From 3262c816a3d7fb1eaabce633caa317887ed549ae Mon Sep 17 00:00:00 2001 From: Greg Banks Date: Mon, 2 Oct 2006 02:17:58 -0700 Subject: [PATCH] knfsd: split svc_serv into pools Split out the list of idle threads and pending sockets from svc_serv into a new svc_pool structure, and allocate a fixed number (in this patch, 1) of pools per svc_serv. The new structure contains a lock which takes over several of the duties of svc_serv->sv_lock, which is now relegated to protecting only sv_tempsocks, sv_permsocks, and sv_tmpcnt in svc_serv. The point is to move the hottest fields out of svc_serv and into svc_pool, allowing a following patch to arrange for a svc_pool per NUMA node or per CPU. This is a major step towards making the NFS server NUMA-friendly. Signed-off-by: Greg Banks Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- net/sunrpc/svcsock.c | 125 ++++++++++++++++++++++++++++++++------------------- 1 file changed, 80 insertions(+), 45 deletions(-) (limited to 'net/sunrpc/svcsock.c') diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index a38df4589ae..b78659adeff 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -46,7 +46,10 @@ /* SMP locking strategy: * - * svc_serv->sv_lock protects most stuff for that service. + * svc_pool->sp_lock protects most of the fields of that pool. + * svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt. + * when both need to be taken (rare), svc_serv->sv_lock is first. + * BKL protects svc_serv->sv_nrthread. * svc_sock->sk_defer_lock protects the svc_sock->sk_deferred list * svc_sock->sk_flags.SK_BUSY prevents a svc_sock being enqueued multiply. * @@ -82,22 +85,22 @@ static struct cache_deferred_req *svc_defer(struct cache_req *req); static int svc_conn_age_period = 6*60; /* - * Queue up an idle server thread. Must have serv->sv_lock held. + * Queue up an idle server thread. Must have pool->sp_lock held. * Note: this is really a stack rather than a queue, so that we only - * use as many different threads as we need, and the rest don't polute + * use as many different threads as we need, and the rest don't pollute * the cache. */ static inline void -svc_serv_enqueue(struct svc_serv *serv, struct svc_rqst *rqstp) +svc_thread_enqueue(struct svc_pool *pool, struct svc_rqst *rqstp) { - list_add(&rqstp->rq_list, &serv->sv_threads); + list_add(&rqstp->rq_list, &pool->sp_threads); } /* - * Dequeue an nfsd thread. Must have serv->sv_lock held. + * Dequeue an nfsd thread. Must have pool->sp_lock held. */ static inline void -svc_serv_dequeue(struct svc_serv *serv, struct svc_rqst *rqstp) +svc_thread_dequeue(struct svc_pool *pool, struct svc_rqst *rqstp) { list_del(&rqstp->rq_list); } @@ -148,6 +151,7 @@ static void svc_sock_enqueue(struct svc_sock *svsk) { struct svc_serv *serv = svsk->sk_server; + struct svc_pool *pool = &serv->sv_pools[0]; struct svc_rqst *rqstp; if (!(svsk->sk_flags & @@ -156,10 +160,10 @@ svc_sock_enqueue(struct svc_sock *svsk) if (test_bit(SK_DEAD, &svsk->sk_flags)) return; - spin_lock_bh(&serv->sv_lock); + spin_lock_bh(&pool->sp_lock); - if (!list_empty(&serv->sv_threads) && - !list_empty(&serv->sv_sockets)) + if (!list_empty(&pool->sp_threads) && + !list_empty(&pool->sp_sockets)) printk(KERN_ERR "svc_sock_enqueue: threads and sockets both waiting??\n"); @@ -179,6 +183,8 @@ svc_sock_enqueue(struct svc_sock *svsk) dprintk("svc: socket %p busy, not enqueued\n", svsk->sk_sk); goto out_unlock; } + BUG_ON(svsk->sk_pool != NULL); + svsk->sk_pool = pool; set_bit(SOCK_NOSPACE, &svsk->sk_sock->flags); if (((atomic_read(&svsk->sk_reserved) + serv->sv_bufsz)*2 @@ -189,19 +195,20 @@ svc_sock_enqueue(struct svc_sock *svsk) dprintk("svc: socket %p no space, %d*2 > %ld, not enqueued\n", svsk->sk_sk, atomic_read(&svsk->sk_reserved)+serv->sv_bufsz, svc_sock_wspace(svsk)); + svsk->sk_pool = NULL; clear_bit(SK_BUSY, &svsk->sk_flags); goto out_unlock; } clear_bit(SOCK_NOSPACE, &svsk->sk_sock->flags); - if (!list_empty(&serv->sv_threads)) { - rqstp = list_entry(serv->sv_threads.next, + if (!list_empty(&pool->sp_threads)) { + rqstp = list_entry(pool->sp_threads.next, struct svc_rqst, rq_list); dprintk("svc: socket %p served by daemon %p\n", svsk->sk_sk, rqstp); - svc_serv_dequeue(serv, rqstp); + svc_thread_dequeue(pool, rqstp); if (rqstp->rq_sock) printk(KERN_ERR "svc_sock_enqueue: server %p, rq_sock=%p!\n", @@ -210,28 +217,30 @@ svc_sock_enqueue(struct svc_sock *svsk) atomic_inc(&svsk->sk_inuse); rqstp->rq_reserved = serv->sv_bufsz; atomic_add(rqstp->rq_reserved, &svsk->sk_reserved); + BUG_ON(svsk->sk_pool != pool); wake_up(&rqstp->rq_wait); } else { dprintk("svc: socket %p put into queue\n", svsk->sk_sk); - list_add_tail(&svsk->sk_ready, &serv->sv_sockets); + list_add_tail(&svsk->sk_ready, &pool->sp_sockets); + BUG_ON(svsk->sk_pool != pool); } out_unlock: - spin_unlock_bh(&serv->sv_lock); + spin_unlock_bh(&pool->sp_lock); } /* - * Dequeue the first socket. Must be called with the serv->sv_lock held. + * Dequeue the first socket. Must be called with the pool->sp_lock held. */ static inline struct svc_sock * -svc_sock_dequeue(struct svc_serv *serv) +svc_sock_dequeue(struct svc_pool *pool) { struct svc_sock *svsk; - if (list_empty(&serv->sv_sockets)) + if (list_empty(&pool->sp_sockets)) return NULL; - svsk = list_entry(serv->sv_sockets.next, + svsk = list_entry(pool->sp_sockets.next, struct svc_sock, sk_ready); list_del_init(&svsk->sk_ready); @@ -250,6 +259,7 @@ svc_sock_dequeue(struct svc_serv *serv) static inline void svc_sock_received(struct svc_sock *svsk) { + svsk->sk_pool = NULL; clear_bit(SK_BUSY, &svsk->sk_flags); svc_sock_enqueue(svsk); } @@ -322,25 +332,33 @@ svc_sock_release(struct svc_rqst *rqstp) /* * External function to wake up a server waiting for data + * This really only makes sense for services like lockd + * which have exactly one thread anyway. */ void svc_wake_up(struct svc_serv *serv) { struct svc_rqst *rqstp; - - spin_lock_bh(&serv->sv_lock); - if (!list_empty(&serv->sv_threads)) { - rqstp = list_entry(serv->sv_threads.next, - struct svc_rqst, - rq_list); - dprintk("svc: daemon %p woken up.\n", rqstp); - /* - svc_serv_dequeue(serv, rqstp); - rqstp->rq_sock = NULL; - */ - wake_up(&rqstp->rq_wait); + unsigned int i; + struct svc_pool *pool; + + for (i = 0; i < serv->sv_nrpools; i++) { + pool = &serv->sv_pools[i]; + + spin_lock_bh(&pool->sp_lock); + if (!list_empty(&pool->sp_threads)) { + rqstp = list_entry(pool->sp_threads.next, + struct svc_rqst, + rq_list); + dprintk("svc: daemon %p woken up.\n", rqstp); + /* + svc_thread_dequeue(pool, rqstp); + rqstp->rq_sock = NULL; + */ + wake_up(&rqstp->rq_wait); + } + spin_unlock_bh(&pool->sp_lock); } - spin_unlock_bh(&serv->sv_lock); } /* @@ -603,7 +621,10 @@ svc_udp_recvfrom(struct svc_rqst *rqstp) /* udp sockets need large rcvbuf as all pending * requests are still in that buffer. sndbuf must * also be large enough that there is enough space - * for one reply per thread. + * for one reply per thread. We count all threads + * rather than threads in a particular pool, which + * provides an upper bound on the number of threads + * which will access the socket. */ svc_sock_setbufsize(svsk->sk_sock, (serv->sv_nrthreads+3) * serv->sv_bufsz, @@ -948,6 +969,11 @@ svc_tcp_recvfrom(struct svc_rqst *rqstp) /* sndbuf needs to have room for one request * per thread, otherwise we can stall even when the * network isn't a bottleneck. + * + * We count all threads rather than threads in a + * particular pool, which provides an upper bound + * on the number of threads which will access the socket. + * * rcvbuf just needs to be able to hold a few requests. * Normally they will be removed from the queue * as soon a a complete request arrives. @@ -1163,13 +1189,16 @@ svc_sock_update_bufs(struct svc_serv *serv) } /* - * Receive the next request on any socket. + * Receive the next request on any socket. This code is carefully + * organised not to touch any cachelines in the shared svc_serv + * structure, only cachelines in the local svc_pool. */ int svc_recv(struct svc_rqst *rqstp, long timeout) { struct svc_sock *svsk =NULL; struct svc_serv *serv = rqstp->rq_server; + struct svc_pool *pool = rqstp->rq_pool; int len; int pages; struct xdr_buf *arg; @@ -1219,15 +1248,15 @@ svc_recv(struct svc_rqst *rqstp, long timeout) if (signalled()) return -EINTR; - spin_lock_bh(&serv->sv_lock); - if ((svsk = svc_sock_dequeue(serv)) != NULL) { + spin_lock_bh(&pool->sp_lock); + if ((svsk = svc_sock_dequeue(pool)) != NULL) { rqstp->rq_sock = svsk; atomic_inc(&svsk->sk_inuse); rqstp->rq_reserved = serv->sv_bufsz; atomic_add(rqstp->rq_reserved, &svsk->sk_reserved); } else { /* No data pending. Go to sleep */ - svc_serv_enqueue(serv, rqstp); + svc_thread_enqueue(pool, rqstp); /* * We have to be able to interrupt this wait @@ -1235,26 +1264,26 @@ svc_recv(struct svc_rqst *rqstp, long timeout) */ set_current_state(TASK_INTERRUPTIBLE); add_wait_queue(&rqstp->rq_wait, &wait); - spin_unlock_bh(&serv->sv_lock); + spin_unlock_bh(&pool->sp_lock); schedule_timeout(timeout); try_to_freeze(); - spin_lock_bh(&serv->sv_lock); + spin_lock_bh(&pool->sp_lock); remove_wait_queue(&rqstp->rq_wait, &wait); if (!(svsk = rqstp->rq_sock)) { - svc_serv_dequeue(serv, rqstp); - spin_unlock_bh(&serv->sv_lock); + svc_thread_dequeue(pool, rqstp); + spin_unlock_bh(&pool->sp_lock); dprintk("svc: server %p, no data yet\n", rqstp); return signalled()? -EINTR : -EAGAIN; } } - spin_unlock_bh(&serv->sv_lock); + spin_unlock_bh(&pool->sp_lock); - dprintk("svc: server %p, socket %p, inuse=%d\n", - rqstp, svsk, atomic_read(&svsk->sk_inuse)); + dprintk("svc: server %p, pool %u, socket %p, inuse=%d\n", + rqstp, pool->sp_id, svsk, atomic_read(&svsk->sk_inuse)); len = svsk->sk_recvfrom(rqstp); dprintk("svc: got len=%d\n", len); @@ -1553,7 +1582,13 @@ svc_delete_socket(struct svc_sock *svsk) if (!test_and_set_bit(SK_DETACHED, &svsk->sk_flags)) list_del_init(&svsk->sk_list); - list_del_init(&svsk->sk_ready); + /* + * We used to delete the svc_sock from whichever list + * it's sk_ready node was on, but we don't actually + * need to. This is because the only time we're called + * while still attached to a queue, the queue itself + * is about to be destroyed (in svc_destroy). + */ if (!test_and_set_bit(SK_DEAD, &svsk->sk_flags)) if (test_bit(SK_TEMP, &svsk->sk_flags)) serv->sv_tmpcnt--; -- cgit v1.2.3-18-g5258