Re: [PATCH v3 4/7] per-cgroup tcp buffers control

[Glauber Costa <glommer@parallels.com>]

On 09/26/2011 11:39 AM, Andrew Vagin wrote:
> We can't change net.ipv4.tcp_mem if a cgroup with memory controller
> isn't mounted.
>
> [root@dhcp-10-30-20-19 ~]# sysctl -w net.ipv4.tcp_mem="3 2 3"
> error: "Invalid argument" setting key "net.ipv4.tcp_mem"
>
> It's because tcp_max_memory is initialized in mem_cgroup_populate:
>
> mem_cgroup_populate->register_kmem_files->sockets_populate->tcp_init_cgroup

Thank you, will fix it

>> +int sockets_populate(struct cgroup *cgrp, struct cgroup_subsys *ss)
>> +{
>> + struct proto *proto;
>> + int ret = 0;
>> +
>> + read_lock(&proto_list_lock);
>> + list_for_each_entry(proto,&proto_list, node) {
>> + if (proto->init_cgroup)
>> + ret |= proto->init_cgroup(proto, cgrp, ss);
>> + }
>> + if (!ret)
>> + goto out;
>> +
>> + list_for_each_entry_continue_reverse(proto,&proto_list, node)
>> + if (proto->destroy_cgroup)
>> + proto->destroy_cgroup(proto, cgrp, ss);
>> +
>> +out:
>> + read_unlock(&proto_list_lock);
>> + return ret;
>> +}
>
>> @@ -198,6 +203,21 @@ static int ipv4_tcp_mem(ctl_table *ctl, int write,
>> if (ret)
>> return ret;
>>
>> +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
>> + rcu_read_lock();
>> + cg = mem_cgroup_from_task(current);
>> + for (i = 0; i< 3; i++)
>> + if (vec[i]> tcp_max_memory(cg)) {
>> + rcu_read_unlock();
>> + return -EINVAL;
>> + }
>