mirror_zfs/tests/zfs-tests
Tom Caputi a8b2e30685 Support re-prioritizing asynchronous prefetches
When sequential scrubs were merged, all calls to arc_read()
(including prefetch IOs) were given ZIO_PRIORITY_ASYNC_READ.
Unfortunately, this behaves badly with an existing issue where
prefetch IOs cannot be re-prioritized after the issue. The
result is that synchronous reads end up in the same vdev_queue
as the scrub IOs and can have (in some workloads) multiple
seconds of latency.

This patch incorporates 2 changes. The first ensures that all
scrub IOs are given ZIO_PRIORITY_SCRUB to allow the vdev_queue
code to differentiate between these I/Os and user prefetches.
Second, this patch introduces zio_change_priority() to provide
the missing capability to upgrade a zio's priority.

Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #6921 
Closes #6926
2017-12-21 09:13:06 -08:00
..
callbacks Multi-modifier protection (MMP) 2017-07-13 13:54:00 -04:00
cmd Enable remaining tests 2017-05-22 12:34:32 -04:00
include Various ZED fixes 2017-12-08 16:58:41 -08:00
tests Support re-prioritizing asynchronous prefetches 2017-12-21 09:13:06 -08:00
Makefile.am OpenZFS 7503 - zfs-test should tail ::zfs_dbgmsg on test failure 2017-04-12 13:36:48 -07:00