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 <glommer@xxxxxxxxxxxxx>
CC: David S. Miller <davem@xxxxxxxxxxxxx>
CC: Hiroyouki Kamezawa <kamezawa.hiroyu@xxxxxxxxxxxxxx>
CC: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
---
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
+#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 */
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);
-
#ifdef CONFIG_PROC_FS
#define PROTO_INUSE_NR 64 /* should be enough for the first time */
struct prot_inuse {
--
1.7.6
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