lustre/lov/lov_qos.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * Copyright (C) 2002, 2003 Cluster File Systems, Inc.
   5  *
   6  *   This file is part of the Lustre file system, http://www.lustre.org
   7  *   Lustre is a trademark of Cluster File Systems, Inc.
   8  *
   9  *   You may have signed or agreed to another license before downloading
  10  *   this software.  If so, you are bound by the terms and conditions
  11  *   of that agreement, and the following does not apply to you.  See the
  12  *   LICENSE file included with this distribution for more information.
  13  *
  14  *   If you did not agree to a different license, then this copy of Lustre
  15  *   is open source software; you can redistribute it and/or modify it
  16  *   under the terms of version 2 of the GNU General Public License as
  17  *   published by the Free Software Foundation.
  18  *
  19  *   In either case, Lustre is distributed in the hope that it will be
  20  *   useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  21  *   of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  *   license text for more details.
  23  */
  24
  25 #ifndef EXPORT_SYMTAB
  26 # define EXPORT_SYMTAB
  27 #endif
  28 #define DEBUG_SUBSYSTEM S_LOV
  29
  30 #ifdef __KERNEL__
  31 #include <libcfs/libcfs.h>
  32 #else
  33 #include <liblustre.h>
  34 #endif
  35
  36 #include <obd_class.h>
  37 #include <obd_lov.h>
  38 #include "lov_internal.h"
  39
  40 /* #define QOS_DEBUG 1 */
  41 #define D_QOS D_OTHER
  42
  43 #define TGT_BAVAIL(i)  (lov->lov_tgts[i]->ltd_exp->exp_obd->obd_osfs.os_bavail*\
  44                         lov->lov_tgts[i]->ltd_exp->exp_obd->obd_osfs.os_bsize)
  45 #define TGT_FFREE(i)   (lov->lov_tgts[i]->ltd_exp->exp_obd->obd_osfs.os_ffree)
  46
  47
  48 int qos_add_tgt(struct obd_device *obd, __u32 index)
  49 {
  50         struct lov_obd *lov = &obd->u.lov;
  51         struct lov_qos_oss *oss, *temposs;
  52         struct obd_export *exp = lov->lov_tgts[index]->ltd_exp;
  53         int rc = 0, found = 0;
  54         ENTRY;
  55
  56         /* We only need this QOS struct on MDT, not clients - but we may not
  57          * have registered the LOV's observer yet, so there's no way to know */
  58         if (!exp || !exp->exp_connection) {
  59                 CERROR("Missing connection\n");
  60                 RETURN(-ENOTCONN);
  61         }
  62
  63         down_write(&lov->lov_qos.lq_rw_sem);
  64         mutex_down(&lov->lov_lock);
  65         list_for_each_entry(oss, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
  66                 if (obd_uuid_equals(&oss->lqo_uuid,
  67                                     &exp->exp_connection->c_remote_uuid)) {
  68                         found++;
  69                         break;
  70                 }
  71         }
  72
  73         if (!found) {
  74                 OBD_ALLOC_PTR(oss);
  75                 if (!oss)
  76                         GOTO(out, rc = -ENOMEM);
  77                 memcpy(&oss->lqo_uuid,
  78                        &exp->exp_connection->c_remote_uuid,
  79                        sizeof(oss->lqo_uuid));
  80         } else {
  81                 /* Assume we have to move this one */
  82                 list_del(&oss->lqo_oss_list);
  83         }
  84
  85         oss->lqo_ost_count++;
  86         lov->lov_tgts[index]->ltd_qos.ltq_oss = oss;
  87
  88         /* Add sorted by # of OSTs.  Find the first entry that we're
  89            bigger than... */
  90         list_for_each_entry(temposs, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
  91                 if (oss->lqo_ost_count > temposs->lqo_ost_count)
  92                         break;
  93         }
  94         /* ...and add before it.  If we're the first or smallest, temposs
  95            points to the list head, and we add to the end. */
  96         list_add_tail(&oss->lqo_oss_list, &temposs->lqo_oss_list);
  97
  98         lov->lov_qos.lq_dirty = 1;
  99         lov->lov_qos.lq_dirty_rr = 1;
 100
 101         CDEBUG(D_QOS, "add tgt %s to OSS %s (%d OSTs)\n",
 102                obd_uuid2str(&lov->lov_tgts[index]->ltd_uuid),
 103                obd_uuid2str(&oss->lqo_uuid),
 104                oss->lqo_ost_count);
 105
 106 out:
 107         mutex_up(&lov->lov_lock);
 108         up_write(&lov->lov_qos.lq_rw_sem);
 109         RETURN(rc);
 110 }
 111
 112 int qos_del_tgt(struct obd_device *obd, __u32 index)
 113 {
 114         struct lov_obd *lov = &obd->u.lov;
 115         struct lov_qos_oss *oss;
 116         int rc = 0;
 117         ENTRY;
 118
 119         if (!lov->lov_tgts[index])
 120                 RETURN(0);
 121
 122         down_write(&lov->lov_qos.lq_rw_sem);
 123
 124         oss = lov->lov_tgts[index]->ltd_qos.ltq_oss;
 125         if (!oss)
 126                 GOTO(out, rc = -ENOENT);
 127
 128         oss->lqo_ost_count--;
 129         if (oss->lqo_ost_count == 0) {
 130                 CDEBUG(D_QOS, "removing OSS %s\n",
 131                        obd_uuid2str(&oss->lqo_uuid));
 132                 list_del(&oss->lqo_oss_list);
 133                 OBD_FREE_PTR(oss);
 134         }
 135
 136         lov->lov_qos.lq_dirty = 1;
 137         lov->lov_qos.lq_dirty_rr = 1;
 138 out:
 139         up_write(&lov->lov_qos.lq_rw_sem);
 140         RETURN(rc);
 141 }
 142
 143 /* Recalculate per-object penalties for OSSs and OSTs,
 144    depends on size of each ost in an oss */
 145 static int qos_calc_ppo(struct obd_device *obd)
 146 {
 147         struct lov_obd *lov = &obd->u.lov;
 148         struct lov_qos_oss *oss;
 149         __u64 ba_max, ba_min, temp;
 150         __u32 num_active;
 151         int rc, i, prio_wide;
 152         ENTRY;
 153
 154         if (!lov->lov_qos.lq_dirty)
 155                 GOTO(out, rc = 0);
 156
 157         num_active = lov->desc.ld_active_tgt_count - 1;
 158         if (num_active < 1)
 159                 GOTO(out, rc = -EAGAIN);
 160
 161         /* find bavail on each OSS */
 162         list_for_each_entry(oss, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
 163                 oss->lqo_bavail = 0;
 164         }
 165         lov->lov_qos.lq_active_oss_count = 0;
 166
 167         /* How badly user wants to select osts "widely" (not recently chosen
 168            and not on recent oss's).  As opposed to "freely" (free space
 169            avail.) 0-256. */
 170         prio_wide = 256 - lov->lov_qos.lq_prio_free;
 171
 172         ba_min = (__u64)(-1);
 173         ba_max = 0;
 174         /* Calculate OST penalty per object */
 175         /* (lov ref taken in alloc_qos) */
 176         for (i = 0; i < lov->desc.ld_tgt_count; i++) {
 177                 if (!lov->lov_tgts[i] || !lov->lov_tgts[i]->ltd_active)
 178                         continue;
 179                 temp = TGT_BAVAIL(i);
 180                 if (!temp)
 181                         continue;
 182                 ba_min = min(temp, ba_min);
 183                 ba_max = max(temp, ba_max);
 184
 185                 /* Count the number of usable OSS's */
 186                 if (lov->lov_tgts[i]->ltd_qos.ltq_oss->lqo_bavail == 0)
 187                         lov->lov_qos.lq_active_oss_count++;
 188                 lov->lov_tgts[i]->ltd_qos.ltq_oss->lqo_bavail += temp;
 189
 190                 /* per-OST penalty is prio * TGT_bavail / (num_ost - 1) / 2 */
 191                 temp >>= 1;
 192                 do_div(temp, num_active);
 193                 lov->lov_tgts[i]->ltd_qos.ltq_penalty_per_obj =
 194                         (temp * prio_wide) >> 8;
 195
 196                 if (lov->lov_qos.lq_reset == 0)
 197                         lov->lov_tgts[i]->ltd_qos.ltq_penalty = 0;
 198         }
 199
 200         num_active = lov->lov_qos.lq_active_oss_count - 1;
 201         if (num_active < 1) {
 202                 /* If there's only 1 OSS, we can't penalize it, so instead
 203                    we have to double the OST penalty */
 204                 num_active = 1;
 205                 for (i = 0; i < lov->desc.ld_tgt_count; i++)
 206                         if (lov->lov_tgts[i])
 207                             lov->lov_tgts[i]->ltd_qos.ltq_penalty_per_obj <<= 1;
 208         }
 209
 210         /* Per-OSS penalty is prio * oss_avail / oss_osts / (num_oss - 1) / 2 */
 211         list_for_each_entry(oss, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
 212                 temp = oss->lqo_bavail >> 1;
 213                 do_div(temp, oss->lqo_ost_count * num_active);
 214                 oss->lqo_penalty_per_obj = (temp * prio_wide) >> 8;
 215                 if (lov->lov_qos.lq_reset == 0)
 216                         oss->lqo_penalty = 0;
 217         }
 218
 219         lov->lov_qos.lq_dirty = 0;
 220         lov->lov_qos.lq_reset = 0;
 221
 222         /* If each ost has almost same free space,
 223          * do rr allocation for better creation performance */
 224         lov->lov_qos.lq_same_space = 0;
 225         temp = ba_max - ba_min;
 226         ba_min = (ba_min * 51) >> 8;     /* 51/256 = .20 */
 227         if (temp < ba_min) {
 228                 /* Difference is less than 20% */
 229                 lov->lov_qos.lq_same_space = 1;
 230                 /* Reset weights for the next time we enter qos mode */
 231                 lov->lov_qos.lq_reset = 0;
 232         }
 233         rc = 0;
 234
 235 out:
 236         if (!rc && lov->lov_qos.lq_same_space)
 237                 RETURN(-EAGAIN);
 238         RETURN(rc);
 239 }
 240
 241 static int qos_calc_weight(struct lov_obd *lov, int i)
 242 {
 243         __u64 temp, temp2;
 244
 245         /* Final ost weight = TGT_BAVAIL - ost_penalty - oss_penalty */
 246         temp = TGT_BAVAIL(i);
 247         temp2 = lov->lov_tgts[i]->ltd_qos.ltq_penalty +
 248                 lov->lov_tgts[i]->ltd_qos.ltq_oss->lqo_penalty;
 249         if (temp < temp2)
 250                 lov->lov_tgts[i]->ltd_qos.ltq_weight = 0;
 251         else
 252                 lov->lov_tgts[i]->ltd_qos.ltq_weight = temp - temp2;
 253         return 0;
 254 }
 255
 256 /* We just used this index for a stripe; adjust everyone's weights */
 257 static int qos_used(struct lov_obd *lov, __u32 index, __u64 *total_wt)
 258 {
 259         struct lov_qos_oss *oss;
 260         int i;
 261         ENTRY;
 262
 263         /* Don't allocate from this stripe anymore, until the next alloc_qos */
 264         lov->lov_tgts[index]->ltd_qos.ltq_usable = 0;
 265
 266         oss = lov->lov_tgts[index]->ltd_qos.ltq_oss;
 267
 268         /* Decay old penalty by half (we're adding max penalty, and don't
 269            want it to run away.) */
 270         lov->lov_tgts[index]->ltd_qos.ltq_penalty >>= 1;
 271         oss->lqo_penalty >>= 1;
 272
 273         /* Set max penalties for this OST and OSS */
 274         lov->lov_tgts[index]->ltd_qos.ltq_penalty +=
 275                 lov->lov_tgts[index]->ltd_qos.ltq_penalty_per_obj *
 276                 lov->desc.ld_active_tgt_count;
 277         oss->lqo_penalty += oss->lqo_penalty_per_obj *
 278                 lov->lov_qos.lq_active_oss_count;
 279
 280         /* Decrease all OSS penalties */
 281         list_for_each_entry(oss, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
 282                 if (oss->lqo_penalty < oss->lqo_penalty_per_obj)
 283                         oss->lqo_penalty = 0;
 284                 else
 285                         oss->lqo_penalty -= oss->lqo_penalty_per_obj;
 286         }
 287
 288         *total_wt = 0;
 289         /* Decrease all OST penalties */
 290         for (i = 0; i < lov->desc.ld_tgt_count; i++) {
 291                 if (!lov->lov_tgts[i] || !lov->lov_tgts[i]->ltd_active)
 292                         continue;
 293                 if (lov->lov_tgts[i]->ltd_qos.ltq_penalty <
 294                     lov->lov_tgts[i]->ltd_qos.ltq_penalty_per_obj)
 295                         lov->lov_tgts[i]->ltd_qos.ltq_penalty = 0;
 296                 else
 297                         lov->lov_tgts[i]->ltd_qos.ltq_penalty -=
 298                         lov->lov_tgts[i]->ltd_qos.ltq_penalty_per_obj;
 299
 300                 qos_calc_weight(lov, i);
 301
 302                 /* Recalc the total weight of usable osts */
 303                 if (lov->lov_tgts[i]->ltd_qos.ltq_usable)
 304                         *total_wt += lov->lov_tgts[i]->ltd_qos.ltq_weight;
 305
 306 #ifdef QOS_DEBUG
 307                 CDEBUG(D_QOS, "recalc tgt %d avail="LPU64
 308                        " ostppo="LPU64" ostp="LPU64" ossppo="LPU64
 309                        " ossp="LPU64" wt="LPU64"\n",
 310                        i, TGT_BAVAIL(i) >> 10,
 311                        lov->lov_tgts[i]->ltd_qos.ltq_penalty_per_obj >> 10,
 312                        lov->lov_tgts[i]->ltd_qos.ltq_penalty >> 10,
 313                        lov->lov_tgts[i]->ltd_qos.ltq_oss->lqo_penalty_per_obj>>10,
 314                        lov->lov_tgts[i]->ltd_qos.ltq_oss->lqo_penalty>>10,
 315                        lov->lov_tgts[i]->ltd_qos.ltq_weight>>10);
 316 #endif
 317         }
 318
 319         RETURN(0);
 320 }
 321
 322 #define LOV_QOS_EMPTY ((__u32)-1)
 323 /* compute optimal round-robin order, based on OSTs per OSS */
 324 static int qos_calc_rr(struct lov_obd *lov)
 325 {
 326         struct lov_qos_oss *oss;
 327         unsigned ost_count, placed, real_count;
 328         int i;
 329         ENTRY;
 330
 331         if (!lov->lov_qos.lq_dirty_rr) {
 332                 LASSERT(lov->lov_qos.lq_rr_size);
 333                 RETURN(0);
 334         }
 335
 336         down_write(&lov->lov_qos.lq_rw_sem);
 337         ost_count = lov->desc.ld_tgt_count;
 338
 339         if (lov->lov_qos.lq_rr_size)
 340                 OBD_FREE(lov->lov_qos.lq_rr_array, lov->lov_qos.lq_rr_size);
 341         lov->lov_qos.lq_rr_size = ost_count *
 342                 sizeof(lov->lov_qos.lq_rr_array[0]);
 343         OBD_ALLOC(lov->lov_qos.lq_rr_array, lov->lov_qos.lq_rr_size);
 344         if (!lov->lov_qos.lq_rr_array) {
 345                 lov->lov_qos.lq_rr_size = 0;
 346                 up_write(&lov->lov_qos.lq_rw_sem);
 347                 RETURN(-ENOMEM);
 348         }
 349
 350         real_count = 0;
 351         for (i = 0; i < ost_count; i++) {
 352                 lov->lov_qos.lq_rr_array[i] = LOV_QOS_EMPTY;
 353                 if (lov->lov_tgts[i])
 354                         real_count++;
 355         }
 356
 357         /* Place all the OSTs from 1 OSS at the same time. */
 358         placed = 0;
 359         list_for_each_entry(oss, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
 360                 int j = 0;
 361                 for (i = 0; i < ost_count; i++) {
 362                         if (lov->lov_tgts[i] &&
 363                             (lov->lov_tgts[i]->ltd_qos.ltq_oss == oss)) {
 364                               /* Evenly space these OSTs across arrayspace */
 365                               int next = j * ost_count / oss->lqo_ost_count;
 366                               while (lov->lov_qos.lq_rr_array[next] !=
 367                                      LOV_QOS_EMPTY)
 368                                       next = (next + 1) % ost_count;
 369                               lov->lov_qos.lq_rr_array[next] = i;
 370                               j++;
 371                               placed++;
 372                       }
 373                 }
 374                 LASSERT(j == oss->lqo_ost_count);
 375         }
 376
 377         lov->lov_qos.lq_dirty_rr = 0;
 378         up_write(&lov->lov_qos.lq_rw_sem);
 379
 380         if (placed != real_count) {
 381                 /* This should never happen */
 382                 LCONSOLE_ERROR_MSG(0x14e, "Failed to place all OSTs in the "
 383                                    "round-robin list (%d of %d).\n",
 384                                    placed, real_count);
 385                 for (i = 0; i < ost_count; i++) {
 386                         LCONSOLE(D_WARNING, "rr #%d ost idx=%d\n", i,
 387                                  lov->lov_qos.lq_rr_array[i]);
 388                 }
 389                 lov->lov_qos.lq_dirty_rr = 1;
 390                 RETURN(-EAGAIN);
 391         }
 392
 393 #ifdef QOS_DEBUG
 394         for (i = 0; i < ost_count; i++) {
 395                 LCONSOLE(D_QOS, "rr #%d ost idx=%d\n", i,
 396                          lov->lov_qos.lq_rr_array[i]);
 397         }
 398 #endif
 399
 400         RETURN(0);
 401 }
 402
 403
 404 void qos_shrink_lsm(struct lov_request_set *set)
 405 {
 406         struct lov_stripe_md *lsm = set->set_oi->oi_md, *lsm_new;
 407         /* XXX LOV STACKING call into osc for sizes */
 408         unsigned oldsize, newsize;
 409
 410         if (set->set_oti && set->set_cookies && set->set_cookie_sent) {
 411                 struct llog_cookie *cookies;
 412                 oldsize = lsm->lsm_stripe_count * sizeof(*cookies);
 413                 newsize = set->set_count * sizeof(*cookies);
 414
 415                 cookies = set->set_cookies;
 416                 oti_alloc_cookies(set->set_oti, set->set_count);
 417                 if (set->set_oti->oti_logcookies) {
 418                         memcpy(set->set_oti->oti_logcookies, cookies, newsize);
 419                         OBD_FREE(cookies, oldsize);
 420                         set->set_cookies = set->set_oti->oti_logcookies;
 421                 } else {
 422                         CWARN("'leaking' %d bytes\n", oldsize - newsize);
 423                 }
 424         }
 425
 426         CWARN("using fewer stripes for object "LPU64": old %u new %u\n",
 427               lsm->lsm_object_id, lsm->lsm_stripe_count, set->set_count);
 428         LASSERT(lsm->lsm_stripe_count >= set->set_count);
 429
 430         newsize = lov_stripe_md_size(set->set_count);
 431         OBD_ALLOC(lsm_new, newsize);
 432         if (lsm_new != NULL) {
 433                 int i;
 434                 memcpy(lsm_new, lsm, sizeof(*lsm));
 435                 for (i = 0; i < lsm->lsm_stripe_count; i++) {
 436                         if (i < set->set_count) {
 437                                 lsm_new->lsm_oinfo[i] = lsm->lsm_oinfo[i];
 438                                 continue;
 439                         }
 440                         OBD_SLAB_FREE(lsm->lsm_oinfo[i], lov_oinfo_slab,
 441                                       sizeof(struct lov_oinfo));
 442                 }
 443                 lsm_new->lsm_stripe_count = set->set_count;
 444                 OBD_FREE(lsm, sizeof(struct lov_stripe_md) +
 445                          lsm->lsm_stripe_count * sizeof(struct lov_oinfo *));
 446                 set->set_oi->oi_md = lsm_new;
 447         } else {
 448                 CWARN("'leaking' few bytes\n");
 449         }
 450 }
 451
 452 int qos_remedy_create(struct lov_request_set *set, struct lov_request *req)
 453 {
 454         struct lov_stripe_md *lsm = set->set_oi->oi_md;
 455         struct lov_obd *lov = &set->set_exp->exp_obd->u.lov;
 456         unsigned ost_idx, ost_count = lov->desc.ld_tgt_count;
 457         int stripe, i, rc = -EIO;
 458         ENTRY;
 459
 460         ost_idx = (req->rq_idx + lsm->lsm_stripe_count) % ost_count;
 461         for (i = 0; i < ost_count; i++, ost_idx = (ost_idx + 1) % ost_count) {
 462                 if (!lov->lov_tgts[ost_idx] ||
 463                     !lov->lov_tgts[ost_idx]->ltd_active)
 464                         continue;
 465                 /* check if objects has been created on this ost */
 466                 for (stripe = 0; stripe < lsm->lsm_stripe_count; stripe++) {
 467                         if (stripe == req->rq_stripe)
 468                                 continue;
 469                         if (ost_idx == lsm->lsm_oinfo[stripe]->loi_ost_idx)
 470                                 break;
 471                 }
 472
 473                 if (stripe >= lsm->lsm_stripe_count) {
 474                         req->rq_idx = ost_idx;
 475                         rc = obd_create(lov->lov_tgts[ost_idx]->ltd_exp,
 476                                         req->rq_oi.oi_oa, &req->rq_oi.oi_md,
 477                                         set->set_oti);
 478                         if (!rc)
 479                                 break;
 480                 }
 481         }
 482         RETURN(rc);
 483 }
 484
 485 static int min_stripe_count(int stripe_cnt, int flags)
 486 {
 487         return (flags & LOV_USES_DEFAULT_STRIPE ?
 488                 stripe_cnt - (stripe_cnt / 4) : stripe_cnt);
 489 }
 490
 491 #define LOV_CREATE_RESEED_MULT 4
 492 #define LOV_CREATE_RESEED_MIN  1000
 493 /* Allocate objects on osts with round-robin algorithm */
 494 static int alloc_rr(struct lov_obd *lov, int *idx_arr, int *stripe_cnt,
 495                     int flags)
 496 {
 497         unsigned array_idx, ost_count = lov->desc.ld_tgt_count;
 498         unsigned ost_active_count = lov->desc.ld_active_tgt_count;
 499         int i, *idx_pos;
 500         __u32 ost_idx;
 501         int ost_start_idx_temp;
 502         int speed = 0;
 503         int stripe_cnt_min = min_stripe_count(*stripe_cnt, flags);
 504         ENTRY;
 505
 506         i = qos_calc_rr(lov);
 507         if (i)
 508                 RETURN(i);
 509
 510         if (--lov->lov_start_count <= 0) {
 511                 lov->lov_start_idx = ll_rand() % ost_count;
 512                 lov->lov_start_count =
 513                         (LOV_CREATE_RESEED_MIN / max(ost_active_count, 1U) +
 514                          LOV_CREATE_RESEED_MULT) * max(ost_active_count, 1U);
 515         } else if (stripe_cnt_min >= ost_active_count ||
 516                    lov->lov_start_idx > ost_count) {
 517                 /* If we have allocated from all of the OSTs, slowly
 518                    precess the next start */
 519                 lov->lov_start_idx %= ost_count;
 520                 if (*stripe_cnt > 1 && (ost_active_count % (*stripe_cnt) != 1))
 521                         ++lov->lov_offset_idx;
 522         }
 523         down_read(&lov->lov_qos.lq_rw_sem);
 524         ost_start_idx_temp = lov->lov_start_idx;
 525
 526 repeat_find :
 527         array_idx = (lov->lov_start_idx + lov->lov_offset_idx) % ost_count;
 528         idx_pos = idx_arr;
 529 #ifdef QOS_DEBUG
 530         CDEBUG(D_QOS, "want %d startidx %d startcnt %d offset %d arrayidx %d\n",
 531                stripe_cnt_min, lov->lov_start_idx, lov->lov_start_count,
 532                lov->lov_offset_idx, array_idx);
 533 #endif
 534
 535         for (i = 0; i < ost_count; i++, array_idx=(array_idx + 1) % ost_count) {
 536                 ++lov->lov_start_idx;
 537                 ost_idx = lov->lov_qos.lq_rr_array[array_idx];
 538 #ifdef QOS_DEBUG
 539                 CDEBUG(D_QOS, "#%d strt %d act %d strp %d ary %d idx %d\n",
 540                        i, lov->lov_start_idx,
 541                        ((ost_idx != LOV_QOS_EMPTY) && lov->lov_tgts[ost_idx]) ?
 542                        lov->lov_tgts[ost_idx]->ltd_active : 0,
 543                        idx_pos - idx_arr, array_idx, ost_idx);
 544 #endif
 545                 if ((ost_idx == LOV_QOS_EMPTY) || !lov->lov_tgts[ost_idx] ||
 546                     !lov->lov_tgts[ost_idx]->ltd_active)
 547                         continue;
 548
 549                 /* Fail Check before osc_precreate() is called
 550                    so we can only 'fail' single OSC. */
 551                 if (OBD_FAIL_CHECK(OBD_FAIL_MDS_OSC_PRECREATE) && ost_idx == 0)
 552                         continue;
 553
 554                 /* Drop slow OSCs if we can */
 555                 if (obd_precreate(lov->lov_tgts[ost_idx]->ltd_exp, speed == 0) >
 556                     speed)
 557                         continue;
 558
 559                 *idx_pos = ost_idx;
 560                 idx_pos++;
 561                 /* We have enough stripes */
 562                 if (idx_pos - idx_arr == *stripe_cnt)
 563                         break;
 564         }
 565         if ((speed < 2) && (idx_pos - idx_arr < stripe_cnt_min)) {
 566                 /* Try again, allowing slower OSCs */
 567                 speed++;
 568                 lov->lov_start_idx = ost_start_idx_temp;
 569                 goto repeat_find;
 570         }
 571
 572         up_read(&lov->lov_qos.lq_rw_sem);
 573
 574         *stripe_cnt = idx_pos - idx_arr;
 575         RETURN(0);
 576 }
 577
 578 /* alloc objects on osts with specific stripe offset */
 579 static int alloc_specific(struct lov_obd *lov, struct lov_stripe_md *lsm,
 580                           int *idx_arr)
 581 {
 582         unsigned ost_idx, ost_count = lov->desc.ld_tgt_count;
 583         int i, *idx_pos;
 584         int speed = 0;
 585         ENTRY;
 586
 587 repeat_find:
 588         ost_idx = lsm->lsm_oinfo[0]->loi_ost_idx;
 589         idx_pos = idx_arr;
 590         for (i = 0; i < ost_count; i++, ost_idx = (ost_idx + 1) % ost_count) {
 591                 if (!lov->lov_tgts[ost_idx] ||
 592                     !lov->lov_tgts[ost_idx]->ltd_active) {
 593                         continue;
 594                 }
 595
 596                 /* Fail Check before osc_precreate() is called
 597                    so we can only 'fail' single OSC. */
 598                 if (OBD_FAIL_CHECK(OBD_FAIL_MDS_OSC_PRECREATE) && ost_idx == 0)
 599                         continue;
 600
 601                 /* Drop slow OSCs if we can */
 602                 if (obd_precreate(lov->lov_tgts[ost_idx]->ltd_exp, speed == 0) >
 603                     speed)
 604                         continue;
 605
 606                 *idx_pos = ost_idx;
 607                 idx_pos++;
 608                 /* We have enough stripes */
 609                 if (idx_pos - idx_arr == lsm->lsm_stripe_count)
 610                         RETURN(0);
 611         }
 612         if (speed < 2) {
 613                 /* Try again, allowing slower OSCs */
 614                 speed++;
 615                 goto repeat_find;
 616         }
 617
 618         /* If we were passed specific striping params, then a failure to
 619          * meet those requirements is an error, since we can't reallocate
 620          * that memory (it might be part of a larger array or something).
 621          *
 622          * We can only get here if lsm_stripe_count was originally > 1.
 623          */
 624         CERROR("can't lstripe objid "LPX64": have "LPSZ" want %u\n",
 625                lsm->lsm_object_id, idx_pos - idx_arr, lsm->lsm_stripe_count);
 626         RETURN(-EFBIG);
 627 }
 628
 629 /* Alloc objects on osts with optimization based on:
 630    - free space
 631    - network resources (shared OSS's)
 632 */
 633 static int alloc_qos(struct obd_export *exp, int *idx_arr, int *stripe_cnt,
 634                      int flags)
 635 {
 636         struct lov_obd *lov = &exp->exp_obd->u.lov;
 637         static time_t last_warn = 0;
 638         time_t now = cfs_time_current_sec();
 639         __u64 total_bavail, total_weight = 0;
 640         __u32 ost_count;
 641         int nfound, good_osts, i, warn = 0, rc = 0;
 642         int stripe_cnt_min = min_stripe_count(*stripe_cnt, flags);
 643         ENTRY;
 644
 645         if (stripe_cnt_min < 1)
 646                 GOTO(out, rc = -EINVAL);
 647
 648         lov_getref(exp->exp_obd);
 649         down_write(&lov->lov_qos.lq_rw_sem);
 650
 651         ost_count = lov->desc.ld_tgt_count;
 652
 653         if (lov->desc.ld_active_tgt_count < 2)
 654                 GOTO(out, rc = -EAGAIN);
 655
 656         rc = qos_calc_ppo(exp->exp_obd);
 657         if (rc)
 658                 GOTO(out, rc);
 659
 660         total_bavail = 0;
 661         good_osts = 0;
 662         /* Warn users about zero available space/inode every 30 min */
 663         if (cfs_time_sub(now, last_warn) > 60 * 30)
 664                 warn = 1;
 665         /* Find all the OSTs that are valid stripe candidates */
 666         for (i = 0; i < ost_count; i++) {
 667                 __u64 bavail;
 668
 669                 if (!lov->lov_tgts[i] || !lov->lov_tgts[i]->ltd_active)
 670                         continue;
 671                 bavail = TGT_BAVAIL(i);
 672                 if (!bavail) {
 673                         if (warn) {
 674                                 CDEBUG(D_QOS, "no free space on %s\n",
 675                                      obd_uuid2str(&lov->lov_tgts[i]->ltd_uuid));
 676                                 last_warn = now;
 677                         }
 678                         continue;
 679                 }
 680                 if (!TGT_FFREE(i)) {
 681                         if (warn) {
 682                                 CDEBUG(D_QOS, "no free inodes on %s\n",
 683                                      obd_uuid2str(&lov->lov_tgts[i]->ltd_uuid));
 684                                 last_warn = now;
 685                         }
 686                         continue;
 687                 }
 688
 689                 /* Fail Check before osc_precreate() is called
 690                    so we can only 'fail' single OSC. */
 691                 if (OBD_FAIL_CHECK(OBD_FAIL_MDS_OSC_PRECREATE) && i == 0)
 692                         continue;
 693
 694                 if (obd_precreate(lov->lov_tgts[i]->ltd_exp, 1) >= 2)
 695                         continue;
 696
 697                 lov->lov_tgts[i]->ltd_qos.ltq_usable = 1;
 698                 qos_calc_weight(lov, i);
 699                 total_bavail += bavail;
 700                 total_weight += lov->lov_tgts[i]->ltd_qos.ltq_weight;
 701
 702                 good_osts++;
 703         }
 704
 705         if (!total_bavail)
 706                 GOTO(out, rc = -ENOSPC);
 707
 708         if (good_osts < stripe_cnt_min)
 709                 GOTO(out, rc = -EAGAIN);
 710
 711         /* We have enough osts */
 712         if (good_osts < *stripe_cnt)
 713                 *stripe_cnt = good_osts;
 714
 715         /* Find enough OSTs with weighted random allocation. */
 716         nfound = 0;
 717         while (nfound < *stripe_cnt) {
 718                 __u64 rand, cur_weight;
 719
 720                 cur_weight = 0;
 721                 rc = -ENODEV;
 722
 723                 if (total_weight) {
 724 #if BITS_PER_LONG == 32
 725                         rand = ll_rand() % (unsigned)total_weight;
 726                         /* If total_weight > 32-bit, first generate the high
 727                          * 32 bits of the random number, then add in the low
 728                          * 32 bits (truncated to the upper limit, if needed) */
 729                         if (total_weight > 0xffffffffULL)
 730                                 rand = (__u64)(ll_rand() %
 731                                           (unsigned)(total_weight >> 32)) << 32;
 732                         else
 733                                 rand = 0;
 734
 735                         if (rand == (total_weight & 0xffffffff00000000ULL))
 736                                 rand |= ll_rand() % (unsigned)total_weight;
 737                         else
 738                                 rand |= ll_rand();
 739
 740 #else
 741                         rand = ((__u64)ll_rand() << 32 | ll_rand()) %
 742                                 total_weight;
 743 #endif
 744                 } else {
 745                         rand = 0;
 746                 }
 747
 748                 /* On average, this will hit larger-weighted osts more often.
 749                    0-weight osts will always get used last (only when rand=0).*/
 750                 for (i = 0; i < ost_count; i++) {
 751                         if (!lov->lov_tgts[i] ||
 752                             !lov->lov_tgts[i]->ltd_qos.ltq_usable)
 753                                 continue;
 754
 755                         cur_weight += lov->lov_tgts[i]->ltd_qos.ltq_weight;
 756                         if (cur_weight >= rand) {
 757 #ifdef QOS_DEBUG
 758                                 CDEBUG(D_QOS, "assigned stripe=%d to idx=%d\n",
 759                                        nfound, i);
 760 #endif
 761                                 idx_arr[nfound++] = i;
 762                                 qos_used(lov, i, &total_weight);
 763                                 rc = 0;
 764                                 break;
 765                         }
 766                 }
 767                 /* should never satisfy below condition */
 768                 if (rc) {
 769                         CERROR("Didn't find any OSTs?\n");
 770                         break;
 771                 }
 772         }
 773         LASSERT(nfound == *stripe_cnt);
 774
 775 out:
 776         up_write(&lov->lov_qos.lq_rw_sem);
 777
 778         if (rc == -EAGAIN)
 779                 rc = alloc_rr(lov, idx_arr, stripe_cnt, flags);
 780
 781         lov_putref(exp->exp_obd);
 782         RETURN(rc);
 783 }
 784
 785 /* return new alloced stripe count on success */
 786 static int alloc_idx_array(struct obd_export *exp, struct lov_stripe_md *lsm,
 787                            int newea, int **idx_arr, int *arr_cnt, int flags)
 788 {
 789         struct lov_obd *lov = &exp->exp_obd->u.lov;
 790         int stripe_cnt = lsm->lsm_stripe_count;
 791         int i, rc = 0;
 792         int *tmp_arr = NULL;
 793         ENTRY;
 794
 795         *arr_cnt = stripe_cnt;
 796         OBD_ALLOC(tmp_arr, *arr_cnt * sizeof(int));
 797         if (tmp_arr == NULL)
 798                 RETURN(-ENOMEM);
 799         for (i = 0; i < *arr_cnt; i++)
 800                 tmp_arr[i] = -1;
 801
 802         if (newea ||
 803             lsm->lsm_oinfo[0]->loi_ost_idx >= lov->desc.ld_tgt_count)
 804                 rc = alloc_qos(exp, tmp_arr, &stripe_cnt, flags);
 805         else
 806                 rc = alloc_specific(lov, lsm, tmp_arr);
 807
 808         if (rc)
 809                 GOTO(out_arr, rc);
 810
 811         *idx_arr = tmp_arr;
 812         RETURN(stripe_cnt);
 813 out_arr:
 814         OBD_FREE(tmp_arr, *arr_cnt * sizeof(int));
 815         *arr_cnt = 0;
 816         RETURN(rc);
 817 }
 818
 819 static void free_idx_array(int *idx_arr, int arr_cnt)
 820 {
 821         if (arr_cnt)
 822                 OBD_FREE(idx_arr, arr_cnt * sizeof(int));
 823 }
 824
 825 int qos_prep_create(struct obd_export *exp, struct lov_request_set *set)
 826 {
 827         struct lov_obd *lov = &exp->exp_obd->u.lov;
 828         struct lov_stripe_md *lsm;
 829         struct obdo *src_oa = set->set_oi->oi_oa;
 830         struct obd_trans_info *oti = set->set_oti;
 831         int i, stripes, rc = 0, newea = 0;
 832         int flag = LOV_USES_ASSIGNED_STRIPE;
 833         int *idx_arr = NULL, idx_cnt = 0;
 834         ENTRY;
 835
 836         LASSERT(src_oa->o_valid & OBD_MD_FLID);
 837
 838         if (set->set_oi->oi_md == NULL) {
 839                 int stripes_def = lov_get_stripecnt(lov, 0);
 840
 841                 /* If the MDS file was truncated up to some size, stripe over
 842                  * enough OSTs to allow the file to be created at that size.
 843                  * This may mean we use more than the default # of stripes. */
 844                 if (src_oa->o_valid & OBD_MD_FLSIZE) {
 845                         obd_size min_bavail = LUSTRE_STRIPE_MAXBYTES;
 846
 847                         /* Find a small number of stripes we can use
 848                            (up to # of active osts). */
 849                         stripes = 1;
 850                         lov_getref(exp->exp_obd);
 851                         for (i = 0; i < lov->desc.ld_tgt_count; i++) {
 852                                 if (!lov->lov_tgts[i] ||
 853                                     !lov->lov_tgts[i]->ltd_active)
 854                                         continue;
 855                                 min_bavail = min(min_bavail, TGT_BAVAIL(i));
 856                                 if (min_bavail * stripes > src_oa->o_size)
 857                                         break;
 858                                 stripes++;
 859                         }
 860                         lov_putref(exp->exp_obd);
 861
 862                         if (stripes < stripes_def)
 863                                 stripes = stripes_def;
 864                 } else {
 865                          flag = LOV_USES_DEFAULT_STRIPE;
 866                          stripes = stripes_def;
 867                 }
 868
 869                 rc = lov_alloc_memmd(&set->set_oi->oi_md, stripes,
 870                                      lov->desc.ld_pattern ?
 871                                      lov->desc.ld_pattern : LOV_PATTERN_RAID0,
 872                                      LOV_MAGIC);
 873                 if (rc < 0)
 874                         GOTO(out_err, rc);
 875                 newea = 1;
 876                 rc = 0;
 877         }
 878
 879         lsm = set->set_oi->oi_md;
 880         lsm->lsm_object_id = src_oa->o_id;
 881         if (!lsm->lsm_stripe_size)
 882                 lsm->lsm_stripe_size = lov->desc.ld_default_stripe_size;
 883         if (!lsm->lsm_pattern) {
 884                 LASSERT(lov->desc.ld_pattern);
 885                 lsm->lsm_pattern = lov->desc.ld_pattern;
 886         }
 887
 888         stripes = alloc_idx_array(exp, lsm, newea, &idx_arr, &idx_cnt, flag);
 889         if (stripes <= 0)
 890                 GOTO(out_err, rc = stripes ? stripes : -EIO);
 891         LASSERTF(stripes <= lsm->lsm_stripe_count,"requested %d allocated %d\n",
 892                  lsm->lsm_stripe_count, stripes);
 893
 894         for (i = 0; i < stripes; i++) {
 895                 struct lov_request *req;
 896                 int ost_idx = idx_arr[i];
 897                 LASSERT(ost_idx >= 0);
 898
 899                 OBD_ALLOC(req, sizeof(*req));
 900                 if (req == NULL)
 901                         GOTO(out_err, rc = -ENOMEM);
 902                 lov_set_add_req(req, set);
 903
 904                 req->rq_buflen = sizeof(*req->rq_oi.oi_md);
 905                 OBD_ALLOC(req->rq_oi.oi_md, req->rq_buflen);
 906                 if (req->rq_oi.oi_md == NULL)
 907                         GOTO(out_err, rc = -ENOMEM);
 908
 909                 OBDO_ALLOC(req->rq_oi.oi_oa);
 910                 if (req->rq_oi.oi_oa == NULL)
 911                         GOTO(out_err, rc = -ENOMEM);
 912
 913                 req->rq_idx = ost_idx;
 914                 req->rq_stripe = i;
 915                 /* create data objects with "parent" OA */
 916                 memcpy(req->rq_oi.oi_oa, src_oa, sizeof(*req->rq_oi.oi_oa));
 917
 918                 /* XXX When we start creating objects on demand, we need to
 919                  *     make sure that we always create the object on the
 920                  *     stripe which holds the existing file size.
 921                  */
 922                 if (src_oa->o_valid & OBD_MD_FLSIZE) {
 923                         req->rq_oi.oi_oa->o_size =
 924                                 lov_size_to_stripe(lsm, src_oa->o_size, i);
 925
 926                         CDEBUG(D_INODE, "stripe %d has size "LPU64"/"LPU64"\n",
 927                                i, req->rq_oi.oi_oa->o_size, src_oa->o_size);
 928                 }
 929
 930         }
 931         LASSERT(set->set_count == stripes);
 932
 933         if (stripes < lsm->lsm_stripe_count)
 934                 qos_shrink_lsm(set);
 935
 936         if (oti && (src_oa->o_valid & OBD_MD_FLCOOKIE)) {
 937                 oti_alloc_cookies(oti, set->set_count);
 938                 if (!oti->oti_logcookies)
 939                         GOTO(out_err, rc = -ENOMEM);
 940                 set->set_cookies = oti->oti_logcookies;
 941         }
 942 out_err:
 943         if (newea && rc)
 944                 obd_free_memmd(exp, &set->set_oi->oi_md);
 945         free_idx_array(idx_arr, idx_cnt);
 946         EXIT;
 947         return rc;
 948 }
 949
 950 void qos_update(struct lov_obd *lov)
 951 {
 952         ENTRY;
 953         lov->lov_qos.lq_dirty = 1;
 954 }
 955