 523 {
 524         ENTRY;
 525
 526         pc->pc_index = index;
 527         pc->pc_cpt = cpt;
 528         init_completion(&pc->pc_starting);
 529         init_completion(&pc->pc_finishing);
 530         spin_lock_init(&pc->pc_lock);
 531
 532         if (index < 0) {
 533                 /* Recovery thread. */
 534                 snprintf(pc->pc_name, sizeof(pc->pc_name), "ptlrpcd_rcv");
 535         } else {
 536                 /* Regular thread. */
 537                 snprintf(pc->pc_name, sizeof(pc->pc_name),
 538                          "ptlrpcd_%02d_%02d", cpt, index);
 539         }
 540
 541         EXIT;
 542 }
 543
 544 /* XXX: We want multiple CPU cores to share the async RPC load. So we
 545  *      start many ptlrpcd threads. We also want to reduce the ptlrpcd
 546  *      overhead caused by data transfer cross-CPU cores. So we bind
 547  *      all ptlrpcd threads to a CPT, in the expectation that CPTs
 548  *      will be defined in a way that matches these boundaries. Within
 549  *      a CPT a ptlrpcd thread can be scheduled on any available core.
 550  *
 551  *      Each ptlrpcd thread has its own request queue. This can cause
 552  *      response delay if the thread is already busy. To help with
 553  *      this we define partner threads: these are other threads bound
 554  *      to the same CPT which will check for work in each other's
 555  *      request queues if they have no work to do.
 556  *
 557  *      The desired number of partner threads can be tuned by setting
 558  *      ptlrpcd_partner_group_size. The default is to create pairs of
 559  *      partner threads.
 560  */
 561 static int ptlrpcd_partners(struct ptlrpcd *pd, int index)
 562 {
 563         struct ptlrpcd_ctl      *pc;
 564         struct ptlrpcd_ctl      **ppc;
 565         int                     first;
 566         int                     i;
 567         int                     rc = 0;
 568         ENTRY;
 569
 570         LASSERT(index >= 0 && index < pd->pd_nthreads);
 571         pc = &pd->pd_threads[index];
 572         pc->pc_npartners = pd->pd_groupsize - 1;
 573
 574         if (pc->pc_npartners <= 0)
 575                 GOTO(out, rc);
 576
 577         OBD_CPT_ALLOC(pc->pc_partners, cfs_cpt_table, pc->pc_cpt,
 578                       sizeof(struct ptlrpcd_ctl *) * pc->pc_npartners);
 579         if (pc->pc_partners == NULL) {
 580                 pc->pc_npartners = 0;
 581                 GOTO(out, rc = -ENOMEM);
 582         }
 583
 584         first = index - index % pd->pd_groupsize;
 585         ppc = pc->pc_partners;
 586         for (i = first; i < first + pd->pd_groupsize; i++) {
 587                 if (i != index)
 588                         *ppc++ = &pd->pd_threads[i];
 589         }
 590 out:
 591         RETURN(rc);
 592 }
 593
 594 int ptlrpcd_start(struct ptlrpcd_ctl *pc)
 595 {
 596         struct task_struct      *task;
 597         int                     rc = 0;
 598         ENTRY;
 599
 600         /*
 601          * Do not allow starting a second thread for one pc.
 602          */
 603         if (test_and_set_bit(LIOD_START, &pc->pc_flags)) {
 604                 CWARN("Starting second thread (%s) for same pc %p\n",
 605                       pc->pc_name, pc);
 606                 RETURN(0);
 607         }
 608
 609         task = kthread_run(ptlrpcd, pc, pc->pc_name);
 610         if (IS_ERR(task))
 611                 GOTO(out_set, rc = PTR_ERR(task));
 612
 613         wait_for_completion(&pc->pc_starting);
 614         rc = pc->pc_error;
 615         if (rc != 0)
 616                 GOTO(out_set, rc);
 617
 618         RETURN(0);
 619
 620 out_set:
 621         if (pc->pc_set != NULL) {
 622                 struct ptlrpc_request_set *set = pc->pc_set;
 623
 624                 spin_lock(&pc->pc_lock);
 625                 pc->pc_set = NULL;
 626                 spin_unlock(&pc->pc_lock);
 627                 ptlrpc_set_destroy(set);
 628         }
 629         clear_bit(LIOD_START, &pc->pc_flags);
 630         RETURN(rc);
 631 }
 632
 633 void ptlrpcd_stop(struct ptlrpcd_ctl *pc, int force)
 634 {
 635         ENTRY;
 636
 637         if (!test_bit(LIOD_START, &pc->pc_flags)) {
 638                 CWARN("Thread for pc %p was not started\n", pc);
 639                 goto out;
 640         }
 641
 642         set_bit(LIOD_STOP, &pc->pc_flags);
 643         if (force)
 644                 set_bit(LIOD_FORCE, &pc->pc_flags);
 645         wake_up(&pc->pc_set->set_waitq);
 646
 647 out:
 648         EXIT;
 649 }
 650
 651 void ptlrpcd_free(struct ptlrpcd_ctl *pc)
 652 {
 653         struct ptlrpc_request_set *set = pc->pc_set;
 654         ENTRY;
 655
 656         if (!test_bit(LIOD_START, &pc->pc_flags)) {
 657                 CWARN("Thread for pc %p was not started\n", pc);
 658                 goto out;
 659         }
 660
 661         wait_for_completion(&pc->pc_finishing);
 662
 663         spin_lock(&pc->pc_lock);
 664         pc->pc_set = NULL;
 665         spin_unlock(&pc->pc_lock);
 666         ptlrpc_set_destroy(set);
 667
 668         clear_bit(LIOD_START, &pc->pc_flags);
 669         clear_bit(LIOD_STOP, &pc->pc_flags);
 670         clear_bit(LIOD_FORCE, &pc->pc_flags);
 671
 672 out:
 673         if (pc->pc_npartners > 0) {
 674                 LASSERT(pc->pc_partners != NULL);
 675
 676                 OBD_FREE(pc->pc_partners,
 677                          sizeof(struct ptlrpcd_ctl *) * pc->pc_npartners);
 678                 pc->pc_partners = NULL;
 679         }
 680         pc->pc_npartners = 0;
 681         pc->pc_error = 0;
 682         EXIT;
 683 }
 684
 685 static void ptlrpcd_fini(void)
 686 {
 687         int     i;
 688         int     j;
 689         int     ncpts;
 690         ENTRY;
 691
 692         if (ptlrpcds != NULL) {
 693                 for (i = 0; i < ptlrpcds_num; i++) {
 694                         if (ptlrpcds[i] == NULL)
 695                                 break;
 696                         for (j = 0; j < ptlrpcds[i]->pd_nthreads; j++)
 697                                 ptlrpcd_stop(&ptlrpcds[i]->pd_threads[j], 0);
 698                         for (j = 0; j < ptlrpcds[i]->pd_nthreads; j++)
 699                                 ptlrpcd_free(&ptlrpcds[i]->pd_threads[j]);
 700                         OBD_FREE(ptlrpcds[i], ptlrpcds[i]->pd_size);
 701                         ptlrpcds[i] = NULL;
 702                 }
 703                 OBD_FREE(ptlrpcds, sizeof(ptlrpcds[0]) * ptlrpcds_num);
 704         }
 705         ptlrpcds_num = 0;
 706
 707         ptlrpcd_stop(&ptlrpcd_rcv, 0);
 708         ptlrpcd_free(&ptlrpcd_rcv);
 709
 710         if (ptlrpcds_cpt_idx != NULL) {
 711                 ncpts = cfs_cpt_number(cfs_cpt_table);
 712                 OBD_FREE(ptlrpcds_cpt_idx, ncpts * sizeof(ptlrpcds_cpt_idx[0]));
 713                 ptlrpcds_cpt_idx = NULL;
 714         }
 715
 716         EXIT;
 717 }
 718
 719 static int ptlrpcd_init(void)
 720 {
 721         int                     nthreads;
 722         int                     groupsize;
 723         int                     size;
 724         int                     i;
 725         int                     j;
 726         int                     rc = 0;
 727         struct cfs_cpt_table    *cptable;
 728         __u32                   *cpts = NULL;
 729         int                     ncpts;
 730         int                     cpt;
 731         struct ptlrpcd          *pd;
 732         ENTRY;
 733
 734         /*
 735          * Determine the CPTs that ptlrpcd threads will run on.
 736          */
 737         cptable = cfs_cpt_table;
 738         ncpts = cfs_cpt_number(cptable);
 739         if (ptlrpcd_cpts != NULL) {
 740                 struct cfs_expr_list    *el;
 741
 742                 size = ncpts * sizeof(ptlrpcds_cpt_idx[0]);
 743                 OBD_ALLOC(ptlrpcds_cpt_idx, size);
 744                 if (ptlrpcds_cpt_idx == NULL)
 745                         GOTO(out, rc = -ENOMEM);
 746
 747                 rc = cfs_expr_list_parse(ptlrpcd_cpts,
 748                                          strlen(ptlrpcd_cpts),
 749                                          0, ncpts - 1, &el);
 750                 if (rc != 0) {
 751                         CERROR("%s: invalid CPT pattern string: %s",
 752                                "ptlrpcd_cpts", ptlrpcd_cpts);
 753                         GOTO(out, rc = -EINVAL);
 754                 }
 755
 756                 rc = cfs_expr_list_values(el, ncpts, &cpts);
 757                 cfs_expr_list_free(el);
 758                 if (rc <= 0) {
 759                         CERROR("%s: failed to parse CPT array %s: %d\n",
 760                                "ptlrpcd_cpts", ptlrpcd_cpts, rc);
 761                         if (rc == 0)
 762                                 rc = -EINVAL;
 763                         GOTO(out, rc);
 764                 }
 765
 766                 /*
 767                  * Create the cpt-to-index map. When there is no match
 768                  * in the cpt table, pick a cpt at random. This could
 769                  * be changed to take the topology of the system into
 770                  * account.
 771                  */
 772                 for (cpt = 0; cpt < ncpts; cpt++) {
 773                         for (i = 0; i < rc; i++)
 774                                 if (cpts[i] == cpt)
 775                                         break;
 776                         if (i >= rc)
 777                                 i = cpt % rc;
 778                         ptlrpcds_cpt_idx[cpt] = i;
 779                 }
 780
 781                 cfs_expr_list_values_free(cpts, rc);
 782                 ncpts = rc;
 783         }
 784         ptlrpcds_num = ncpts;
 785
 786         size = ncpts * sizeof(ptlrpcds[0]);
 787         OBD_ALLOC(ptlrpcds, size);
 788         if (ptlrpcds == NULL)
 789                 GOTO(out, rc = -ENOMEM);
 790
 791         /*
 792          * The max_ptlrpcds parameter is obsolete, but do something
 793          * sane if it has been tuned, and complain if
 794          * ptlrpcd_per_cpt_max has also been tuned.
 795          */
 796         if (max_ptlrpcds != 0) {
 797                 CWARN("max_ptlrpcds is obsolete.\n");
 798                 if (ptlrpcd_per_cpt_max == 0) {
 799                         ptlrpcd_per_cpt_max = max_ptlrpcds / ncpts;
 800                         /* Round up if there is a remainder. */
 801                         if (max_ptlrpcds % ncpts != 0)
 802                                 ptlrpcd_per_cpt_max++;
 803                         CWARN("Setting ptlrpcd_per_cpt_max = %d\n",
 804                               ptlrpcd_per_cpt_max);
 805                 } else {
 806                         CWARN("ptlrpd_per_cpt_max is also set!\n");
 807                 }
 808         }
 809
 810         /*
 811          * The ptlrpcd_bind_policy parameter is obsolete, but do
 812          * something sane if it has been tuned, and complain if
 813          * ptlrpcd_partner_group_size is also tuned.
 814          */
 815         if (ptlrpcd_bind_policy != 0) {
 816                 CWARN("ptlrpcd_bind_policy is obsolete.\n");
 817                 if (ptlrpcd_partner_group_size == 0) {
 818                         switch (ptlrpcd_bind_policy) {
 819                         case 1: /* PDB_POLICY_NONE */
 820                         case 2: /* PDB_POLICY_FULL */
 821                                 ptlrpcd_partner_group_size = 1;
 822                                 break;
 823                         case 3: /* PDB_POLICY_PAIR */
 824                                 ptlrpcd_partner_group_size = 2;
 825                                 break;
 826                         case 4: /* PDB_POLICY_NEIGHBOR */
 827 #ifdef CONFIG_NUMA
 828                                 ptlrpcd_partner_group_size = -1; /* CPT */
 829 #else
 830                                 ptlrpcd_partner_group_size = 3; /* Triplets */
 831 #endif
 832                                 break;
 833                         default: /* Illegal value, use the default. */
 834                                 ptlrpcd_partner_group_size = 2;
 835                                 break;
 836                         }
 837                         CWARN("Setting ptlrpcd_partner_group_size = %d\n",
 838                               ptlrpcd_partner_group_size);
 839                 } else {
 840                         CWARN("ptlrpcd_partner_group_size is also set!\n");
 841                 }
 842         }
 843
 844         if (ptlrpcd_partner_group_size == 0)
 845                 ptlrpcd_partner_group_size = 2;
 846         else if (ptlrpcd_partner_group_size < 0)
 847                 ptlrpcd_partner_group_size = -1;
 848         else if (ptlrpcd_per_cpt_max > 0 &&
 849                  ptlrpcd_partner_group_size > ptlrpcd_per_cpt_max)
 850                 ptlrpcd_partner_group_size = ptlrpcd_per_cpt_max;
 851
 852         /*
 853          * Start the recovery thread first.
 854          */
 855         set_bit(LIOD_RECOVERY, &ptlrpcd_rcv.pc_flags);
 856         ptlrpcd_ctl_init(&ptlrpcd_rcv, -1, CFS_CPT_ANY);
 857         rc = ptlrpcd_start(&ptlrpcd_rcv);
 858         if (rc < 0)
 859                 GOTO(out, rc);
 860
 861         for (i = 0; i < ncpts; i++) {
 862                 if (cpts == NULL)
 863                         cpt = i;
 864                 else
 865                         cpt = cpts[i];
 866
 867                 nthreads = cfs_cpt_weight(cptable, cpt);
 868                 if (ptlrpcd_per_cpt_max > 0 && ptlrpcd_per_cpt_max < nthreads)
 869                         nthreads = ptlrpcd_per_cpt_max;
 870                 if (nthreads < 2)
 871                         nthreads = 2;
 872
 873                 if (ptlrpcd_partner_group_size <= 0) {
 874                         groupsize = nthreads;
 875                 } else if (nthreads <= ptlrpcd_partner_group_size) {
 876                         groupsize = nthreads;
 877                 } else {
 878                         groupsize = ptlrpcd_partner_group_size;
 879                         if (nthreads % groupsize != 0)
 880                                 nthreads += groupsize - (nthreads % groupsize);
 881                 }
 882
 883                 size = offsetof(struct ptlrpcd, pd_threads[nthreads]);
 884                 OBD_CPT_ALLOC(pd, cptable, cpt, size);
 885                 if (!pd)
 886                         GOTO(out, rc = -ENOMEM);
 887                 pd->pd_size      = size;
 888                 pd->pd_index     = i;
 889                 pd->pd_cpt       = cpt;
 890                 pd->pd_cursor    = 0;
 891                 pd->pd_nthreads  = nthreads;
 892                 pd->pd_groupsize = groupsize;
 893                 ptlrpcds[i] = pd;
 894
 895                 /*
 896                  * The ptlrpcd threads in a partner group can access
 897                  * each other's struct ptlrpcd_ctl, so these must be
 898                  * initialized before any thead is started.
 899                  */
 900                 for (j = 0; j < nthreads; j++) {
 901                         ptlrpcd_ctl_init(&pd->pd_threads[j], j, cpt);
 902                         rc = ptlrpcd_partners(pd, j);
 903                         if (rc < 0)
 904                                 GOTO(out, rc);
 905                 }
 906
 907                 /* XXX: We start nthreads ptlrpc daemons on this cpt.
 908                  *      Each of them can process any non-recovery
 909                  *      async RPC to improve overall async RPC
 910                  *      efficiency.
 911                  *
 912                  *      But there are some issues with async I/O RPCs
 913                  *      and async non-I/O RPCs processed in the same
 914                  *      set under some cases. The ptlrpcd may be
 915                  *      blocked by some async I/O RPC(s), then will
 916                  *      cause other async non-I/O RPC(s) can not be
 917                  *      processed in time.
 918                  *
 919                  *      Maybe we should distinguish blocked async RPCs
 920                  *      from non-blocked async RPCs, and process them
 921                  *      in different ptlrpcd sets to avoid unnecessary
 922                  *      dependency. But how to distribute async RPCs
 923                  *      load among all the ptlrpc daemons becomes
 924                  *      another trouble.
 925                  */
 926                 for (j = 0; j < nthreads; j++) {
 927                         rc = ptlrpcd_start(&pd->pd_threads[j]);
 928                         if (rc < 0)
 929                                 GOTO(out, rc);
 930                 }
 931         }
 932 out:
 933         if (rc != 0)
 934                 ptlrpcd_fini();
 935
 936         RETURN(rc);
 937 }
 938
 939 int ptlrpcd_addref(void)
 940 {
 941         int rc = 0;
 942         ENTRY;
 943
 944         mutex_lock(&ptlrpcd_mutex);
 945         if (++ptlrpcd_users == 1) {
 946                 rc = ptlrpcd_init();
 947                 if (rc < 0)
 948                         ptlrpcd_users--;
 949         }
 950         mutex_unlock(&ptlrpcd_mutex);
 951         RETURN(rc);
 952 }
 953 EXPORT_SYMBOL(ptlrpcd_addref);
 954
 955 void ptlrpcd_decref(void)
 956 {
 957         mutex_lock(&ptlrpcd_mutex);
 958         if (--ptlrpcd_users == 0)
 959                 ptlrpcd_fini();
 960         mutex_unlock(&ptlrpcd_mutex);
 961 }
 962 EXPORT_SYMBOL(ptlrpcd_decref);
 963 /** @} ptlrpcd */