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, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 021110-1307, USA
24 * Copyright (c) 2011, 2012, Whamcloud, Inc.
27 * This file is part of Lustre, http://www.lustre.org/
28 * Lustre is a trademark of Sun Microsystems, Inc.
32 * portal & match routines
34 * Author: liang@whamcloud.com
37 #define DEBUG_SUBSYSTEM S_LNET
39 #include <lnet/lib-lnet.h>
41 /* NB: add /proc interfaces in upcoming patches */
43 CFS_MODULE_PARM(portal_rotor, "i", int, 0644,
44 "redirect PUTs to different cpu-partitions");
47 lnet_ptl_match_type(unsigned int index, lnet_process_id_t match_id,
48 __u64 mbits, __u64 ignore_bits)
50 struct lnet_portal *ptl = the_lnet.ln_portals[index];
53 unique = ignore_bits == 0 &&
54 match_id.nid != LNET_NID_ANY &&
55 match_id.pid != LNET_PID_ANY;
57 LASSERT(!lnet_ptl_is_unique(ptl) || !lnet_ptl_is_wildcard(ptl));
59 /* prefer to check w/o any lock */
60 if (likely(lnet_ptl_is_unique(ptl) || lnet_ptl_is_wildcard(ptl)))
63 /* unset, new portal */
65 /* check again with lock */
66 if (unlikely(lnet_ptl_is_unique(ptl) || lnet_ptl_is_wildcard(ptl))) {
73 lnet_ptl_setopt(ptl, LNET_PTL_MATCH_UNIQUE);
75 lnet_ptl_setopt(ptl, LNET_PTL_MATCH_WILDCARD);
82 if ((lnet_ptl_is_unique(ptl) && !unique) ||
83 (lnet_ptl_is_wildcard(ptl) && unique))
89 lnet_ptl_enable_mt(struct lnet_portal *ptl, int cpt)
91 struct lnet_match_table *mtable = ptl->ptl_mtables[cpt];
94 /* with hold of both lnet_res_lock(cpt) and lnet_ptl_lock */
95 LASSERT(lnet_ptl_is_wildcard(ptl));
97 mtable->mt_enabled = 1;
99 ptl->ptl_mt_maps[ptl->ptl_mt_nmaps] = cpt;
100 for (i = ptl->ptl_mt_nmaps - 1; i >= 0; i--) {
101 LASSERT(ptl->ptl_mt_maps[i] != cpt);
102 if (ptl->ptl_mt_maps[i] < cpt)
106 ptl->ptl_mt_maps[i + 1] = ptl->ptl_mt_maps[i];
107 ptl->ptl_mt_maps[i] = cpt;
114 lnet_ptl_disable_mt(struct lnet_portal *ptl, int cpt)
116 struct lnet_match_table *mtable = ptl->ptl_mtables[cpt];
119 /* with hold of both lnet_res_lock(cpt) and lnet_ptl_lock */
120 LASSERT(lnet_ptl_is_wildcard(ptl));
122 if (LNET_CPT_NUMBER == 1)
123 return; /* never disable the only match-table */
125 mtable->mt_enabled = 0;
127 LASSERT(ptl->ptl_mt_nmaps > 0 &&
128 ptl->ptl_mt_nmaps <= LNET_CPT_NUMBER);
130 /* remove it from mt_maps */
132 for (i = 0; i < ptl->ptl_mt_nmaps; i++) {
133 if (ptl->ptl_mt_maps[i] >= cpt) /* overwrite it */
134 ptl->ptl_mt_maps[i] = ptl->ptl_mt_maps[i + 1];
139 lnet_try_match_md(lnet_libmd_t *md,
140 struct lnet_match_info *info, struct lnet_msg *msg)
142 /* ALWAYS called holding the lnet_res_lock, and can't lnet_res_unlock;
143 * lnet_match_blocked_msg() relies on this to avoid races */
145 unsigned int mlength;
146 lnet_me_t *me = md->md_me;
149 if (lnet_md_exhausted(md))
150 return LNET_MATCHMD_NONE | LNET_MATCHMD_EXHAUSTED;
152 /* mismatched MD op */
153 if ((md->md_options & info->mi_opc) == 0)
154 return LNET_MATCHMD_NONE;
156 /* mismatched ME nid/pid? */
157 if (me->me_match_id.nid != LNET_NID_ANY &&
158 me->me_match_id.nid != info->mi_id.nid)
159 return LNET_MATCHMD_NONE;
161 if (me->me_match_id.pid != LNET_PID_ANY &&
162 me->me_match_id.pid != info->mi_id.pid)
163 return LNET_MATCHMD_NONE;
165 /* mismatched ME matchbits? */
166 if (((me->me_match_bits ^ info->mi_mbits) & ~me->me_ignore_bits) != 0)
167 return LNET_MATCHMD_NONE;
169 /* Hurrah! This _is_ a match; check it out... */
171 if ((md->md_options & LNET_MD_MANAGE_REMOTE) == 0)
172 offset = md->md_offset;
174 offset = info->mi_roffset;
176 if ((md->md_options & LNET_MD_MAX_SIZE) != 0) {
177 mlength = md->md_max_size;
178 LASSERT(md->md_offset + mlength <= md->md_length);
180 mlength = md->md_length - offset;
183 if (info->mi_rlength <= mlength) { /* fits in allowed space */
184 mlength = info->mi_rlength;
185 } else if ((md->md_options & LNET_MD_TRUNCATE) == 0) {
186 /* this packet _really_ is too big */
187 CERROR("Matching packet from %s, match "LPU64
188 " length %d too big: %d left, %d allowed\n",
189 libcfs_id2str(info->mi_id), info->mi_mbits,
190 info->mi_rlength, md->md_length - offset, mlength);
192 return LNET_MATCHMD_DROP;
195 /* Commit to this ME/MD */
196 CDEBUG(D_NET, "Incoming %s index %x from %s of "
197 "length %d/%d into md "LPX64" [%d] + %d\n",
198 (info->mi_opc == LNET_MD_OP_PUT) ? "put" : "get",
199 info->mi_portal, libcfs_id2str(info->mi_id), mlength,
200 info->mi_rlength, md->md_lh.lh_cookie, md->md_niov, offset);
202 lnet_msg_attach_md(msg, md, offset, mlength);
203 md->md_offset = offset + mlength;
205 if (!lnet_md_exhausted(md))
206 return LNET_MATCHMD_OK;
208 /* Auto-unlink NOW, so the ME gets unlinked if required.
209 * We bumped md->md_refcount above so the MD just gets flagged
210 * for unlink when it is finalized. */
211 if ((md->md_flags & LNET_MD_FLAG_AUTO_UNLINK) != 0)
214 return LNET_MATCHMD_OK | LNET_MATCHMD_EXHAUSTED;
217 static struct lnet_match_table *
218 lnet_match2mt(struct lnet_portal *ptl, lnet_process_id_t id, __u64 mbits)
220 if (LNET_CPT_NUMBER == 1)
221 return ptl->ptl_mtables[0]; /* the only one */
223 /* if it's a unique portal, return match-table hashed by NID */
224 return lnet_ptl_is_unique(ptl) ?
225 ptl->ptl_mtables[lnet_cpt_of_nid(id.nid)] : NULL;
228 struct lnet_match_table *
229 lnet_mt_of_attach(unsigned int index, lnet_process_id_t id,
230 __u64 mbits, __u64 ignore_bits, lnet_ins_pos_t pos)
232 struct lnet_portal *ptl;
233 struct lnet_match_table *mtable;
235 /* NB: called w/o lock */
236 LASSERT(index < the_lnet.ln_nportals);
238 if (!lnet_ptl_match_type(index, id, mbits, ignore_bits))
241 ptl = the_lnet.ln_portals[index];
243 mtable = lnet_match2mt(ptl, id, mbits);
244 if (mtable != NULL) /* unique portal or only one match-table */
247 /* it's a wildcard portal */
251 case LNET_INS_BEFORE:
253 /* posted by no affinity thread, always hash to specific
254 * match-table to avoid buffer stealing which is heavy */
255 return ptl->ptl_mtables[ptl->ptl_index % LNET_CPT_NUMBER];
257 /* posted by cpu-affinity thread */
258 return ptl->ptl_mtables[lnet_cpt_current()];
262 struct lnet_match_table *
263 lnet_mt_of_match(unsigned int index, lnet_process_id_t id, __u64 mbits)
265 struct lnet_match_table *mtable;
266 struct lnet_portal *ptl;
271 /* NB: called w/o lock */
272 LASSERT(index < the_lnet.ln_nportals);
273 ptl = the_lnet.ln_portals[index];
275 LASSERT(lnet_ptl_is_wildcard(ptl) || lnet_ptl_is_unique(ptl));
277 mtable = lnet_match2mt(ptl, id, mbits);
281 /* it's a wildcard portal */
283 cpt = lnet_cpt_current();
284 if (ptl->ptl_mtables[cpt]->mt_enabled)
285 return ptl->ptl_mtables[cpt];
288 rotor = ptl->ptl_rotor++;
289 cpt = rotor % LNET_CPT_NUMBER;
291 if (!ptl->ptl_mtables[cpt]->mt_enabled) {
292 /* is there any active entry for this portal? */
293 nmaps = ptl->ptl_mt_nmaps;
294 /* map to an active mtable to avoid heavy "stealing" */
296 /* NB: there is possibility that ptl_mt_maps is being
297 * changed because we are not under protection of
298 * lnet_ptl_lock, but it shouldn't hurt anything */
299 cpt = ptl->ptl_mt_maps[rotor % nmaps];
303 return ptl->ptl_mtables[cpt];
307 lnet_mt_match_head(struct lnet_match_table *mtable,
308 lnet_process_id_t id, __u64 mbits)
310 struct lnet_portal *ptl = the_lnet.ln_portals[mtable->mt_portal];
312 if (lnet_ptl_is_wildcard(ptl)) {
313 return &mtable->mt_mlist;
316 unsigned long hash = mbits + id.nid + id.pid;
318 LASSERT(lnet_ptl_is_unique(ptl));
319 hash = cfs_hash_long(hash, LNET_MT_HASH_BITS);
320 return &mtable->mt_mhash[hash];
325 lnet_mt_match_md(struct lnet_match_table *mtable,
326 struct lnet_match_info *info, struct lnet_msg *msg)
334 /* NB: only wildcard portal can return LNET_MATCHMD_EXHAUSTED */
335 if (lnet_ptl_is_wildcard(the_lnet.ln_portals[mtable->mt_portal]))
336 exhausted = LNET_MATCHMD_EXHAUSTED;
338 head = lnet_mt_match_head(mtable, info->mi_id, info->mi_mbits);
340 cfs_list_for_each_entry_safe(me, tmp, head, me_list) {
341 /* ME attached but MD not attached yet */
342 if (me->me_md == NULL)
345 LASSERT(me == me->me_md->md_me);
347 rc = lnet_try_match_md(me->me_md, info, msg);
348 if ((rc & LNET_MATCHMD_EXHAUSTED) == 0)
349 exhausted = 0; /* mlist is not empty */
351 if ((rc & LNET_MATCHMD_FINISH) != 0) {
352 /* don't return EXHAUSTED bit because we don't know
353 * whether the mlist is empty or not */
354 return rc & ~LNET_MATCHMD_EXHAUSTED;
358 if (info->mi_opc == LNET_MD_OP_GET ||
359 !lnet_ptl_is_lazy(the_lnet.ln_portals[info->mi_portal]))
360 return LNET_MATCHMD_DROP | exhausted;
362 return LNET_MATCHMD_NONE | exhausted;
366 lnet_ptl_match_early(struct lnet_portal *ptl, struct lnet_msg *msg)
370 /* message arrived before any buffer posting on this portal,
371 * simply delay or drop this message */
372 if (likely(lnet_ptl_is_wildcard(ptl) || lnet_ptl_is_unique(ptl)))
376 /* check it again with hold of lock */
377 if (lnet_ptl_is_wildcard(ptl) || lnet_ptl_is_unique(ptl)) {
378 lnet_ptl_unlock(ptl);
382 if (lnet_ptl_is_lazy(ptl)) {
383 if (msg->msg_rx_ready_delay) {
384 msg->msg_rx_delayed = 1;
385 cfs_list_add_tail(&msg->msg_list,
386 &ptl->ptl_msg_delayed);
388 rc = LNET_MATCHMD_NONE;
390 rc = LNET_MATCHMD_DROP;
393 lnet_ptl_unlock(ptl);
398 lnet_ptl_match_delay(struct lnet_portal *ptl,
399 struct lnet_match_info *info, struct lnet_msg *msg)
401 int first = ptl->ptl_mt_maps[0]; /* read w/o lock */
405 /* steal buffer from other CPTs, and delay it if nothing to steal,
406 * this function is more expensive than a regular match, but we
407 * don't expect it can happen a lot */
408 LASSERT(lnet_ptl_is_wildcard(ptl));
410 for (i = 0; i < LNET_CPT_NUMBER; i++) {
411 struct lnet_match_table *mtable;
414 cpt = (first + i) % LNET_CPT_NUMBER;
415 mtable = ptl->ptl_mtables[cpt];
416 if (i != 0 && i != LNET_CPT_NUMBER - 1 && !mtable->mt_enabled)
422 if (i == 0) { /* the first try, attach on stealing list */
423 cfs_list_add_tail(&msg->msg_list,
424 &ptl->ptl_msg_stealing);
427 if (!cfs_list_empty(&msg->msg_list)) { /* on stealing list */
428 rc = lnet_mt_match_md(mtable, info, msg);
430 if ((rc & LNET_MATCHMD_EXHAUSTED) != 0 &&
432 lnet_ptl_disable_mt(ptl, cpt);
434 if ((rc & LNET_MATCHMD_FINISH) != 0)
435 cfs_list_del_init(&msg->msg_list);
438 /* could be matched by lnet_ptl_attach_md()
439 * which is called by another thread */
440 rc = msg->msg_md == NULL ?
441 LNET_MATCHMD_DROP : LNET_MATCHMD_OK;
444 if (!cfs_list_empty(&msg->msg_list) && /* not matched yet */
445 (i == LNET_CPT_NUMBER - 1 || /* the last CPT */
446 ptl->ptl_mt_nmaps == 0 || /* no active CPT */
447 (ptl->ptl_mt_nmaps == 1 && /* the only active CPT */
448 ptl->ptl_mt_maps[0] == cpt))) {
449 /* nothing to steal, delay or drop */
450 cfs_list_del_init(&msg->msg_list);
452 if (lnet_ptl_is_lazy(ptl)) {
453 msg->msg_rx_delayed = 1;
454 cfs_list_add_tail(&msg->msg_list,
455 &ptl->ptl_msg_delayed);
456 rc = LNET_MATCHMD_NONE;
458 rc = LNET_MATCHMD_DROP;
462 lnet_ptl_unlock(ptl);
463 lnet_res_unlock(cpt);
465 if ((rc & LNET_MATCHMD_FINISH) != 0 || msg->msg_rx_delayed)
473 lnet_ptl_match_md(struct lnet_match_info *info, struct lnet_msg *msg)
475 struct lnet_match_table *mtable;
476 struct lnet_portal *ptl;
479 CDEBUG(D_NET, "Request from %s of length %d into portal %d "
480 "MB="LPX64"\n", libcfs_id2str(info->mi_id),
481 info->mi_rlength, info->mi_portal, info->mi_mbits);
483 if (info->mi_portal >= the_lnet.ln_nportals) {
484 CERROR("Invalid portal %d not in [0-%d]\n",
485 info->mi_portal, the_lnet.ln_nportals);
486 return LNET_MATCHMD_DROP;
489 ptl = the_lnet.ln_portals[info->mi_portal];
490 rc = lnet_ptl_match_early(ptl, msg);
491 if (rc != 0) /* matched or delayed early message */
494 mtable = lnet_mt_of_match(info->mi_portal,
495 info->mi_id, info->mi_mbits);
496 lnet_res_lock(mtable->mt_cpt);
498 if (the_lnet.ln_shutdown) {
499 rc = LNET_MATCHMD_DROP;
503 rc = lnet_mt_match_md(mtable, info, msg);
504 if ((rc & LNET_MATCHMD_EXHAUSTED) != 0 && mtable->mt_enabled) {
506 lnet_ptl_disable_mt(ptl, mtable->mt_cpt);
507 lnet_ptl_unlock(ptl);
510 if ((rc & LNET_MATCHMD_FINISH) != 0) /* matched or dropping */
513 if (!msg->msg_rx_ready_delay)
516 LASSERT(lnet_ptl_is_lazy(ptl));
517 LASSERT(!msg->msg_rx_delayed);
519 /* NB: we don't expect "delay" can happen a lot */
520 if (lnet_ptl_is_unique(ptl) || LNET_CPT_NUMBER == 1) {
523 msg->msg_rx_delayed = 1;
524 cfs_list_add_tail(&msg->msg_list, &ptl->ptl_msg_delayed);
526 lnet_ptl_unlock(ptl);
527 lnet_res_unlock(mtable->mt_cpt);
530 lnet_res_unlock(mtable->mt_cpt);
531 rc = lnet_ptl_match_delay(ptl, info, msg);
534 if (msg->msg_rx_delayed) {
536 "Delaying %s from %s ptl %d MB "LPX64" off %d len %d\n",
537 info->mi_opc == LNET_MD_OP_PUT ? "PUT" : "GET",
538 libcfs_id2str(info->mi_id), info->mi_portal,
539 info->mi_mbits, info->mi_roffset, info->mi_rlength);
543 lnet_res_unlock(mtable->mt_cpt);
545 /* EXHAUSTED bit is only meaningful for internal functions */
546 return rc & ~LNET_MATCHMD_EXHAUSTED;
550 lnet_ptl_detach_md(lnet_me_t *me, lnet_libmd_t *md)
552 LASSERT(me->me_md == md && md->md_me == me);
558 /* called with lnet_res_lock held */
560 lnet_ptl_attach_md(lnet_me_t *me, lnet_libmd_t *md,
561 cfs_list_t *matches, cfs_list_t *drops)
563 struct lnet_portal *ptl = the_lnet.ln_portals[me->me_portal];
564 struct lnet_match_table *mtable;
571 LASSERT(md->md_refcount == 0); /* a brand new MD */
576 cpt = lnet_cpt_of_cookie(md->md_lh.lh_cookie);
577 mtable = ptl->ptl_mtables[cpt];
579 if (cfs_list_empty(&ptl->ptl_msg_stealing) &&
580 cfs_list_empty(&ptl->ptl_msg_delayed) &&
585 head = &ptl->ptl_msg_stealing;
587 cfs_list_for_each_entry_safe(msg, tmp, head, msg_list) {
588 struct lnet_match_info info;
592 LASSERT(msg->msg_rx_delayed || head == &ptl->ptl_msg_stealing);
595 info.mi_id.nid = hdr->src_nid;
596 info.mi_id.pid = hdr->src_pid;
597 info.mi_opc = LNET_MD_OP_PUT;
598 info.mi_portal = hdr->msg.put.ptl_index;
599 info.mi_rlength = hdr->payload_length;
600 info.mi_roffset = hdr->msg.put.offset;
601 info.mi_mbits = hdr->msg.put.match_bits;
603 rc = lnet_try_match_md(md, &info, msg);
605 exhausted = (rc & LNET_MATCHMD_EXHAUSTED) != 0;
606 if ((rc & LNET_MATCHMD_NONE) != 0) {
612 /* Hurrah! This _is_ a match */
613 LASSERT((rc & LNET_MATCHMD_FINISH) != 0);
614 cfs_list_del_init(&msg->msg_list);
616 if (head == &ptl->ptl_msg_stealing) {
619 /* stealing thread will handle the message */
623 if ((rc & LNET_MATCHMD_OK) != 0) {
624 cfs_list_add_tail(&msg->msg_list, matches);
626 CDEBUG(D_NET, "Resuming delayed PUT from %s portal %d "
627 "match "LPU64" offset %d length %d.\n",
628 libcfs_id2str(info.mi_id),
629 info.mi_portal, info.mi_mbits,
630 info.mi_roffset, info.mi_rlength);
632 cfs_list_add_tail(&msg->msg_list, drops);
639 if (!exhausted && head == &ptl->ptl_msg_stealing) {
640 head = &ptl->ptl_msg_delayed;
644 if (lnet_ptl_is_wildcard(ptl) && !exhausted && !mtable->mt_enabled)
645 lnet_ptl_enable_mt(ptl, cpt);
647 lnet_ptl_unlock(ptl);
651 lnet_ptl_cleanup(struct lnet_portal *ptl)
653 struct lnet_match_table *mtable;
656 if (ptl->ptl_mtables == NULL) /* uninitialized portal */
659 LASSERT(cfs_list_empty(&ptl->ptl_msg_delayed));
660 LASSERT(cfs_list_empty(&ptl->ptl_msg_stealing));
662 # ifdef HAVE_LIBPTHREAD
663 pthread_mutex_destroy(&ptl->ptl_lock);
666 cfs_percpt_for_each(mtable, i, ptl->ptl_mtables) {
671 if (mtable->mt_mhash == NULL) /* uninitialized match-table */
674 mhash = mtable->mt_mhash;
676 while (!cfs_list_empty(&mtable->mt_mlist)) {
677 me = cfs_list_entry(mtable->mt_mlist.next,
679 CERROR("Active wildcard ME %p on exit\n", me);
680 cfs_list_del(&me->me_list);
684 for (j = 0; j < LNET_MT_HASH_SIZE; j++) {
685 while (!cfs_list_empty(&mhash[j])) {
686 me = cfs_list_entry(mhash[j].next,
688 CERROR("Active unique ME %p on exit\n", me);
689 cfs_list_del(&me->me_list);
694 LIBCFS_FREE(mhash, sizeof(*mhash) * LNET_MT_HASH_SIZE);
697 cfs_percpt_free(ptl->ptl_mtables);
698 ptl->ptl_mtables = NULL;
702 lnet_ptl_setup(struct lnet_portal *ptl, int index)
704 struct lnet_match_table *mtable;
709 ptl->ptl_mtables = cfs_percpt_alloc(lnet_cpt_table(),
710 sizeof(struct lnet_match_table));
711 if (ptl->ptl_mtables == NULL) {
712 CERROR("Failed to create match table for portal %d\n", index);
716 ptl->ptl_index = index;
717 CFS_INIT_LIST_HEAD(&ptl->ptl_msg_delayed);
718 CFS_INIT_LIST_HEAD(&ptl->ptl_msg_stealing);
720 cfs_spin_lock_init(&ptl->ptl_lock);
722 # ifdef HAVE_LIBPTHREAD
723 pthread_mutex_init(&ptl->ptl_lock, NULL);
726 cfs_percpt_for_each(mtable, i, ptl->ptl_mtables) {
727 LIBCFS_CPT_ALLOC(mhash, lnet_cpt_table(), i,
728 sizeof(*mhash) * LNET_MT_HASH_SIZE);
730 CERROR("Failed to create match hash for portal %d\n",
735 mtable->mt_mhash = mhash;
736 for (j = 0; j < LNET_MT_HASH_SIZE; j++)
737 CFS_INIT_LIST_HEAD(&mhash[j]);
739 CFS_INIT_LIST_HEAD(&mtable->mt_mlist);
740 mtable->mt_portal = index;
746 lnet_ptl_cleanup(ptl);
751 lnet_portals_destroy(void)
755 if (the_lnet.ln_portals == NULL)
758 for (i = 0; i < the_lnet.ln_nportals; i++)
759 lnet_ptl_cleanup(the_lnet.ln_portals[i]);
761 cfs_array_free(the_lnet.ln_portals);
762 the_lnet.ln_portals = NULL;
766 lnet_portals_create(void)
771 size = offsetof(struct lnet_portal, ptl_mt_maps[LNET_CPT_NUMBER]);
773 the_lnet.ln_nportals = MAX_PORTALS;
774 the_lnet.ln_portals = cfs_array_alloc(the_lnet.ln_nportals, size);
775 if (the_lnet.ln_portals == NULL) {
776 CERROR("Failed to allocate portals table\n");
780 for (i = 0; i < the_lnet.ln_nportals; i++) {
781 if (lnet_ptl_setup(the_lnet.ln_portals[i], i)) {
782 lnet_portals_destroy();
791 * Turn on the lazy portal attribute. Use with caution!
793 * This portal attribute only affects incoming PUT requests to the portal,
794 * and is off by default. By default, if there's no matching MD for an
795 * incoming PUT request, it is simply dropped. With the lazy attribute on,
796 * such requests are queued indefinitely until either a matching MD is
797 * posted to the portal or the lazy attribute is turned off.
799 * It would prevent dropped requests, however it should be regarded as the
800 * last line of defense - i.e. users must keep a close watch on active
801 * buffers on a lazy portal and once it becomes too low post more buffers as
802 * soon as possible. This is because delayed requests usually have detrimental
803 * effects on underlying network connections. A few delayed requests often
804 * suffice to bring an underlying connection to a complete halt, due to flow
805 * control mechanisms.
807 * There's also a DOS attack risk. If users don't post match-all MDs on a
808 * lazy portal, a malicious peer can easily stop a service by sending some
809 * PUT requests with match bits that won't match any MD. A routed server is
810 * especially vulnerable since the connections to its neighbor routers are
811 * shared among all clients.
813 * \param portal Index of the portal to enable the lazy attribute on.
815 * \retval 0 On success.
816 * \retval -EINVAL If \a portal is not a valid index.
819 LNetSetLazyPortal(int portal)
821 struct lnet_portal *ptl;
823 if (portal < 0 || portal >= the_lnet.ln_nportals)
826 CDEBUG(D_NET, "Setting portal %d lazy\n", portal);
827 ptl = the_lnet.ln_portals[portal];
829 lnet_res_lock(LNET_LOCK_EX);
832 lnet_ptl_setopt(ptl, LNET_PTL_LAZY);
834 lnet_ptl_unlock(ptl);
835 lnet_res_unlock(LNET_LOCK_EX);
841 * Turn off the lazy portal attribute. Delayed requests on the portal,
842 * if any, will be all dropped when this function returns.
844 * \param portal Index of the portal to disable the lazy attribute on.
846 * \retval 0 On success.
847 * \retval -EINVAL If \a portal is not a valid index.
850 LNetClearLazyPortal(int portal)
852 struct lnet_portal *ptl;
853 CFS_LIST_HEAD (zombies);
855 if (portal < 0 || portal >= the_lnet.ln_nportals)
858 ptl = the_lnet.ln_portals[portal];
860 lnet_res_lock(LNET_LOCK_EX);
863 if (!lnet_ptl_is_lazy(ptl)) {
864 lnet_ptl_unlock(ptl);
865 lnet_res_unlock(LNET_LOCK_EX);
869 if (the_lnet.ln_shutdown)
870 CWARN("Active lazy portal %d on exit\n", portal);
872 CDEBUG(D_NET, "clearing portal %d lazy\n", portal);
874 /* grab all the blocked messages atomically */
875 cfs_list_splice_init(&ptl->ptl_msg_delayed, &zombies);
877 lnet_ptl_unsetopt(ptl, LNET_PTL_LAZY);
879 lnet_ptl_unlock(ptl);
880 lnet_res_unlock(LNET_LOCK_EX);
882 lnet_drop_delayed_msg_list(&zombies, "Clearing lazy portal attr");