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>
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 0551b6b..1e66f24 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -318,6 +318,8 @@
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 @@
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 @@
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 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 @@
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 @@
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);
+
+/*----------------------------------------------------------------------------*/