Re: [PATCH 1/3] f2fs: avoid using __GFP_NOFAIL

From: Michal Hocko
Date: Mon Nov 06 2017 - 11:23:10 EST


On Tue 07-11-17 00:08:25, Chao Yu wrote:
[...]
> BTW, I notice the comments of __GFP_NOFAIL, what does this mean?
> * Using this flag for costly allocations is _highly_ discouraged.

This means that using __GFP_NOFAIL for high order allocations
(especially those with order > PAGE_ALLOC_COSTLY_ORDER) are highly
discouraged because we those are quite hard to get and looping inside
the allocator basically for ever is not a wise thing to do. That being
said replacing __GFP_NOFAIL by an open coded retry loop might make sense
for those e.g. to check signals or other termination conditions.
--
Michal Hocko
SUSE Labs