Re: [patch] mm: oom_kill: revert 3% system memory bonus for privileged tasks

Johannes Weiner
2014-01-24T04:05:44Z

On Tue, Jan 21, 2014 at 08:53:07PM -0800, David Rientjes wrote:
> On Thu, 16 Jan 2014, Johannes Weiner wrote:
>
> > > Unfortunately, I think this could potentially be too much of a bonus. On
> > > your same 32GB machine, if a root process is using 18GB and a user process
> > > is using 14GB, the user process ends up getting selected while the current
> > > discount of 3% still selects the root process.
> > >
> > > I do like the idea of scaling this bonus depending on points, however. I
> > > think it would be better if we could scale the discount but also limit it
> > > to some sane value.
> >
> > I just reverted to the /= 4 because we had that for a long time and it
> > seemed to work. I don't really mind either way as long as we get rid
> > of that -3%. Do you have a suggestion?
> >
>
> How about simply using 3% of the root process's points so that root
> processes get some bonus compared to non-root processes with the same
> memory usage and it's scaled to the usage rather than amount of available
> memory?
>
> So rather than points /= 4, we do
>
> if (has_capability_noaudit(p, CAP_SYS_ADMIN))
> points -= (points * 3) / 100;
>
> instead. Sound good?

Yes, should be okay.

Do you want to send a patch? Want me to update mine?