diff options
| author | Tom Caputi <[email protected]> | 2017-12-21 12:13:06 -0500 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2017-12-21 09:13:06 -0800 |
| commit | a8b2e30685c9214ccfd0181977540e080340df4e (patch) | |
| tree | db07450d097c27b1e3d627f8ae58387cad9d0038 /include/sys/vdev.h | |
| parent | 993669a7bf17a26843630c547999be0b27483497 (diff) | |
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 <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Tom Caputi <[email protected]>
Closes #6921
Closes #6926
Diffstat (limited to 'include/sys/vdev.h')
| -rw-r--r-- | include/sys/vdev.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/sys/vdev.h b/include/sys/vdev.h index 473d2691c..bc2f4f0ea 100644 --- a/include/sys/vdev.h +++ b/include/sys/vdev.h @@ -123,6 +123,7 @@ extern void vdev_queue_init(vdev_t *vd); extern void vdev_queue_fini(vdev_t *vd); extern zio_t *vdev_queue_io(zio_t *zio); extern void vdev_queue_io_done(zio_t *zio); +extern void vdev_queue_change_io_priority(zio_t *zio, zio_priority_t priority); extern int vdev_queue_length(vdev_t *vd); extern uint64_t vdev_queue_last_offset(vdev_t *vd); |