diff options
Diffstat (limited to 'net/sunrpc')
| -rw-r--r-- | net/sunrpc/svc_xprt.c | 100 |
1 files changed, 30 insertions, 70 deletions
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index 18e87791350f..80112c45aad1 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -380,7 +380,6 @@ void svc_xprt_do_enqueue(struct svc_xprt *xprt) struct svc_pool *pool; struct svc_rqst *rqstp = NULL; int cpu; - bool queued = false; if (!svc_xprt_has_something_to_do(xprt)) goto out; @@ -401,58 +400,25 @@ void svc_xprt_do_enqueue(struct svc_xprt *xprt) atomic_long_inc(&pool->sp_stats.packets); -redo_search: + dprintk("svc: transport %p put into queue\n", xprt); + spin_lock_bh(&pool->sp_lock); + list_add_tail(&xprt->xpt_ready, &pool->sp_sockets); + pool->sp_stats.sockets_queued++; + spin_unlock_bh(&pool->sp_lock); + /* find a thread for this xprt */ rcu_read_lock(); list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) { - /* Do a lockless check first */ - if (test_bit(RQ_BUSY, &rqstp->rq_flags)) + if (test_and_set_bit(RQ_BUSY, &rqstp->rq_flags)) continue; - - /* - * Once the xprt has been queued, it can only be dequeued by - * the task that intends to service it. All we can do at that - * point is to try to wake this thread back up so that it can - * do so. - */ - if (!queued) { - spin_lock_bh(&rqstp->rq_lock); - if (test_and_set_bit(RQ_BUSY, &rqstp->rq_flags)) { - /* already busy, move on... */ - spin_unlock_bh(&rqstp->rq_lock); - continue; - } - - /* this one will do */ - rqstp->rq_xprt = xprt; - svc_xprt_get(xprt); - spin_unlock_bh(&rqstp->rq_lock); - } - rcu_read_unlock(); - atomic_long_inc(&pool->sp_stats.threads_woken); wake_up_process(rqstp->rq_task); - put_cpu(); - goto out; - } - rcu_read_unlock(); - - /* - * We didn't find an idle thread to use, so we need to queue the xprt. - * Do so and then search again. If we find one, we can't hook this one - * up to it directly but we can wake the thread up in the hopes that it - * will pick it up once it searches for a xprt to service. - */ - if (!queued) { - queued = true; - dprintk("svc: transport %p put into queue\n", xprt); - spin_lock_bh(&pool->sp_lock); - list_add_tail(&xprt->xpt_ready, &pool->sp_sockets); - pool->sp_stats.sockets_queued++; - spin_unlock_bh(&pool->sp_lock); - goto redo_search; + goto out_unlock; } + set_bit(SP_CONGESTED, &pool->sp_flags); rqstp = NULL; +out_unlock: + rcu_read_unlock(); put_cpu(); out: trace_svc_xprt_do_enqueue(xprt, rqstp); @@ -721,38 +687,25 @@ rqst_should_sleep(struct svc_rqst *rqstp) static struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp, long timeout) { - struct svc_xprt *xprt; struct svc_pool *pool = rqstp->rq_pool; long time_left = 0; /* rq_xprt should be clear on entry */ WARN_ON_ONCE(rqstp->rq_xprt); - /* Normally we will wait up to 5 seconds for any required - * cache information to be provided. - */ - rqstp->rq_chandle.thread_wait = 5*HZ; - - xprt = svc_xprt_dequeue(pool); - if (xprt) { - rqstp->rq_xprt = xprt; - - /* As there is a shortage of threads and this request - * had to be queued, don't allow the thread to wait so - * long for cache updates. - */ - rqstp->rq_chandle.thread_wait = 1*HZ; - clear_bit(SP_TASK_PENDING, &pool->sp_flags); - return xprt; - } + rqstp->rq_xprt = svc_xprt_dequeue(pool); + if (rqstp->rq_xprt) + goto out_found; /* * We have to be able to interrupt this wait * to bring down the daemons ... */ set_current_state(TASK_INTERRUPTIBLE); + smp_mb__before_atomic(); + clear_bit(SP_CONGESTED, &pool->sp_flags); clear_bit(RQ_BUSY, &rqstp->rq_flags); - smp_mb(); + smp_mb__after_atomic(); if (likely(rqst_should_sleep(rqstp))) time_left = schedule_timeout(timeout); @@ -761,13 +714,11 @@ static struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp, long timeout) try_to_freeze(); - spin_lock_bh(&rqstp->rq_lock); set_bit(RQ_BUSY, &rqstp->rq_flags); - spin_unlock_bh(&rqstp->rq_lock); - - xprt = rqstp->rq_xprt; - if (xprt != NULL) - return xprt; + smp_mb__after_atomic(); + rqstp->rq_xprt = svc_xprt_dequeue(pool); + if (rqstp->rq_xprt) + goto out_found; if (!time_left) atomic_long_inc(&pool->sp_stats.threads_timedout); @@ -775,6 +726,15 @@ static struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp, long timeout) if (signalled() || kthread_should_stop()) return ERR_PTR(-EINTR); return ERR_PTR(-EAGAIN); +out_found: + /* Normally we will wait up to 5 seconds for any required + * cache information to be provided. + */ + if (!test_bit(SP_CONGESTED, &pool->sp_flags)) + rqstp->rq_chandle.thread_wait = 5*HZ; + else + rqstp->rq_chandle.thread_wait = 1*HZ; + return rqstp->rq_xprt; } static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt) |