Re: [PATCH 2/2] Explicitly call tcp creation and init from memcontrol.c

[Glauber Costa]

 On 12/15/2011 09:00 PM, David Miller wrote:
> From: Glauber Costa<glommer@xxxxxxxxxxxxx>
> Date: Thu, 15 Dec 2011 13:34:32 +0400
>
> > Walking the proto_list holds a read_lock, which prevents us from doing
> > allocations. Splitting the tcp create function into create + init is
> > good, but it is not enough since create_files will do allocations as well
> > (dentry ones, mostly).
> >
> > Since this does not involve any protocol state, I propose we call the tcp
> > functions explicitly from memcontrol.c
> >
> > With this, we lose by now the ability of doing cgroup memcontrol for
> > protocols that are loaded as modules. But at least the ones I have in mind
> > won't really need it (tcp_ipv6 being the only one, but it uses the same data
> > structures as tcp_ipv4). So I believe this to be the simpler solution to this
> > problem.
> >
> > Signed-off-by: Glauber Costa<glommer@xxxxxxxxxxxxx>
>
> This is an unnecessary limitation, please fix this properly otherwise
> DCCP, SCTP, etc. won't be supportable with this stuff.

How about the following patch then ? I am keeping protocols that has the 
cgroup stuff on in a separate list, that can be protected by a mutex. 
Therefore we can allocate without going into troubles.

Let me know if you still have objections, I'll be happy to address them.