Messages in this thread | | | Date | Wed, 10 Sep 2008 15:56:55 -0700 | From | "Ranjit Manomohan" <> | Subject | Re: [PATCH 1/2] Traffic control cgroups subsystem |
| |
On Wed, Sep 10, 2008 at 3:01 PM, Thomas Graf <tgraf@suug.ch> wrote: > * Ranjit Manomohan <ranjitm@google.com> 2008-09-10 10:42 >> +void cgroup_tc_set_sock_classid(struct sock *sk) >> +{ >> + if (sk) >> + sk->sk_cgroup_classid = cgroup_tc_classid(current); >> +} >> + >> @@ -1170,6 +1171,8 @@ static int __sock_create(struct net *net, int family, int type, int protocol, >> if (err < 0) >> goto out_module_put; >> >> + cgroup_tc_set_sock_classid(sock->sk); >> + >> /* >> * Now to bump the refcnt of the [loadable] module that owns this >> * socket at sock_release time we decrement its refcnt. >> @@ -1444,6 +1447,8 @@ asmlinkage long sys_accept(int fd, struct sockaddr __user *upeer_sockaddr, >> if (err < 0) >> goto out_fd; >> >> + cgroup_tc_set_sock_classid(newsock->sk); >> + >> if (upeer_sockaddr) { >> if (newsock->ops->getname(newsock, (struct sockaddr *)address, >> &len, 2) < 0) { > > The big disadvantage of this method is that it does not allow to change > the classid for sockets which already exist. It inherits the classid > at socket creation time and then sticks to it. So if you want to follow > this approach I'd suggest to at least store a reference to the cgroup > state and reference count it properly. >
I had considered adding support for moving tasks between cgroups by going through all the open fds of the task and updating the sockets (in the cgroup attach method). It is a very heavy weight operation and not considered a common use case (and even undesirable at times) so I dropped the idea. I can add it back in if it is considered essential.
> As for the locking that you mentioned in the other thread. IMHO it is > not possible to lookup a socket without taking at least one lock, but > I might be wrong there. Actually I think it will take even more locks > as different locks are used to f.e. protect listening and established > tcp sockets.
That is correct for ingress, for egress the sk is already available in the skb so should be fine.
-Thanks, Ranjit
>
| |