Re: [PATCH] dm ioctl: Restore __GFP_HIGH in copy_params()

From: Michal Hocko
Date: Fri May 19 2017 - 03:47:01 EST


On Thu 18-05-17 19:50:46, Junaid Shahid wrote:
> (Adding back the correct linux-mm email address and also adding linux-kernel.)
>
> On Thursday, May 18, 2017 01:41:33 PM David Rientjes wrote:
[...]
> > Let's ask Mikulas, who changed this from PF_MEMALLOC to __GFP_HIGH,
> > assuming there was a reason to do it in the first place in two different
> > ways.

Hmm, the old PF_MEMALLOC used to have the following comment
/*
* Trying to avoid low memory issues when a device is
* suspended.
*/

I am not really sure what that means but __GFP_HIGH certainly have a
different semantic than PF_MEMALLOC. The later grants the full access to
the memory reserves while the prior on partial access. If this is _really_
needed then it deserves a comment explaining why.
--
Michal Hocko
SUSE Labs