We can improve the performance of writes to zvols by using
dmu_tx_hold_write_by_dnode() instead of dmu_tx_hold_write(). This
reduces lock contention on the first block of the dnode object, and also
reduces the amount of CPU needed. The benefit will be highest with
multi-threaded async writes (i.e. writes that don't call zil_commit()).
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10184
20f287855a