tcp buffer limitation: per-cgroup limit

This patch uses the "tcp.limit_in_bytes" field of the kmem_cgroup to
effectively control the amount of kernel memory pinned by a cgroup.

This value is ignored in the root cgroup, and in all others,
caps the value specified by the admin in the net namespaces'
view of tcp_sysctl_mem.

If namespaces are being used, the admin is allowed to set a
value bigger than cgroup's maximum, the same way it is allowed
to set pretty much unlimited values in a real box.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: Hiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com>
CC: David S. Miller <davem@davemloft.net>
CC: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Glauber Costa 2011-12-11 21:47:06 +00:00 committed by David S. Miller
parent 3dc43e3e4d
commit 3aaabe2342
4 changed files with 152 additions and 2 deletions

View file

@ -24,6 +24,7 @@
#include <net/cipso_ipv4.h>
#include <net/inet_frag.h>
#include <net/ping.h>
#include <net/tcp_memcontrol.h>
static int zero;
static int tcp_retr1_max = 255;
@ -182,6 +183,9 @@ static int ipv4_tcp_mem(ctl_table *ctl, int write,
int ret;
unsigned long vec[3];
struct net *net = current->nsproxy->net_ns;
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
struct mem_cgroup *memcg;
#endif
ctl_table tmp = {
.data = &vec,
@ -198,6 +202,16 @@ static int ipv4_tcp_mem(ctl_table *ctl, int write,
if (ret)
return ret;
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
rcu_read_lock();
memcg = mem_cgroup_from_task(current);
tcp_prot_mem(memcg, vec[0], 0);
tcp_prot_mem(memcg, vec[1], 1);
tcp_prot_mem(memcg, vec[2], 2);
rcu_read_unlock();
#endif
net->ipv4.sysctl_tcp_mem[0] = vec[0];
net->ipv4.sysctl_tcp_mem[1] = vec[1];
net->ipv4.sysctl_tcp_mem[2] = vec[2];