[PATCH -mm] memcg: do not trigger OOM from add_to_page_cache_locked

[Michal Hocko]

[CCing also Johannes - the thread started here:
https://lkml.org/lkml/2012/11/21/497]

On Mon 26-11-12 01:38:55, azurIt wrote:
> >This is hackish but it should help you in this case. Kamezawa, what do
> >you think about that? Should we generalize this and prepare something
> >like mem_cgroup_cache_charge_locked which would add __GFP_NORETRY
> >automatically and use the function whenever we are in a locked context?
> >To be honest I do not like this very much but nothing more sensible
> >(without touching non-memcg paths) comes to my mind.
> 
> 
> I installed kernel with this patch, will report back if problem occurs
> again OR in few weeks if everything will be ok. Thank you!

Now that I am looking at the patch closer it will not work because it
depends on other patch which is not merged yet and even that one would
help on its own because __GFP_NORETRY doesn't break the charge loop.
Sorry I have missed that...

The patch bellow should help though. (it is based on top of the current
-mm tree but I will send a backport to 3.2 in the reply as well)
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