linux/net/sunrpc/stats.c
Chuck Lever ae09531d3c SUNRPC: Proper metric accounting when RPC is not transmitted
I noticed recently that during an xfstests on a krb5i mount, the
retransmit count for certain operations had gone negative, and the
backlog value became unreasonably large. I recall that Andy has
pointed this out to me in the past.

When call_refresh fails to find a valid credential for an RPC, the
RPC exits immediately without sending anything on the wire. This
leaves rq_ntrans, rq_xtime, and rq_rtt set to zero.

The solution for om_queue is to not add the to RPC's running backlog
queue total whenever rq_xtime is zero.

For om_ntrans, it's a bit more difficult. A zero rq_ntrans causes
om_ops to become larger than om_ntrans. The design of the RPC
metrics API assumes that ntrans will always be equal to or larger
than the ops count. The result is that when an RPC fails to find
credentials, the RPC operation's reported retransmit count, which is
computed in user space as the difference between ops and ntrans,
goes negative.

Ideally the kernel API should report a separate retransmit and
"exited before initial transmission" metric, so that user space can
sort out the difference properly.

To avoid kernel API changes and changes to the way rq_ntrans is used
when performing transport locking, account for untransmitted RPCs
so that om_ntrans keeps up with om_ops: always add one or more to
om_ntrans.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-11-29 16:45:44 -05:00

308 lines
7.6 KiB
C

/*
* linux/net/sunrpc/stats.c
*
* procfs-based user access to generic RPC statistics. The stats files
* reside in /proc/net/rpc.
*
* The read routines assume that the buffer passed in is just big enough.
* If you implement an RPC service that has its own stats routine which
* appends the generic RPC stats, make sure you don't exceed the PAGE_SIZE
* limit.
*
* Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/metrics.h>
#include <linux/rcupdate.h>
#include "netns.h"
#define RPCDBG_FACILITY RPCDBG_MISC
/*
* Get RPC client stats
*/
static int rpc_proc_show(struct seq_file *seq, void *v) {
const struct rpc_stat *statp = seq->private;
const struct rpc_program *prog = statp->program;
unsigned int i, j;
seq_printf(seq,
"net %u %u %u %u\n",
statp->netcnt,
statp->netudpcnt,
statp->nettcpcnt,
statp->nettcpconn);
seq_printf(seq,
"rpc %u %u %u\n",
statp->rpccnt,
statp->rpcretrans,
statp->rpcauthrefresh);
for (i = 0; i < prog->nrvers; i++) {
const struct rpc_version *vers = prog->version[i];
if (!vers)
continue;
seq_printf(seq, "proc%u %u",
vers->number, vers->nrprocs);
for (j = 0; j < vers->nrprocs; j++)
seq_printf(seq, " %u",
vers->procs[j].p_count);
seq_putc(seq, '\n');
}
return 0;
}
static int rpc_proc_open(struct inode *inode, struct file *file)
{
return single_open(file, rpc_proc_show, PDE_DATA(inode));
}
static const struct file_operations rpc_proc_fops = {
.owner = THIS_MODULE,
.open = rpc_proc_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
/*
* Get RPC server stats
*/
void svc_seq_show(struct seq_file *seq, const struct svc_stat *statp) {
const struct svc_program *prog = statp->program;
const struct svc_procedure *proc;
const struct svc_version *vers;
unsigned int i, j;
seq_printf(seq,
"net %u %u %u %u\n",
statp->netcnt,
statp->netudpcnt,
statp->nettcpcnt,
statp->nettcpconn);
seq_printf(seq,
"rpc %u %u %u %u %u\n",
statp->rpccnt,
statp->rpcbadfmt+statp->rpcbadauth+statp->rpcbadclnt,
statp->rpcbadfmt,
statp->rpcbadauth,
statp->rpcbadclnt);
for (i = 0; i < prog->pg_nvers; i++) {
if (!(vers = prog->pg_vers[i]) || !(proc = vers->vs_proc))
continue;
seq_printf(seq, "proc%d %u", i, vers->vs_nproc);
for (j = 0; j < vers->vs_nproc; j++, proc++)
seq_printf(seq, " %u", proc->pc_count);
seq_putc(seq, '\n');
}
}
EXPORT_SYMBOL_GPL(svc_seq_show);
/**
* rpc_alloc_iostats - allocate an rpc_iostats structure
* @clnt: RPC program, version, and xprt
*
*/
struct rpc_iostats *rpc_alloc_iostats(struct rpc_clnt *clnt)
{
struct rpc_iostats *stats;
int i;
stats = kcalloc(clnt->cl_maxproc, sizeof(*stats), GFP_KERNEL);
if (stats) {
for (i = 0; i < clnt->cl_maxproc; i++)
spin_lock_init(&stats[i].om_lock);
}
return stats;
}
EXPORT_SYMBOL_GPL(rpc_alloc_iostats);
/**
* rpc_free_iostats - release an rpc_iostats structure
* @stats: doomed rpc_iostats structure
*
*/
void rpc_free_iostats(struct rpc_iostats *stats)
{
kfree(stats);
}
EXPORT_SYMBOL_GPL(rpc_free_iostats);
/**
* rpc_count_iostats_metrics - tally up per-task stats
* @task: completed rpc_task
* @op_metrics: stat structure for OP that will accumulate stats from @task
*/
void rpc_count_iostats_metrics(const struct rpc_task *task,
struct rpc_iostats *op_metrics)
{
struct rpc_rqst *req = task->tk_rqstp;
ktime_t delta, now;
if (!op_metrics || !req)
return;
now = ktime_get();
spin_lock(&op_metrics->om_lock);
op_metrics->om_ops++;
/* kernel API: om_ops must never become larger than om_ntrans */
op_metrics->om_ntrans += max(req->rq_ntrans, 1);
op_metrics->om_timeouts += task->tk_timeouts;
op_metrics->om_bytes_sent += req->rq_xmit_bytes_sent;
op_metrics->om_bytes_recv += req->rq_reply_bytes_recvd;
if (ktime_to_ns(req->rq_xtime)) {
delta = ktime_sub(req->rq_xtime, task->tk_start);
op_metrics->om_queue = ktime_add(op_metrics->om_queue, delta);
}
op_metrics->om_rtt = ktime_add(op_metrics->om_rtt, req->rq_rtt);
delta = ktime_sub(now, task->tk_start);
op_metrics->om_execute = ktime_add(op_metrics->om_execute, delta);
spin_unlock(&op_metrics->om_lock);
}
EXPORT_SYMBOL_GPL(rpc_count_iostats_metrics);
/**
* rpc_count_iostats - tally up per-task stats
* @task: completed rpc_task
* @stats: array of stat structures
*
* Uses the statidx from @task
*/
void rpc_count_iostats(const struct rpc_task *task, struct rpc_iostats *stats)
{
rpc_count_iostats_metrics(task,
&stats[task->tk_msg.rpc_proc->p_statidx]);
}
EXPORT_SYMBOL_GPL(rpc_count_iostats);
static void _print_name(struct seq_file *seq, unsigned int op,
struct rpc_procinfo *procs)
{
if (procs[op].p_name)
seq_printf(seq, "\t%12s: ", procs[op].p_name);
else if (op == 0)
seq_printf(seq, "\t NULL: ");
else
seq_printf(seq, "\t%12u: ", op);
}
void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt)
{
struct rpc_iostats *stats = clnt->cl_metrics;
struct rpc_xprt *xprt;
unsigned int op, maxproc = clnt->cl_maxproc;
if (!stats)
return;
seq_printf(seq, "\tRPC iostats version: %s ", RPC_IOSTATS_VERS);
seq_printf(seq, "p/v: %u/%u (%s)\n",
clnt->cl_prog, clnt->cl_vers, clnt->cl_program->name);
rcu_read_lock();
xprt = rcu_dereference(clnt->cl_xprt);
if (xprt)
xprt->ops->print_stats(xprt, seq);
rcu_read_unlock();
seq_printf(seq, "\tper-op statistics\n");
for (op = 0; op < maxproc; op++) {
struct rpc_iostats *metrics = &stats[op];
_print_name(seq, op, clnt->cl_procinfo);
seq_printf(seq, "%lu %lu %lu %Lu %Lu %Lu %Lu %Lu\n",
metrics->om_ops,
metrics->om_ntrans,
metrics->om_timeouts,
metrics->om_bytes_sent,
metrics->om_bytes_recv,
ktime_to_ms(metrics->om_queue),
ktime_to_ms(metrics->om_rtt),
ktime_to_ms(metrics->om_execute));
}
}
EXPORT_SYMBOL_GPL(rpc_print_iostats);
/*
* Register/unregister RPC proc files
*/
static inline struct proc_dir_entry *
do_register(struct net *net, const char *name, void *data,
const struct file_operations *fops)
{
struct sunrpc_net *sn;
dprintk("RPC: registering /proc/net/rpc/%s\n", name);
sn = net_generic(net, sunrpc_net_id);
return proc_create_data(name, 0, sn->proc_net_rpc, fops, data);
}
struct proc_dir_entry *
rpc_proc_register(struct net *net, struct rpc_stat *statp)
{
return do_register(net, statp->program->name, statp, &rpc_proc_fops);
}
EXPORT_SYMBOL_GPL(rpc_proc_register);
void
rpc_proc_unregister(struct net *net, const char *name)
{
struct sunrpc_net *sn;
sn = net_generic(net, sunrpc_net_id);
remove_proc_entry(name, sn->proc_net_rpc);
}
EXPORT_SYMBOL_GPL(rpc_proc_unregister);
struct proc_dir_entry *
svc_proc_register(struct net *net, struct svc_stat *statp, const struct file_operations *fops)
{
return do_register(net, statp->program->pg_name, statp, fops);
}
EXPORT_SYMBOL_GPL(svc_proc_register);
void
svc_proc_unregister(struct net *net, const char *name)
{
struct sunrpc_net *sn;
sn = net_generic(net, sunrpc_net_id);
remove_proc_entry(name, sn->proc_net_rpc);
}
EXPORT_SYMBOL_GPL(svc_proc_unregister);
int rpc_proc_init(struct net *net)
{
struct sunrpc_net *sn;
dprintk("RPC: registering /proc/net/rpc\n");
sn = net_generic(net, sunrpc_net_id);
sn->proc_net_rpc = proc_mkdir("rpc", net->proc_net);
if (sn->proc_net_rpc == NULL)
return -ENOMEM;
return 0;
}
void rpc_proc_exit(struct net *net)
{
dprintk("RPC: unregistering /proc/net/rpc\n");
remove_proc_entry("rpc", net->proc_net);
}