Searched hist:b88efd43f900d608560211a18a38d450f8192948 (Results 1 – 1 of 1) sorted by relevance
| /openbmc/linux/drivers/md/ |
| H A D | dm-mpath.c | diff b88efd43f900d608560211a18a38d450f8192948 Fri Sep 09 18:26:19 CDT 2016 Mike Snitzer <snitzer@redhat.com> dm mpath: delay the requeue of blk-mq requests while all paths down
Return DM_MAPIO_DELAY_REQUEUE from .clone_and_map_rq. Also, return
false from .busy, if all paths are down, so that blk-mq requests get
mapped via .clone_and_map_rq -- which results in DM_MAPIO_DELAY_REQUEUE
being returned to dm-rq.
This change allows for a noticeable reduction in cpu utilization
(reduced kworker load) while all paths are down, e.g.:
system CPU idleness (as measured by fio's --idle-prof=system):
before: system: 86.58%
after: system: 98.60%
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
|