Messages in this thread | | | Date | Tue, 1 Feb 2011 08:50:21 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [patch 2/3] memcg: prevent endless loop when charging huge pages to near-limit group |
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On Mon, 31 Jan 2011 14:41:31 -0800 Andrew Morton <akpm@linux-foundation.org> wrote:
> On Mon, 31 Jan 2011 15:03:54 +0100 > Johannes Weiner <hannes@cmpxchg.org> wrote: > > > +static inline bool res_counter_check_margin(struct res_counter *cnt, > > + unsigned long bytes) > > +{ > > + bool ret; > > + unsigned long flags; > > + > > + spin_lock_irqsave(&cnt->lock, flags); > > + ret = cnt->limit - cnt->usage >= bytes; > > + spin_unlock_irqrestore(&cnt->lock, flags); > > + return ret; > > +} > > + > > static inline bool res_counter_check_under_soft_limit(struct res_counter *cnt) > > { > > bool ret; > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > index 73ea323..c28072f 100644 > > --- a/mm/memcontrol.c > > +++ b/mm/memcontrol.c > > @@ -1111,6 +1111,15 @@ static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem) > > return false; > > } > > > > +static bool mem_cgroup_check_margin(struct mem_cgroup *mem, unsigned long bytes) > > +{ > > + if (!res_counter_check_margin(&mem->res, bytes)) > > + return false; > > + if (do_swap_account && !res_counter_check_margin(&mem->memsw, bytes)) > > + return false; > > + return true; > > +} > > argh. > > If you ever have a function with the string "check" in its name, it's a > good sign that you did something wrong. > > Check what? Against what? Returning what? > > mem_cgroup_check_under_limit() isn't toooo bad - the name tells you > what's being checked and tells you what to expect the return value to > mean. > > But "res_counter_check_margin" and "mem_cgroup_check_margin" are just > awful. Something like > > bool res_counter_may_charge(counter, bytes) > > would be much clearer. > > If we really want to stick with the "check" names (perhaps as an ironic > reference to res_counter's past mistakes) then please at least document > the sorry things? >
Ah, I ack the concept of patch.
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Johannes, could you change name ? I'm sorry.
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