Fix short-lived txg caused by autotrim

Current autotrim causes short-lived txg through:

1. calling txg_wait_synced() in metaslab_enable()
2. calling txg_wait_open() with should_quiesce = true

This patch addresses all the issues mentioned above.

A new cv, vdev_autotrim_kick_cv is added to kick autotrim activity.
It will be signaled once a txg is synced so that it does not change 
the original autotrim pace. Also because it is a cv, the wait is 
interruptible which speeds up the vdev_autotrim_stop_wait() call.

Finally, combining big zfs_txg_timeout, txg_wait_open() also causes
delay when exporting a pool.

Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: jxdking <[email protected]>
Issue #8993
Closes #12194

0 files changed, 0 insertions, 0 deletions