nfs: probe for LOCALIO when v3 client reconnects to server
Re-enabling NFSv3 LOCALIO is made more complex (than NFSv4) because v3
is stateless. As such, the hueristic used to identify a LOCALIO probe
point is more adhoc by nature: if/when NFSv3 client IO begins to
complete again in terms of normal RPC-based NFSv3 server IO, attempt
nfs_local_probe_async().
Care is taken to throttle the frequency of nfs_local_probe_async(),
otherwise there could be a flood of repeat calls to
nfs_local_probe_async().
The throttle is admin controlled using a new module parameter for
nfsv3, e.g.:
echo 512 > /sys/module/nfsv3/parameters/nfs3_localio_probe_throttle
Probe for NFSv3 LOCALIO every N IO requests (512 in this case). Must
be power-of-2, defaults to 0 (probing disabled).
On systems that expect to use LOCALIO with NFSv3 the admin should
configure the 'nfs3_localio_probe_throttle' module parameter.
This commit backfills module parameter documentation in localio.rst
Signed-off-by: Mike Snitzer <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Signed-off-by: Anna Schumaker <[email protected]>
4 files changed
