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, 2017, 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,
  86                  "Max ptlrpcd thread count to be started (obsolete).");
  87
  88 /*
  89  * ptlrpcd_bind_policy is obsolete, but retained to ensure that
  90  * the kernel module will load on a system where it has been tuned.
  91  * A value other than 0 implies it was tuned, in which case the value
  92  * is used to derive a setting for ptlrpcd_partner_group_size.
  93  */
  94 static int ptlrpcd_bind_policy;
  95 module_param(ptlrpcd_bind_policy, int, 0644);
  96 MODULE_PARM_DESC(ptlrpcd_bind_policy,
  97                  "Ptlrpcd threads binding mode (obsolete).");
  98
  99 /*
 100  * ptlrpcd_per_cpt_max: The maximum number of ptlrpcd threads to run
 101  * in a CPT.
 102  */
 103 static int ptlrpcd_per_cpt_max;
 104 module_param(ptlrpcd_per_cpt_max, int, 0644);
 105 MODULE_PARM_DESC(ptlrpcd_per_cpt_max,
 106                  "Max ptlrpcd thread count to be started per CPT.");
 107
 108 /*
 109  * ptlrpcd_partner_group_size: The desired number of threads in each
 110  * ptlrpcd partner thread group. Default is 2, corresponding to the
 111  * old PDB_POLICY_PAIR. A negative value makes all ptlrpcd threads in
 112  * a CPT partners of each other.
 113  */
 114 static int ptlrpcd_partner_group_size;
 115 module_param(ptlrpcd_partner_group_size, int, 0644);
 116 MODULE_PARM_DESC(ptlrpcd_partner_group_size,
 117                  "Number of ptlrpcd threads in a partner group.");
 118
 119 /*
 120  * ptlrpcd_cpts: A CPT string describing the CPU partitions that
 121  * ptlrpcd threads should run on. Used to make ptlrpcd threads run on
 122  * a subset of all CPTs.
 123  *
 124  * ptlrpcd_cpts=2
 125  * ptlrpcd_cpts=[2]
 126  *   run ptlrpcd threads only on CPT 2.
 127  *
 128  * ptlrpcd_cpts=0-3
 129  * ptlrpcd_cpts=[0-3]
 130  *   run ptlrpcd threads on CPTs 0, 1, 2, and 3.
 131  *
 132  * ptlrpcd_cpts=[0-3,5,7]
 133  *   run ptlrpcd threads on CPTS 0, 1, 2, 3, 5, and 7.
 134  */
 135 static char *ptlrpcd_cpts;
 136 module_param(ptlrpcd_cpts, charp, 0644);
 137 MODULE_PARM_DESC(ptlrpcd_cpts,
 138                  "CPU partitions ptlrpcd threads should run in");
 139
 140 /* ptlrpcds_cpt_idx maps cpt numbers to an index in the ptlrpcds array. */
 141 static int              *ptlrpcds_cpt_idx;
 142
 143 /* ptlrpcds_num is the number of entries in the ptlrpcds array. */
 144 static int              ptlrpcds_num;
 145 static struct ptlrpcd   **ptlrpcds;
 146
 147 /*
 148  * In addition to the regular thread pool above, there is a single
 149  * global recovery thread. Recovery isn't critical for performance,
 150  * and doesn't block, but must always be able to proceed, and it is
 151  * possible that all normal ptlrpcd threads are blocked. Hence the
 152  * need for a dedicated thread.
 153  */
 154 static struct ptlrpcd_ctl ptlrpcd_rcv;
 155
 156 struct mutex ptlrpcd_mutex;
 157 static int ptlrpcd_users = 0;
 158
 159 void ptlrpcd_wake(struct ptlrpc_request *req)
 160 {
 161         struct ptlrpc_request_set *set = req->rq_set;
 162
 163         LASSERT(set != NULL);
 164         wake_up(&set->set_waitq);
 165 }
 166 EXPORT_SYMBOL(ptlrpcd_wake);
 167
 168 static struct ptlrpcd_ctl *
 169 ptlrpcd_select_pc(struct ptlrpc_request *req)
 170 {
 171         struct ptlrpcd  *pd;
 172         int             cpt;
 173         int             idx;
 174
 175         if (req != NULL && req->rq_send_state != LUSTRE_IMP_FULL)
 176                 return &ptlrpcd_rcv;
 177
 178         cpt = cfs_cpt_current(cfs_cpt_tab, 1);
 179         if (ptlrpcds_cpt_idx == NULL)
 180                 idx = cpt;
 181         else
 182                 idx = ptlrpcds_cpt_idx[cpt];
 183         pd = ptlrpcds[idx];
 184
 185         /* We do not care whether it is strict load balance. */
 186         idx = pd->pd_cursor;
 187         if (++idx == pd->pd_nthreads)
 188                 idx = 0;
 189         pd->pd_cursor = idx;
 190
 191         return &pd->pd_threads[idx];
 192 }
 193
 194 /**
 195  * Move all request from an existing request set to the ptlrpcd queue.
 196  * All requests from the set must be in phase RQ_PHASE_NEW.
 197  */
 198 void ptlrpcd_add_rqset(struct ptlrpc_request_set *set)
 199 {
 200         struct list_head *tmp, *pos;
 201         struct ptlrpcd_ctl *pc;
 202         struct ptlrpc_request_set *new;
 203         int count, i;
 204
 205         pc = ptlrpcd_select_pc(NULL);
 206         new = pc->pc_set;
 207
 208         list_for_each_safe(pos, tmp, &set->set_requests) {
 209                 struct ptlrpc_request *req =
 210                         list_entry(pos, struct ptlrpc_request,
 211                                    rq_set_chain);
 212
 213                 LASSERT(req->rq_phase == RQ_PHASE_NEW);
 214                 req->rq_set = new;
 215                 req->rq_queued_time = ktime_get_seconds();
 216         }
 217
 218         spin_lock(&new->set_new_req_lock);
 219         list_splice_init(&set->set_requests, &new->set_new_requests);
 220         i = atomic_read(&set->set_remaining);
 221         count = atomic_add_return(i, &new->set_new_count);
 222         atomic_set(&set->set_remaining, 0);
 223         spin_unlock(&new->set_new_req_lock);
 224         if (count == i) {
 225                 wake_up(&new->set_waitq);
 226
 227                 /*
 228                  * XXX: It maybe unnecessary to wakeup all the partners. But to
 229                  *      guarantee the async RPC can be processed ASAP, we have
 230                  *      no other better choice. It maybe fixed in future.
 231                  */
 232                 for (i = 0; i < pc->pc_npartners; i++)
 233                         wake_up(&pc->pc_partners[i]->pc_set->set_waitq);
 234         }
 235 }
 236
 237 /**
 238  * Return transferred RPCs count.
 239  */
 240 static int ptlrpcd_steal_rqset(struct ptlrpc_request_set *des,
 241                                struct ptlrpc_request_set *src)
 242 {
 243         struct ptlrpc_request *req, *tmp;
 244         int rc = 0;
 245
 246         spin_lock(&src->set_new_req_lock);
 247         if (likely(!list_empty(&src->set_new_requests))) {
 248                 list_for_each_entry_safe(req, tmp, &src->set_new_requests,
 249                                          rq_set_chain)
 250                         req->rq_set = des;
 251
 252                 list_splice_init(&src->set_new_requests,
 253                                  &des->set_requests);
 254                 rc = atomic_read(&src->set_new_count);
 255                 atomic_add(rc, &des->set_remaining);
 256                 atomic_set(&src->set_new_count, 0);
 257         }
 258         spin_unlock(&src->set_new_req_lock);
 259         return rc;
 260 }
 261
 262 /**
 263  * Requests that are added to the ptlrpcd queue are sent via
 264  * ptlrpcd_check->ptlrpc_check_set().
 265  */
 266 void ptlrpcd_add_req(struct ptlrpc_request *req)
 267 {
 268         struct ptlrpcd_ctl *pc;
 269
 270         if (req->rq_reqmsg)
 271                 lustre_msg_set_jobid(req->rq_reqmsg, NULL);
 272
 273         spin_lock(&req->rq_lock);
 274         if (req->rq_invalid_rqset) {
 275                 req->rq_invalid_rqset = 0;
 276                 spin_unlock(&req->rq_lock);
 277                 if (wait_event_idle_timeout(req->rq_set_waitq,
 278                                             req->rq_set == NULL,
 279                                             cfs_time_seconds(5)) == 0)
 280                         l_wait_event_abortable(req->rq_set_waitq,
 281                                                req->rq_set == NULL);
 282         } else if (req->rq_set) {
 283                 /*
 284                  * If we have a vaid "rq_set", just reuse it to avoid double
 285                  * linked.
 286                  */
 287                 LASSERT(req->rq_phase == RQ_PHASE_NEW);
 288                 LASSERT(req->rq_send_state == LUSTRE_IMP_REPLAY);
 289
 290                 /* ptlrpc_check_set will decrease the count */
 291                 atomic_inc(&req->rq_set->set_remaining);
 292                 spin_unlock(&req->rq_lock);
 293                 wake_up(&req->rq_set->set_waitq);
 294                 return;
 295         } else {
 296                 spin_unlock(&req->rq_lock);
 297         }
 298
 299         pc = ptlrpcd_select_pc(req);
 300
 301         DEBUG_REQ(D_INFO, req, "add req [%p] to pc [%s+%d]",
 302                   req, pc->pc_name, pc->pc_index);
 303
 304         ptlrpc_set_add_new_req(pc, req);
 305 }
 306 EXPORT_SYMBOL(ptlrpcd_add_req);
 307
 308 static inline void ptlrpc_reqset_get(struct ptlrpc_request_set *set)
 309 {
 310         atomic_inc(&set->set_refcount);
 311 }
 312
 313 /**
 314  * Check if there is more work to do on ptlrpcd set.
 315  * Returns 1 if yes.
 316  */
 317 static int ptlrpcd_check(struct lu_env *env, struct ptlrpcd_ctl *pc)
 318 {
 319         struct ptlrpc_request *req, *tmp;
 320         struct ptlrpc_request_set *set = pc->pc_set;
 321         int rc = 0;
 322         int rc2;
 323
 324         ENTRY;
 325
 326         if (atomic_read(&set->set_new_count)) {
 327                 spin_lock(&set->set_new_req_lock);
 328                 if (likely(!list_empty(&set->set_new_requests))) {
 329                         list_splice_init(&set->set_new_requests,
 330                                              &set->set_requests);
 331                         atomic_add(atomic_read(&set->set_new_count),
 332                                    &set->set_remaining);
 333                         atomic_set(&set->set_new_count, 0);
 334                         /*
 335                          * Need to calculate its timeout.
 336                          */
 337                         rc = 1;
 338                 }
 339                 spin_unlock(&set->set_new_req_lock);
 340         }
 341
 342         /*
 343          * We should call lu_env_refill() before handling new requests to make
 344          * sure that env key the requests depending on really exists.
 345          */
 346         rc2 = lu_env_refill(env);
 347         if (rc2 != 0) {
 348                 /*
 349                  * XXX This is very awkward situation, because
 350                  * execution can neither continue (request
 351                  * interpreters assume that env is set up), nor repeat
 352                  * the loop (as this potentially results in a tight
 353                  * loop of -ENOMEM's).
 354                  *
 355                  * Fortunately, refill only ever does something when
 356                  * new modules are loaded, i.e., early during boot up.
 357                  */
 358                 CERROR("Failure to refill session: %d\n", rc2);
 359                 RETURN(rc);
 360         }
 361
 362         if (atomic_read(&set->set_remaining))
 363                 rc |= ptlrpc_check_set(env, set);
 364
 365         /*
 366          * NB: ptlrpc_check_set has already moved complted request at the
 367          * head of seq::set_requests
 368          */
 369         list_for_each_entry_safe(req, tmp, &set->set_requests, rq_set_chain) {
 370                 if (req->rq_phase != RQ_PHASE_COMPLETE)
 371                         break;
 372
 373                 list_del_init(&req->rq_set_chain);
 374                 req->rq_set = NULL;
 375                 ptlrpc_req_finished(req);
 376         }
 377
 378         if (rc == 0) {
 379                 /*
 380                  * If new requests have been added, make sure to wake up.
 381                  */
 382                 rc = atomic_read(&set->set_new_count);
 383
 384                 /*
 385                  * If we have nothing to do, check whether we can take some
 386                  * work from our partner threads.
 387                  */
 388                 if (rc == 0 && pc->pc_npartners > 0) {
 389                         struct ptlrpcd_ctl *partner;
 390                         struct ptlrpc_request_set *ps;
 391                         int first = pc->pc_cursor;
 392
 393                         do {
 394                                 partner = pc->pc_partners[pc->pc_cursor++];
 395                                 if (pc->pc_cursor >= pc->pc_npartners)
 396                                         pc->pc_cursor = 0;
 397                                 if (partner == NULL)
 398                                         continue;
 399
 400                                 spin_lock(&partner->pc_lock);
 401                                 ps = partner->pc_set;
 402                                 if (ps == NULL) {
 403                                         spin_unlock(&partner->pc_lock);
 404                                         continue;
 405                                 }
 406
 407                                 ptlrpc_reqset_get(ps);
 408                                 spin_unlock(&partner->pc_lock);
 409
 410                                 if (atomic_read(&ps->set_new_count)) {
 411                                         rc = ptlrpcd_steal_rqset(set, ps);
 412                                         if (rc > 0)
 413                                                 CDEBUG(D_RPCTRACE,
 414                                                        "transfer %d async RPCs [%d->%d]\n",
 415                                                        rc, partner->pc_index,
 416                                                        pc->pc_index);
 417                                 }
 418                                 ptlrpc_reqset_put(ps);
 419                         } while (rc == 0 && pc->pc_cursor != first);
 420                 }
 421         }
 422
 423         RETURN(rc || test_bit(LIOD_STOP, &pc->pc_flags));
 424 }
 425
 426 /**
 427  * Main ptlrpcd thread.
 428  * ptlrpc's code paths like to execute in process context, so we have this
 429  * thread which spins on a set which contains the rpcs and sends them.
 430  */
 431 static int ptlrpcd(void *arg)
 432 {
 433         struct ptlrpcd_ctl              *pc = arg;
 434         struct ptlrpc_request_set       *set;
 435         struct lu_context               ses = { 0 };
 436         struct lu_env                   env = { .le_ses = &ses };
 437         int                             rc = 0;
 438         int                             exit = 0;
 439
 440         ENTRY;
 441         if (cfs_cpt_bind(cfs_cpt_tab, pc->pc_cpt) != 0)
 442                 CWARN("Failed to bind %s on CPT %d\n", pc->pc_name, pc->pc_cpt);
 443
 444         /*
 445          * Allocate the request set after the thread has been bound
 446          * above. This is safe because no requests will be queued
 447          * until all ptlrpcd threads have confirmed that they have
 448          * successfully started.
 449          */
 450         set = ptlrpc_prep_set();
 451         if (set == NULL)
 452                 GOTO(failed, rc = -ENOMEM);
 453         spin_lock(&pc->pc_lock);
 454         pc->pc_set = set;
 455         spin_unlock(&pc->pc_lock);
 456
 457         /* Both client and server (MDT/OST) may use the environment. */
 458         rc = lu_context_init(&env.le_ctx, LCT_MD_THREAD |
 459                                           LCT_DT_THREAD |
 460                                           LCT_CL_THREAD |
 461                                           LCT_REMEMBER  |
 462                                           LCT_NOREF);
 463         if (rc != 0)
 464                 GOTO(failed, rc);
 465         rc = lu_context_init(env.le_ses, LCT_SESSION  |
 466                                          LCT_REMEMBER |
 467                                          LCT_NOREF);
 468         if (rc != 0) {
 469                 lu_context_fini(&env.le_ctx);
 470                 GOTO(failed, rc);
 471         }
 472
 473         complete(&pc->pc_starting);
 474
 475         /*
 476          * This mainloop strongly resembles ptlrpc_set_wait() except that our
 477          * set never completes.  ptlrpcd_check() calls ptlrpc_check_set() when
 478          * there are requests in the set. New requests come in on the set's
 479          * new_req_list and ptlrpcd_check() moves them into the set.
 480          */
 481         do {
 482                 time64_t timeout;
 483
 484                 timeout = ptlrpc_set_next_timeout(set);
 485
 486                 lu_context_enter(&env.le_ctx);
 487                 lu_context_enter(env.le_ses);
 488                 if (timeout == 0)
 489                         wait_event_idle(set->set_waitq,
 490                                         ptlrpcd_check(&env, pc));
 491                 else if (wait_event_idle_timeout(set->set_waitq,
 492                                                  ptlrpcd_check(&env, pc),
 493                                                  cfs_time_seconds(timeout))
 494                          == 0)
 495                         ptlrpc_expired_set(set);
 496                 lu_context_exit(&env.le_ctx);
 497                 lu_context_exit(env.le_ses);
 498
 499                 /*
 500                  * Abort inflight rpcs for forced stop case.
 501                  */
 502                 if (test_bit(LIOD_STOP, &pc->pc_flags)) {
 503                         if (test_bit(LIOD_FORCE, &pc->pc_flags))
 504                                 ptlrpc_abort_set(set);
 505                         exit++;
 506                 }
 507
 508                 /*
 509                  * Let's make one more loop to make sure that ptlrpcd_check()
 510                  * copied all raced new rpcs into the set so we can kill them.
 511                  */
 512         } while (exit < 2);
 513
 514         /*
 515          * Wait for inflight requests to drain.
 516          */
 517         if (!list_empty(&set->set_requests))
 518                 ptlrpc_set_wait(&env, set);
 519         lu_context_fini(&env.le_ctx);
 520         lu_context_fini(env.le_ses);
 521
 522         complete(&pc->pc_finishing);
 523
 524         return 0;
 525
 526 failed:
 527         pc->pc_error = rc;
 528         complete(&pc->pc_starting);
 529         RETURN(rc);
 530 }
 531
 532 static void ptlrpcd_ctl_init(struct ptlrpcd_ctl *pc, int index, int cpt)
 533 {
 534         ENTRY;
 535
 536         pc->pc_index = index;
 537         pc->pc_cpt = cpt;
 538         init_completion(&pc->pc_starting);
 539         init_completion(&pc->pc_finishing);
 540         spin_lock_init(&pc->pc_lock);
 541
 542         if (index < 0) {
 543                 /* Recovery thread. */
 544                 snprintf(pc->pc_name, sizeof(pc->pc_name), "ptlrpcd_rcv");
 545         } else {
 546                 /* Regular thread. */
 547                 snprintf(pc->pc_name, sizeof(pc->pc_name),
 548                          "ptlrpcd_%02d_%02d", cpt, index);
 549         }
 550
 551         EXIT;
 552 }
 553
 554 /* XXX: We want multiple CPU cores to share the async RPC load. So we
 555  *      start many ptlrpcd threads. We also want to reduce the ptlrpcd
 556  *      overhead caused by data transfer cross-CPU cores. So we bind
 557  *      all ptlrpcd threads to a CPT, in the expectation that CPTs
 558  *      will be defined in a way that matches these boundaries. Within
 559  *      a CPT a ptlrpcd thread can be scheduled on any available core.
 560  *
 561  *      Each ptlrpcd thread has its own request queue. This can cause
 562  *      response delay if the thread is already busy. To help with
 563  *      this we define partner threads: these are other threads bound
 564  *      to the same CPT which will check for work in each other's
 565  *      request queues if they have no work to do.
 566  *
 567  *      The desired number of partner threads can be tuned by setting
 568  *      ptlrpcd_partner_group_size. The default is to create pairs of
 569  *      partner threads.
 570  */
 571 static int ptlrpcd_partners(struct ptlrpcd *pd, int index)
 572 {
 573         struct ptlrpcd_ctl      *pc;
 574         struct ptlrpcd_ctl      **ppc;
 575         int                     first;
 576         int                     i;
 577         int                     rc = 0;
 578
 579         ENTRY;
 580
 581         LASSERT(index >= 0 && index < pd->pd_nthreads);
 582         pc = &pd->pd_threads[index];
 583         pc->pc_npartners = pd->pd_groupsize - 1;
 584
 585         if (pc->pc_npartners <= 0)
 586                 GOTO(out, rc);
 587
 588         OBD_CPT_ALLOC(pc->pc_partners, cfs_cpt_tab, pc->pc_cpt,
 589                       sizeof(struct ptlrpcd_ctl *) * pc->pc_npartners);
 590         if (pc->pc_partners == NULL) {
 591                 pc->pc_npartners = 0;
 592                 GOTO(out, rc = -ENOMEM);
 593         }
 594
 595         first = index - index % pd->pd_groupsize;
 596         ppc = pc->pc_partners;
 597         for (i = first; i < first + pd->pd_groupsize; i++) {
 598                 if (i != index)
 599                         *ppc++ = &pd->pd_threads[i];
 600         }
 601 out:
 602         RETURN(rc);
 603 }
 604
 605 int ptlrpcd_start(struct ptlrpcd_ctl *pc)
 606 {
 607         struct task_struct      *task;
 608         int                     rc = 0;
 609
 610         ENTRY;
 611
 612         /*
 613          * Do not allow starting a second thread for one pc.
 614          */
 615         if (test_and_set_bit(LIOD_START, &pc->pc_flags)) {
 616                 CWARN("Starting second thread (%s) for same pc %p\n",
 617                       pc->pc_name, pc);
 618                 RETURN(0);
 619         }
 620
 621         task = kthread_run(ptlrpcd, pc, "%s", pc->pc_name);
 622         if (IS_ERR(task))
 623                 GOTO(out_set, rc = PTR_ERR(task));
 624
 625         wait_for_completion(&pc->pc_starting);
 626         rc = pc->pc_error;
 627         if (rc != 0)
 628                 GOTO(out_set, rc);
 629
 630         RETURN(0);
 631
 632 out_set:
 633         if (pc->pc_set != NULL) {
 634                 struct ptlrpc_request_set *set = pc->pc_set;
 635
 636                 spin_lock(&pc->pc_lock);
 637                 pc->pc_set = NULL;
 638                 spin_unlock(&pc->pc_lock);
 639                 ptlrpc_set_destroy(set);
 640         }
 641         clear_bit(LIOD_START, &pc->pc_flags);
 642         RETURN(rc);
 643 }
 644
 645 void ptlrpcd_stop(struct ptlrpcd_ctl *pc, int force)
 646 {
 647         ENTRY;
 648
 649         if (!test_bit(LIOD_START, &pc->pc_flags)) {
 650                 CWARN("Thread for pc %p was not started\n", pc);
 651                 goto out;
 652         }
 653
 654         set_bit(LIOD_STOP, &pc->pc_flags);
 655         if (force)
 656                 set_bit(LIOD_FORCE, &pc->pc_flags);
 657         wake_up(&pc->pc_set->set_waitq);
 658
 659 out:
 660         EXIT;
 661 }
 662
 663 void ptlrpcd_free(struct ptlrpcd_ctl *pc)
 664 {
 665         struct ptlrpc_request_set *set = pc->pc_set;
 666
 667         ENTRY;
 668
 669         if (!test_bit(LIOD_START, &pc->pc_flags)) {
 670                 CWARN("Thread for pc %p was not started\n", pc);
 671                 goto out;
 672         }
 673
 674         wait_for_completion(&pc->pc_finishing);
 675
 676         spin_lock(&pc->pc_lock);
 677         pc->pc_set = NULL;
 678         spin_unlock(&pc->pc_lock);
 679         ptlrpc_set_destroy(set);
 680
 681         clear_bit(LIOD_START, &pc->pc_flags);
 682         clear_bit(LIOD_STOP, &pc->pc_flags);
 683         clear_bit(LIOD_FORCE, &pc->pc_flags);
 684
 685 out:
 686         if (pc->pc_npartners > 0) {
 687                 LASSERT(pc->pc_partners != NULL);
 688
 689                 OBD_FREE_PTR_ARRAY(pc->pc_partners, pc->pc_npartners);
 690                 pc->pc_partners = NULL;
 691         }
 692         pc->pc_npartners = 0;
 693         pc->pc_error = 0;
 694         EXIT;
 695 }
 696
 697 static void ptlrpcd_fini(void)
 698 {
 699         int     i;
 700         int     j;
 701         int     ncpts;
 702
 703         ENTRY;
 704
 705         if (ptlrpcds != NULL) {
 706                 for (i = 0; i < ptlrpcds_num; i++) {
 707                         if (ptlrpcds[i] == NULL)
 708                                 break;
 709                         for (j = 0; j < ptlrpcds[i]->pd_nthreads; j++)
 710                                 ptlrpcd_stop(&ptlrpcds[i]->pd_threads[j], 0);
 711                         for (j = 0; j < ptlrpcds[i]->pd_nthreads; j++)
 712                                 ptlrpcd_free(&ptlrpcds[i]->pd_threads[j]);
 713                         OBD_FREE(ptlrpcds[i], ptlrpcds[i]->pd_size);
 714                         ptlrpcds[i] = NULL;
 715                 }
 716                 OBD_FREE_PTR_ARRAY(ptlrpcds, ptlrpcds_num);
 717         }
 718         ptlrpcds_num = 0;
 719
 720         ptlrpcd_stop(&ptlrpcd_rcv, 0);
 721         ptlrpcd_free(&ptlrpcd_rcv);
 722
 723         if (ptlrpcds_cpt_idx != NULL) {
 724                 ncpts = cfs_cpt_number(cfs_cpt_tab);
 725                 OBD_FREE_PTR_ARRAY(ptlrpcds_cpt_idx, ncpts);
 726                 ptlrpcds_cpt_idx = NULL;
 727         }
 728
 729         EXIT;
 730 }
 731
 732 static int ptlrpcd_init(void)
 733 {
 734         int                     nthreads;
 735         int                     groupsize;
 736         int                     size;
 737         int                     i;
 738         int                     j;
 739         int                     rc = 0;
 740         struct cfs_cpt_table    *cptable;
 741         __u32                   *cpts = NULL;
 742         int                     ncpts;
 743         int                     cpt;
 744         struct ptlrpcd          *pd;
 745
 746         ENTRY;
 747
 748         /*
 749          * Determine the CPTs that ptlrpcd threads will run on.
 750          */
 751         cptable = cfs_cpt_tab;
 752         ncpts = cfs_cpt_number(cptable);
 753         if (ptlrpcd_cpts != NULL) {
 754                 struct cfs_expr_list *el;
 755
 756                 size = ncpts * sizeof(ptlrpcds_cpt_idx[0]);
 757                 OBD_ALLOC(ptlrpcds_cpt_idx, size);
 758                 if (ptlrpcds_cpt_idx == NULL)
 759                         GOTO(out, rc = -ENOMEM);
 760
 761                 rc = cfs_expr_list_parse(ptlrpcd_cpts,
 762                                          strlen(ptlrpcd_cpts),
 763                                          0, ncpts - 1, &el);
 764                 if (rc != 0) {
 765                         CERROR("%s: invalid CPT pattern string: %s",
 766                                "ptlrpcd_cpts", ptlrpcd_cpts);
 767                         GOTO(out, rc = -EINVAL);
 768                 }
 769
 770                 rc = cfs_expr_list_values(el, ncpts, &cpts);
 771                 cfs_expr_list_free(el);
 772                 if (rc <= 0) {
 773                         CERROR("%s: failed to parse CPT array %s: %d\n",
 774                                "ptlrpcd_cpts", ptlrpcd_cpts, rc);
 775                         if (rc == 0)
 776                                 rc = -EINVAL;
 777                         GOTO(out, rc);
 778                 }
 779
 780                 /*
 781                  * Create the cpt-to-index map. When there is no match
 782                  * in the cpt table, pick a cpt at random. This could
 783                  * be changed to take the topology of the system into
 784                  * account.
 785                  */
 786                 for (cpt = 0; cpt < ncpts; cpt++) {
 787                         for (i = 0; i < rc; i++)
 788                                 if (cpts[i] == cpt)
 789                                         break;
 790                         if (i >= rc)
 791                                 i = cpt % rc;
 792                         ptlrpcds_cpt_idx[cpt] = i;
 793                 }
 794
 795                 cfs_expr_list_values_free(cpts, rc);
 796                 ncpts = rc;
 797         }
 798         ptlrpcds_num = ncpts;
 799
 800         size = ncpts * sizeof(ptlrpcds[0]);
 801         OBD_ALLOC(ptlrpcds, size);
 802         if (ptlrpcds == NULL)
 803                 GOTO(out, rc = -ENOMEM);
 804
 805         /*
 806          * The max_ptlrpcds parameter is obsolete, but do something
 807          * sane if it has been tuned, and complain if
 808          * ptlrpcd_per_cpt_max has also been tuned.
 809          */
 810         if (max_ptlrpcds != 0) {
 811                 CWARN("max_ptlrpcds is obsolete.\n");
 812                 if (ptlrpcd_per_cpt_max == 0) {
 813                         ptlrpcd_per_cpt_max = max_ptlrpcds / ncpts;
 814                         /* Round up if there is a remainder. */
 815                         if (max_ptlrpcds % ncpts != 0)
 816                                 ptlrpcd_per_cpt_max++;
 817                         CWARN("Setting ptlrpcd_per_cpt_max = %d\n",
 818                               ptlrpcd_per_cpt_max);
 819                 } else {
 820                         CWARN("ptlrpd_per_cpt_max is also set!\n");
 821                 }
 822         }
 823
 824         /*
 825          * The ptlrpcd_bind_policy parameter is obsolete, but do
 826          * something sane if it has been tuned, and complain if
 827          * ptlrpcd_partner_group_size is also tuned.
 828          */
 829         if (ptlrpcd_bind_policy != 0) {
 830                 CWARN("ptlrpcd_bind_policy is obsolete.\n");
 831                 if (ptlrpcd_partner_group_size == 0) {
 832                         switch (ptlrpcd_bind_policy) {
 833                         case 1: /* PDB_POLICY_NONE */
 834                         case 2: /* PDB_POLICY_FULL */
 835                                 ptlrpcd_partner_group_size = 1;
 836                                 break;
 837                         case 3: /* PDB_POLICY_PAIR */
 838                                 ptlrpcd_partner_group_size = 2;
 839                                 break;
 840                         case 4: /* PDB_POLICY_NEIGHBOR */
 841 #ifdef CONFIG_NUMA
 842                                 ptlrpcd_partner_group_size = -1; /* CPT */
 843 #else
 844                                 ptlrpcd_partner_group_size = 3; /* Triplets */
 845 #endif
 846                                 break;
 847                         default: /* Illegal value, use the default. */
 848                                 ptlrpcd_partner_group_size = 2;
 849                                 break;
 850                         }
 851                         CWARN("Setting ptlrpcd_partner_group_size = %d\n",
 852                               ptlrpcd_partner_group_size);
 853                 } else {
 854                         CWARN("ptlrpcd_partner_group_size is also set!\n");
 855                 }
 856         }
 857
 858         if (ptlrpcd_partner_group_size == 0)
 859                 ptlrpcd_partner_group_size = 2;
 860         else if (ptlrpcd_partner_group_size < 0)
 861                 ptlrpcd_partner_group_size = -1;
 862         else if (ptlrpcd_per_cpt_max > 0 &&
 863                  ptlrpcd_partner_group_size > ptlrpcd_per_cpt_max)
 864                 ptlrpcd_partner_group_size = ptlrpcd_per_cpt_max;
 865
 866         /*
 867          * Start the recovery thread first.
 868          */
 869         set_bit(LIOD_RECOVERY, &ptlrpcd_rcv.pc_flags);
 870         ptlrpcd_ctl_init(&ptlrpcd_rcv, -1, CFS_CPT_ANY);
 871         rc = ptlrpcd_start(&ptlrpcd_rcv);
 872         if (rc < 0)
 873                 GOTO(out, rc);
 874
 875         for (i = 0; i < ncpts; i++) {
 876                 if (cpts == NULL)
 877                         cpt = i;
 878                 else
 879                         cpt = cpts[i];
 880
 881                 nthreads = cfs_cpt_weight(cptable, cpt);
 882                 if (ptlrpcd_per_cpt_max > 0 && ptlrpcd_per_cpt_max < nthreads)
 883                         nthreads = ptlrpcd_per_cpt_max;
 884                 if (nthreads < 2)
 885                         nthreads = 2;
 886
 887                 if (ptlrpcd_partner_group_size <= 0) {
 888                         groupsize = nthreads;
 889                 } else if (nthreads <= ptlrpcd_partner_group_size) {
 890                         groupsize = nthreads;
 891                 } else {
 892                         groupsize = ptlrpcd_partner_group_size;
 893                         if (nthreads % groupsize != 0)
 894                                 nthreads += groupsize - (nthreads % groupsize);
 895                 }
 896
 897                 size = offsetof(struct ptlrpcd, pd_threads[nthreads]);
 898                 OBD_CPT_ALLOC(pd, cptable, cpt, size);
 899
 900                 if (!pd)
 901                         GOTO(out, rc = -ENOMEM);
 902                 pd->pd_size      = size;
 903                 pd->pd_index     = i;
 904                 pd->pd_cpt       = cpt;
 905                 pd->pd_cursor    = 0;
 906                 pd->pd_nthreads  = nthreads;
 907                 pd->pd_groupsize = groupsize;
 908                 ptlrpcds[i] = pd;
 909
 910                 /*
 911                  * The ptlrpcd threads in a partner group can access
 912                  * each other's struct ptlrpcd_ctl, so these must be
 913                  * initialized before any thead is started.
 914                  */
 915                 for (j = 0; j < nthreads; j++) {
 916                         ptlrpcd_ctl_init(&pd->pd_threads[j], j, cpt);
 917                         rc = ptlrpcd_partners(pd, j);
 918                         if (rc < 0)
 919                                 GOTO(out, rc);
 920                 }
 921
 922                 /* XXX: We start nthreads ptlrpc daemons on this cpt.
 923                  *      Each of them can process any non-recovery
 924                  *      async RPC to improve overall async RPC
 925                  *      efficiency.
 926                  *
 927                  *      But there are some issues with async I/O RPCs
 928                  *      and async non-I/O RPCs processed in the same
 929                  *      set under some cases. The ptlrpcd may be
 930                  *      blocked by some async I/O RPC(s), then will
 931                  *      cause other async non-I/O RPC(s) can not be
 932                  *      processed in time.
 933                  *
 934                  *      Maybe we should distinguish blocked async RPCs
 935                  *      from non-blocked async RPCs, and process them
 936                  *      in different ptlrpcd sets to avoid unnecessary
 937                  *      dependency. But how to distribute async RPCs
 938                  *      load among all the ptlrpc daemons becomes
 939                  *      another trouble.
 940                  */
 941                 for (j = 0; j < nthreads; j++) {
 942                         rc = ptlrpcd_start(&pd->pd_threads[j]);
 943                         if (rc < 0)
 944                                 GOTO(out, rc);
 945                 }
 946         }
 947 out:
 948         if (rc != 0)
 949                 ptlrpcd_fini();
 950
 951         RETURN(rc);
 952 }
 953
 954 int ptlrpcd_addref(void)
 955 {
 956         int rc = 0;
 957
 958         ENTRY;
 959
 960         mutex_lock(&ptlrpcd_mutex);
 961         if (++ptlrpcd_users == 1) {
 962                 rc = ptlrpcd_init();
 963                 if (rc < 0)
 964                         ptlrpcd_users--;
 965         }
 966         mutex_unlock(&ptlrpcd_mutex);
 967         RETURN(rc);
 968 }
 969 EXPORT_SYMBOL(ptlrpcd_addref);
 970
 971 void ptlrpcd_decref(void)
 972 {
 973         mutex_lock(&ptlrpcd_mutex);
 974         if (--ptlrpcd_users == 0)
 975                 ptlrpcd_fini();
 976         mutex_unlock(&ptlrpcd_mutex);
 977 }
 978 EXPORT_SYMBOL(ptlrpcd_decref);
 979 /** @} ptlrpcd */