Re: [PATCH 1/2] dracut: add team device support

[Cong Wang <amwang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On Mon, 2012-12-03 at 13:27 +0800, Dave Young wrote:
> On 12/03/2012 11:27 AM, Cong Wang wrote:
> 
> > On Mon, 2012-12-03 at 11:11 +0800, Dave Young wrote:
> >>> -    instmods =drivers/net/phy ecb arc4 bridge stp llc ipv6 bonding
> >> 8021q af_packet virtio_net
> >>> +    instmods =drivers/net/phy ecb arc4 bridge stp llc ipv6 bonding
> >> 8021q af_packet virtio_net =drivers/net/team
> >>
> >>
> >>
> >> 40network installs all related kernel modules. This will create a big
> >> initramfs though some of them are not used at all.
> >>
> >> I'm thinking it's better to conditionally install them. In the long
> >> run
> >> maybe network module should be splited to to multiple modules.
> >>
> >> And for now I think it's better to install them only if there's team
> >> related user space tools in running system. 
> > 
> > It is not as easy as what you think, users may specify their network
> > config at _run time_ via cmdline, so it is not easy to know which kernel
> > module will be used until we get all the cmdline.
> 
> 
> I agree it's not easy. But for team support if there's no team user
> space utility the 2nd kernel setup will fail, isn't it?

Yes, bridge too.

> 
> > 
> > For kdump, one solution is removing all unnecessary stuffs including
> > kernel modules and user-space utitlies at setup time, because kdump
> > parses the network config at setup time. Obviously this only applies for
> > kdump, for others, e.g. anaconda, this problem still exists, but they
> > probably don't care about the memory usage as much as kdump.
> 
> 
> I will thinking more about the kdump solution. But even for anaconda,
> smaller initramfs size is also good to have.

It saves too little, as nowadays we all have 4G+ memory even a KVM
guest.

% ls -lh /lib/modules/3.6.7-4.fc16.x86_64/kernel/drivers/net/team/team*
-rwxr--r--. 1 root root  42K Nov 21
04:44 /lib/modules/3.6.7-4.fc16.x86_64/kernel/drivers/net/team/team.ko
-rwxr--r--. 1 root root 6.3K Nov 21
04:44 /lib/modules/3.6.7-4.fc16.x86_64/kernel/drivers/net/team/team_mode_activebackup.ko
-rwxr--r--. 1 root root 5.8K Nov 21
04:44 /lib/modules/3.6.7-4.fc16.x86_64/kernel/drivers/net/team/team_mode_broadcast.ko
-rwxr--r--. 1 root root  15K Nov 21
04:44 /lib/modules/3.6.7-4.fc16.x86_64/kernel/drivers/net/team/team_mode_loadbalance.ko
-rwxr--r--. 1 root root 5.5K Nov 21
04:44 /lib/modules/3.6.7-4.fc16.x86_64/kernel/drivers/net/team/team_mode_roundrobin.ko


> 
> > 
> > However, I don't think this is relevant here, we should do this in a
> > different patch. It is unfair to only blame team driver here, there are
> > already some other modules in the same line anyway...
> 
> 
> This is not a blame for team code, just begin to consider the impact to
> initramfs size. It's good to start do it once we notice it.
> .

On my machine, bridge.ko is 146K, bonding.ko is 198K, both are more than
the total size of all team modules. You shall start even earlier. :)