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 | |
| 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')
| -rw-r--r-- | include/sys/arc_impl.h | 1 | ||||
| -rw-r--r-- | include/sys/trace_arc.h | 2 | ||||
| -rw-r--r-- | include/sys/vdev.h | 1 | ||||
| -rw-r--r-- | include/sys/zio.h | 2 |
4 files changed, 5 insertions, 1 deletions
diff --git a/include/sys/arc_impl.h b/include/sys/arc_impl.h index e39cf6a8f..a923449d9 100644 --- a/include/sys/arc_impl.h +++ b/include/sys/arc_impl.h @@ -98,6 +98,7 @@ struct arc_callback { boolean_t acb_noauth; uint64_t acb_dsobj; zio_t *acb_zio_dummy; + zio_t *acb_zio_head; arc_callback_t *acb_next; }; diff --git a/include/sys/trace_arc.h b/include/sys/trace_arc.h index 74a76520d..c40b58e32 100644 --- a/include/sys/trace_arc.h +++ b/include/sys/trace_arc.h @@ -108,7 +108,7 @@ DEFINE_ARC_BUF_HDR_EVENT(zfs_arc__evict); DEFINE_ARC_BUF_HDR_EVENT(zfs_arc__delete); DEFINE_ARC_BUF_HDR_EVENT(zfs_new_state__mru); DEFINE_ARC_BUF_HDR_EVENT(zfs_new_state__mfu); -DEFINE_ARC_BUF_HDR_EVENT(zfs_arc__sync__wait__for__async); +DEFINE_ARC_BUF_HDR_EVENT(zfs_arc__async__upgrade__sync); DEFINE_ARC_BUF_HDR_EVENT(zfs_arc__demand__hit__predictive__prefetch); DEFINE_ARC_BUF_HDR_EVENT(zfs_l2arc__hit); DEFINE_ARC_BUF_HDR_EVENT(zfs_l2arc__miss); 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); diff --git a/include/sys/zio.h b/include/sys/zio.h index 1f9f48268..8beea7adf 100644 --- a/include/sys/zio.h +++ b/include/sys/zio.h @@ -586,6 +586,8 @@ extern void zio_vdev_io_bypass(zio_t *zio); extern void zio_vdev_io_reissue(zio_t *zio); extern void zio_vdev_io_redone(zio_t *zio); +extern void zio_change_priority(zio_t *pio, zio_priority_t priority); + extern void zio_checksum_verified(zio_t *zio); extern int zio_worst_error(int e1, int e2); |