On 10/15/2024 4:56 PM, Luck, Tony wrote:
Another way to "disable hardoffline but still set HWPoison" I can
think of is, make the HWPOISON flag apply at page_size level, instead
of always set at the compound head. At least from hugetlb's
perspective, is it a good idea?
Many years ago someone looked at breaking up hugetlb pages
when a memory error occurred so that just 4K was lost instead
of the entire huge page. At that time the conclusion was that
doing so would require locks to be taken/released around all
hugetlb map/unmap operations. An unacceptable performance
issue for common operations to handle very rare memory error
events.
I don't know if that is still true. There's been a lot of restructure
to memory management code since then.
The HGM for hugetlbfs
<https://lore.kernel.org/linux-mm/20230306191944.GA15773@monkey/#r>
project attempted this as well.
https://lore.kernel.org/linux-mm/20230306191944.GA15773@monkey/
-jan
-Tony
