Re: [PATCH v2 3/9] socket: initial cgroup code.

On 09/07/2011 07:17 PM, Kirill A. Shutemov wrote:

On Wed, Sep 07, 2011 at 01:23:13AM -0300, Glauber Costa wrote:

quoted

We aim to control the amount of kernel memory pinned at any
time by tcp sockets. To lay the foundations for this work,
this patch adds a pointer to the kmem_cgroup to the socket
structure.

Signed-off-by: Glauber Costa<redacted>
CC: David S. Miller<davem@davemloft.net>
CC: Hiroyouki Kamezawa<redacted>
CC: Eric W. Biederman<redacted>
---
  include/linux/kmem_cgroup.h |   29 +++++++++++++++++++++++++++++
  include/net/sock.h          |    2 ++
  net/core/sock.c             |    5 ++---
  3 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/include/linux/kmem_cgroup.h b/include/linux/kmem_cgroup.h
index 0e4a74b..77076d8 100644
--- a/include/linux/kmem_cgroup.h
+++ b/include/linux/kmem_cgroup.h

@@ -49,5 +49,34 @@ static inline struct kmem_cgroup *kcg_from_task(struct task_struct *tsk)
  	return NULL;
  }
  #endif /* CONFIG_CGROUP_KMEM */
+
+#ifdef CONFIG_INET

Will it break something if you define the helpers even if CONFIG_INET
is not defined?
It will be much cleaner. You can reuse ifdef CONFIG_CGROUP_KMEM in this
case.

The helpers inside CONFIG_INET are needed for the network code, regardless of kmem cgroup is defined or not, not the other way around.

So I could remove CONFIG_INET, but I can't possibly move it inside
CONFIG_CGROUP_KMEM. So this buy us nothing.

quoted

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

quoted

@@ -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);
-

Wrong patch?

Yes, it is. Thanks for noticing.


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