knfsd: add file to export stats about nfsd pools

Add /proc/fs/nfsd/pool_stats to export to userspace various
statistics about the operation of rpc server thread pools.

This patch is based on a forward-ported version of
knfsd-add-pool-thread-stats which has been shipping in the SGI
"Enhanced NFS" product since 2006 and which was previously
posted:

http://article.gmane.org/gmane.linux.nfs/10375

It has also been updated thus:

 * moved EXPORT_SYMBOL() to near the function it exports
 * made the new struct struct seq_operations const
 * used SEQ_START_TOKEN instead of ((void *)1)
 * merged fix from SGI PV 990526 "sunrpc: use dprintk instead of
   printk in svc_pool_stats_*()" by Harshula Jayasuriya.
 * merged fix from SGI PV 964001 "Crash reading pool_stats before
   nfsds are started".

Signed-off-by: Greg Banks <gnb@sgi.com>
Signed-off-by: Harshula Jayasuriya <harshula@sgi.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
This commit is contained in:
Greg Banks 2009-01-13 21:26:36 +11:00 committed by J. Bruce Fields
parent 59a252ff8c
commit 03cf6c9f49
4 changed files with 129 additions and 1 deletions

View File

@ -60,6 +60,7 @@ enum {
NFSD_FO_UnlockFS,
NFSD_Threads,
NFSD_Pool_Threads,
NFSD_Pool_Stats,
NFSD_Versions,
NFSD_Ports,
NFSD_MaxBlkSize,
@ -172,6 +173,16 @@ static const struct file_operations exports_operations = {
.owner = THIS_MODULE,
};
extern int nfsd_pool_stats_open(struct inode *inode, struct file *file);
static struct file_operations pool_stats_operations = {
.open = nfsd_pool_stats_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
.owner = THIS_MODULE,
};
/*----------------------------------------------------------------------------*/
/*
* payload - write methods
@ -1246,6 +1257,7 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
[NFSD_Fh] = {"filehandle", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Threads] = {"threads", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Pool_Threads] = {"pool_threads", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Pool_Stats] = {"pool_stats", &pool_stats_operations, S_IRUGO},
[NFSD_Versions] = {"versions", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Ports] = {"portlist", &transaction_ops, S_IWUSR|S_IRUGO},
[NFSD_MaxBlkSize] = {"max_block_size", &transaction_ops, S_IWUSR|S_IRUGO},

View File

@ -546,3 +546,10 @@ nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1);
return 1;
}
int nfsd_pool_stats_open(struct inode *inode, struct file *file)
{
if (nfsd_serv == NULL)
return -ENODEV;
return svc_pool_stats_open(nfsd_serv, file);
}

View File

@ -24,6 +24,15 @@
*/
typedef int (*svc_thread_fn)(void *);
/* statistics for svc_pool structures */
struct svc_pool_stats {
unsigned long packets;
unsigned long sockets_queued;
unsigned long threads_woken;
unsigned long overloads_avoided;
unsigned long threads_timedout;
};
/*
*
* RPC service thread pool.
@ -42,6 +51,7 @@ struct svc_pool {
unsigned int sp_nrthreads; /* # of threads in pool */
struct list_head sp_all_threads; /* all server threads */
int sp_nwaking; /* number of threads woken but not yet active */
struct svc_pool_stats sp_stats; /* statistics on pool operation */
} ____cacheline_aligned_in_smp;
/*
@ -396,6 +406,7 @@ struct svc_serv * svc_create_pooled(struct svc_program *, unsigned int,
sa_family_t, void (*shutdown)(struct svc_serv *),
svc_thread_fn, struct module *);
int svc_set_num_threads(struct svc_serv *, struct svc_pool *, int);
int svc_pool_stats_open(struct svc_serv *serv, struct file *file);
void svc_destroy(struct svc_serv *);
int svc_process(struct svc_rqst *);
int svc_register(const struct svc_serv *, const unsigned short,

View File

@ -318,6 +318,8 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
goto out_unlock;
}
pool->sp_stats.packets++;
/* Mark transport as busy. It will remain in this state until
* the provider calls svc_xprt_received. We update XPT_BUSY
* atomically because it also guards against trying to enqueue
@ -355,6 +357,7 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
if (pool->sp_nwaking >= SVC_MAX_WAKING) {
/* too many threads are runnable and trying to wake up */
thread_avail = 0;
pool->sp_stats.overloads_avoided++;
}
if (thread_avail) {
@ -374,11 +377,13 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
rqstp->rq_waking = 1;
pool->sp_nwaking++;
pool->sp_stats.threads_woken++;
BUG_ON(xprt->xpt_pool != pool);
wake_up(&rqstp->rq_wait);
} else {
dprintk("svc: transport %p put into queue\n", xprt);
list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
pool->sp_stats.sockets_queued++;
BUG_ON(xprt->xpt_pool != pool);
}
@ -591,6 +596,7 @@ int svc_recv(struct svc_rqst *rqstp, long timeout)
int pages;
struct xdr_buf *arg;
DECLARE_WAITQUEUE(wait, current);
long time_left;
dprintk("svc: server %p waiting for data (to = %ld)\n",
rqstp, timeout);
@ -676,12 +682,14 @@ int svc_recv(struct svc_rqst *rqstp, long timeout)
add_wait_queue(&rqstp->rq_wait, &wait);
spin_unlock_bh(&pool->sp_lock);
schedule_timeout(timeout);
time_left = schedule_timeout(timeout);
try_to_freeze();
spin_lock_bh(&pool->sp_lock);
remove_wait_queue(&rqstp->rq_wait, &wait);
if (!time_left)
pool->sp_stats.threads_timedout++;
xprt = rqstp->rq_xprt;
if (!xprt) {
@ -1114,3 +1122,93 @@ int svc_xprt_names(struct svc_serv *serv, char *buf, int buflen)
return totlen;
}
EXPORT_SYMBOL_GPL(svc_xprt_names);
/*----------------------------------------------------------------------------*/
static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
{
unsigned int pidx = (unsigned int)*pos;
struct svc_serv *serv = m->private;
dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
lock_kernel();
/* bump up the pseudo refcount while traversing */
svc_get(serv);
unlock_kernel();
if (!pidx)
return SEQ_START_TOKEN;
return (pidx > serv->sv_nrpools ? NULL : &serv->sv_pools[pidx-1]);
}
static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
{
struct svc_pool *pool = p;
struct svc_serv *serv = m->private;
dprintk("svc_pool_stats_next, *pos=%llu\n", *pos);
if (p == SEQ_START_TOKEN) {
pool = &serv->sv_pools[0];
} else {
unsigned int pidx = (pool - &serv->sv_pools[0]);
if (pidx < serv->sv_nrpools-1)
pool = &serv->sv_pools[pidx+1];
else
pool = NULL;
}
++*pos;
return pool;
}
static void svc_pool_stats_stop(struct seq_file *m, void *p)
{
struct svc_serv *serv = m->private;
lock_kernel();
/* this function really, really should have been called svc_put() */
svc_destroy(serv);
unlock_kernel();
}
static int svc_pool_stats_show(struct seq_file *m, void *p)
{
struct svc_pool *pool = p;
if (p == SEQ_START_TOKEN) {
seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken overloads-avoided threads-timedout\n");
return 0;
}
seq_printf(m, "%u %lu %lu %lu %lu %lu\n",
pool->sp_id,
pool->sp_stats.packets,
pool->sp_stats.sockets_queued,
pool->sp_stats.threads_woken,
pool->sp_stats.overloads_avoided,
pool->sp_stats.threads_timedout);
return 0;
}
static const struct seq_operations svc_pool_stats_seq_ops = {
.start = svc_pool_stats_start,
.next = svc_pool_stats_next,
.stop = svc_pool_stats_stop,
.show = svc_pool_stats_show,
};
int svc_pool_stats_open(struct svc_serv *serv, struct file *file)
{
int err;
err = seq_open(file, &svc_pool_stats_seq_ops);
if (!err)
((struct seq_file *) file->private_data)->private = serv;
return err;
}
EXPORT_SYMBOL(svc_pool_stats_open);
/*----------------------------------------------------------------------------*/