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(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 #define LOV_CREATE_RESEED_MULT 4
 486 #define LOV_CREATE_RESEED_MIN  1000
 487 /* Allocate objects on osts with round-robin algorithm */
 488 static int alloc_rr(struct lov_obd *lov, int *idx_arr, int *stripe_cnt)
 489 {
 490         unsigned array_idx, ost_count = lov->desc.ld_tgt_count;
 491         unsigned ost_active_count = lov->desc.ld_active_tgt_count;
 492         int i, *idx_pos = idx_arr;
 493         __u32 ost_idx;
 494         ENTRY;
 495
 496         i = qos_calc_rr(lov);
 497         if (i)
 498                 RETURN(i);
 499
 500         if (--lov->lov_start_count <= 0) {
 501                 lov->lov_start_idx = ll_rand() % ost_count;
 502                 lov->lov_start_count =
 503                         (LOV_CREATE_RESEED_MIN / max(ost_active_count, 1U) +
 504                          LOV_CREATE_RESEED_MULT) * max(ost_active_count, 1U);
 505         } else if (*stripe_cnt >= ost_active_count ||
 506                    lov->lov_start_idx > ost_count) {
 507                 /* If we have allocated from all of the OSTs, slowly
 508                    precess the next start */
 509                 lov->lov_start_idx %= ost_count;
 510                 ++lov->lov_offset_idx;
 511         }
 512         array_idx = (lov->lov_start_idx + lov->lov_offset_idx) % ost_count;
 513 #ifdef QOS_DEBUG
 514         CDEBUG(D_QOS, "want %d startidx %d startcnt %d offset %d arrayidx %d\n",
 515                *stripe_cnt, lov->lov_start_idx, lov->lov_start_count,
 516                lov->lov_offset_idx, array_idx);
 517 #endif
 518
 519         down_read(&lov->lov_qos.lq_rw_sem);
 520         for (i = 0; i < ost_count; i++, array_idx=(array_idx + 1) % ost_count) {
 521                 ++lov->lov_start_idx;
 522                 ost_idx = lov->lov_qos.lq_rr_array[array_idx];
 523 #ifdef QOS_DEBUG
 524                 CDEBUG(D_QOS, "#%d strt %d act %d strp %d ary %d idx %d\n",
 525                        i, lov->lov_start_idx,
 526                        ((ost_idx != LOV_QOS_EMPTY) && lov->lov_tgts[ost_idx]) ?
 527                        lov->lov_tgts[ost_idx]->ltd_active : 0,
 528                        idx_pos - idx_arr, array_idx, ost_idx);
 529 #endif
 530                 if ((ost_idx == LOV_QOS_EMPTY) || !lov->lov_tgts[ost_idx] ||
 531                     !lov->lov_tgts[ost_idx]->ltd_active)
 532                         continue;
 533                 *idx_pos = ost_idx;
 534                 idx_pos++;
 535                 /* We have enough stripes */
 536                 if (idx_pos - idx_arr == *stripe_cnt)
 537                         break;
 538         }
 539         up_read(&lov->lov_qos.lq_rw_sem);
 540
 541         *stripe_cnt = idx_pos - idx_arr;
 542         RETURN(0);
 543 }
 544
 545 /* alloc objects on osts with specific stripe offset */
 546 static int alloc_specific(struct lov_obd *lov, struct lov_stripe_md *lsm,
 547                           int *idx_arr)
 548 {
 549         unsigned ost_idx, ost_count = lov->desc.ld_tgt_count;
 550         int i, *idx_pos = idx_arr;
 551         ENTRY;
 552
 553         ost_idx = lsm->lsm_oinfo[0]->loi_ost_idx;
 554         for (i = 0; i < ost_count; i++, ost_idx = (ost_idx + 1) % ost_count) {
 555                 if (!lov->lov_tgts[ost_idx] ||
 556                     !lov->lov_tgts[ost_idx]->ltd_active) {
 557                         continue;
 558                 }
 559                 *idx_pos = ost_idx;
 560                 idx_pos++;
 561                 /* got enough ost */
 562                 if (idx_pos - idx_arr == lsm->lsm_stripe_count)
 563                         RETURN(0);
 564         }
 565         /* If we were passed specific striping params, then a failure to
 566          * meet those requirements is an error, since we can't reallocate
 567          * that memory (it might be part of a larger array or something).
 568          *
 569          * We can only get here if lsm_stripe_count was originally > 1.
 570          */
 571         CERROR("can't lstripe objid "LPX64": have "LPSZ" want %u\n",
 572                lsm->lsm_object_id, idx_pos - idx_arr, lsm->lsm_stripe_count);
 573         RETURN(-EFBIG);
 574 }
 575
 576 /* Alloc objects on osts with optimization based on:
 577    - free space
 578    - network resources (shared OSS's)
 579 */
 580 static int alloc_qos(struct obd_export *exp, int *idx_arr, int *stripe_cnt)
 581 {
 582         struct lov_obd *lov = &exp->exp_obd->u.lov;
 583         static time_t last_warn = 0;
 584         time_t now = cfs_time_current_sec();
 585         __u64 total_bavail, total_weight = 0;
 586         __u32 ost_count;
 587         int nfound, good_osts, i, warn = 0, rc = 0;
 588         ENTRY;
 589
 590         lov_getref(exp->exp_obd);
 591         down_write(&lov->lov_qos.lq_rw_sem);
 592
 593         ost_count = lov->desc.ld_tgt_count;
 594
 595         if (lov->desc.ld_active_tgt_count < 2)
 596                 GOTO(out, rc = -EAGAIN);
 597
 598         rc = qos_calc_ppo(exp->exp_obd);
 599         if (rc)
 600                 GOTO(out, rc);
 601
 602         total_bavail = 0;
 603         good_osts = 0;
 604         /* Warn users about zero available space/inode every 30 min */
 605         if (cfs_time_sub(now, last_warn) > 60 * 30)
 606                 warn = 1;
 607         /* Find all the OSTs that are valid stripe candidates */
 608         for (i = 0; i < ost_count; i++) {
 609                 __u64 bavail;
 610
 611                 if (!lov->lov_tgts[i] || !lov->lov_tgts[i]->ltd_active)
 612                         continue;
 613                 bavail = TGT_BAVAIL(i);
 614                 if (!bavail) {
 615                         if (warn) {
 616                                 CDEBUG(D_QOS, "no free space on %s\n",
 617                                      obd_uuid2str(&lov->lov_tgts[i]->ltd_uuid));
 618                                 last_warn = now;
 619                         }
 620                         continue;
 621                 }
 622                 if (!TGT_FFREE(i)) {
 623                         if (warn) {
 624                                 CDEBUG(D_QOS, "no free inodes on %s\n",
 625                                      obd_uuid2str(&lov->lov_tgts[i]->ltd_uuid));
 626                                 last_warn = now;
 627                         }
 628                         continue;
 629                 }
 630
 631                 lov->lov_tgts[i]->ltd_qos.ltq_usable = 1;
 632                 qos_calc_weight(lov, i);
 633                 total_bavail += bavail;
 634                 total_weight += lov->lov_tgts[i]->ltd_qos.ltq_weight;
 635
 636                 good_osts++;
 637         }
 638
 639         if (!total_bavail)
 640                 GOTO(out, rc = -ENOSPC);
 641
 642         /* if we don't have enough good OSTs, we reduce the stripe count. */
 643         if (good_osts < *stripe_cnt)
 644                 *stripe_cnt = good_osts;
 645
 646         if (!*stripe_cnt)
 647                 GOTO(out, rc = -EAGAIN);
 648
 649         /* Find enough OSTs with weighted random allocation. */
 650         nfound = 0;
 651         while (nfound < *stripe_cnt) {
 652                 __u64 rand, cur_weight;
 653
 654                 cur_weight = 0;
 655                 rc = -ENODEV;
 656
 657                 if (total_weight) {
 658 #if BITS_PER_LONG == 32
 659                         rand = ll_rand() % (unsigned)total_weight;
 660                         /* If total_weight > 32-bit, first generate the high
 661                          * 32 bits of the random number, then add in the low
 662                          * 32 bits (truncated to the upper limit, if needed) */
 663                         if (total_weight > 0xffffffffULL)
 664                                 rand = (__u64)(ll_rand() %
 665                                           (unsigned)(total_weight >> 32)) << 32;
 666                         else
 667                                 rand = 0;
 668
 669                         if (rand == (total_weight & 0xffffffff00000000ULL))
 670                                 rand |= ll_rand() % (unsigned)total_weight;
 671                         else
 672                                 rand |= ll_rand();
 673
 674 #else
 675                         rand = ((__u64)ll_rand() << 32 | ll_rand()) %
 676                                 total_weight;
 677 #endif
 678                 } else {
 679                         rand = 0;
 680                 }
 681
 682                 /* On average, this will hit larger-weighted osts more often.
 683                    0-weight osts will always get used last (only when rand=0).*/
 684                 for (i = 0; i < ost_count; i++) {
 685                         if (!lov->lov_tgts[i] ||
 686                             !lov->lov_tgts[i]->ltd_qos.ltq_usable)
 687                                 continue;
 688                         cur_weight += lov->lov_tgts[i]->ltd_qos.ltq_weight;
 689                         if (cur_weight >= rand) {
 690 #ifdef QOS_DEBUG
 691                                 CDEBUG(D_QOS, "assigned stripe=%d to idx=%d\n",
 692                                        nfound, i);
 693 #endif
 694                                 idx_arr[nfound++] = i;
 695                                 qos_used(lov, i, &total_weight);
 696                                 rc = 0;
 697                                 break;
 698                         }
 699                 }
 700                 /* should never satisfy below condition */
 701                 if (rc) {
 702                         CERROR("Didn't find any OSTs?\n");
 703                         break;
 704                 }
 705         }
 706         LASSERT(nfound == *stripe_cnt);
 707
 708 out:
 709         up_write(&lov->lov_qos.lq_rw_sem);
 710
 711         if (rc == -EAGAIN)
 712                 rc = alloc_rr(lov, idx_arr, stripe_cnt);
 713
 714         lov_putref(exp->exp_obd);
 715         RETURN(rc);
 716 }
 717
 718 /* return new alloced stripe count on success */
 719 static int alloc_idx_array(struct obd_export *exp, struct lov_stripe_md *lsm,
 720                            int newea, int **idx_arr, int *arr_cnt)
 721 {
 722         struct lov_obd *lov = &exp->exp_obd->u.lov;
 723         int stripe_cnt = lsm->lsm_stripe_count;
 724         int i, rc = 0;
 725         int *tmp_arr = NULL;
 726         ENTRY;
 727
 728         *arr_cnt = stripe_cnt;
 729         OBD_ALLOC(tmp_arr, *arr_cnt * sizeof(int));
 730         if (tmp_arr == NULL)
 731                 RETURN(-ENOMEM);
 732         for (i = 0; i < *arr_cnt; i++)
 733                 tmp_arr[i] = -1;
 734
 735         if (newea ||
 736             lsm->lsm_oinfo[0]->loi_ost_idx >= lov->desc.ld_tgt_count)
 737                 rc = alloc_qos(exp, tmp_arr, &stripe_cnt);
 738         else
 739                 rc = alloc_specific(lov, lsm, tmp_arr);
 740
 741         if (rc)
 742                 GOTO(out_arr, rc);
 743
 744         *idx_arr = tmp_arr;
 745         RETURN(stripe_cnt);
 746 out_arr:
 747         OBD_FREE(tmp_arr, *arr_cnt * sizeof(int));
 748         *arr_cnt = 0;
 749         RETURN(rc);
 750 }
 751
 752 static void free_idx_array(int *idx_arr, int arr_cnt)
 753 {
 754         if (arr_cnt)
 755                 OBD_FREE(idx_arr, arr_cnt * sizeof(int));
 756 }
 757
 758 int qos_prep_create(struct obd_export *exp, struct lov_request_set *set)
 759 {
 760         struct lov_obd *lov = &exp->exp_obd->u.lov;
 761         struct lov_stripe_md *lsm;
 762         struct obdo *src_oa = set->set_oi->oi_oa;
 763         struct obd_trans_info *oti = set->set_oti;
 764         int i, stripes, rc = 0, newea = 0;
 765         int *idx_arr, idx_cnt = 0;
 766         ENTRY;
 767
 768         LASSERT(src_oa->o_valid & OBD_MD_FLID);
 769
 770         if (set->set_oi->oi_md == NULL) {
 771                 int stripe_cnt = lov_get_stripecnt(lov, 0);
 772
 773                 /* If the MDS file was truncated up to some size, stripe over
 774                  * enough OSTs to allow the file to be created at that size.
 775                  * This may mean we use more than the default # of stripes. */
 776                 if (src_oa->o_valid & OBD_MD_FLSIZE) {
 777                         obd_size min_bavail = LUSTRE_STRIPE_MAXBYTES;
 778
 779                         /* Find a small number of stripes we can use
 780                            (up to # of active osts). */
 781                         stripes = 1;
 782                         lov_getref(exp->exp_obd);
 783                         for (i = 0; i < lov->desc.ld_tgt_count; i++) {
 784                                 if (!lov->lov_tgts[i] ||
 785                                     !lov->lov_tgts[i]->ltd_active)
 786                                         continue;
 787                                 min_bavail = min(min_bavail, TGT_BAVAIL(i));
 788                                 if (min_bavail * stripes > src_oa->o_size)
 789                                         break;
 790                                 stripes++;
 791                         }
 792                         lov_putref(exp->exp_obd);
 793
 794                         if (stripes < stripe_cnt)
 795                                 stripes = stripe_cnt;
 796                 } else {
 797                         stripes = stripe_cnt;
 798                 }
 799
 800                 rc = lov_alloc_memmd(&set->set_oi->oi_md, stripes,
 801                                      lov->desc.ld_pattern ?
 802                                      lov->desc.ld_pattern : LOV_PATTERN_RAID0,
 803                                      LOV_MAGIC);
 804                 if (rc < 0)
 805                         GOTO(out_err, rc);
 806                 rc = 0;
 807                 newea = 1;
 808         }
 809
 810         lsm = set->set_oi->oi_md;
 811         lsm->lsm_object_id = src_oa->o_id;
 812         if (!lsm->lsm_stripe_size)
 813                 lsm->lsm_stripe_size = lov->desc.ld_default_stripe_size;
 814         if (!lsm->lsm_pattern) {
 815                 LASSERT(lov->desc.ld_pattern);
 816                 lsm->lsm_pattern = lov->desc.ld_pattern;
 817         }
 818
 819         stripes = alloc_idx_array(exp, lsm, newea, &idx_arr, &idx_cnt);
 820         if (stripes <= 0)
 821                 GOTO(out_err, rc = stripes ? stripes : -EIO);
 822         LASSERTF(stripes <= lsm->lsm_stripe_count,"requested %d allocated %d\n",
 823                  lsm->lsm_stripe_count, stripes);
 824
 825         for (i = 0; i < stripes; i++) {
 826                 struct lov_request *req;
 827                 int ost_idx = idx_arr[i];
 828                 LASSERT(ost_idx >= 0);
 829
 830                 OBD_ALLOC(req, sizeof(*req));
 831                 if (req == NULL)
 832                         GOTO(out_err, rc = -ENOMEM);
 833                 lov_set_add_req(req, set);
 834
 835                 req->rq_buflen = sizeof(*req->rq_oi.oi_md);
 836                 OBD_ALLOC(req->rq_oi.oi_md, req->rq_buflen);
 837                 if (req->rq_oi.oi_md == NULL)
 838                         GOTO(out_err, rc = -ENOMEM);
 839
 840                 req->rq_oi.oi_oa = obdo_alloc();
 841                 if (req->rq_oi.oi_oa == NULL)
 842                         GOTO(out_err, rc = -ENOMEM);
 843
 844                 req->rq_idx = ost_idx;
 845                 req->rq_stripe = i;
 846                 /* create data objects with "parent" OA */
 847                 memcpy(req->rq_oi.oi_oa, src_oa, sizeof(*req->rq_oi.oi_oa));
 848
 849                 /* XXX When we start creating objects on demand, we need to
 850                  *     make sure that we always create the object on the
 851                  *     stripe which holds the existing file size.
 852                  */
 853                 if (src_oa->o_valid & OBD_MD_FLSIZE) {
 854                         req->rq_oi.oi_oa->o_size =
 855                                 lov_size_to_stripe(lsm, src_oa->o_size, i);
 856
 857                         CDEBUG(D_INODE, "stripe %d has size "LPU64"/"LPU64"\n",
 858                                i, req->rq_oi.oi_oa->o_size, src_oa->o_size);
 859                 }
 860
 861         }
 862         LASSERT(set->set_count == stripes);
 863
 864         if (stripes < lsm->lsm_stripe_count)
 865                 qos_shrink_lsm(set);
 866
 867         if (oti && (src_oa->o_valid & OBD_MD_FLCOOKIE)) {
 868                 oti_alloc_cookies(oti, set->set_count);
 869                 if (!oti->oti_logcookies)
 870                         GOTO(out_err, rc = -ENOMEM);
 871                 set->set_cookies = oti->oti_logcookies;
 872         }
 873 out_err:
 874         if (newea && rc)
 875                 obd_free_memmd(exp, &set->set_oi->oi_md);
 876         free_idx_array(idx_arr, idx_cnt);
 877         EXIT;
 878         return rc;
 879 }
 880
 881 void qos_update(struct lov_obd *lov)
 882 {
 883         ENTRY;
 884         lov->lov_qos.lq_dirty = 1;
 885 }
 886