[LTP] [PATCH] tst_pollute_memory(): Set minimal safety margin to 64MB

[Naresh Kamboju]

On Wed, 20 Jan 2021 at 20:23, Cyril Hrubis <chrubis@suse.cz> wrote:
>
> Hi!
> > > > -     safety = 4096 * SAFE_SYSCONF(_SC_PAGESIZE) / info.mem_unit;
> > > > +     safety = MAX(4096 * SAFE_SYSCONF(_SC_PAGESIZE), 64 * 1024 * 1024);
> > > > +     safety /= info.mem_unit;
> > >
> > > I guess that this is safe enough for the release, since it will only
> > > increase the safety margin.
> > >
> > > Naresh can you please test this patch ASAP?
> >
> > I have applied your patch and rebuilt completely and retested
> > ioctl_sg01 test case in a loop on three different devices.
> >
> > 1 PASS out of 20 runs with overcommit_memory 0 on x86_64.
> > 1 PASS out of 20 runs with overcommit_memory 1 on x86_64.
> >
> > Which means 19 times the test case triggered oom-killer and the test was broken.
>
> So it looks like 64MB is not enough in your case.
>
> Does it work with 128MB or 256MB?
>
> i.e.:
>
> safety = MAX(4096 * SAFE_SYSCONF(_SC_PAGESIZE), 128 * 1024 * 1024);
> safety = MAX(4096 * SAFE_SYSCONF(_SC_PAGESIZE), 256 * 1024 * 1024);


I will test with these changes and get back to you.

Meanwhile,

20 PASS out of 20 runs with overcommit_memory 2 on x86_64.

- Naresh