linux/fs/nfsd/stats.c
Amir Goldstein e567b98ce9 nfsd: protect concurrent access to nfsd stats counters
nfsd stats counters can be updated by concurrent nfsd threads without any
protection.

Convert some nfsd_stats and nfsd_net struct members to use percpu counters.

The longest_chain* members of struct nfsd_net remain unprotected.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-01-25 09:36:27 -05:00

147 lines
3.5 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* procfs-based user access to knfsd statistics
*
* /proc/net/rpc/nfsd
*
* Format:
* rc <hits> <misses> <nocache>
* Statistsics for the reply cache
* fh <stale> <deprecated filehandle cache stats>
* statistics for filehandle lookup
* io <bytes-read> <bytes-written>
* statistics for IO throughput
* th <threads> <deprecated thread usage histogram stats>
* number of threads
* ra <deprecated ra-cache stats>
*
* plus generic RPC stats (see net/sunrpc/stats.c)
*
* Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/seq_file.h>
#include <linux/module.h>
#include <linux/sunrpc/stats.h>
#include <net/net_namespace.h>
#include "nfsd.h"
struct nfsd_stats nfsdstats;
struct svc_stat nfsd_svcstats = {
.program = &nfsd_program,
};
static int nfsd_proc_show(struct seq_file *seq, void *v)
{
int i;
seq_printf(seq, "rc %lld %lld %lld\nfh %lld 0 0 0 0\nio %lld %lld\n",
percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_RC_HITS]),
percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_RC_MISSES]),
percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_RC_NOCACHE]),
percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_FH_STALE]),
percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_IO_READ]),
percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_IO_WRITE]));
/* thread usage: */
seq_printf(seq, "th %u 0", nfsdstats.th_cnt);
/* deprecated thread usage histogram stats */
for (i = 0; i < 10; i++)
seq_puts(seq, " 0.000");
/* deprecated ra-cache stats */
seq_puts(seq, "\nra 0 0 0 0 0 0 0 0 0 0 0 0\n");
/* show my rpc info */
svc_seq_show(seq, &nfsd_svcstats);
#ifdef CONFIG_NFSD_V4
/* Show count for individual nfsv4 operations */
/* Writing operation numbers 0 1 2 also for maintaining uniformity */
seq_printf(seq,"proc4ops %u", LAST_NFS4_OP + 1);
for (i = 0; i <= LAST_NFS4_OP; i++) {
seq_printf(seq, " %lld",
percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_NFS4_OP(i)]));
}
seq_putc(seq, '\n');
#endif
return 0;
}
static int nfsd_proc_open(struct inode *inode, struct file *file)
{
return single_open(file, nfsd_proc_show, NULL);
}
static const struct proc_ops nfsd_proc_ops = {
.proc_open = nfsd_proc_open,
.proc_read = seq_read,
.proc_lseek = seq_lseek,
.proc_release = single_release,
};
int nfsd_percpu_counters_init(struct percpu_counter counters[], int num)
{
int i, err = 0;
for (i = 0; !err && i < num; i++)
err = percpu_counter_init(&counters[i], 0, GFP_KERNEL);
if (!err)
return 0;
for (; i > 0; i--)
percpu_counter_destroy(&counters[i-1]);
return err;
}
void nfsd_percpu_counters_reset(struct percpu_counter counters[], int num)
{
int i;
for (i = 0; i < num; i++)
percpu_counter_set(&counters[i], 0);
}
void nfsd_percpu_counters_destroy(struct percpu_counter counters[], int num)
{
int i;
for (i = 0; i < num; i++)
percpu_counter_destroy(&counters[i]);
}
static int nfsd_stat_counters_init(void)
{
return nfsd_percpu_counters_init(nfsdstats.counter, NFSD_STATS_COUNTERS_NUM);
}
static void nfsd_stat_counters_destroy(void)
{
nfsd_percpu_counters_destroy(nfsdstats.counter, NFSD_STATS_COUNTERS_NUM);
}
int nfsd_stat_init(void)
{
int err;
err = nfsd_stat_counters_init();
if (err)
return err;
svc_proc_register(&init_net, &nfsd_svcstats, &nfsd_proc_ops);
return 0;
}
void nfsd_stat_shutdown(void)
{
nfsd_stat_counters_destroy();
svc_proc_unregister(&init_net, "nfsd");
}