Messages in this thread | | | Date | Fri, 9 Dec 2011 10:43:00 -0200 | From | Glauber Costa <> | Subject | Re: [PATCH v8 3/9] socket: initial cgroup code. |
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On 12/09/2011 12:05 AM, KAMEZAWA Hiroyuki wrote: > On Mon, 5 Dec 2011 19:34:57 -0200 > Glauber Costa<glommer@parallels.com> wrote: > >> The goal of this work is to move the memory pressure tcp >> controls to a cgroup, instead of just relying on global >> conditions. >> >> To avoid excessive overhead in the network fast paths, >> the code that accounts allocated memory to a cgroup is >> hidden inside a static_branch(). This branch is patched out >> until the first non-root cgroup is created. So when nobody >> is using cgroups, even if it is mounted, no significant performance >> penalty should be seen. >> >> This patch handles the generic part of the code, and has nothing >> tcp-specific. >> >> Signed-off-by: Glauber Costa<glommer@parallels.com> >> CC: Kirill A. Shutemov<kirill@shutemov.name> >> CC: KAMEZAWA Hiroyuki<kamezawa.hiroyu@jp.fujtsu.com> >> CC: David S. Miller<davem@davemloft.net> >> CC: Eric W. Biederman<ebiederm@xmission.com> >> CC: Eric Dumazet<eric.dumazet@gmail.com> > > I already replied Reviewed-by: but... Feel free. Reviews, the more, the merrier.
> > >> +/* Writing them here to avoid exposing memcg's inner layout */ >> +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM >> +#ifdef CONFIG_INET >> +#include<net/sock.h> >> + >> +static bool mem_cgroup_is_root(struct mem_cgroup *memcg); >> +void sock_update_memcg(struct sock *sk) >> +{ >> + /* A socket spends its whole life in the same cgroup */ >> + if (sk->sk_cgrp) { >> + WARN_ON(1); >> + return; >> + } >> + if (static_branch(&memcg_socket_limit_enabled)) { >> + struct mem_cgroup *memcg; >> + >> + BUG_ON(!sk->sk_prot->proto_cgroup); >> + >> + rcu_read_lock(); >> + memcg = mem_cgroup_from_task(current); >> + if (!mem_cgroup_is_root(memcg)) { >> + mem_cgroup_get(memcg); >> + sk->sk_cgrp = sk->sk_prot->proto_cgroup(memcg); >> + } >> + rcu_read_unlock(); >> + } >> +} > > Here, you do mem_cgroup_get() if !mem_cgroup_is_root(). > > >> +EXPORT_SYMBOL(sock_update_memcg); >> + >> +void sock_release_memcg(struct sock *sk) >> +{ >> + if (static_branch(&memcg_socket_limit_enabled)&& sk->sk_cgrp) { >> + struct mem_cgroup *memcg; >> + WARN_ON(!sk->sk_cgrp->memcg); >> + memcg = sk->sk_cgrp->memcg; >> + mem_cgroup_put(memcg); >> + } >> +} >> > > You don't check !mem_cgroup_is_root(). Hm, root memcg will not be freed > by this ? > No, I don't. But I check if sk->sk_cgrp is filled. So it is implied, because we only fill in this value if !mem_cgroup_is_root().
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