Re: [PATCH v3 6/7] tcp buffer limitation: per-cgroup limit

From: Greg Thelen
Date: Thu Sep 22 2011 - 02:02:19 EST


On Sun, Sep 18, 2011 at 5:56 PM, Glauber Costa <glommer@xxxxxxxxxxxxx> wrote:
> +static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
> +{
> +       return (mem == root_mem_cgroup);
> +}
> +

Why are you adding a copy of mem_cgroup_is_root(). I see one already
in v3.0. Was it deleted in a previous patch?

> +static int tcp_write_maxmem(struct cgroup *cgrp, struct cftype *cft, u64 val)
> +{
> +       struct mem_cgroup *sg = mem_cgroup_from_cont(cgrp);
> +       struct mem_cgroup *parent = parent_mem_cgroup(sg);
> +       struct net *net = current->nsproxy->net_ns;
> +       int i;
> +
> +       if (!cgroup_lock_live_group(cgrp))
> +               return -ENODEV;

Why is cgroup_lock_live_cgroup() needed here? Does it protect updates
to sg->tcp_prot_mem[*]?

> +static u64 tcp_read_maxmem(struct cgroup *cgrp, struct cftype *cft)
> +{
> +       struct mem_cgroup *sg = mem_cgroup_from_cont(cgrp);
> +       u64 ret;
> +
> +       if (!cgroup_lock_live_group(cgrp))
> +               return -ENODEV;

Why is cgroup_lock_live_cgroup() needed here? Does it protect updates
to sg->tcp_max_memory?
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