4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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.
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).
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
23 * This file is part of Lustre, http://www.lustre.org/
25 * lustre/obdclass/lu_tgt_descs.c
27 * Lustre target descriptions
28 * These are the only exported functions, they provide some generic
29 * infrastructure for target description management used by LOD/LMV
33 #define DEBUG_SUBSYSTEM S_CLASS
35 #include <linux/module.h>
36 #include <linux/list.h>
37 #include <linux/random.h>
38 #include <libcfs/libcfs.h>
39 #include <libcfs/libcfs_hash.h> /* hash_long() */
40 #include <libcfs/linux/linux-mem.h>
41 #include <obd_class.h>
42 #include <obd_support.h>
43 #include <lustre_disk.h>
44 #include <lustre_fid.h>
45 #include <lu_object.h>
48 * lu_prandom_u64_max - returns a pseudo-random u64 number in interval
51 * \param[in] ep_ro right open interval endpoint
53 * \retval a pseudo-random 64-bit number that is in interval [0, ep_ro).
55 u64 lu_prandom_u64_max(u64 ep_ro)
60 #if BITS_PER_LONG == 32
62 * If ep_ro > 32-bit, first generate the high
63 * 32 bits of the random number, then add in the low
64 * 32 bits (truncated to the upper limit, if needed)
66 if (ep_ro > 0xffffffffULL)
67 rand = (u64)prandom_u32_max((u32)(ep_ro >> 32)) << 32;
69 if (rand == (ep_ro & 0xffffffff00000000ULL))
70 rand |= prandom_u32_max((u32)ep_ro);
72 rand |= prandom_u32();
74 rand = ((u64)prandom_u32() << 32 | prandom_u32()) % ep_ro;
80 EXPORT_SYMBOL(lu_prandom_u64_max);
83 * Add a new target to Quality of Service (QoS) target table.
85 * Add a new MDT/OST target to the structure representing an OSS. Resort the
86 * list of known MDSs/OSSs by the number of MDTs/OSTs attached to each MDS/OSS.
87 * The MDS/OSS list is protected internally and no external locking is required.
89 * \param[in] qos lu_qos data
90 * \param[in] tgt target description
92 * \retval 0 on success
93 * \retval -ENOMEM on error
95 int lu_qos_add_tgt(struct lu_qos *qos, struct lu_tgt_desc *tgt)
97 struct lu_svr_qos *svr = NULL;
98 struct lu_svr_qos *tempsvr;
99 struct obd_export *exp = tgt->ltd_exp;
106 down_write(&qos->lq_rw_sem);
108 * a bit hacky approach to learn NID of corresponding connection
109 * but there is no official API to access information like this
112 list_for_each_entry(svr, &qos->lq_svr_list, lsq_svr_list) {
113 if (obd_uuid_equals(&svr->lsq_uuid,
114 &exp->exp_connection->c_remote_uuid)) {
118 if (svr->lsq_id > id)
125 GOTO(out, rc = -ENOMEM);
126 memcpy(&svr->lsq_uuid, &exp->exp_connection->c_remote_uuid,
127 sizeof(svr->lsq_uuid));
131 /* Assume we have to move this one */
132 list_del(&svr->lsq_svr_list);
135 svr->lsq_tgt_count++;
136 tgt->ltd_qos.ltq_svr = svr;
138 CDEBUG(D_OTHER, "add tgt %s to server %s (%d targets)\n",
139 obd_uuid2str(&tgt->ltd_uuid), obd_uuid2str(&svr->lsq_uuid),
143 * Add sorted by # of tgts. Find the first entry that we're
146 list_for_each_entry(tempsvr, &qos->lq_svr_list, lsq_svr_list) {
147 if (svr->lsq_tgt_count > tempsvr->lsq_tgt_count)
151 * ...and add before it. If we're the first or smallest, tempsvr
152 * points to the list head, and we add to the end.
154 list_add_tail(&svr->lsq_svr_list, &tempsvr->lsq_svr_list);
156 set_bit(LQ_DIRTY, &qos->lq_flags);
157 #ifdef HAVE_SERVER_SUPPORT
158 set_bit(LQ_DIRTY, &qos->lq_rr.lqr_flags);
161 up_write(&qos->lq_rw_sem);
164 EXPORT_SYMBOL(lu_qos_add_tgt);
167 * Remove MDT/OST target from QoS table.
169 * Removes given MDT/OST target from QoS table and releases related
170 * MDS/OSS structure if no target remain on the MDS/OSS.
172 * \param[in] qos lu_qos data
173 * \param[in] ltd target description
175 * \retval 0 on success
176 * \retval -ENOENT if no server was found
178 static int lu_qos_del_tgt(struct lu_qos *qos, struct lu_tgt_desc *ltd)
180 struct lu_svr_qos *svr;
185 down_write(&qos->lq_rw_sem);
186 svr = ltd->ltd_qos.ltq_svr;
188 GOTO(out, rc = -ENOENT);
190 svr->lsq_tgt_count--;
191 if (svr->lsq_tgt_count == 0) {
192 CDEBUG(D_OTHER, "removing server %s\n",
193 obd_uuid2str(&svr->lsq_uuid));
194 list_del(&svr->lsq_svr_list);
195 ltd->ltd_qos.ltq_svr = NULL;
199 set_bit(LQ_DIRTY, &qos->lq_flags);
200 #ifdef HAVE_SERVER_SUPPORT
201 set_bit(LQ_DIRTY, &qos->lq_rr.lqr_flags);
204 up_write(&qos->lq_rw_sem);
208 static inline __u64 tgt_statfs_bavail(struct lu_tgt_desc *tgt)
210 struct obd_statfs *statfs = &tgt->ltd_statfs;
212 return statfs->os_bavail * statfs->os_bsize;
215 static inline __u64 tgt_statfs_iavail(struct lu_tgt_desc *tgt)
217 return tgt->ltd_statfs.os_ffree;
221 * Calculate weight for a given tgt.
223 * The final tgt weight is bavail >> 16 * iavail >> 8 minus the tgt and server
224 * penalties. See ltd_qos_penalties_calc() for how penalties are calculated.
226 * \param[in] tgt target descriptor
228 void lu_tgt_qos_weight_calc(struct lu_tgt_desc *tgt)
230 struct lu_tgt_qos *ltq = &tgt->ltd_qos;
233 ltq->ltq_avail = (tgt_statfs_bavail(tgt) >> 16) *
234 (tgt_statfs_iavail(tgt) >> 8);
235 penalty = ltq->ltq_penalty + ltq->ltq_svr->lsq_penalty;
236 if (ltq->ltq_avail < penalty)
239 ltq->ltq_weight = ltq->ltq_avail - penalty;
241 EXPORT_SYMBOL(lu_tgt_qos_weight_calc);
244 * Allocate and initialize target table.
246 * A helper function to initialize the target table and allocate
247 * a bitmap of the available targets.
249 * \param[in] ltd target's table to initialize
250 * \param[in] is_mdt target table for MDTs
252 * \retval 0 on success
253 * \retval negative negated errno on error
255 int lu_tgt_descs_init(struct lu_tgt_descs *ltd, bool is_mdt)
257 mutex_init(<d->ltd_mutex);
258 init_rwsem(<d->ltd_rw_sem);
261 * the tgt array and bitmap are allocated/grown dynamically as tgts are
262 * added to the LOD/LMV, see lu_tgt_descs_add()
264 ltd->ltd_tgt_bitmap = bitmap_zalloc(BITS_PER_LONG, GFP_NOFS);
265 if (!ltd->ltd_tgt_bitmap)
268 ltd->ltd_tgts_size = BITS_PER_LONG;
269 ltd->ltd_death_row = 0;
270 ltd->ltd_refcount = 0;
272 /* Set up allocation policy (QoS and RR) */
273 INIT_LIST_HEAD(<d->ltd_qos.lq_svr_list);
274 init_rwsem(<d->ltd_qos.lq_rw_sem);
275 set_bit(LQ_DIRTY, <d->ltd_qos.lq_flags);
276 set_bit(LQ_RESET, <d->ltd_qos.lq_flags);
277 ltd->ltd_is_mdt = is_mdt;
278 /* MDT imbalance threshold is low to balance across MDTs
279 * relatively quickly, because each directory may result
280 * in a large number of files/subdirs created therein.
283 ltd->ltd_lmv_desc.ld_pattern = LMV_HASH_TYPE_DEFAULT;
284 ltd->ltd_qos.lq_prio_free = LMV_QOS_DEF_PRIO_FREE * 256 / 100;
285 ltd->ltd_qos.lq_threshold_rr =
286 LMV_QOS_DEF_THRESHOLD_RR_PCT * 256 / 100;
288 ltd->ltd_qos.lq_prio_free = LOV_QOS_DEF_PRIO_FREE * 256 / 100;
289 ltd->ltd_qos.lq_threshold_rr =
290 LOV_QOS_DEF_THRESHOLD_RR_PCT * 256 / 100;
295 EXPORT_SYMBOL(lu_tgt_descs_init);
298 * Free bitmap and target table pages.
300 * \param[in] ltd target table
302 void lu_tgt_descs_fini(struct lu_tgt_descs *ltd)
306 bitmap_free(ltd->ltd_tgt_bitmap);
307 for (i = 0; i < ARRAY_SIZE(ltd->ltd_tgt_idx); i++) {
308 if (ltd->ltd_tgt_idx[i])
309 OBD_FREE_PTR(ltd->ltd_tgt_idx[i]);
311 ltd->ltd_tgts_size = 0;
313 EXPORT_SYMBOL(lu_tgt_descs_fini);
316 * Expand size of target table.
318 * When the target table is full, we have to extend the table. To do so,
319 * we allocate new memory with some reserve, move data from the old table
320 * to the new one and release memory consumed by the old table.
322 * \param[in] ltd target table
323 * \param[in] newsize new size of the table
325 * \retval 0 on success
326 * \retval -ENOMEM if reallocation failed
328 static int lu_tgt_descs_resize(struct lu_tgt_descs *ltd, __u32 newsize)
330 unsigned long *new_bitmap, *old_bitmap = NULL;
332 /* someone else has already resize the array */
333 if (newsize <= ltd->ltd_tgts_size)
336 new_bitmap = bitmap_zalloc(newsize, GFP_NOFS);
340 if (ltd->ltd_tgts_size > 0) {
341 /* the bitmap already exists, copy data from old one */
342 bitmap_copy(new_bitmap, ltd->ltd_tgt_bitmap,
344 old_bitmap = ltd->ltd_tgt_bitmap;
347 ltd->ltd_tgts_size = newsize;
348 ltd->ltd_tgt_bitmap = new_bitmap;
350 bitmap_free(old_bitmap);
352 CDEBUG(D_CONFIG, "tgt size: %d\n", ltd->ltd_tgts_size);
358 * Add new target to target table.
360 * Extend target table if it's full, update target table and bitmap.
361 * Notice we need to take ltd_rw_sem exclusively before entry to ensure
364 * \param[in] ltd target table
365 * \param[in] tgt new target desc
367 * \retval 0 on success
368 * \retval -ENOMEM if reallocation failed
369 * -EEXIST if target existed
371 int ltd_add_tgt(struct lu_tgt_descs *ltd, struct lu_tgt_desc *tgt)
373 __u32 index = tgt->ltd_index;
378 if (index >= ltd->ltd_tgts_size) {
381 if (index > TGT_PTRS * TGT_PTRS_PER_BLOCK)
384 while (newsize < index + 1)
385 newsize = newsize << 1;
387 rc = lu_tgt_descs_resize(ltd, newsize);
390 } else if (test_bit(index, ltd->ltd_tgt_bitmap)) {
394 if (ltd->ltd_tgt_idx[index / TGT_PTRS_PER_BLOCK] == NULL) {
395 OBD_ALLOC_PTR(ltd->ltd_tgt_idx[index / TGT_PTRS_PER_BLOCK]);
396 if (ltd->ltd_tgt_idx[index / TGT_PTRS_PER_BLOCK] == NULL)
400 LTD_TGT(ltd, tgt->ltd_index) = tgt;
401 set_bit(tgt->ltd_index, ltd->ltd_tgt_bitmap);
403 ltd->ltd_lov_desc.ld_tgt_count++;
405 ltd->ltd_lov_desc.ld_active_tgt_count++;
409 EXPORT_SYMBOL(ltd_add_tgt);
412 * Delete target from target table
414 void ltd_del_tgt(struct lu_tgt_descs *ltd, struct lu_tgt_desc *tgt)
416 lu_qos_del_tgt(<d->ltd_qos, tgt);
417 LTD_TGT(ltd, tgt->ltd_index) = NULL;
418 clear_bit(tgt->ltd_index, ltd->ltd_tgt_bitmap);
419 ltd->ltd_lov_desc.ld_tgt_count--;
421 ltd->ltd_lov_desc.ld_active_tgt_count--;
423 EXPORT_SYMBOL(ltd_del_tgt);
426 * Calculate penalties per-tgt and per-server
428 * Re-calculate penalties when the configuration changes, active targets
429 * change and after statfs refresh (all these are reflected by lq_dirty flag).
430 * On every tgt and server: decay the penalty by half for every 8x the update
431 * interval that the device has been idle. That gives lots of time for the
432 * statfs information to be updated (which the penalty is only a proxy for),
433 * and avoids penalizing server/tgt under light load.
434 * See lu_qos_tgt_weight_calc() for how penalties are factored into the weight.
436 * \param[in] ltd lu_tgt_descs
438 * \retval 0 on success
439 * \retval -EAGAIN the number of tgt isn't enough or all tgt spaces are
442 int ltd_qos_penalties_calc(struct lu_tgt_descs *ltd)
444 struct lu_qos *qos = <d->ltd_qos;
445 struct lov_desc *desc = <d->ltd_lov_desc;
446 struct lu_tgt_desc *tgt;
447 struct lu_svr_qos *svr;
448 __u64 ba_max, ba_min, ba;
449 __u64 ia_max, ia_min, ia = 1;
457 if (!test_bit(LQ_DIRTY, &qos->lq_flags))
460 num_active = desc->ld_active_tgt_count - 1;
462 GOTO(out, rc = -EAGAIN);
464 /* find bavail on each server */
465 list_for_each_entry(svr, &qos->lq_svr_list, lsq_svr_list) {
467 /* if inode is not counted, set to 1 to ignore */
468 svr->lsq_iavail = ltd->ltd_is_mdt ? 0 : 1;
470 qos->lq_active_svr_count = 0;
473 * How badly user wants to select targets "widely" (not recently chosen
474 * and not on recent MDS's). As opposed to "freely" (free space avail.)
477 prio_wide = 256 - qos->lq_prio_free;
479 ba_min = (__u64)(-1);
481 ia_min = (__u64)(-1);
483 now = ktime_get_real_seconds();
485 /* Calculate server penalty per object */
486 ltd_foreach_tgt(ltd, tgt) {
487 if (!tgt->ltd_active)
490 /* when inode is counted, bavail >> 16 to avoid overflow */
491 ba = tgt_statfs_bavail(tgt);
499 ba_min = min(ba, ba_min);
500 ba_max = max(ba, ba_max);
502 /* Count the number of usable servers */
503 if (tgt->ltd_qos.ltq_svr->lsq_bavail == 0)
504 qos->lq_active_svr_count++;
505 tgt->ltd_qos.ltq_svr->lsq_bavail += ba;
507 if (ltd->ltd_is_mdt) {
508 /* iavail >> 8 to avoid overflow */
509 ia = tgt_statfs_iavail(tgt) >> 8;
513 ia_min = min(ia, ia_min);
514 ia_max = max(ia, ia_max);
516 tgt->ltd_qos.ltq_svr->lsq_iavail += ia;
521 * prio * bavail * iavail / (num_tgt - 1) / 2
523 tgt->ltd_qos.ltq_penalty_per_obj = prio_wide * ba * ia >> 8;
524 do_div(tgt->ltd_qos.ltq_penalty_per_obj, num_active);
525 tgt->ltd_qos.ltq_penalty_per_obj >>= 1;
527 age = (now - tgt->ltd_qos.ltq_used) >> 3;
528 if (test_bit(LQ_RESET, &qos->lq_flags) ||
529 age > 32 * desc->ld_qos_maxage)
530 tgt->ltd_qos.ltq_penalty = 0;
531 else if (age > desc->ld_qos_maxage)
532 /* Decay tgt penalty. */
533 tgt->ltd_qos.ltq_penalty >>= age / desc->ld_qos_maxage;
536 num_active = qos->lq_active_svr_count - 1;
537 if (num_active < 1) {
539 * If there's only 1 server, we can't penalize it, so instead
540 * we have to double the tgt penalty
543 ltd_foreach_tgt(ltd, tgt) {
544 if (!tgt->ltd_active)
547 tgt->ltd_qos.ltq_penalty_per_obj <<= 1;
552 * Per-server penalty is
553 * prio * bavail * iavail / server_tgts / (num_svr - 1) / 2
555 list_for_each_entry(svr, &qos->lq_svr_list, lsq_svr_list) {
556 ba = svr->lsq_bavail;
557 ia = svr->lsq_iavail;
558 svr->lsq_penalty_per_obj = prio_wide * ba * ia >> 8;
559 do_div(svr->lsq_penalty_per_obj,
560 svr->lsq_tgt_count * num_active);
561 svr->lsq_penalty_per_obj >>= 1;
563 age = (now - svr->lsq_used) >> 3;
564 if (test_bit(LQ_RESET, &qos->lq_flags) ||
565 age > 32 * desc->ld_qos_maxage)
566 svr->lsq_penalty = 0;
567 else if (age > desc->ld_qos_maxage)
568 /* Decay server penalty. */
569 svr->lsq_penalty >>= age / desc->ld_qos_maxage;
572 clear_bit(LQ_DIRTY, &qos->lq_flags);
573 clear_bit(LQ_RESET, &qos->lq_flags);
576 * If each tgt has almost same free space, do rr allocation for better
577 * creation performance
579 clear_bit(LQ_SAME_SPACE, &qos->lq_flags);
580 if ((ba_max * (256 - qos->lq_threshold_rr)) >> 8 < ba_min &&
581 (ia_max * (256 - qos->lq_threshold_rr)) >> 8 < ia_min) {
582 set_bit(LQ_SAME_SPACE, &qos->lq_flags);
583 /* Reset weights for the next time we enter qos mode */
584 set_bit(LQ_RESET, &qos->lq_flags);
589 if (!rc && test_bit(LQ_SAME_SPACE, &qos->lq_flags))
594 EXPORT_SYMBOL(ltd_qos_penalties_calc);
597 * Re-calculate penalties and weights of all tgts.
599 * The function is called when some target was used for a new object. In
600 * this case we should re-calculate all the weights to keep new allocations
603 * \param[in] ltd lu_tgt_descs
604 * \param[in] tgt recently used tgt
605 * \param[out] total_wt new total weight for the pool
609 int ltd_qos_update(struct lu_tgt_descs *ltd, struct lu_tgt_desc *tgt,
612 struct lu_qos *qos = <d->ltd_qos;
613 struct lu_tgt_qos *ltq;
614 struct lu_svr_qos *svr;
621 /* Don't allocate on this device anymore, until the next alloc_qos */
627 * Decay old penalty by half (we're adding max penalty, and don't
628 * want it to run away.)
630 ltq->ltq_penalty >>= 1;
631 svr->lsq_penalty >>= 1;
633 /* mark the server and tgt as recently used */
634 ltq->ltq_used = svr->lsq_used = ktime_get_real_seconds();
636 /* Set max penalties for this tgt and server */
637 ltq->ltq_penalty += ltq->ltq_penalty_per_obj *
638 ltd->ltd_lov_desc.ld_active_tgt_count;
639 svr->lsq_penalty += svr->lsq_penalty_per_obj *
640 qos->lq_active_svr_count;
642 /* Decrease all MDS penalties */
643 list_for_each_entry(svr, &qos->lq_svr_list, lsq_svr_list) {
644 if (svr->lsq_penalty < svr->lsq_penalty_per_obj)
645 svr->lsq_penalty = 0;
647 svr->lsq_penalty -= svr->lsq_penalty_per_obj;
651 /* Decrease all tgt penalties */
652 ltd_foreach_tgt(ltd, tgt) {
653 if (!tgt->ltd_active)
657 if (ltq->ltq_penalty < ltq->ltq_penalty_per_obj)
658 ltq->ltq_penalty = 0;
660 ltq->ltq_penalty -= ltq->ltq_penalty_per_obj;
662 lu_tgt_qos_weight_calc(tgt);
664 /* Recalc the total weight of usable osts */
666 *total_wt += ltq->ltq_weight;
668 CDEBUG(D_OTHER, "recalc tgt %d usable=%d bavail=%llu ffree=%llu tgtppo=%llu tgtp=%llu svrppo=%llu svrp=%llu wt=%llu\n",
669 tgt->ltd_index, ltq->ltq_usable,
670 tgt_statfs_bavail(tgt) >> 16,
671 tgt_statfs_iavail(tgt) >> 8,
672 ltq->ltq_penalty_per_obj >> 10,
673 ltq->ltq_penalty >> 10,
674 ltq->ltq_svr->lsq_penalty_per_obj >> 10,
675 ltq->ltq_svr->lsq_penalty >> 10,
676 ltq->ltq_weight >> 10);
681 EXPORT_SYMBOL(ltd_qos_update);