Re: IFQ_ENQUEUE argument refactor (was Re: RFC: ALTQ caller refactor)

[Kengo NAKAHARA <k-nakahara%iij.ad.jp@localhost>]

Hi,

On 2016/04/05 16:38, Joerg Sonnenberger wrote:
> On Tue, Apr 05, 2016 at 01:11:01PM +0900, Kengo NAKAHARA wrote:
>> (Q2) How do I decide the data is too large or not?
>> e.g. ALTQ case, the data is struct altq_pktattr whose members are void *,
>> int, and void *.
>>     http://nxr.netbsd.org/xref/src/sys/altq/if_altq.h#86
>> Is this three member struct too large?
>> another PACKET_TAG_PF m_tag case, the data is struct pf_mtag
>>     http://nxr.netbsd.org/xref/src/sys/dist/pf/net/pf_mtag.h#46
>> How about this pattern?
> 
> Look at struct pkthdr. It's currently 2 pointers and 4 ints in the first
> mbuf of every packet. We want to avoid pushing too much into it as the
> rest of the mbuf is used for data, so "reasonable" small packets, we
> want to completely stay in the first mbuf. The total size of a mbuf is
> currently either 256 or 512 Bytes, mbuf header is < 60 Bytes, so
> assuming that reasonable small means < 80 Bytes, we have around 120
> Bytes or so to spend on the packet header.

Thank you very much for your great helpful comments.

How about Q1?


Thanks,

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Internet Initiative Japan Inc.

Device Engineering Section,
IoT Platform Development Department,
Network Division,
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Kengo NAKAHARA <k-nakahara%iij.ad.jp@localhost>