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

[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

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