Fixed PR13146 by not allowing memory allocations to sleep

[Frank Ch. Eigler]

mjw wrote:

> [...]
>> I cannot find what precisely triggers/causes the oom-killer to kick in.
>> I hoped a GFP_WILLING_TO_WAIT_BUT_DONT_KILL_ANYBODY_JUST_BECAUSE_OF_ME
>> flag would exist, but it isn't clear to me which GFP flag/combination
>> that actually corresponds to.
>
> Looking at the kernel sources it seems that flag is __GFP_NORETRY.
> [...]

We used to use __GFP_NORETRY for e.g. map allocation, since commit
132c23b4 some years ago.  So I think this just swings our pendulum
back to a previous point.

- FChE