dm mpath: return DM_MAPIO_REQUEUE on blk-mq rq allocation failure

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blk-mq will rerun queue via RESTART or dispatch wake after one request
is completed, so not necessary to wait random time for requeuing, we
should trust blk-mq to do it.

More importantly, we need to return BLK_STS_RESOURCE to blk-mq so that
dequeuing from the I/O scheduler can be stopped, this results in
improved I/O merging.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

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Ming Lei 2018-01-11 14:01:56 +08:00 • committed by Mike Snitzer

parent 4b259fc4a8

commit 050af08ffb

1 changed files with 13 additions and 1 deletions

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drivers/md/dm-mpath.c

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