diff options
| author | Brian Behlendorf <[email protected]> | 2012-10-05 10:39:35 -0700 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2012-10-05 12:39:59 -0700 |
| commit | 7bd04f2d7d99780f190d4027e6e81fc0df11ba95 (patch) | |
| tree | 20919bfb2d5dc2e9e997386f36a7ae5ae4ef7060 /module/zfs | |
| parent | 089fa91bc51dc10da5a75a6d9fff77f186fccb23 (diff) | |
Set default zvol elevator to noop
It doesn't make sense for a zvol to use the default system I/O
scheduler because it is a virtual device. Therefore, we change
the default scheduler to 'noop' for zvols provided that the
elevator_change() function is available. This interface has
been available since Linux 2.6.36 and appears in the RHEL 6.x
kernels.
We deliberately do not implement the method for older kernels
because it was racy and could result in system crashes. It's
better to simply manually tune the scheduler for these kernels.
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #1017
Diffstat (limited to 'module/zfs')
| -rw-r--r-- | module/zfs/zvol.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c index b07476c42..c3bd25c3b 100644 --- a/module/zfs/zvol.c +++ b/module/zfs/zvol.c @@ -1159,6 +1159,7 @@ static zvol_state_t * zvol_alloc(dev_t dev, const char *name) { zvol_state_t *zv; + int error = 0; zv = kmem_zalloc(sizeof (zvol_state_t), KM_SLEEP); if (zv == NULL) @@ -1168,6 +1169,15 @@ zvol_alloc(dev_t dev, const char *name) if (zv->zv_queue == NULL) goto out_kmem; +#ifdef HAVE_ELEVATOR_CHANGE + error = elevator_change(zv->zv_queue, "noop"); +#endif /* HAVE_ELEVATOR_CHANGE */ + if (error) { + printk("ZFS: Unable to set \"%s\" scheduler for zvol %s: %d\n", + "noop", name, error); + goto out_queue; + } + #ifdef HAVE_BLK_QUEUE_FLUSH blk_queue_flush(zv->zv_queue, VDEV_REQ_FLUSH | VDEV_REQ_FUA); #else |