From: Yang Yingliang <yangyingliang@huawei•com>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: <davem@davemloft•net>, <netdev@vger•kernel.org>,
<brouer@redhat•com>, <jpirko@redhat•com>, <jbrouer@redhat•com>
Subject: Re: [PATCH net v4 1/2] net: sched: tbf: fix calculation of max_size
Date: Tue, 3 Dec 2013 15:44:07 +0800 [thread overview]
Message-ID: <529D8BC7.4050005@huawei.com> (raw)
In-Reply-To: <1386046793.30495.12.camel@edumazet-glaptop2.roam.corp.google.com>
On 2013/12/3 12:59, Eric Dumazet wrote:
> On Tue, 2013-12-03 at 11:26 +0800, Yang Yingliang wrote:
>
>> + for (max_size = 0; max_size < MAX_PKT_LEN; max_size++)
>> + if (psched_l2t_ns(&q->rate, max_size) > q->buffer)
>> + break;
>> + if (--max_size <= 0)
>> + goto unlock_done;
>> +
>
> This seems dubious. With your new code, max_size < 65536
>
> Prior code had :
>
> for (n = 0; n < 256; n++)
> if (rtab->data[n] > qopt->buffer)
> break;
> max_size = (n << qopt->rate.cell_log) - 1;
>
> So we could have much bigger max_size.
>
> The reason I ask is that its possible to have qdisc_pkt_len(skb) being
> bigger than 65536, for TCP packets with low MSS value.
>
Hmmm, if qdisc_pkt_len(skb) is bigger than 65536, skb_is_gso(skb) is true,
it will go into tbf_segment(). If I am wrong, please point me out, thanks!
BTW, 65536 is suggested by Jesper, I'm a little uncertain about it. He is, too.
Do you or some other developers have stronger opinions on this?
Thanks!
Yang
next prev parent reply other threads:[~2013-12-03 7:44 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-03 3:26 [PATCH net v4 0/2] net: sched: fix some issues Yang Yingliang
2013-12-03 3:26 ` [PATCH net v4 1/2] net: sched: tbf: fix calculation of max_size Yang Yingliang
2013-12-03 4:51 ` Eric Dumazet
2013-12-03 6:09 ` Yang Yingliang
2013-12-03 4:59 ` Eric Dumazet
2013-12-03 7:44 ` Yang Yingliang [this message]
2013-12-03 8:12 ` Eric Dumazet
2013-12-03 9:47 ` Yang Yingliang
2013-12-03 11:32 ` Yang Yingliang
2013-12-03 14:51 ` Eric Dumazet
2013-12-04 1:53 ` Yang Yingliang
2013-12-03 3:26 ` [PATCH net v4 2/2] net: sched: htb: fix calculation of quantum Yang Yingliang
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