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SUNRPC: Add documenting comments in net/sunrpc/timer.c
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Clean up: provide documenting comments for the functions in
net/sunrpc/timer.c.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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Chuck Lever authored and Trond Myklebust committed Aug 9, 2009
1 parent 9dc3b09 commit c05988c
Showing 1 changed file with 29 additions and 16 deletions.
45 changes: 29 additions & 16 deletions net/sunrpc/timer.c
Original file line number Diff line number Diff line change
Expand Up @@ -25,8 +25,13 @@
#define RPC_RTO_INIT (HZ/5)
#define RPC_RTO_MIN (HZ/10)

void
rpc_init_rtt(struct rpc_rtt *rt, unsigned long timeo)
/**
* rpc_init_rtt - Initialize an RPC RTT estimator context
* @rt: context to initialize
* @timeo: initial timeout value, in jiffies
*
*/
void rpc_init_rtt(struct rpc_rtt *rt, unsigned long timeo)
{
unsigned long init = 0;
unsigned i;
Expand All @@ -43,12 +48,16 @@ rpc_init_rtt(struct rpc_rtt *rt, unsigned long timeo)
}
EXPORT_SYMBOL_GPL(rpc_init_rtt);

/*
/**
* rpc_update_rtt - Update an RPC RTT estimator context
* @rt: context to update
* @timer: timer array index (request type)
* @m: recent actual RTT, in jiffies
*
* NB: When computing the smoothed RTT and standard deviation,
* be careful not to produce negative intermediate results.
*/
void
rpc_update_rtt(struct rpc_rtt *rt, unsigned timer, long m)
void rpc_update_rtt(struct rpc_rtt *rt, unsigned timer, long m)
{
long *srtt, *sdrtt;

Expand Down Expand Up @@ -79,21 +88,25 @@ rpc_update_rtt(struct rpc_rtt *rt, unsigned timer, long m)
}
EXPORT_SYMBOL_GPL(rpc_update_rtt);

/*
* 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.
/**
* rpc_calc_rto - Provide an estimated timeout value
* @rt: context to use for calculation
* @timer: timer array index (request type)
*
* 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 frequently issued RPCs, and a fixed default for the others.
*
* The justification for doing "other" this way is that these RPCs
* happen so infrequently that timer estimation 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
*/

unsigned long
rpc_calc_rto(struct rpc_rtt *rt, unsigned timer)
unsigned long rpc_calc_rto(struct rpc_rtt *rt, unsigned timer)
{
unsigned long res;

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