Re: [PATCH 1/2] mm/memcontrol.c: remove meaningless while loop in mem_cgroup_iter()

[Michal Hocko]

On Tue 22-04-14 18:17:09, Jianyu Zhan wrote:
> On Tue, Apr 22, 2014 at 5:47 PM, Michal Hocko <mhocko@xxxxxxx> wrote:
> > What about
> >   3. last_visited == last_node in the tree
> >
> > __mem_cgroup_iter_next returns NULL and the iterator would return
> > without visiting anything.
> 
> Hi,  Michal,
> 
> yep,  if 3 last_visited == last_node, then this means we have done a round-trip,
> thus __mem_cgroup_iter_next returns NULL, in turn mem_cgroup_iter() return NULL.

Sorry, I should have been more specific that I was talking about
mem_cgroup_reclaim_cookie path where the iteration for this particular
zone and priority ended at the last node without finishing the full
roundtrip last time. This new iteration (prev==NULL) wants to continue
and it should start a new roundtrip.

Makes sense?
-- 
Michal Hocko
SUSE Labs
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