[LTP] [PATCH v2] syscalls/readahead02: limit max readahead to backing device max_readahead_kb

[Amir Goldstein]

On Thu, Mar 7, 2019 at 1:25 PM Jan Stancek <jstancek@redhat.com> wrote:
>
>
> ----- Original Message -----
> > > > Try to set bdi limit of test device on setup() to testfile_size before
> > > > reading
> > > > back the value?
> > > > If that fails try testfile_size / 2 etc.
> > >
> > > Maybe, but we would need to start lower (2M). Kernels prior to
> > > commit 600e19afc5f8a6c18ea49cee9511c5797db02391 will just ignore it.
> > >
> >
> > Ah. Thanks for the reference.
> > But kernels prior to this commit SHOULD fail the test if they
> > don't comply with explicit readahead() request that is below 2M
>
> Yes, agreed.
>
> > and bdi limit.
>
> What I meant was, that we can try bumping bdi limit, but our
> max readahead length has to be capped to MIN(bdi limit, 2M).
>
> Does that make sense?
>

It does to me.

Thanks,
Amir.