Re: [PATCH v1 1/5] mm, hwpoison, hugetlb: introduce SUBPAGE_INDEX_HWPOISON to save raw error page

[David Hildenbrand]

On 02.06.22 07:06, Naoya Horiguchi wrote:
> From: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
> 
> When handling memory error on a hugetlb page, the error handler tries to
> dissolve and turn it into 4kB pages.  If it's successfully dissolved,
> PageHWPoison flag is moved to the raw error page, so that's all right.
> However, dissolve sometimes fails, then the error page is left as
> hwpoisoned hugepage. It's useful if we can retry to dissolve it to save
> healthy pages, but that's not possible now because the information about
> where the raw error page is lost.
> 
> Use the private field of a tail page to keep that information.  The code
> path of shrinking hugepage pool used this info to try delayed dissolve.
> This only keeps one hwpoison page for now, which might be OK because it's
> simple and multiple hwpoison pages in a hugepage can be rare. But it can
> be extended in the future.
> 
>

But what would happen now if you have multiple successive MCE events on
such a page now?

-- 
Thanks,

David / dhildenb