Subject: Re: [PATCH v2 6/9] per-cgroup tcp buffers control

From: Li Zefan <[email-masked]>
Date: Wed, 07 Sep 2011 15:32:47 +0800

> +#ifdef CONFIG_INET
> +#include <net/sock.h>
> +static inline void sock_update_kmem_cgrp(struct sock *sk)
> +{
> +#ifdef CONFIG_CGROUP_KMEM
> +	sk->sk_cgrp = kcg_from_task(current);
> +
> +	/*
> +	 * We don't need to protect against anything task-related, because
> +	 * we are basically stuck with the sock pointer that won't change,
> +	 * even if the task that originated the socket changes cgroups.
> +	 *
> +	 * What we do have to guarantee, is that the chain leading us to
> +	 * the top level won't change under our noses. Incrementing the
> +	 * reference count via cgroup_exclude_rmdir guarantees that.
> +	 */
> +	cgroup_exclude_rmdir(&sk->sk_cgrp->css);
> +#endif

must be protected by rcu_read_lock.

> +}
> +
> +static inline void sock_release_kmem_cgrp(struct sock *sk)
> +{
> +#ifdef CONFIG_CGROUP_KMEM
> +	cgroup_release_and_wakeup_rmdir(&sk->sk_cgrp->css);
> +#endif
> +}

Ugly. Just use the way you define kcg_from_task().

> +
> +#endif /* CONFIG_INET */
>  #endif /* _LINUX_KMEM_CGROUP_H */
>  
> diff --git a/include/net/sock.h b/include/net/sock.h
> index 8e4062f..709382f 100644
> --- a/include/net/sock.h
> +++ b/include/net/sock.h
> @@ -228,6 +228,7 @@ struct sock_common {
>    *	@sk_security: used by security modules
>    *	@sk_mark: generic packet mark
>    *	@sk_classid: this socket's cgroup classid
> +  *	@sk_cgrp: this socket's kernel memory (kmem) cgroup 
>    *	@sk_write_pending: a write to stream socket waits to start
>    *	@sk_state_change: callback to indicate change in the state of the sock
>    *	@sk_data_ready: callback to indicate there is data to be processed
> @@ -339,6 +340,7 @@ struct sock {
>  #endif
>  	__u32			sk_mark;
>  	u32			sk_classid;
> +	struct kmem_cgroup	*sk_cgrp;
>  	void			(*sk_state_change)(struct sock *sk);
>  	void			(*sk_data_ready)(struct sock *sk, int bytes);
>  	void			(*sk_write_space)(struct sock *sk);
> diff --git a/net/core/sock.c b/net/core/sock.c
> index 3449df8..7109864 100644
> --- a/net/core/sock.c
> +++ b/net/core/sock.c
> @@ -1139,6 +1139,7 @@ struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
>  		atomic_set(&sk->sk_wmem_alloc, 1);
>  
>  		sock_update_classid(sk);
> +		sock_update_kmem_cgrp(sk);
>  	}
>  
>  	return sk;
> @@ -1170,6 +1171,7 @@ static void __sk_free(struct sock *sk)
>  		put_cred(sk->sk_peer_cred);
>  	put_pid(sk->sk_peer_pid);
>  	put_net(sock_net(sk));
> +	sock_release_kmem_cgrp(sk);
>  	sk_prot_free(sk->sk_prot_creator, sk);
>  }
>  
> @@ -2252,9 +2254,6 @@ void sk_common_release(struct sock *sk)
>  }
>  EXPORT_SYMBOL(sk_common_release);
>  
> -static DEFINE_RWLOCK(proto_list_lock);
> -static LIST_HEAD(proto_list);
> -

compile error.

you should do compile test after each single patch.

>  #ifdef CONFIG_PROC_FS
>  #define PROTO_INUSE_NR	64	/* should be enough for the first time */
>  struct prot_inuse {

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