On 1/9/20 2:48 PM, Li Xinhai wrote:
> oops, I didn't write the code correctly. I should wrote it as
>
> if (pfn >= hpage_pfn && pfn - hpage_pfn < hpage_nr_pages(hpage)) {
> VM_BUG_ON_PAGE(PageHuge(hpage) && pfn != hpage_pfn, hpage);
> return true;
> }
>
> return false;
>
> hpage_nr_pages(hpage) give us HPAGE_PMD_NR for THP and hugetlbfs page,
> but remapping PTE to a differrnt hugetlbfs page still allowed, so put the BUG code
> into this condition is necessary. By this way, if it was not a exact match for PageHuge,
> then it is a bug.
Thank you. I think we all agree on what the proposed code is doing.
However, we would like to know why you believe this code should be added.
For example,
- Did you actually encounter this situation (PageHuge(hpage) && pfn !=
hpage_pfn)?
- Did you discover some code path where we are likely to encounter this
situation?
- Some other reason?
--
Mike Kravetz
