Re: [PATCH v5 0/3] mm: Implement ECC handling for pfn with no struct page

[Ankit Agrawal]

>>
>> v2 -> v3
>> - Rebased to v6.17-rc7.
>> - Skipped the unmapping of PFNMAP during reception of poison. Suggested by
>> Jason Gunthorpe, Jiaqi Yan, Vikram Sethi (Thanks!)
>> - Updated the check to prevent multiple registration to the same PFN
>> range using interval_tree_iter_first. Thanks Shameer Kolothum for the
>> suggestion.
>> - Removed the callback function in the nvgrace-gpu requiring tracking of
>> poisoned PFN as it isn't required anymore.
>
> Hi Ankit,
>
>
> I get that for nvgrace-gpu driver, you removed pfn_address_space_ops
> because there is no need to unmap poisoned HBM page.
>
> What about the nvgrace-egm driver? Now that you removed the
> pfn_address_space_ops callback from pfn_address_space in [1], how can
> nvgrace-egm driver know the poisoned EGM pages at runtime?
>
> I expect the functionality to return retired pages should also include
> runtime poisoned pages, which are not in the list queried from
> egm-retired-pages-data-base during initialization. Or maybe my
> expection is wrong/obsolete?

Hi Jiaqi, yes the EGM code will include consideration for runtime
poisoned pages as well. It will now instead make use of the
pfn_to_vma_pgoff callback merged through https://github.com/torvalds/linux/commit/e6dbcb7c0e7b508d443a9aa6f77f63a2f83b1ae4

> [1] https://lore.kernel.org/linux-mm/20230920140210.12663-2-ankita@xxxxxxxxxx
> [2] https://lore.kernel.org/kvm/20250904040828.319452-12-ankita@xxxxxxxxxx