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| author | Bart Van Assche <bart.vanassche@sandisk.com> | 2017-04-27 19:11:24 +0200 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2017-04-27 23:08:45 +0200 |
| commit | ca5beb76c32af33e5be4e01c85c8bd5a067c4543 (patch) | |
| tree | da891f5543130b6f7ead7bc135d1d203104471eb /Documentation/kernel-per-CPU-kthreads.txt | |
| parent | dm: introduce enum dm_queue_mode to cleanup related code (diff) | |
| download | linux-ca5beb76c32af33e5be4e01c85c8bd5a067c4543.tar.xz linux-ca5beb76c32af33e5be4e01c85c8bd5a067c4543.zip | |
dm mpath: micro-optimize the hot path relative to MPATHF_QUEUE_IF_NO_PATH
Instead of checking MPATHF_QUEUE_IF_NO_PATH,
MPATHF_SAVED_QUEUE_IF_NO_PATH and the no_flush flag to decide whether
or not to push back a request (or bio) if there are no paths available,
only clear MPATHF_QUEUE_IF_NO_PATH in queue_if_no_path() if no_flush has
not been set. The result is that only a single bit has to be tested in
the hot path to decide whether or not a request must be pushed back and
also that m->lock does not have to be taken in the hot path.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'Documentation/kernel-per-CPU-kthreads.txt')
0 files changed, 0 insertions, 0 deletions