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-rw-r--r--net/sunrpc/timer.c45
1 files changed, 29 insertions, 16 deletions
diff --git a/net/sunrpc/timer.c b/net/sunrpc/timer.c
index 31becbf09263..dd824341c349 100644
--- a/net/sunrpc/timer.c
+++ b/net/sunrpc/timer.c
@@ -25,8 +25,13 @@
25#define RPC_RTO_INIT (HZ/5) 25#define RPC_RTO_INIT (HZ/5)
26#define RPC_RTO_MIN (HZ/10) 26#define RPC_RTO_MIN (HZ/10)
27 27
28void 28/**
29rpc_init_rtt(struct rpc_rtt *rt, unsigned long timeo) 29 * rpc_init_rtt - Initialize an RPC RTT estimator context
30 * @rt: context to initialize
31 * @timeo: initial timeout value, in jiffies
32 *
33 */
34void rpc_init_rtt(struct rpc_rtt *rt, unsigned long timeo)
30{ 35{
31 unsigned long init = 0; 36 unsigned long init = 0;
32 unsigned i; 37 unsigned i;
@@ -43,12 +48,16 @@ rpc_init_rtt(struct rpc_rtt *rt, unsigned long timeo)
43} 48}
44EXPORT_SYMBOL_GPL(rpc_init_rtt); 49EXPORT_SYMBOL_GPL(rpc_init_rtt);
45 50
46/* 51/**
52 * rpc_update_rtt - Update an RPC RTT estimator context
53 * @rt: context to update
54 * @timer: timer array index (request type)
55 * @m: recent actual RTT, in jiffies
56 *
47 * NB: When computing the smoothed RTT and standard deviation, 57 * NB: When computing the smoothed RTT and standard deviation,
48 * be careful not to produce negative intermediate results. 58 * be careful not to produce negative intermediate results.
49 */ 59 */
50void 60void rpc_update_rtt(struct rpc_rtt *rt, unsigned timer, long m)
51rpc_update_rtt(struct rpc_rtt *rt, unsigned timer, long m)
52{ 61{
53 long *srtt, *sdrtt; 62 long *srtt, *sdrtt;
54 63
@@ -79,21 +88,25 @@ rpc_update_rtt(struct rpc_rtt *rt, unsigned timer, long m)
79} 88}
80EXPORT_SYMBOL_GPL(rpc_update_rtt); 89EXPORT_SYMBOL_GPL(rpc_update_rtt);
81 90
82/* 91/**
83 * Estimate rto for an nfs rpc sent via. an unreliable datagram. 92 * rpc_calc_rto - Provide an estimated timeout value
84 * Use the mean and mean deviation of rtt for the appropriate type of rpc 93 * @rt: context to use for calculation
85 * for the frequent rpcs and a default for the others. 94 * @timer: timer array index (request type)
86 * The justification for doing "other" this way is that these rpcs 95 *
87 * happen so infrequently that timer est. would probably be stale. 96 * Estimate RTO for an NFS RPC sent via an unreliable datagram. Use
88 * Also, since many of these rpcs are 97 * the mean and mean deviation of RTT for the appropriate type of RPC
89 * non-idempotent, a conservative timeout is desired. 98 * for frequently issued RPCs, and a fixed default for the others.
99 *
100 * The justification for doing "other" this way is that these RPCs
101 * happen so infrequently that timer estimation would probably be
102 * stale. Also, since many of these RPCs are non-idempotent, a
103 * conservative timeout is desired.
104 *
90 * getattr, lookup, 105 * getattr, lookup,
91 * read, write, commit - A+4D 106 * read, write, commit - A+4D
92 * other - timeo 107 * other - timeo
93 */ 108 */
94 109unsigned long rpc_calc_rto(struct rpc_rtt *rt, unsigned timer)
95unsigned long
96rpc_calc_rto(struct rpc_rtt *rt, unsigned timer)
97{ 110{
98 unsigned long res; 111 unsigned long res;
99 112