Hi Mat,
* Mat Martineau <mathewm@xxxxxxxxxxxxxx> [2010-09-27 14:22:07 -0700]:
>
> Gustavo -
>
> On Mon, 27 Sep 2010, Gustavo F. Padovan wrote:
>
> > Setting both this value to MPS * TxWin * 1.2 guarantees that we are
> > reserving space to fit the whole txwindow in the memory, and that
> > sendmsg() will block when the transmission window is full avoid
> > overloading the system memory.
> > I don't have a strong reason about the 1.2 constant in the account, we
> > can do another tests in the future and change that value.
> >
> > Signed-off-by: Gustavo F. Padovan <padovan@xxxxxxxxxxxxxx>
> > ---
> > net/bluetooth/l2cap_core.c | 10 +++++++++-
> > 1 files changed, 9 insertions(+), 1 deletions(-)
> >
> > diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> > index 44aa034..1e2ab05 100644
> > --- a/net/bluetooth/l2cap_core.c
> > +++ b/net/bluetooth/l2cap_core.c
> > @@ -3129,9 +3129,17 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hdr
> > l2cap_pi(sk)->next_tx_seq = 0;
> > l2cap_pi(sk)->expected_tx_seq = 0;
> > __skb_queue_head_init(TX_QUEUE(sk));
> > - if (l2cap_pi(sk)->mode == L2CAP_MODE_ERTM)
> > + if (l2cap_pi(sk)->mode == L2CAP_MODE_ERTM) {
> > l2cap_ertm_init(sk);
> >
> > + sk->sk_sndbuf = (l2cap_pi(sk)->remote_tx_win * 1.2 *
> > + (sizeof(struct l2cap_pinfo) +
> > + l2cap_pi(sk)->mps));
> > + sk->sk_rcvbuf = (l2cap_pi(sk)->tx_win * 1.2 *
> > + (sizeof(struct l2cap_pinfo) +
> > + l2cap_pi(sk)->remote_mps));
> > + }
> > +
> > l2cap_chan_ready(sk);
> > }
> >
> > --
> > 1.7.3
Thanks a lot for your comments, I'll rework the patches and then resend.
>
> I think sizeof(struct sk_buff) would be better than
> sizeof(struct l2cap_pinfo), since these limits apply to data buffers,
> not per-socket overhead.
Sure.
>
> The 1.2 constant would need to be increased if we allow ERTM MPS
> bigger than the HCI MTU, since there would be multiple sk_buffs per
> PDU. However, the calculation could be updated when those MPS changes
> are made.
Yes, we can change that when we start to allow MPS greater than HCI MTU.
>
> It would also help to enforce some limits:
> SOCK_MIN_SNDBUF < sk->sk_sndbuf < sysctl_wmem_max
> SOCK_MIN_RCVBUF < sk->sk_rcvbuf < sysctl_rmem_max
Sure.
--
Gustavo F. Padovan
ProFUSION embedded systems - http://profusion.mobi
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