Re: [PATCHv2 1/8] khugepaged: Add self test

From: Kirill A. Shutemov
Date: Fri Apr 10 2020 - 07:47:43 EST


On Mon, Apr 06, 2020 at 10:59:52AM -0400, Zi Yan wrote:
> I ran this test with all patches from this series applied to Linusâs tree, but still see several failures. Is it expected?
> The config file is attached. Let me know if I miss anything. BTW, I am running in a VM.
>
> Thanks.
>
> The output:
>
> â ~ sudo ./khugepaged
> Save THP and khugepaged settings... OK
> Adjust settings... OK
> Allocate huge page on fault... OK
> Split huge PMD on MADV_DONTNEED... OK
> Collapse fully populated PTE table.... Fail

I was able to reproduce the issue. And it's fun failure mode.

How did you get the test case inside the VM? Copy-paste source using 'cat'
or something similar inside the VM?

It screwed up CHECK_HUGE_FMT and CHECK_SWAP_FMT for me. Double back slash
was converted to single. As result check_huge() and check_swap() gave the
false-negative result all the time.

Could you check that the source of the test-case is not mangled and
re-test if it is.

--
Kirill A. Shutemov