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

Andrew Wagin
2011-09-28T11:58:16Z

* 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?

* 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.

>+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,