[ofa-general] Re: [PATCH 03/10] dev.c changes.

Krishna Kumar2 krkumar2 at in.ibm.com
Fri Jul 20 05:33:56 PDT 2007


(My Notes crashed when I hit the Send button, so not sure if this went
out).

__________________

Patrick McHardy <kaber at trash.net> wrote on 07/20/2007 04:50:37 PM:

> 32 bytes? I count 16, - 4 for the pointer, so its 12 bytes of waste.
> If you'd use it for gso_skb it would come down to 8 bytes. struct
> net_device is a pig already, and there are better ways to reduce this
> than starting to allocating single members with a few bytes IMO.

Currently, this allocated pointer is an indication to let kernel users
(qdisc_restart, setting/resetting tx_batch_skbs) know whether batching
is enabled or disabled. Removing the pointer and making it static means
those users cannot figure out this information . Adding another field to
netdev may be a bad idea, so I am thinking of overloading dev->features
to add a new flag (other than NETIF_F_BATCH_SKBS, since that is a driver
capabilities flag) which can be set/cleared based on NETIF_F_BATCH_SKBS
bit. Does this approach sound OK ?

Thanks,

- KK




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