From: David Daney <ddaney@caviumnetworks•com>
To: Ben Hutchings <bhutchings@solarflare•com>
Cc: Stephen Hemminger <shemminger@vyatta•com>,
David Miller <davem@davemloft•net>,
netdev@vger•kernel.org
Subject: Re: [RFC] NAPI as kobject proposal
Date: Wed, 03 Feb 2010 13:38:45 -0800 [thread overview]
Message-ID: <4B69ECE5.7060803@caviumnetworks.com> (raw)
In-Reply-To: <1265232216.2116.46.camel@achroite.uk.solarflarecom.com>
Ben Hutchings wrote:
> On Fri, 2010-01-29 at 10:18 -0800, Stephen Hemminger wrote:
>> The NAPI interface structure in current kernels is managed by the driver.
>> As part of receive packet steering there is a requirement to add an
>> additional parameter to this for the CPU map. And this map needs to
>> have an API to set it.
>>
>> The right way to do this in the kernel model is to make NAPI into
>> a kobject and associate it back with the network device (parent).
>> This isn't wildly difficult but does change some of the API for
>> network device drivers because:
>> 1. They need to handle another possible error on setup
>> 2. NAPI object needs to be dynamically allocated
>> separately (not as part of netdev_priv)
>> 3. Driver should pass index that can be uses as part of
>> name (easier than scanning)
>>
>> Eventually, there will be:
>> /sys/class/net/eth0/napi0/
>> weight
>> cpumap
>
> I think the NAPI objects should be created as children of a bus device
> and then linked from the net device directories, e.g.
>
> /sys/devices/.../ net/eth0/
> napi0 -> ../../napi/napi0
> eth1/
> napi0 -> ../../napi/napi0
> napi/napi0/
> weight
> cpumap
>
This seems right.
Some drivers have a single napi object logically associated with
multiple interfaces. Although the current architecture forces us to
associate the napi object with a single net_device, it would be nice to
move towards something that allows sharing a napi object between
multiple devices.
David Daney
next prev parent reply other threads:[~2010-02-03 21:54 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-29 18:18 [RFC] NAPI as kobject proposal Stephen Hemminger
2010-02-03 21:23 ` Ben Hutchings
2010-02-03 21:26 ` Al Viro
2010-02-03 21:41 ` Stephen Hemminger
2010-02-03 21:38 ` David Daney [this message]
2010-02-04 1:33 ` David Miller
2010-02-04 1:58 ` Stephen Hemminger
2010-02-04 2:17 ` David Miller
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