blob: 7383873fa93c8f8b957d5d15bb01d228b7efd320 [file] [log] [blame]
#include <linux/version.h>
#include <linux/types.h>
#include <linux/unistd.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/xprt.h>
#include <linux/sunrpc/timer.h>
#define RPC_RTO_MAX (60*HZ)
#define RPC_RTO_INIT (HZ/5)
#define RPC_RTO_MIN (HZ/10)
void
rpc_init_rtt(struct rpc_rtt *rt, long timeo)
{
long t = (timeo - RPC_RTO_INIT) << 3;
int i;
rt->timeo = timeo;
if (t < 0)
t = 0;
for (i = 0; i < 5; i++) {
rt->srtt[i] = t;
rt->sdrtt[i] = RPC_RTO_INIT;
}
memset(rt->ntimeouts, 0, sizeof(rt->ntimeouts));
}
void
rpc_update_rtt(struct rpc_rtt *rt, int timer, long m)
{
long *srtt, *sdrtt;
if (timer-- == 0)
return;
if (m == 0)
m = 1;
srtt = &rt->srtt[timer];
m -= *srtt >> 3;
*srtt += m;
if (m < 0)
m = -m;
sdrtt = &rt->sdrtt[timer];
m -= *sdrtt >> 2;
*sdrtt += m;
/* Set lower bound on the variance */
if (*sdrtt < RPC_RTO_MIN)
*sdrtt = RPC_RTO_MIN;
}
/*
* Estimate rto for an nfs rpc sent via. an unreliable datagram.
* Use the mean and mean deviation of rtt for the appropriate type of rpc
* for the frequent rpcs and a default for the others.
* The justification for doing "other" this way is that these rpcs
* happen so infrequently that timer est. would probably be stale.
* Also, since many of these rpcs are
* non-idempotent, a conservative timeout is desired.
* getattr, lookup,
* read, write, commit - A+4D
* other - timeo
*/
long
rpc_calc_rto(struct rpc_rtt *rt, int timer)
{
long res;
if (timer-- == 0)
return rt->timeo;
res = (rt->srtt[timer] >> 3) + rt->sdrtt[timer];
if (res > RPC_RTO_MAX)
res = RPC_RTO_MAX;
return res;
}