2 * Copyright (c) 2009-2010 Fabio Checconi
3 * Copyright (c) 2009-2010 Luigi Rizzo, Universita` di Pisa
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * Main control module for geom-based disk schedulers ('sched').
35 * A 'sched' node is typically inserted transparently between
36 * an existing provider pp and its original geom gp
40 * using the command "geom sched insert <provider>" and
41 * resulting in the following topology
43 * [pp --> sched_gp --> cp] [new_pp --> gp ... ]
45 * Deletion "geom sched destroy <provider>.sched." restores the
46 * original chain. The normal "geom sched create <provide>"
50 * Internally, the 'sched' uses the following data structures
52 * geom{} g_sched_softc{} g_gsched{}
53 * +----------+ +---------------+ +-------------+
54 * | softc *-|--->| sc_gsched *-|-->| gs_init |
55 * | ... | | | | gs_fini |
56 * | | | [ hash table] | | gs_start |
57 * +----------+ | | | ... |
63 * +---------------+ | algorithm- |
67 * A g_sched_softc{} is created with a "geom sched insert" call.
68 * In turn this instantiates a specific scheduling algorithm,
69 * which sets sc_gsched to point to the algorithm callbacks,
70 * and calls gs_init() to create the g_*_softc{} .
71 * The other callbacks (gs_start, gs_next, ...) are invoked
74 * g_sched_softc{} is defined in g_sched.h and mostly used here;
75 * g_gsched{}, and the gs_callbacks, are documented in gs_scheduler.h;
76 * g_*_softc{} is defined/implemented by each algorithm (gs_*.c)
79 * When a bio is received on the provider, it goes to the
80 * g_sched_start() which calls gs_start() to initially queue it;
81 * then we call g_sched_dispatch() that loops around gs_next()
82 * to select zero or more bio's to be sent downstream.
84 * g_sched_dispatch() can also be called as a result of a timeout,
85 * e.g. when doing anticipation or pacing requests.
87 * When a bio comes back, it goes to g_sched_done() which in turn
88 * calls gs_done(). The latter does any necessary housekeeping in
89 * the scheduling algorithm, and may decide to call g_sched_dispatch()
90 * to send more bio's downstream.
92 * If an algorithm needs per-flow queues, these are created
93 * calling gs_init_class() and destroyed with gs_fini_class(),
94 * and they are also inserted in the hash table implemented in
97 * If an algorithm is replaced, or a transparently-inserted node is
98 * removed with "geom sched destroy", we need to remove all references
99 * to the g_*_softc{} and g_sched_softc from the bio's still in
100 * the scheduler. g_sched_forced_dispatch() helps doing this.
101 * XXX need to explain better.
104 #include <sys/cdefs.h>
105 #include <sys/param.h>
106 #include <sys/systm.h>
107 #include <sys/kernel.h>
108 #include <sys/module.h>
109 #include <sys/lock.h>
110 #include <sys/mutex.h>
112 #include <sys/limits.h>
113 #include <sys/hash.h>
114 #include <sys/sbuf.h>
115 #include <sys/sysctl.h>
116 #include <sys/malloc.h>
117 #include <sys/proc.h> /* we access curthread */
118 #include <geom/geom.h>
119 #include "gs_scheduler.h"
120 #include "g_sched.h" /* geom hooks */
123 * Size of the per-geom hash table storing traffic classes.
124 * We may decide to change it at a later time, it has no ABI
125 * implications as it is only used for run-time allocations.
127 #define G_SCHED_HASH_SIZE 32
129 static int g_sched_destroy(struct g_geom *gp, boolean_t force);
130 static int g_sched_destroy_geom(struct gctl_req *req,
131 struct g_class *mp, struct g_geom *gp);
132 static void g_sched_config(struct gctl_req *req, struct g_class *mp,
134 static struct g_geom *g_sched_taste(struct g_class *mp,
135 struct g_provider *pp, int flags __unused);
136 static void g_sched_dumpconf(struct sbuf *sb, const char *indent,
137 struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp);
138 static void g_sched_init(struct g_class *mp);
139 static void g_sched_fini(struct g_class *mp);
140 static int g_sched_ioctl(struct g_provider *pp, u_long cmd, void *data,
141 int fflag, struct thread *td);
143 struct g_class g_sched_class = {
144 .name = G_SCHED_CLASS_NAME,
145 .version = G_VERSION,
146 .ctlreq = g_sched_config,
147 .taste = g_sched_taste,
148 .destroy_geom = g_sched_destroy_geom,
149 .init = g_sched_init,
150 .ioctl = g_sched_ioctl,
154 MALLOC_DEFINE(M_GEOM_SCHED, "GEOM_SCHED", "Geom schedulers data structures");
157 * Global variables describing the state of the geom_sched module.
158 * There is only one static instance of this structure.
160 LIST_HEAD(gs_list, g_gsched); /* type, link field */
161 struct geom_sched_vars {
163 struct gs_list gs_scheds; /* list of algorithms */
165 u_int gs_sched_count; /* how many algorithms ? */
166 u_int gs_patched; /* g_io_request was patched */
168 u_int gs_initialized;
169 u_int gs_expire_secs; /* expiration of hash entries */
171 struct bio_queue_head gs_pending;
174 /* The following are for stats, usually protected by gs_mtx. */
175 u_long gs_requests; /* total requests */
176 u_long gs_done; /* total done */
177 u_int gs_in_flight; /* requests in flight */
178 u_int gs_writes_in_flight;
179 u_int gs_bytes_in_flight;
180 u_int gs_write_bytes_in_flight;
182 char gs_names[256]; /* names of schedulers */
185 static struct geom_sched_vars me = {
186 .gs_expire_secs = 10,
189 SYSCTL_DECL(_kern_geom);
190 SYSCTL_NODE(_kern_geom, OID_AUTO, sched, CTLFLAG_RW, 0,
193 SYSCTL_UINT(_kern_geom_sched, OID_AUTO, in_flight_wb, CTLFLAG_RD,
194 &me.gs_write_bytes_in_flight, 0, "Write bytes in flight");
196 SYSCTL_UINT(_kern_geom_sched, OID_AUTO, in_flight_b, CTLFLAG_RD,
197 &me.gs_bytes_in_flight, 0, "Bytes in flight");
199 SYSCTL_UINT(_kern_geom_sched, OID_AUTO, in_flight_w, CTLFLAG_RD,
200 &me.gs_writes_in_flight, 0, "Write Requests in flight");
202 SYSCTL_UINT(_kern_geom_sched, OID_AUTO, in_flight, CTLFLAG_RD,
203 &me.gs_in_flight, 0, "Requests in flight");
205 SYSCTL_ULONG(_kern_geom_sched, OID_AUTO, done, CTLFLAG_RD,
206 &me.gs_done, 0, "Total done");
208 SYSCTL_ULONG(_kern_geom_sched, OID_AUTO, requests, CTLFLAG_RD,
209 &me.gs_requests, 0, "Total requests");
211 SYSCTL_STRING(_kern_geom_sched, OID_AUTO, algorithms, CTLFLAG_RD,
212 &me.gs_names, 0, "Algorithm names");
214 SYSCTL_UINT(_kern_geom_sched, OID_AUTO, alg_count, CTLFLAG_RD,
215 &me.gs_sched_count, 0, "Number of algorithms");
217 SYSCTL_UINT(_kern_geom_sched, OID_AUTO, debug, CTLFLAG_RW,
218 &me.gs_debug, 0, "Debug level");
220 SYSCTL_UINT(_kern_geom_sched, OID_AUTO, expire_secs, CTLFLAG_RW,
221 &me.gs_expire_secs, 0, "Expire time in seconds");
224 * g_sched calls the scheduler algorithms with this lock held.
225 * The locking functions are exposed so the scheduler algorithms can also
226 * protect themselves e.g. when running a callout handler.
229 g_sched_lock(struct g_geom *gp)
231 struct g_sched_softc *sc = gp->softc;
233 mtx_lock(&sc->sc_mtx);
237 g_sched_unlock(struct g_geom *gp)
239 struct g_sched_softc *sc = gp->softc;
241 mtx_unlock(&sc->sc_mtx);
245 * Support functions to handle references to the module,
246 * which are coming from devices using this scheduler.
249 g_gsched_ref(struct g_gsched *gsp)
252 atomic_add_int(&gsp->gs_refs, 1);
256 g_gsched_unref(struct g_gsched *gsp)
259 atomic_add_int(&gsp->gs_refs, -1);
263 * Update the stats when this request is done.
266 g_sched_update_stats(struct bio *bio)
271 me.gs_bytes_in_flight -= bio->bio_length;
272 if (bio->bio_cmd & BIO_WRITE) {
273 me.gs_writes_in_flight--;
274 me.gs_write_bytes_in_flight -= bio->bio_length;
279 * Dispatch any pending request.
282 g_sched_forced_dispatch(struct g_geom *gp)
284 struct g_sched_softc *sc = gp->softc;
285 struct g_gsched *gsp = sc->sc_gsched;
288 KASSERT(mtx_owned(&sc->sc_mtx),
289 ("sc_mtx not owned during forced dispatch"));
291 while ((bp = gsp->gs_next(sc->sc_data, 1)) != NULL)
292 g_io_request(bp, LIST_FIRST(&gp->consumer));
296 * The main dispatch loop, called either here after the start
297 * routine, or by scheduling algorithms when they receive a timeout
298 * or a 'done' notification. Does not share code with the forced
299 * dispatch path, since the gs_done() callback can call us.
302 g_sched_dispatch(struct g_geom *gp)
304 struct g_sched_softc *sc = gp->softc;
305 struct g_gsched *gsp = sc->sc_gsched;
308 KASSERT(mtx_owned(&sc->sc_mtx), ("sc_mtx not owned during dispatch"));
310 if ((sc->sc_flags & G_SCHED_FLUSHING))
313 while ((bp = gsp->gs_next(sc->sc_data, 0)) != NULL)
314 g_io_request(bp, LIST_FIRST(&gp->consumer));
318 * Recent (8.0 and above) versions of FreeBSD have support to
319 * register classifiers of disk requests. The classifier is
320 * invoked by g_io_request(), and stores the information into
321 * bp->bio_classifier1.
323 * Support for older versions, which is left here only for
324 * documentation purposes, relies on two hacks:
325 * 1. classification info is written into the bio_caller1
326 * field of the topmost node in the bio chain. This field
327 * is rarely used, but this module is incompatible with
328 * those that use bio_caller1 for other purposes,
329 * such as ZFS and gjournal;
330 * 2. g_io_request() is patched in-memory when the module is
331 * loaded, so that the function calls a classifier as its
332 * first thing. g_io_request() is restored when the module
333 * is unloaded. This functionality is only supported for
334 * x86 and amd64, other architectures need source code changes.
338 * Lookup the identity of the issuer of the original request.
339 * In the current implementation we use the curthread of the
340 * issuer, but different mechanisms may be implemented later
341 * so we do not make assumptions on the return value which for
342 * us is just an opaque identifier.
346 g_sched_classify(struct bio *bp)
349 #if __FreeBSD_version > 800098
350 /* we have classifier fields in the struct bio */
351 #define HAVE_BIO_CLASSIFIER
352 return ((u_long)bp->bio_classifier1);
354 #warning old version!!!
355 while (bp->bio_parent != NULL)
358 return ((u_long)bp->bio_caller1);
362 /* Return the hash chain for the given key. */
363 static inline struct g_hash *
364 g_sched_hash(struct g_sched_softc *sc, u_long key)
367 return (&sc->sc_hash[key & sc->sc_mask]);
371 * Helper function for the children classes, which takes
372 * a geom and a bio and returns the private descriptor
373 * associated to the request. This involves fetching
374 * the classification field and [al]locating the
375 * corresponding entry in the hash table.
378 g_sched_get_class(struct g_geom *gp, struct bio *bp)
380 struct g_sched_softc *sc;
381 struct g_sched_class *gsc;
382 struct g_gsched *gsp;
383 struct g_hash *bucket;
387 key = g_sched_classify(bp);
388 bucket = g_sched_hash(sc, key);
389 LIST_FOREACH(gsc, bucket, gsc_clist) {
390 if (key == gsc->gsc_key) {
392 return (gsc->gsc_priv);
397 gsc = malloc(sizeof(*gsc) + gsp->gs_priv_size,
398 M_GEOM_SCHED, M_NOWAIT | M_ZERO);
402 if (gsp->gs_init_class(sc->sc_data, gsc->gsc_priv)) {
403 free(gsc, M_GEOM_SCHED);
407 gsc->gsc_refs = 2; /* 1 for the hash table, 1 for the caller. */
409 LIST_INSERT_HEAD(bucket, gsc, gsc_clist);
411 gsc->gsc_expire = ticks + me.gs_expire_secs * hz;
413 return (gsc->gsc_priv);
417 * Release a reference to the per-client descriptor,
420 g_sched_put_class(struct g_geom *gp, void *priv)
422 struct g_sched_class *gsc;
423 struct g_sched_softc *sc;
425 gsc = g_sched_priv2class(priv);
426 gsc->gsc_expire = ticks + me.gs_expire_secs * hz;
428 if (--gsc->gsc_refs > 0)
432 sc->sc_gsched->gs_fini_class(sc->sc_data, priv);
434 LIST_REMOVE(gsc, gsc_clist);
435 free(gsc, M_GEOM_SCHED);
439 g_sched_hash_fini(struct g_geom *gp, struct g_hash *hp, u_long mask,
440 struct g_gsched *gsp, void *data)
442 struct g_sched_class *cp, *cp2;
448 if (data && gsp->gs_hash_unref)
449 gsp->gs_hash_unref(data);
451 for (i = 0; i < G_SCHED_HASH_SIZE; i++) {
452 LIST_FOREACH_SAFE(cp, &hp[i], gsc_clist, cp2)
453 g_sched_put_class(gp, cp->gsc_priv);
456 hashdestroy(hp, M_GEOM_SCHED, mask);
459 static struct g_hash *
460 g_sched_hash_init(struct g_gsched *gsp, u_long *mask, int flags)
464 if (gsp->gs_priv_size == 0)
467 hash = hashinit_flags(G_SCHED_HASH_SIZE, M_GEOM_SCHED, mask, flags);
473 g_sched_flush_classes(struct g_geom *gp)
475 struct g_sched_softc *sc;
476 struct g_sched_class *cp, *cp2;
481 if (!sc->sc_hash || ticks - sc->sc_flush_ticks <= 0)
484 for (i = 0; i < G_SCHED_HASH_SIZE; i++) {
485 LIST_FOREACH_SAFE(cp, &sc->sc_hash[i], gsc_clist, cp2) {
486 if (cp->gsc_refs == 1 && ticks - cp->gsc_expire > 0)
487 g_sched_put_class(gp, cp->gsc_priv);
491 sc->sc_flush_ticks = ticks + me.gs_expire_secs * hz;
495 * Wait for the completion of any outstanding request. To ensure
496 * that this does not take forever the caller has to make sure that
497 * no new request enter the scehduler before calling us.
499 * Must be called with the gp mutex held and topology locked.
502 g_sched_wait_pending(struct g_geom *gp)
504 struct g_sched_softc *sc = gp->softc;
505 int endticks = ticks + hz;
509 while (sc->sc_pending && endticks - ticks >= 0)
510 msleep(gp, &sc->sc_mtx, 0, "sched_wait_pending", hz / 4);
512 return (sc->sc_pending ? ETIMEDOUT : 0);
516 g_sched_remove_locked(struct g_geom *gp, struct g_gsched *gsp)
518 struct g_sched_softc *sc = gp->softc;
521 /* Set the flushing flag: new bios will not enter the scheduler. */
522 sc->sc_flags |= G_SCHED_FLUSHING;
524 g_sched_forced_dispatch(gp);
525 error = g_sched_wait_pending(gp);
529 /* No more requests pending or in flight from the old gsp. */
531 g_sched_hash_fini(gp, sc->sc_hash, sc->sc_mask, gsp, sc->sc_data);
535 * Avoid deadlock here by releasing the gp mutex and reacquiring
536 * it once done. It should be safe, since no reconfiguration or
537 * destruction can take place due to the geom topology lock; no
538 * new request can use the current sc_data since we flagged the
539 * geom as being flushed.
542 gsp->gs_fini(sc->sc_data);
545 sc->sc_gsched = NULL;
550 sc->sc_flags &= ~G_SCHED_FLUSHING;
556 g_sched_remove(struct g_geom *gp, struct g_gsched *gsp)
561 error = g_sched_remove_locked(gp, gsp); /* gsp is surely non-null */
568 * Support function for create/taste -- locate the desired
569 * algorithm and grab a reference to it.
571 static struct g_gsched *
572 g_gsched_find(const char *name)
574 struct g_gsched *gsp = NULL;
576 mtx_lock(&me.gs_mtx);
577 LIST_FOREACH(gsp, &me.gs_scheds, glist) {
578 if (strcmp(name, gsp->gs_name) == 0) {
583 mtx_unlock(&me.gs_mtx);
589 * Rebuild the list of scheduler names.
590 * To be called with me.gs_mtx lock held.
593 g_gsched_build_names(struct g_gsched *gsp)
596 struct g_gsched *cur;
599 LIST_FOREACH(cur, &me.gs_scheds, glist) {
600 l = strlen(cur->gs_name);
601 if (l + pos + 1 + 1 < sizeof(me.gs_names)) {
603 me.gs_names[pos++] = ' ';
604 strcpy(me.gs_names + pos, cur->gs_name);
608 me.gs_names[pos] = '\0';
612 * Register or unregister individual scheduling algorithms.
615 g_gsched_register(struct g_gsched *gsp)
617 struct g_gsched *cur;
620 mtx_lock(&me.gs_mtx);
621 LIST_FOREACH(cur, &me.gs_scheds, glist) {
622 if (strcmp(gsp->gs_name, cur->gs_name) == 0)
626 G_SCHED_DEBUG(0, "A scheduler named %s already"
627 "exists.", gsp->gs_name);
630 LIST_INSERT_HEAD(&me.gs_scheds, gsp, glist);
633 g_gsched_build_names(gsp);
635 mtx_unlock(&me.gs_mtx);
640 struct g_gsched_unregparm {
641 struct g_gsched *gup_gsp;
646 g_gsched_unregister(void *arg, int flag)
648 struct g_gsched_unregparm *parm = arg;
649 struct g_gsched *gsp = parm->gup_gsp, *cur, *tmp;
650 struct g_sched_softc *sc;
651 struct g_geom *gp, *gp_tmp;
658 if (flag == EV_CANCEL)
661 mtx_lock(&me.gs_mtx);
663 LIST_FOREACH_SAFE(gp, &g_sched_class.geom, geom, gp_tmp) {
664 if (gp->class != &g_sched_class)
665 continue; /* Should not happen. */
668 if (sc->sc_gsched == gsp) {
669 error = g_sched_remove(gp, gsp);
675 LIST_FOREACH_SAFE(cur, &me.gs_scheds, glist, tmp) {
679 if (gsp->gs_refs != 1) {
680 G_SCHED_DEBUG(0, "%s still in use.",
682 parm->gup_error = EBUSY;
684 LIST_REMOVE(gsp, glist);
686 g_gsched_build_names(gsp);
692 G_SCHED_DEBUG(0, "%s not registered.", gsp->gs_name);
693 parm->gup_error = ENOENT;
697 mtx_unlock(&me.gs_mtx);
701 g_gsched_global_init(void)
704 if (!me.gs_initialized) {
705 G_SCHED_DEBUG(0, "Initializing global data.");
706 mtx_init(&me.gs_mtx, "gsched", NULL, MTX_DEF);
707 LIST_INIT(&me.gs_scheds);
708 gs_bioq_init(&me.gs_pending);
709 me.gs_initialized = 1;
714 * Module event called when a scheduling algorithm module is loaded or
718 g_gsched_modevent(module_t mod, int cmd, void *arg)
720 struct g_gsched *gsp = arg;
721 struct g_gsched_unregparm parm;
724 G_SCHED_DEBUG(0, "Modevent %d.", cmd);
727 * If the module is loaded at boot, the geom thread that calls
728 * g_sched_init() might actually run after g_gsched_modevent(),
729 * so make sure that the module is properly initialized.
731 g_gsched_global_init();
736 error = g_gsched_register(gsp);
737 G_SCHED_DEBUG(0, "Loaded module %s error %d.",
738 gsp->gs_name, error);
740 g_retaste(&g_sched_class);
747 error = g_waitfor_event(g_gsched_unregister,
748 &parm, M_WAITOK, NULL);
750 error = parm.gup_error;
751 G_SCHED_DEBUG(0, "Unloaded module %s error %d.",
752 gsp->gs_name, error);
760 #define TRC_BIO_EVENT(e, bp) g_sched_trace_bio_ ## e (bp)
763 g_sched_type(struct bio *bp)
766 if (0 != (bp->bio_cmd & BIO_READ))
768 else if (0 != (bp->bio_cmd & BIO_WRITE))
774 g_sched_trace_bio_START(struct bio *bp)
777 CTR5(KTR_GSCHED, "S %lu %c %lu/%lu %lu", g_sched_classify(bp),
778 g_sched_type(bp), bp->bio_offset / ULONG_MAX,
779 bp->bio_offset, bp->bio_length);
783 g_sched_trace_bio_DONE(struct bio *bp)
786 CTR5(KTR_GSCHED, "D %lu %c %lu/%lu %lu", g_sched_classify(bp),
787 g_sched_type(bp), bp->bio_offset / ULONG_MAX,
788 bp->bio_offset, bp->bio_length);
791 #define TRC_BIO_EVENT(e, bp)
795 * g_sched_done() and g_sched_start() dispatch the geom requests to
796 * the scheduling algorithm in use.
799 g_sched_done(struct bio *bio)
801 struct g_geom *gp = bio->bio_caller2;
802 struct g_sched_softc *sc = gp->softc;
804 TRC_BIO_EVENT(DONE, bio);
806 KASSERT(bio->bio_caller1, ("null bio_caller1 in g_sched_done"));
810 g_sched_update_stats(bio);
811 sc->sc_gsched->gs_done(sc->sc_data, bio);
812 if (!--sc->sc_pending)
815 g_sched_flush_classes(gp);
822 g_sched_start(struct bio *bp)
824 struct g_geom *gp = bp->bio_to->geom;
825 struct g_sched_softc *sc = gp->softc;
828 TRC_BIO_EVENT(START, bp);
829 G_SCHED_LOGREQ(bp, "Request received.");
831 cbp = g_clone_bio(bp);
833 g_io_deliver(bp, ENOMEM);
836 cbp->bio_done = g_sched_done;
837 cbp->bio_to = LIST_FIRST(&gp->provider);
838 KASSERT(cbp->bio_to != NULL, ("NULL provider"));
840 /* We only schedule reads and writes. */
841 if (0 == (bp->bio_cmd & (BIO_READ | BIO_WRITE)))
844 G_SCHED_LOGREQ(cbp, "Sending request.");
848 * Call the algorithm's gs_start to queue the request in the
849 * scheduler. If gs_start fails then pass the request down,
850 * otherwise call g_sched_dispatch() which tries to push
851 * one or more requests down.
853 if (!sc->sc_gsched || (sc->sc_flags & G_SCHED_FLUSHING) ||
854 sc->sc_gsched->gs_start(sc->sc_data, cbp)) {
859 * We use bio_caller1 to mark requests that are scheduled
860 * so make sure it is not NULL.
862 if (cbp->bio_caller1 == NULL)
863 cbp->bio_caller1 = &me; /* anything not NULL */
865 cbp->bio_caller2 = gp;
868 /* Update general stats. */
871 me.gs_bytes_in_flight += bp->bio_length;
872 if (bp->bio_cmd & BIO_WRITE) {
873 me.gs_writes_in_flight++;
874 me.gs_write_bytes_in_flight += bp->bio_length;
876 g_sched_dispatch(gp);
881 cbp->bio_done = g_std_done;
882 cbp->bio_caller1 = NULL; /* not scheduled */
883 g_io_request(cbp, LIST_FIRST(&gp->consumer));
887 * The next few functions are the geom glue.
890 g_sched_orphan(struct g_consumer *cp)
894 g_sched_destroy(cp->geom, 1);
898 g_sched_access(struct g_provider *pp, int dr, int dw, int de)
901 struct g_consumer *cp;
905 cp = LIST_FIRST(&gp->consumer);
906 error = g_access(cp, dr, dw, de);
912 g_sched_temporary_start(struct bio *bio)
915 mtx_lock(&me.gs_mtx);
917 gs_bioq_disksort(&me.gs_pending, bio);
918 mtx_unlock(&me.gs_mtx);
922 g_sched_flush_pending(g_start_t *start)
926 while ((bp = gs_bioq_takefirst(&me.gs_pending)))
931 g_insert_proxy(struct g_geom *gp, struct g_provider *newpp,
932 struct g_geom *dstgp, struct g_provider *pp, struct g_consumer *cp)
934 struct g_sched_softc *sc = gp->softc;
935 g_start_t *saved_start, *flush = g_sched_start;
936 int error = 0, endticks = ticks + hz;
938 g_cancel_event(newpp); /* prevent taste() */
939 /* copy private fields */
940 newpp->private = pp->private;
941 newpp->index = pp->index;
943 /* Queue all the early requests coming for us. */
945 saved_start = pp->geom->start;
946 dstgp->start = g_sched_temporary_start;
948 while (pp->nstart - pp->nend != me.gs_npending &&
949 endticks - ticks >= 0)
950 tsleep(pp, PRIBIO, "-", hz/10);
952 if (pp->nstart - pp->nend != me.gs_npending) {
958 /* link pp to this geom */
959 LIST_REMOVE(pp, provider);
961 LIST_INSERT_HEAD(&gp->provider, pp, provider);
964 * replicate the counts from the parent in the
965 * new provider and consumer nodes
967 cp->acr = newpp->acr = pp->acr;
968 cp->acw = newpp->acw = pp->acw;
969 cp->ace = newpp->ace = pp->ace;
970 sc->sc_flags |= G_SCHED_PROXYING;
973 dstgp->start = saved_start;
975 g_sched_flush_pending(flush);
981 * Create a geom node for the device passed as *pp.
982 * If successful, add a reference to this gsp.
985 g_sched_create(struct gctl_req *req, struct g_class *mp,
986 struct g_provider *pp, struct g_gsched *gsp, int proxy)
988 struct g_sched_softc *sc = NULL;
989 struct g_geom *gp, *dstgp;
990 struct g_provider *newpp = NULL;
991 struct g_consumer *cp = NULL;
997 snprintf(name, sizeof(name), "%s%s", pp->name, G_SCHED_SUFFIX);
998 LIST_FOREACH(gp, &mp->geom, geom) {
999 if (strcmp(gp->name, name) == 0) {
1000 gctl_error(req, "Geom %s already exists.",
1006 gp = g_new_geomf(mp, name);
1007 dstgp = proxy ? pp->geom : gp; /* where do we link the provider */
1009 sc = g_malloc(sizeof(*sc), M_WAITOK | M_ZERO);
1010 sc->sc_gsched = gsp;
1011 sc->sc_data = gsp->gs_init(gp);
1012 if (sc->sc_data == NULL) {
1017 sc->sc_hash = g_sched_hash_init(gsp, &sc->sc_mask, HASH_WAITOK);
1020 * Do not initialize the flush mechanism, will be initialized
1021 * on the first insertion on the hash table.
1024 mtx_init(&sc->sc_mtx, "g_sched_mtx", NULL, MTX_DEF);
1027 gp->start = g_sched_start;
1028 gp->orphan = g_sched_orphan;
1029 gp->access = g_sched_access;
1030 gp->dumpconf = g_sched_dumpconf;
1032 newpp = g_new_providerf(dstgp, gp->name);
1033 newpp->mediasize = pp->mediasize;
1034 newpp->sectorsize = pp->sectorsize;
1036 cp = g_new_consumer(gp);
1037 error = g_attach(cp, proxy ? newpp : pp);
1039 gctl_error(req, "Cannot attach to provider %s.",
1044 g_error_provider(newpp, 0);
1046 error = g_insert_proxy(gp, newpp, dstgp, pp, cp);
1050 G_SCHED_DEBUG(0, "Device %s created.", gp->name);
1058 if (cp->provider != NULL)
1060 g_destroy_consumer(cp);
1063 g_destroy_provider(newpp);
1065 g_sched_hash_fini(gp, sc->sc_hash, sc->sc_mask,
1068 gsp->gs_fini(sc->sc_data);
1076 * Support for dynamic switching of scheduling algorithms.
1077 * First initialize the data structures for the new algorithm,
1078 * then call g_sched_remove_locked() to flush all references
1079 * to the old one, finally link the new algorithm.
1082 g_sched_change_algo(struct gctl_req *req, struct g_class *mp,
1083 struct g_provider *pp, struct g_gsched *gsp)
1085 struct g_sched_softc *sc;
1087 struct g_hash *newh;
1095 data = gsp->gs_init(gp);
1099 newh = g_sched_hash_init(gsp, &mask, HASH_WAITOK);
1100 if (gsp->gs_priv_size && !newh) {
1106 if (sc->sc_gsched) { /* can be NULL in some cases */
1107 error = g_sched_remove_locked(gp, sc->sc_gsched);
1113 sc->sc_gsched = gsp;
1124 g_sched_hash_fini(gp, newh, mask, gsp, data);
1135 * Stop the request flow directed to the proxy, redirecting the new
1136 * requests to the me.gs_pending queue.
1138 static struct g_provider *
1139 g_detach_proxy(struct g_geom *gp)
1141 struct g_consumer *cp;
1142 struct g_provider *pp, *newpp;
1145 pp = LIST_FIRST(&gp->provider);
1148 cp = LIST_FIRST(&gp->consumer);
1151 newpp = cp->provider;
1156 pp->geom->start = g_sched_temporary_start;
1160 printf("%s error detaching proxy %s\n", __FUNCTION__, gp->name);
1166 g_sched_blackhole(struct bio *bp)
1169 g_io_deliver(bp, ENXIO);
1173 g_reparent_provider(struct g_provider *pp, struct g_geom *gp,
1174 struct g_provider *newpp)
1177 LIST_REMOVE(pp, provider);
1179 pp->private = newpp->private;
1180 pp->index = newpp->index;
1183 LIST_INSERT_HEAD(&gp->provider, pp, provider);
1187 g_unproxy_provider(struct g_provider *oldpp, struct g_provider *newpp)
1189 struct g_geom *gp = oldpp->geom;
1191 g_reparent_provider(oldpp, newpp->geom, newpp);
1194 * Hackish: let the system destroy the old provider for us, just
1195 * in case someone attached a consumer to it, in which case a
1196 * direct call to g_destroy_provider() would not work.
1198 g_reparent_provider(newpp, gp, NULL);
1202 * Complete the proxy destruction, linking the old provider to its
1203 * original geom, and destroying the proxy provider. Also take care
1204 * of issuing the pending requests collected in me.gs_pending (if any).
1207 g_destroy_proxy(struct g_geom *gp, struct g_provider *oldpp)
1209 struct g_consumer *cp;
1210 struct g_provider *newpp;
1213 cp = LIST_FIRST(&gp->consumer);
1216 newpp = cp->provider;
1220 /* Relink the provider to its original geom. */
1221 g_unproxy_provider(oldpp, newpp);
1223 /* Detach consumer from provider, and destroy provider. */
1224 cp->acr = newpp->acr = 0;
1225 cp->acw = newpp->acw = 0;
1226 cp->ace = newpp->ace = 0;
1229 /* Send the pending bios through the right start function. */
1230 g_sched_flush_pending(oldpp->geom->start);
1234 printf("%s error destroying proxy %s\n", __FUNCTION__, gp->name);
1236 /* We cannot send the pending bios anywhere... */
1237 g_sched_flush_pending(g_sched_blackhole);
1243 g_sched_destroy(struct g_geom *gp, boolean_t force)
1245 struct g_provider *pp, *oldpp = NULL;
1246 struct g_sched_softc *sc;
1247 struct g_gsched *gsp;
1250 g_topology_assert();
1254 if (!(sc->sc_flags & G_SCHED_PROXYING)) {
1255 pp = LIST_FIRST(&gp->provider);
1256 if (pp && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
1257 const char *msg = force ?
1258 "but we force removal" : "cannot remove";
1260 G_SCHED_DEBUG(!force,
1261 "Device %s is still open (r%dw%de%d), %s.",
1262 pp->name, pp->acr, pp->acw, pp->ace, msg);
1266 G_SCHED_DEBUG(0, "Device %s removed.", gp->name);
1269 oldpp = g_detach_proxy(gp);
1271 gsp = sc->sc_gsched;
1274 * XXX bad hack here: force a dispatch to release
1275 * any reference to the hash table still held by
1280 * We are dying here, no new requests should enter
1281 * the scheduler. This is granted by the topolgy,
1282 * either in case we were proxying (new bios are
1283 * being redirected) or not (see the access check
1286 g_sched_forced_dispatch(gp);
1287 error = g_sched_wait_pending(gp);
1291 * Not all the requests came home: this might happen
1292 * under heavy load, or if we were waiting for any
1293 * bio which is served in the event path (see
1294 * geom_slice.c for an example of how this can
1295 * happen). Try to restore a working configuration
1298 if ((sc->sc_flags & G_SCHED_PROXYING) && oldpp) {
1299 g_sched_flush_pending(force ?
1300 g_sched_blackhole : g_sched_start);
1304 * In the forced destroy case there is not so much
1305 * we can do, we have pending bios that will call
1306 * g_sched_done() somehow, and we don't want them
1307 * to crash the system using freed memory. We tell
1308 * the user that something went wrong, and leak some
1310 * Note: the callers using force = 1 ignore the
1314 G_SCHED_DEBUG(0, "Pending requests while "
1315 " destroying geom, some memory leaked.");
1322 g_sched_hash_fini(gp, sc->sc_hash, sc->sc_mask,
1325 gsp->gs_fini(sc->sc_data);
1326 g_gsched_unref(gsp);
1327 sc->sc_gsched = NULL;
1330 if ((sc->sc_flags & G_SCHED_PROXYING) && oldpp) {
1331 error = g_destroy_proxy(gp, oldpp);
1335 G_SCHED_DEBUG(0, "Unrecoverable error while "
1336 "destroying a proxy geom, leaking some "
1344 mtx_destroy(&sc->sc_mtx);
1348 g_wither_geom(gp, ENXIO);
1354 g_sched_destroy_geom(struct gctl_req *req, struct g_class *mp,
1358 return (g_sched_destroy(gp, 0));
1362 * Functions related to the classification of requests.
1364 * On recent FreeBSD versions (8.0 and above), we store a reference
1365 * to the issuer of a request in bp->bio_classifier1 as soon
1366 * as the bio is posted to the geom queue (and not later, because
1367 * requests are managed by the g_down thread afterwards).
1369 * On older versions of the system (but this code is not used
1370 * in any existing release), we [ab]use the caller1 field in the
1371 * root element of the bio tree to store the classification info.
1372 * The marking is done at the beginning of g_io_request()
1373 * and only if we find that the field is NULL.
1375 * To avoid rebuilding the kernel, this module will patch the
1376 * initial part of g_io_request() so it jumps to some hand-coded
1377 * assembly that does the marking and then executes the original
1378 * body of g_io_request().
1380 * fake_ioreq[] is architecture-specific machine code
1381 * that implements the above. CODE_SIZE, STORE_SIZE etc.
1382 * are constants used in the patching routine. Look at the
1383 * code in g_ioreq_patch() for the details.
1386 #ifndef HAVE_BIO_CLASSIFIER
1388 * Support for old FreeBSD versions
1390 #if defined(__i386__)
1391 #define CODE_SIZE 29
1392 #define STORE_SIZE 5
1394 #define SIZE (CODE_SIZE + STORE_SIZE + EPILOGUE)
1396 static u_char fake_ioreq[SIZE] = {
1397 0x8b, 0x44, 0x24, 0x04, /* mov bp, %eax */
1399 0x89, 0xc2, /* mov %eax, %edx # edx = bp */
1400 0x8b, 0x40, 0x64, /* mov bp->bio_parent, %eax */
1401 0x85, 0xc0, /* test %eax, %eax */
1402 0x75, 0xf7, /* jne 1b */
1403 0x8b, 0x42, 0x30, /* mov bp->bp_caller1, %eax */
1404 0x85, 0xc0, /* test %eax, %eax */
1405 0x75, 0x09, /* jne 2f */
1406 0x64, 0xa1, 0x00, 0x00, /* mov %fs:0, %eax */
1408 0x89, 0x42, 0x30, /* mov %eax, bp->bio_caller1 */
1410 0x55, 0x89, 0xe5, 0x57, 0x56,
1411 0xe9, 0x00, 0x00, 0x00, 0x00, /* jmp back... */
1413 #elif defined(__amd64)
1414 #define CODE_SIZE 38
1415 #define STORE_SIZE 6
1417 #define SIZE (CODE_SIZE + STORE_SIZE + EPILOGUE)
1419 static u_char fake_ioreq[SIZE] = {
1420 0x48, 0x89, 0xf8, /* mov bp, %rax */
1422 0x48, 0x89, 0xc2, /* mov %rax, %rdx # rdx = bp */
1423 0x48, 0x8b, 0x82, 0xa8, /* mov bp->bio_parent, %rax */
1425 0x48, 0x85, 0xc0, /* test %rax, %rax */
1426 0x75, 0xf1, /* jne 1b */
1427 0x48, 0x83, 0x7a, 0x58, /* cmp $0, bp->bp_caller1 */
1429 0x75, 0x0d, /* jne 2f */
1430 0x65, 0x48, 0x8b, 0x04, /* mov %gs:0, %rax */
1431 0x25, 0x00, 0x00, 0x00,
1433 0x48, 0x89, 0x42, 0x58, /* mov %rax, bp->bio_caller1 */
1435 0x55, 0x48, 0x89, 0xe5, 0x41, 0x56,
1436 0xe9, 0x00, 0x00, 0x00, 0x00, /* jmp back... */
1438 #else /* neither x86 nor amd64 */
1440 g_new_io_request(struct bio *bp, struct g_consumer *cp)
1442 struct bio *top = bp;
1445 * bio classification: if bio_caller1 is available in the
1446 * root of the 'struct bio' tree, store there the thread id
1447 * of the thread that originated the request.
1448 * More sophisticated classification schemes can be used.
1450 while (top->bio_parent)
1451 top = top->bio_parent;
1453 if (top->bio_caller1 == NULL)
1454 top->bio_caller1 = curthread;
1457 #error please add the code above in g_new_io_request() to the beginning of \
1458 /sys/geom/geom_io.c::g_io_request(), and remove this line.
1459 #endif /* end of arch-specific code */
1471 original = (u_char *)g_io_request;
1473 found = !bcmp(original, fake_ioreq + CODE_SIZE, STORE_SIZE);
1477 /* Jump back to the original + STORE_SIZE. */
1478 ofs = (original + STORE_SIZE) - (fake_ioreq + SIZE);
1479 bcopy(&ofs, fake_ioreq + CODE_SIZE + STORE_SIZE + 1, 4);
1481 /* Patch the original address with a jump to the trampoline. */
1482 *original = 0xe9; /* jump opcode */
1483 ofs = fake_ioreq - (original + 5);
1484 bcopy(&ofs, original + 1, 4);
1492 * Restore the original code, this is easy.
1495 g_ioreq_restore(void)
1499 if (me.gs_patched) {
1500 original = (u_char *)g_io_request;
1501 bcopy(fake_ioreq + CODE_SIZE, original, STORE_SIZE);
1507 g_classifier_ini(void)
1514 g_classifier_fini(void)
1520 /*--- end of support code for older FreeBSD versions */
1522 #else /* HAVE_BIO_CLASSIFIER */
1525 * Classifier support for recent FreeBSD versions: we use
1526 * a very simple classifier, only use curthread to tag a request.
1527 * The classifier is registered at module load, and unregistered
1531 g_sched_tag(void *arg, struct bio *bp)
1534 bp->bio_classifier1 = curthread;
1538 static struct g_classifier_hook g_sched_classifier = {
1539 .func = g_sched_tag,
1543 g_classifier_ini(void)
1546 g_register_classifier(&g_sched_classifier);
1550 g_classifier_fini(void)
1553 g_unregister_classifier(&g_sched_classifier);
1555 #endif /* HAVE_BIO_CLASSIFIER */
1558 g_sched_init(struct g_class *mp)
1561 g_gsched_global_init();
1563 G_SCHED_DEBUG(0, "Loading: mp = %p, g_sched_class = %p.",
1564 mp, &g_sched_class);
1566 /* Patch g_io_request to store classification info in the bio. */
1571 g_sched_fini(struct g_class *mp)
1574 g_classifier_fini();
1576 G_SCHED_DEBUG(0, "Unloading...");
1578 KASSERT(LIST_EMPTY(&me.gs_scheds), ("still registered schedulers"));
1579 mtx_destroy(&me.gs_mtx);
1583 g_sched_ioctl(struct g_provider *pp, u_long cmd, void *data, int fflag,
1586 struct g_consumer *cp;
1589 cp = LIST_FIRST(&pp->geom->consumer);
1592 gp = cp->provider->geom;
1593 if (gp->ioctl == NULL)
1595 return (gp->ioctl(cp->provider, cmd, data, fflag, td));
1599 * Read the i-th argument for a request, skipping the /dev/
1600 * prefix if present.
1603 g_sched_argi(struct gctl_req *req, int i)
1605 static const char *dev_prefix = "/dev/";
1608 int l = strlen(dev_prefix);
1610 snprintf(param, sizeof(param), "arg%d", i);
1611 name = gctl_get_asciiparam(req, param);
1613 gctl_error(req, "No 'arg%d' argument", i);
1614 else if (strncmp(name, dev_prefix, l) == 0)
1620 * Fetch nargs and do appropriate checks.
1623 g_sched_get_nargs(struct gctl_req *req)
1627 nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
1628 if (nargs == NULL) {
1629 gctl_error(req, "No 'nargs' argument");
1633 gctl_error(req, "Missing device(s).");
1638 * Check whether we should add the class on certain volumes when
1639 * this geom is created. Right now this is under control of a kenv
1640 * variable containing the names of all devices that we care about.
1641 * Probably we should only support transparent insertion as the
1642 * preferred mode of operation.
1644 static struct g_geom *
1645 g_sched_taste(struct g_class *mp, struct g_provider *pp,
1648 struct g_gsched *gsp = NULL; /* the . algorithm we want */
1649 const char *s; /* generic string pointer */
1650 const char *taste_names; /* devices we like */
1653 g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__,
1654 mp->name, pp->name);
1655 g_topology_assert();
1657 G_SCHED_DEBUG(2, "Tasting %s.", pp->name);
1660 /* do not taste on ourselves */
1661 if (pp->geom->class == mp)
1664 taste_names = getenv("geom.sched.taste");
1665 if (taste_names == NULL)
1668 l = strlen(pp->name);
1669 for (s = taste_names; *s &&
1670 (s = strstr(s, pp->name)); s++) {
1671 /* further checks for an exact match */
1672 if ( (s == taste_names || s[-1] == ' ') &&
1673 (s[l] == '\0' || s[l] == ' ') )
1678 G_SCHED_DEBUG(0, "Attach device %s match [%s]\n",
1681 /* look up the provider name in the list */
1682 s = getenv("geom.sched.algo");
1686 gsp = g_gsched_find(s); /* also get a reference */
1688 G_SCHED_DEBUG(0, "Bad '%s' algorithm.", s);
1692 /* XXX create with 1 as last argument ? */
1693 g_sched_create(NULL, mp, pp, gsp, 0);
1694 g_gsched_unref(gsp);
1700 g_sched_ctl_create(struct gctl_req *req, struct g_class *mp, int proxy)
1702 struct g_provider *pp;
1703 struct g_gsched *gsp;
1707 g_topology_assert();
1709 name = gctl_get_asciiparam(req, "algo");
1711 gctl_error(req, "No '%s' argument", "algo");
1715 gsp = g_gsched_find(name); /* also get a reference */
1717 gctl_error(req, "Bad algorithm '%s'", name);
1721 nargs = g_sched_get_nargs(req);
1724 * Run on the arguments, and break on any error.
1725 * We look for a device name, but skip the /dev/ prefix if any.
1727 for (i = 0; i < nargs; i++) {
1728 name = g_sched_argi(req, i);
1731 pp = g_provider_by_name(name);
1733 G_SCHED_DEBUG(1, "Provider %s is invalid.", name);
1734 gctl_error(req, "Provider %s is invalid.", name);
1737 if (g_sched_create(req, mp, pp, gsp, proxy) != 0)
1741 g_gsched_unref(gsp);
1745 g_sched_ctl_configure(struct gctl_req *req, struct g_class *mp)
1747 struct g_provider *pp;
1748 struct g_gsched *gsp;
1752 g_topology_assert();
1754 name = gctl_get_asciiparam(req, "algo");
1756 gctl_error(req, "No '%s' argument", "algo");
1760 gsp = g_gsched_find(name); /* also get a reference */
1762 gctl_error(req, "Bad algorithm '%s'", name);
1766 nargs = g_sched_get_nargs(req);
1769 * Run on the arguments, and break on any error.
1770 * We look for a device name, but skip the /dev/ prefix if any.
1772 for (i = 0; i < nargs; i++) {
1773 name = g_sched_argi(req, i);
1776 pp = g_provider_by_name(name);
1777 if (pp == NULL || pp->geom->class != mp) {
1778 G_SCHED_DEBUG(1, "Provider %s is invalid.", name);
1779 gctl_error(req, "Provider %s is invalid.", name);
1782 if (g_sched_change_algo(req, mp, pp, gsp) != 0)
1786 g_gsched_unref(gsp);
1789 static struct g_geom *
1790 g_sched_find_geom(struct g_class *mp, const char *name)
1794 LIST_FOREACH(gp, &mp->geom, geom) {
1795 if (strcmp(gp->name, name) == 0)
1802 g_sched_ctl_destroy(struct gctl_req *req, struct g_class *mp)
1804 int nargs, *force, error, i;
1808 g_topology_assert();
1810 nargs = g_sched_get_nargs(req);
1812 force = gctl_get_paraml(req, "force", sizeof(*force));
1813 if (force == NULL) {
1814 gctl_error(req, "No 'force' argument");
1818 for (i = 0; i < nargs; i++) {
1819 name = g_sched_argi(req, i);
1823 gp = g_sched_find_geom(mp, name);
1825 G_SCHED_DEBUG(1, "Device %s is invalid.", name);
1826 gctl_error(req, "Device %s is invalid.", name);
1830 error = g_sched_destroy(gp, *force);
1832 gctl_error(req, "Cannot destroy device %s (error=%d).",
1840 g_sched_config(struct gctl_req *req, struct g_class *mp, const char *verb)
1844 g_topology_assert();
1846 version = gctl_get_paraml(req, "version", sizeof(*version));
1847 if (version == NULL) {
1848 gctl_error(req, "No '%s' argument.", "version");
1852 if (*version != G_SCHED_VERSION) {
1853 gctl_error(req, "Userland and kernel parts are "
1858 if (strcmp(verb, "create") == 0) {
1859 g_sched_ctl_create(req, mp, 0);
1861 } else if (strcmp(verb, "insert") == 0) {
1862 g_sched_ctl_create(req, mp, 1);
1864 } else if (strcmp(verb, "configure") == 0) {
1865 g_sched_ctl_configure(req, mp);
1867 } else if (strcmp(verb, "destroy") == 0) {
1868 g_sched_ctl_destroy(req, mp);
1872 gctl_error(req, "Unknown verb.");
1876 g_sched_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
1877 struct g_consumer *cp, struct g_provider *pp)
1879 struct g_sched_softc *sc = gp->softc;
1880 struct g_gsched *gsp = sc->sc_gsched;
1881 if (indent == NULL) { /* plaintext */
1882 sbuf_printf(sb, " algo %s", gsp ? gsp->gs_name : "--");
1884 if (gsp != NULL && gsp->gs_dumpconf)
1885 gsp->gs_dumpconf(sb, indent, gp, cp, pp);
1888 DECLARE_GEOM_CLASS(g_sched_class, g_sched);
1889 MODULE_VERSION(geom_sched, 0);