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| author | Chuck Lever <chuck.lever@oracle.com> | 2020-05-02 17:37:44 +0300 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2020-05-18 17:21:21 +0300 |
| commit | ca4faf543a33373bed3650812d5f0cd0bd295b1a (patch) | |
| tree | 557c33f5f34050f49e27961857ba4e52ad4945da /net/sunrpc/svc_xprt.c | |
| parent | b9bbe6ed63b2b9f2c9ee5cbd0f2c946a2723f4ce (diff) | |
| download | linux-ca4faf543a33373bed3650812d5f0cd0bd295b1a.tar.xz | |
SUNRPC: Move xpt_mutex into socket xpo_sendto methods
It appears that the RPC/RDMA transport does not need serialization
of calls to its xpo_sendto method. Move the mutex into the socket
methods that still need that serialization.
Tail latencies are unambiguously better with this patch applied.
fio randrw 8KB 70/30 on NFSv3, smaller numbers are better:
clat percentiles (usec):
With xpt_mutex:
r | 99.99th=[ 8848]
w | 99.99th=[ 9634]
Without xpt_mutex:
r | 99.99th=[ 8586]
w | 99.99th=[ 8979]
Serializing the construction of RPC/RDMA transport headers is not
really necessary at this point, because the Linux NFS server
implementation never changes its credit grant on a connection. If
that should change, then svc_rdma_sendto will need to serialize
access to the transport's credit grant fields.
Reported-by: kbuild test robot <lkp@intel.com>
[ cel: fix uninitialized variable warning ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'net/sunrpc/svc_xprt.c')
| -rw-r--r-- | net/sunrpc/svc_xprt.c | 12 |
1 files changed, 3 insertions, 9 deletions
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index 2284ff038dad..07cdbf7d5764 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -914,16 +914,10 @@ int svc_send(struct svc_rqst *rqstp) xb->page_len + xb->tail[0].iov_len; trace_svc_sendto(xb); - - /* Grab mutex to serialize outgoing data. */ - mutex_lock(&xprt->xpt_mutex); trace_svc_stats_latency(rqstp); - if (test_bit(XPT_DEAD, &xprt->xpt_flags) - || test_bit(XPT_CLOSE, &xprt->xpt_flags)) - len = -ENOTCONN; - else - len = xprt->xpt_ops->xpo_sendto(rqstp); - mutex_unlock(&xprt->xpt_mutex); + + len = xprt->xpt_ops->xpo_sendto(rqstp); + trace_svc_send(rqstp, len); svc_xprt_release(rqstp); |