patch-2.4.20 linux-2.4.20/net/sunrpc/timer.c

• Lines: 75
• Date: Thu Nov 28 15:53:16 2002
• Orig file: linux-2.4.19/net/sunrpc/timer.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/net/sunrpc/timer.c linux-2.4.20/net/sunrpc/timer.c
@@ -0,0 +1,74 @@
+#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 (2)
+
+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;
+	}
+	atomic_set(&rt->ntimeouts, 0);
+}
+
+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;
+}