Re: [PATCH 1.2/2] mm: introduce memalloc_nofs_{save,restore} API

From: Michal Hocko
Date: Wed Apr 27 2016 - 09:07:23 EST


On Wed 27-04-16 13:54:35, Michal Hocko wrote:
> From: Michal Hocko <mhocko@xxxxxxxx>
>

Ups missed Dave's note about:

> GFP_NOFS context is used for the following 4 reasons currently
> - to prevent from deadlocks when the lock held by the allocation
> context would be needed during the memory reclaim
> - to prevent from stack overflows during the reclaim because
> the allocation is performed from a deep context already
> - to prevent lockups when the allocation context depends on
> other reclaimers to make a forward progress indirectly
> - just in case because this would be safe from the fs POV

- silence lockdep false positives
--
Michal Hocko
SUSE Labs