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| author | Brian Behlendorf <[email protected]> | 2015-09-24 16:32:25 -0700 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2015-09-25 12:47:31 -0700 |
| commit | 5592404784d3125cbeb6df002674867c009c8b48 (patch) | |
| tree | 4ae2c1d2e180906e718138b5680c7ca996aeba99 /module/avl | |
| parent | ef5b2e1048eeeb7a81d932d38e52d897b33fca54 (diff) | |
Fix synchronous behavior in __vdev_disk_physio()
Commit b39c22b set the READ_SYNC and WRITE_SYNC flags for a bio
based on the ZIO_PRIORITY_* flag passed in. This had the unnoticed
side-effect of making the vdev_disk_io_start() synchronous for
certain I/Os.
This in turn resulted in vdev_disk_io_start() being able to
re-dispatch zio's which would result in a RCU stalls when a disk
was removed from the system. Additionally, this could negatively
impact performance and explains the performance regressions reported
in both #3829 and #3780.
This patch resolves the issue by making the blocking behavior
dependent on a 'wait' flag being passed rather than overloading
the passed bio flags.
Finally, the WRITE_SYNC and READ_SYNC behavior is restricted to
non-rotational devices where there is no benefit to queuing to
aggregate the I/O.
Signed-off-by: Brian Behlendorf <[email protected]>
Issue #3652
Issue #3780
Issue #3785
Issue #3817
Issue #3821
Issue #3829
Issue #3832
Issue #3870
Diffstat (limited to 'module/avl')
0 files changed, 0 insertions, 0 deletions