On Sun, Mar 31, 2019 at 04:53:46PM +0800, Xin Long wrote:
> Now when sending packets, sk_mem_charge() and sk_mem_uncharge() have been
> used to set sk_forward_alloc. We just need to call sk_wmem_schedule() to
> check if the allocated should be raised, and call sk_mem_reclaim() to
> check if the allocated should be reduced when it's under memory pressure.
>
> If sk_wmem_schedule() returns false, which means no memory is allowed to
> allocate, it will block and wait for memory to become available.
>
> Note different from tcp, sctp wait_for_buf happens before allocating any
> skb, so memory accounting check is done with the whole msg_len before it
> too.
>
> Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
> ---
> net/sctp/socket.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 6140471..06c6f4a 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -1913,7 +1913,10 @@ static int sctp_sendmsg_to_asoc(struct sctp_association *asoc,
> if (sctp_wspace(asoc) < (int)msg_len)
> sctp_prsctp_prune(asoc, sinfo, msg_len - sctp_wspace(asoc));
>
> - if (sctp_wspace(asoc) <= 0) {
> + if (sk_under_memory_pressure(sk))
> + sk_mem_reclaim(sk);
> +
> + if (sctp_wspace(asoc) <= 0 || !sk_wmem_schedule(sk, msg_len)) {
> timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
> err = sctp_wait_for_sndbuf(asoc, &timeo, msg_len);
> if (err)
> @@ -8891,7 +8894,10 @@ static int sctp_wait_for_sndbuf(struct sctp_association *asoc, long *timeo_p,
> goto do_error;
> if (signal_pending(current))
> goto do_interrupted;
> - if ((int)msg_len <= sctp_wspace(asoc))
> + if (sk_under_memory_pressure(sk))
> + sk_mem_reclaim(sk);
> + if ((int)msg_len <= sctp_wspace(asoc) &&
> + sk_wmem_schedule(sk, msg_len))
> break;
>
> /* Let another process have a go. Since we are going
> --
> 2.1.0
>
