Merge branch 'for-2.6.30' of git://linux-nfs.org/~bfields/linux
[pandora-kernel.git] / net / sunrpc / svc_xprt.c
index 2819ee0..c200d92 100644 (file)
@@ -14,6 +14,8 @@
 
 #define RPCDBG_FACILITY        RPCDBG_SVCXPRT
 
+#define SVC_MAX_WAKING 5
+
 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt);
 static int svc_deferred_recv(struct svc_rqst *rqstp);
 static struct cache_deferred_req *svc_defer(struct cache_req *req);
@@ -301,6 +303,7 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
        struct svc_pool *pool;
        struct svc_rqst *rqstp;
        int cpu;
+       int thread_avail;
 
        if (!(xprt->xpt_flags &
              ((1<<XPT_CONN)|(1<<XPT_DATA)|(1<<XPT_CLOSE)|(1<<XPT_DEFERRED))))
@@ -312,18 +315,14 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
 
        spin_lock_bh(&pool->sp_lock);
 
-       if (!list_empty(&pool->sp_threads) &&
-           !list_empty(&pool->sp_sockets))
-               printk(KERN_ERR
-                      "svc_xprt_enqueue: "
-                      "threads and transports both waiting??\n");
-
        if (test_bit(XPT_DEAD, &xprt->xpt_flags)) {
                /* Don't enqueue dead transports */
                dprintk("svc: transport %p is dead, not enqueued\n", 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
@@ -356,7 +355,15 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
        }
 
  process:
-       if (!list_empty(&pool->sp_threads)) {
+       /* Work out whether threads are available */
+       thread_avail = !list_empty(&pool->sp_threads);  /* threads are asleep */
+       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) {
                rqstp = list_entry(pool->sp_threads.next,
                                   struct svc_rqst,
                                   rq_list);
@@ -371,11 +378,15 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
                svc_xprt_get(xprt);
                rqstp->rq_reserved = serv->sv_max_mesg;
                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);
        }
 
@@ -588,6 +599,7 @@ 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);
@@ -636,6 +648,11 @@ int svc_recv(struct svc_rqst *rqstp, long timeout)
                return -EINTR;
 
        spin_lock_bh(&pool->sp_lock);
+       if (rqstp->rq_waking) {
+               rqstp->rq_waking = 0;
+               pool->sp_nwaking--;
+               BUG_ON(pool->sp_nwaking < 0);
+       }
        xprt = svc_xprt_dequeue(pool);
        if (xprt) {
                rqstp->rq_xprt = xprt;
@@ -668,12 +685,14 @@ 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) {
@@ -958,7 +977,7 @@ static struct cache_deferred_req *svc_defer(struct cache_req *req)
        struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
        struct svc_deferred_req *dr;
 
-       if (rqstp->rq_arg.page_len)
+       if (rqstp->rq_arg.page_len || !rqstp->rq_usedeferral)
                return NULL; /* if more than a page, give up FIXME */
        if (rqstp->rq_deferred) {
                dr = rqstp->rq_deferred;
@@ -1112,3 +1131,93 @@ 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);
+
+/*----------------------------------------------------------------------------*/