From 0af3442af7c4c5b06e72708d7dd937974d1b4114 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Sun, 14 Jan 2018 15:28:29 -0500 Subject: [PATCH] SUNRPC: Add explicit rescheduling points in the receive path When reading the reply from the server, insert an explicit cond_resched() to avoid starving higher priority tasks. Signed-off-by: Trond Myklebust --- net/sunrpc/xprtsock.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 620be573d78b..18803021f242 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -1005,6 +1005,7 @@ static void xs_local_data_receive(struct sock_xprt *transport) struct sock *sk; int err; +restart: mutex_lock(&transport->recv_mutex); sk = transport->inet; if (sk == NULL) @@ -1018,6 +1019,11 @@ static void xs_local_data_receive(struct sock_xprt *transport) } if (!test_and_clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state)) break; + if (need_resched()) { + mutex_unlock(&transport->recv_mutex); + cond_resched(); + goto restart; + } } out: mutex_unlock(&transport->recv_mutex); @@ -1096,6 +1102,7 @@ static void xs_udp_data_receive(struct sock_xprt *transport) struct sock *sk; int err; +restart: mutex_lock(&transport->recv_mutex); sk = transport->inet; if (sk == NULL) @@ -1109,6 +1116,11 @@ static void xs_udp_data_receive(struct sock_xprt *transport) } if (!test_and_clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state)) break; + if (need_resched()) { + mutex_unlock(&transport->recv_mutex); + cond_resched(); + goto restart; + } } out: mutex_unlock(&transport->recv_mutex); @@ -1528,16 +1540,16 @@ static void xs_tcp_data_receive(struct sock_xprt *transport) .arg.data = xprt, }; unsigned long total = 0; - int loop; int read = 0; +restart: mutex_lock(&transport->recv_mutex); sk = transport->inet; if (sk == NULL) goto out; /* We use rd_desc to pass struct xprt to xs_tcp_data_recv */ - for (loop = 0; loop < 64; loop++) { + for (;;) { rd_desc.count = RPC_TCP_READ_CHUNK_SZ; lock_sock(sk); read = tcp_read_sock(sk, &rd_desc, xs_tcp_data_recv); @@ -1548,6 +1560,11 @@ static void xs_tcp_data_receive(struct sock_xprt *transport) } release_sock(sk); total += read; + if (need_resched()) { + mutex_unlock(&transport->recv_mutex); + cond_resched(); + goto restart; + } } if (test_bit(XPRT_SOCK_DATA_READY, &transport->sock_state)) queue_work(xprtiod_workqueue, &transport->recv_worker);