Re: [trivial PATCH] Remove pointless next_mz nullification in mem_cgroup_soft_limit_reclaim

[Zhu Yanhai <zhu.yanhai@gmail.com>]

Got it. Sorry, my fault :)

-zyh

2011/3/29 Michal Hocko <mhocko@suse.cz>:
> On Tue 29-03-11 21:40:13, Zhu Yanhai wrote:
>> Michal,
>> IIUC it's to prevent the infinite loop, as in the end of the do-while
>> there's
>> if (!nr_reclaimed &&
>>     (next_mz == NULL ||
>>     loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
>>               break;
>
>> so the loop will break earlier if all groups are iterated once and no
>> pages are freed.
>
> The code (in mmotm 2011-03-10-16-42) reads:
>                        do {
>                                [skipped comments]
>                                next_mz =
>                                __mem_cgroup_largest_soft_limit_node(mctz);
>                                if (next_mz == mz) {
>                                        css_put(&next_mz->mem->css);
>                                        next_mz = NULL;
>                                } else /* next_mz == NULL or other memcg */
>                                        break;
>                        } while (1);
>
> So we do not break out of the loop and start a new iteration if next_mz == mz
> and assign next_mz again.
> Am I missing something?
> --
> Michal Hocko
> SUSE Labs
> SUSE LINUX s.r.o.
> Lihovarska 1060/12
> 190 00 Praha 9
> Czech Republic
>