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MigeljanImeribehlendorf
MigeljanImeri
authored and
behlendorf
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Add vdev property to disable vdev io scheduler
Added vdev property to disable the vdev io scheduler. The intention behind this property is to improve IOPS performance when using o_direct. Signed-off-by: MigeljanImeri <[email protected]>
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14 files changed

+212
-2
lines changed

14 files changed

+212
-2
lines changed

‎include/sys/fs/zfs.h‎

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -385,9 +385,23 @@ typedef enum {
385385
VDEV_PROP_TRIM_SUPPORT,
386386
VDEV_PROP_TRIM_ERRORS,
387387
VDEV_PROP_SLOW_IOS,
388+
VDEV_PROP_SCHEDULER,
388389
VDEV_NUM_PROPS
389390
} vdev_prop_t;
390391

392+
/*
393+
* Different scheduling behaviors for vdev prop io_scheduler.
394+
* VDEV_SCHEDULER_AUTO = Don't queue if vdev is nonrot and backed by blkdev,
395+
* queue otherwise.
396+
* VDEV_SCHEDULER_CLASSIC = Always queue.
397+
* VDEV_SCHEDULER_NONE = Never Queue.
398+
*/
399+
typedef enum {
400+
VDEV_SCHEDULER_AUTO,
401+
VDEV_SCHEDULER_CLASSIC,
402+
VDEV_SCHEDULER_NONE
403+
} vdev_scheduler_type_t;
404+
391405
/*
392406
* Dataset property functions shared between libzfs and kernel.
393407
*/

‎include/sys/vdev_impl.h‎

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -423,6 +423,7 @@ struct vdev {
423423
boolean_t vdev_resilver_deferred; /* resilver deferred */
424424
boolean_t vdev_kobj_flag; /* kobj event record */
425425
boolean_t vdev_attaching; /* vdev attach ashift handling */
426+
boolean_t vdev_is_blkdev; /* vdev is backed by block device */
426427
vdev_queue_t vdev_queue; /* I/O deadline schedule queue */
427428
spa_aux_vdev_t *vdev_aux; /* for l2cache and spares vdevs */
428429
zio_t *vdev_probe_zio; /* root of current probe */
@@ -466,6 +467,7 @@ struct vdev {
466467
uint64_t vdev_io_t;
467468
uint64_t vdev_slow_io_n;
468469
uint64_t vdev_slow_io_t;
470+
uint64_t vdev_scheduler; /* control how I/Os are submitted */
469471
};
470472

471473
#define VDEV_PAD_SIZE (8 << 10)

‎lib/libzfs/libzfs.abi‎

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -6116,7 +6116,8 @@
61166116
<enumerator name='VDEV_PROP_TRIM_SUPPORT' value='49'/>
61176117
<enumerator name='VDEV_PROP_TRIM_ERRORS' value='50'/>
61186118
<enumerator name='VDEV_PROP_SLOW_IOS' value='51'/>
6119-
<enumerator name='VDEV_NUM_PROPS' value='52'/>
6119+
<enumerator name='VDEV_PROP_SCHEDULER' value='52'/>
6120+
<enumerator name='VDEV_NUM_PROPS' value='53'/>
61206121
</enum-decl>
61216122
<typedef-decl name='vdev_prop_t' type-id='1573bec8' id='5aa5c90c'/>
61226123
<class-decl name='zpool_load_policy' size-in-bits='256' is-struct='yes' visibility='default' id='2f65b36f'>

‎man/man7/vdevprops.7‎

Lines changed: 16 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -157,6 +157,22 @@ If this device should perform new allocations, used to disable a device
157157
when it is scheduled for later removal.
158158
See
159159
.Xr zpool-remove 8 .
160+
.It Sy io_scheduler Ns = Ns Sy auto Ns | Ns Sy classic Ns | Ns Sy none
161+
Controls how I/O requests are added to the vdev queue when reading or
162+
writing to this vdev.
163+
.It Sy auto
164+
Does not add I/O requests to the vdev queue if the vdev is backed by a
165+
non-rotational block device.
166+
This can sometimes improve performance for direct IOs.
167+
I/O requests will be added to the vdev queue if the vdev is backed by a
168+
rotational block device or file.
169+
This is the default behavior.
170+
.It Sy classic
171+
Always adds I/O requests to the vdev queue.
172+
.It Sy none
173+
Never adds I/O requests to the vdev queue.
174+
This is not recommended for vdevs backed by spinning disks as it could
175+
result in starvation.
160176
.El
161177
.Ss User Properties
162178
In addition to the standard native properties, ZFS supports arbitrary user

‎module/os/freebsd/zfs/vdev_geom.c‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -968,6 +968,9 @@ vdev_geom_open(vdev_t *vd, uint64_t *psize, uint64_t *max_psize,
968968
else
969969
vd->vdev_nonrot = B_FALSE;
970970

971+
/* Is backed by a block device. */
972+
vd->vdev_is_blkdev = B_TRUE;
973+
971974
/* Set when device reports it supports TRIM. */
972975
error = g_getattr("GEOM::candelete", cp, &has_trim);
973976
vd->vdev_has_trim = (error == 0 && has_trim);

‎module/os/linux/zfs/vdev_disk.c‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -447,6 +447,9 @@ vdev_disk_open(vdev_t *v, uint64_t *psize, uint64_t *max_psize,
447447
/* Inform the ZIO pipeline that we are non-rotational */
448448
v->vdev_nonrot = blk_queue_nonrot(bdev_get_queue(bdev));
449449

450+
/* Is backed by a block device. */
451+
v->vdev_is_blkdev = B_TRUE;
452+
450453
/* Physical volume size in bytes for the partition */
451454
*psize = bdev_capacity(bdev);
452455

‎module/zcommon/zpool_prop.c‎

Lines changed: 11 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -326,6 +326,13 @@ vdev_prop_init(void)
326326
{ NULL }
327327
};
328328

329+
static const zprop_index_t vdevschedulertype_table[] = {
330+
{ "auto", VDEV_SCHEDULER_AUTO },
331+
{ "classic", VDEV_SCHEDULER_CLASSIC },
332+
{ "none", VDEV_SCHEDULER_NONE },
333+
{ NULL }
334+
};
335+
329336
struct zfs_mod_supported_features *sfeatures =
330337
zfs_mod_list_supported(ZFS_SYSFS_VDEV_PROPERTIES);
331338

@@ -470,6 +477,10 @@ vdev_prop_init(void)
470477
zprop_register_index(VDEV_PROP_TRIM_SUPPORT, "trim_support", 0,
471478
PROP_READONLY, ZFS_TYPE_VDEV, "on | off", "TRIMSUP",
472479
boolean_table, sfeatures);
480+
zprop_register_index(VDEV_PROP_SCHEDULER, "scheduler",
481+
VDEV_SCHEDULER_AUTO, PROP_DEFAULT, ZFS_TYPE_VDEV,
482+
"auto | classic | none", "IO_SCHEDULER", vdevschedulertype_table,
483+
sfeatures);
473484

474485
/* default index properties */
475486
zprop_register_index(VDEV_PROP_FAILFAST, "failfast", B_TRUE,

‎module/zfs/vdev.c‎

Lines changed: 18 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -722,6 +722,8 @@ vdev_alloc_common(spa_t *spa, uint_t id, uint64_t guid, vdev_ops_t *ops)
722722
vd->vdev_slow_io_n = vdev_prop_default_numeric(VDEV_PROP_SLOW_IO_N);
723723
vd->vdev_slow_io_t = vdev_prop_default_numeric(VDEV_PROP_SLOW_IO_T);
724724

725+
vd->vdev_scheduler = vdev_prop_default_numeric(VDEV_PROP_SCHEDULER);
726+
725727
list_link_init(&vd->vdev_config_dirty_node);
726728
list_link_init(&vd->vdev_state_dirty_node);
727729
list_link_init(&vd->vdev_initialize_node);
@@ -3890,6 +3892,12 @@ vdev_load(vdev_t *vd)
38903892
if (error && error != ENOENT)
38913893
vdev_dbgmsg(vd, "vdev_load: zap_lookup(zap=%llu) "
38923894
"failed [error=%d]", (u_longlong_t)zapobj, error);
3895+
3896+
error = vdev_prop_get_int(vd, VDEV_PROP_SCHEDULER,
3897+
&vd->vdev_scheduler);
3898+
if (error && error != ENOENT)
3899+
vdev_dbgmsg(vd, "vdev_load: zap_lookup(zap=%llu) "
3900+
"failed [error=%d]", (u_longlong_t)zapobj, error);
38933901
}
38943902

38953903
/*
@@ -6125,6 +6133,15 @@ vdev_prop_set(vdev_t *vd, nvlist_t *innvl, nvlist_t *outnvl)
61256133
}
61266134
vd->vdev_slow_io_t = intval;
61276135
break;
6136+
case VDEV_PROP_SCHEDULER:
6137+
if (nvpair_value_uint64(elem, &intval) != 0) {
6138+
error = EINVAL;
6139+
break;
6140+
}
6141+
if (vd->vdev_ops->vdev_op_leaf) {
6142+
vd->vdev_scheduler = intval;
6143+
}
6144+
break;
61286145
default:
61296146
/* Most processing is done in vdev_props_set_sync */
61306147
break;
@@ -6488,6 +6505,7 @@ vdev_prop_get(vdev_t *vd, nvlist_t *innvl, nvlist_t *outnvl)
64886505
case VDEV_PROP_IO_T:
64896506
case VDEV_PROP_SLOW_IO_N:
64906507
case VDEV_PROP_SLOW_IO_T:
6508+
case VDEV_PROP_SCHEDULER:
64916509
err = vdev_prop_get_int(vd, prop, &intval);
64926510
if (err && err != ENOENT)
64936511
break;

‎module/zfs/vdev_file.c‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -109,6 +109,9 @@ vdev_file_open(vdev_t *vd, uint64_t *psize, uint64_t *max_psize,
109109
*/
110110
vd->vdev_nonrot = B_TRUE;
111111

112+
/* Is not backed by a block device. */
113+
vd->vdev_is_blkdev = B_FALSE;
114+
112115
/*
113116
* Allow TRIM on file based vdevs. This may not always be supported,
114117
* since it depends on your kernel version and underlying filesystem

‎module/zfs/vdev_queue.c‎

Lines changed: 41 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -879,6 +879,38 @@ vdev_queue_io_to_issue(vdev_queue_t *vq)
879879
return (zio);
880880
}
881881

882+
static boolean_t
883+
vdev_should_queue_zio(zio_t *zio)
884+
{
885+
vdev_t *vd = zio->io_vd;
886+
boolean_t should_queue = B_TRUE;
887+
888+
/*
889+
* Add zio with ZIO_FLAG_NODATA to queue as bypass code
890+
* currently does not handle certain cases (gang abd, raidz
891+
* write aggregation).
892+
*/
893+
if (zio->io_flags & ZIO_FLAG_NODATA)
894+
return (B_TRUE);
895+
896+
switch (vd->vdev_scheduler) {
897+
case VDEV_SCHEDULER_AUTO:
898+
if (vd->vdev_nonrot && vd->vdev_is_blkdev)
899+
should_queue = B_FALSE;
900+
break;
901+
case VDEV_SCHEDULER_CLASSIC:
902+
should_queue = B_TRUE;
903+
break;
904+
case VDEV_SCHEDULER_NONE:
905+
should_queue = B_FALSE;
906+
break;
907+
default:
908+
should_queue = B_TRUE;
909+
break;
910+
}
911+
return (should_queue);
912+
}
913+
882914
zio_t *
883915
vdev_queue_io(zio_t *zio)
884916
{
@@ -922,6 +954,11 @@ vdev_queue_io(zio_t *zio)
922954
zio->io_flags |= ZIO_FLAG_DONT_QUEUE;
923955
zio->io_timestamp = gethrtime();
924956

957+
if (!vdev_should_queue_zio(zio)) {
958+
zio->io_queue_state = ZIO_QS_NONE;
959+
return (zio);
960+
}
961+
925962
mutex_enter(&vq->vq_lock);
926963
vdev_queue_io_add(vq, zio);
927964
nio = vdev_queue_io_to_issue(vq);
@@ -954,6 +991,10 @@ vdev_queue_io_done(zio_t *zio)
954991
vq->vq_io_complete_ts = now;
955992
vq->vq_io_delta_ts = zio->io_delta = now - zio->io_timestamp;
956993

994+
if (zio->io_queue_state == ZIO_QS_NONE) {
995+
return;
996+
}
997+
957998
mutex_enter(&vq->vq_lock);
958999
vdev_queue_pending_remove(vq, zio);
9591000

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