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| author | Mike Snitzer | 2016-02-17 21:04:05 +0100 |
|---|---|---|
| committer | Mike Snitzer | 2016-02-23 04:34:42 +0100 |
| commit | b0b477c7e0dd93f8916d106018ded1331b81bf61 (patch) | |
| tree | 0b8329486138c196dc07855bbf43ad9130efbea1 /drivers/md/dm-mpath.c | |
| parent | dm path selector: remove 'repeat_count' return from .select_path hook (diff) | |
| download | kernel-qcow2-linux-b0b477c7e0dd93f8916d106018ded1331b81bf61.tar.gz kernel-qcow2-linux-b0b477c7e0dd93f8916d106018ded1331b81bf61.tar.xz kernel-qcow2-linux-b0b477c7e0dd93f8916d106018ded1331b81bf61.zip | |
dm round robin: use percpu 'repeat_count' and 'current_path'
Now that dm-mpath core is lockless in the per-IO fast path it is
critical, for performance, to have the .select_path hook
(rr_select_path) also be as lockless as possible.
The new percpu members of 'struct selector' allow for lockless support
of 'repeat_count' governed repeat use of a previously selected path. If
a path fails while it is 'current_path' the worst case is concurrent IO
might be mapped to the failed path until the .fail_path hook
(rr_fail_path) is called.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-mpath.c')
0 files changed, 0 insertions, 0 deletions