Re: [RFC PATCH 0/2] improve vmalloc allocation

Michal Hocko
2018-10-23T17:05:37Z

On Tue 23-10-18 08:26:40, Matthew Wilcox wrote:
> On Tue, Oct 23, 2018 at 09:02:56AM -0600, Shuah Khan wrote:
[...]
> > The way it can be handled is by adding a test module under lib. test_kmod,
> > test_sysctl, test_user_copy etc.
>
> The problem is that said module can only invoke functions which are
> exported using EXPORT_SYMBOL. And there's a cost to exporting them,
> which I don't think we're willing to pay, purely to get test coverage.

Yes, I think we do not want to export internal functionality which might
be still interesting for the testing coverage. Maybe we want something
like EXPORT_SYMBOL_KSELFTEST which would allow to link within the
kselftest machinery but it wouldn't allow the same for general modules
and will not give any API promisses.

I wouldn't be surprised if we found some cases of EXPORT_SYMBOL* just to
make a symbol available for testing which would be unfortunate.
--
Michal Hocko
SUSE Labs