diff options
author | Matt Johnston <matt@fugro-fsi.com.au> | 2012-12-21 10:15:34 +0800 |
---|---|---|
committer | Brian Behlendorf <behlendorf1@llnl.gov> | 2013-01-07 10:51:04 -0800 |
commit | 72f53c5694bfd57b56e79fc3b7c4390bce4072d2 (patch) | |
tree | f71ac31075af2f780e11b00276aa272ced5921ff /module | |
parent | 15f9d4e1c2b0ee26546e79d599df1b2adc2e5026 (diff) |
Revert part of "Log I/Os longer than zio_delay_max (30s default)"
This reverts commit 9dcb97198338ba2d8764dd5604b278118612f74
which was originally introduced to debug occasional slow I/Os.
These I/Os would complete eventually but were observed to take
several 100 seconds.
The root cause of this issue was the CFQ scheduler which can,
under certain conditions, excessively delay an I/O from being
issued to the device. This issue was mitigated somewhat by
commit 84daaddedbfc9cf4bd1490d8a6f4b2967051e308 which ensures
the I/O elevator gets changed even for DM style devices.
This change isn't in any way harmful but it does conflict with
a required change to properly account from I/O wait time.
Because Linux does not export the io_schedule_timeout() function
we must instead rely on io_schedule() via cv_wait_io().
The additional debugging information which was added to the
delay event has been intentionally left in place.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Diffstat (limited to 'module')
-rw-r--r-- | module/zfs/zio.c | 32 |
1 files changed, 10 insertions, 22 deletions
diff --git a/module/zfs/zio.c b/module/zfs/zio.c index bcfc081d1..ece3329d0 100644 --- a/module/zfs/zio.c +++ b/module/zfs/zio.c @@ -1305,34 +1305,18 @@ __zio_execute(zio_t *zio) int zio_wait(zio_t *zio) { - uint64_t timeout; int error; ASSERT(zio->io_stage == ZIO_STAGE_OPEN); ASSERT(zio->io_executor == NULL); zio->io_waiter = curthread; - timeout = ddi_get_lbolt() + (zio_delay_max / MILLISEC * hz); __zio_execute(zio); mutex_enter(&zio->io_lock); - while (zio->io_executor != NULL) { - /* - * Wake up periodically to prevent the kernel from complaining - * about a blocked task. However, check zio_delay_max to see - * if the I/O has exceeded the timeout and post an ereport. - */ - cv_timedwait_interruptible(&zio->io_cv, &zio->io_lock, - ddi_get_lbolt() + hz); - - if (timeout && (ddi_get_lbolt() > timeout)) { - zio->io_delay = zio_delay_max; - zfs_ereport_post(FM_EREPORT_ZFS_DELAY, - zio->io_spa, zio->io_vd, zio, 0, 0); - timeout = 0; - } - } + while (zio->io_executor != NULL) + cv_wait(&zio->io_cv, &zio->io_lock); mutex_exit(&zio->io_lock); error = zio->io_error; @@ -2905,11 +2889,15 @@ zio_done(zio_t *zio) vdev_stat_update(zio, zio->io_size); /* - * When an I/O completes but was slow post an ereport. + * If this I/O is attached to a particular vdev is slow, exeeding + * 30 seconds to complete, post an error described the I/O delay. + * We ignore these errors if the device is currently unavailable. */ - if (zio->io_delay >= zio_delay_max) - zfs_ereport_post(FM_EREPORT_ZFS_DELAY, zio->io_spa, - zio->io_vd, zio, 0, 0); + if (zio->io_delay >= zio_delay_max) { + if (zio->io_vd != NULL && !vdev_is_dead(zio->io_vd)) + zfs_ereport_post(FM_EREPORT_ZFS_DELAY, zio->io_spa, + zio->io_vd, zio, 0, 0); + } if (zio->io_error) { /* |