Re: suspicious __GFP_NOMEMALLOC in selinux

From: Michal Hocko
Date: Thu Aug 10 2017 - 03:02:13 EST


On Tue 08-08-17 09:34:15, Paul Moore wrote:
> On Mon, Aug 7, 2017 at 2:58 AM, Michal Hocko <mhocko@xxxxxxxxxx> wrote:
> > On Fri 04-08-17 13:12:04, Paul Moore wrote:
> >> On Fri, Aug 4, 2017 at 3:56 AM, Michal Hocko <mhocko@xxxxxxxxxx> wrote:
> > [...]
> >> > Btw. Should I resend the patch or somebody will take it from this email
> >> > thread?
> >>
> >> No, unless your mailer mangled the patch I should be able to pull it
> >> from this thread. However, I'm probably going to let this sit until
> >> early next week on the odd chance that anyone else wants to comment on
> >> the flag choice. I'll send another reply once I merge the patch.
> >
> > OK, there is certainly no hurry for merging this. Thanks!
> > --
> > Michal Hocko
> > SUSE Labs
>
> Merged into selinux/next with this patch description, and your
> sign-off (I had to munge the description a bit based on the thread).
> Are you okay with this, especially your sign-off?

Yes. Thanks!

>
> commit 476accbe2f6ef69caeebe99f52a286e12ac35aee
> Author: Michal Hocko <mhocko@xxxxxxxxxx>
> Date: Thu Aug 3 10:11:52 2017 +0200
>
> selinux: use GFP_NOWAIT in the AVC kmem_caches
>
> There is a strange __GFP_NOMEMALLOC usage pattern in SELinux,
> specifically GFP_ATOMIC | __GFP_NOMEMALLOC which doesn't make much
> sense. GFP_ATOMIC on its own allows to access memory reserves while
> __GFP_NOMEMALLOC dictates we cannot use memory reserves. Replace this
> with the much more sane GFP_NOWAIT in the AVC code as we can tolerate
> memory allocation failures in that code.
>
> Signed-off-by: Michal Hocko <mhocko@xxxxxxxxxx>
> Acked-by: Mel Gorman <mgorman@xxxxxxx>
> Signed-off-by: Paul Moore <paul@xxxxxxxxxxxxxx>
>
> --
> paul moore
> www.paul-moore.com

--
Michal Hocko
SUSE Labs