Re: [PATCH v2 4/7] per-cgroup tcp buffers control

Glauber Costa
2011-09-28T12:12:27Z

On 09/28/2011 08:58 AM, Andrew Wagin wrote:
> * tcp_destroy_cgroup_fill() is executed for each cgroup and
> initializes some proto methods. proto_list is global and we can
> initialize each proto one time. Do we need this really?
>
> * And when a cgroup is destroyed, it cleans proto methods
> (tcp_destroy_cgroup_fill), how other cgroups will work after that?

I've already realized that, and removed destruction from my upcoming
series. Thanks

> * What about proto, which is registered when cgroup mounted?
>
> My opinion that we may initialize proto by the following way:
>
> +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM+ .enter_memory_pressure
> = tcp_enter_memory_pressure_nocg,
> + .sockets_allocated = sockets_allocated_tcp_nocg,
> + .memory_allocated = memory_allocated_tcp_nocg,
> + .memory_pressure = memory_pressure_tcp_nocg,
> +#else
> .enter_memory_pressure = tcp_enter_memory_pressure,
> .sockets_allocated = sockets_allocated_tcp,
> .memory_allocated = memory_allocated_tcp,
> .memory_pressure = memory_pressure_tcp,
> +#endif
>
> It should work, because the root memory cgroup always exists.
Yeah, I was still doing the initialization through cgroups, but I think
this works.

The reason I was keeping it cgroup's initialization method, was because
we have a parameter that allowed kmem accounting to be disabled.
But Kame suggested we'd remove it, and so I did.

>
>> +int tcp_init_cgroup_fill(struct proto *prot, struct cgroup *cgrp,
>> + struct cgroup_subsys *ss)
>> +{
>> + prot->enter_memory_pressure = tcp_enter_memory_pressure;
>> + prot->memory_allocated = memory_allocated_tcp;
>> + prot->prot_mem = tcp_sysctl_mem;
>> + prot->sockets_allocated = sockets_allocated_tcp;
>> + prot->memory_pressure = memory_pressure_tcp;
>> +
>> + return 0;
>> +}
>
>
>> +void tcp_destroy_cgroup_fill(struct proto *prot, struct cgroup *cgrp,
>> + struct cgroup_subsys *ss)
>> +{
>> + prot->enter_memory_pressure = tcp_enter_memory_pressure_nocg;
>> + prot->memory_allocated = memory_allocated_tcp_nocg;
>> + prot->prot_mem = tcp_sysctl_mem_nocg;
>> + prot->sockets_allocated = sockets_allocated_tcp_nocg;
>> + prot->memory_pressure = memory_pressure_tcp_nocg;
>>
>
>> @@ -2220,12 +2220,16 @@ struct proto tcpv6_prot = {
>> .hash = tcp_v6_hash,
>> .unhash = inet_unhash,
>> .get_port = inet_csk_get_port
>> + .enter_memory_pressure = tcp_enter_memory_pressure_nocg,
>> + .sockets_allocated = sockets_allocated_tcp_nocg,
>> + .memory_allocated = memory_allocated_tcp_nocg,
>> + .memory_pressure = memory_pressure_tcp_nocg,