Re: [PATCH mmotm/next] memcg-mm-introduce-lowlimit-reclaim-fix2.patch

From: Michal Hocko
Date: Wed May 28 2014 - 03:44:16 EST


On Tue 27-05-14 14:36:04, Hugh Dickins wrote:
> mem_cgroup_within_guarantee() oopses in _raw_spin_lock_irqsave() when
> booted with cgroup_disable=memory. Fix that in the obvious inelegant
> way for now - though I hope we are moving towards a world in which
> almost all of the mem_cgroup_disabled() tests will vanish, with a
> root_mem_cgroup which can handle the basics even when disabled.
>
> I bet there's a neater way of doing this, rearranging the loop (and we
> shall want to avoid spinlocking on root_mem_cgroup when we reach that
> new world), but that's the kind of thing I'd get wrong in a hurry!
>
> Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>

Acked-by: Michal Hocko <mhocko@xxxxxxx>

Thanks!

> ---
>
> mm/memcontrol.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> --- mmotm/mm/memcontrol.c 2014-05-21 18:12:18.072022438 -0700
> +++ linux/mm/memcontrol.c 2014-05-21 19:34:30.608546905 -0700
> @@ -2793,6 +2793,9 @@ static struct mem_cgroup *mem_cgroup_loo
> bool mem_cgroup_within_guarantee(struct mem_cgroup *memcg,
> struct mem_cgroup *root)
> {
> + if (mem_cgroup_disabled())
> + return false;
> +
> do {
> if (!res_counter_low_limit_excess(&memcg->res))
> return true;

--
Michal Hocko
SUSE Labs
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