- Add flags argument to dm_bufio_client_create and introduce
DM_BUFIO_CLIENT_NO_SLEEP flag to have dm-bufio use spinlock rather
than mutex for its locking.
- Add optional "try_verify_in_tasklet" feature to DM verity target.
This feature gives users the option to improve IO latency by using a
tasklet to verify, using hashes in bufio's cache, rather than wait
to schedule a work item via workqueue. But if there is a bufio cache
miss, or an error, then the tasklet will fallback to using workqueue.
- Incremental changes to both dm-bufio and the DM verity target to use
jump_label to minimize cost of branching associated with the niche
"try_verify_in_tasklet" feature. DM-bufio in particular is used by
quite a few other DM targets so it doesn't make sense to incur
additional bufio cost in those targets purely for the benefit of
this niche verity feature if the feature isn't ever used.
- Optimize verity_verify_io, which is used by both workqueue and
tasklet based verification, if FEC is not configured or tasklet
based verification isn't used.
- Remove DM verity target's verify_wq's use of the WQ_CPU_INTENSIVE
flag since it uses WQ_UNBOUND. Also, use the WQ_HIGHPRI flag if
"try_verify_in_tasklet" is specified.
dm verity: have verify_wq use WQ_HIGHPRI if "try_verify_in_tasklet"
Allow verify_wq to preempt softirq since verification in tasklet will
fall-back to using it for error handling (or if the bufio cache
doesn't have required hashes).
Suggested-by: Nathan Huckleberry <nhuck@google.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
1 file changed
