SUNRPC: serialize iostats updates

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Occasionally mountstats reports a negative retransmission rate.
Ensure that two RPCs completing concurrently don't confuse the sums
in the transport's op_metrics array.

Since pNFS filelayout can invoke rpc_count_iostats() on another
transport from xprt_release(), we can't rely on simply holding the
transport_lock in xprt_release(). There's nothing for it but hard
serialization. One spin lock per RPC operation should make this as
painless as it can be.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

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Chuck Lever 2014-11-08 20:15:09 -05:00 • committed by Anna Schumaker

parent 5d01410fe4

commit edef1297f3

2 changed files with 19 additions and 5 deletions

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include/linux/sunrpc/metrics.h

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