RPC: Do not block on skb allocation If we get something like the following, [ 125.300636] [] schedule_timeout+0x54/0xa5 [ 125.305931] [] io_schedule_timeout+0x29/0x33 [ 125.311495] [] blk_congestion_wait+0x70/0x85 [ 125.317058] [] throttle_vm_writeout+0x69/0x7d [ 125.322720] [] shrink_zone+0xe0/0xfa [ 125.327560] [] shrink_caches+0x6d/0x6f [ 125.332581] [] try_to_free_pages+0xd0/0x1b5 [ 125.338056] [] __alloc_pages+0x135/0x2e8 [ 125.343258] [] tcp_sendmsg+0xaa0/0xb78 [ 125.348281] [] inet_sendmsg+0x48/0x53 [ 125.353212] [] sock_sendmsg+0xb8/0xd3 [ 125.358147] [] kernel_sendmsg+0x42/0x4f [ 125.363259] [] sock_no_sendpage+0x5e/0x77 [ 125.368556] [] xs_tcp_send_request+0x2af/0x375 then the socket is blocked until memory is reclaimed, and no progress can ever be made. Try to access the emergency pools by using GFP_ATOMIC. Signed-off-by: Trond Myklebust --- net/sunrpc/xprtsock.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 0a51fd4..77e8800 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -990,6 +990,7 @@ static void xs_udp_connect_worker(void * sk->sk_data_ready = xs_udp_data_ready; sk->sk_write_space = xs_udp_write_space; sk->sk_no_check = UDP_CSUM_NORCV; + sk->sk_allocation = GFP_ATOMIC; xprt_set_connected(xprt); @@ -1074,6 +1075,7 @@ static void xs_tcp_connect_worker(void * sk->sk_data_ready = xs_tcp_data_ready; sk->sk_state_change = xs_tcp_state_change; sk->sk_write_space = xs_tcp_write_space; + sk->sk_allocation = GFP_ATOMIC; /* socket options */ sk->sk_userlocks |= SOCK_BINDPORT_LOCK;