On Mon, Aug 10, 2020 at 11:45:36PM -0400, Qian Cai wrote:

quoted

On Aug 10, 2020, at 11:11 PM, HORIGUCHI NAOYA(堀口　直也) [off-list ref] wrote:

I'm still not sure why the test succeeded by reverting these because
current mainline kernel provides similar mechanism to prevent reuse of
soft offlined page. So this success seems to me something suspicious.

Even if we call munmap() on the range, it still can’t be be reused? If so, how to recover those memory then?

No, it can't, because soft offline isolates the physical page.
so even after calling munmap(), the side effect remains on the page.
In your random.c, memory online/offline resets the status of hwpoison.
So you can reallocate hugepages in another run of the program.

quoted

To investigate more, I want to have additional info about the page states
of the relevant pages after soft offlining.  Could you collect it by the
following steps?

Do you want to collect those from the failed or succeed kernel?

I'd like to check on the succeeded kernel.
Sorry for the lack of information.

Thanks,
Naoya Horiguchi
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