Hi David, I have some question,
On 2024/8/2 16:02, Kefeng Wang wrote:
...
*/
- if (PageHWPoison(page)) {
+ if (unlikely(PageHWPoison(page))) {
+ folio = page_folio(page);
+
if (WARN_ON(folio_test_lru(folio)))
folio_isolate_lru(folio);
+
if (folio_mapped(folio))
- try_to_unmap(folio, TTU_IGNORE_MLOCK);
+ unmap_posioned_folio(folio, TTU_IGNORE_MLOCK);
+
+ if (folio_test_large(folio))
+ pfn = folio_pfn(folio) + folio_nr_pages(folio) - 1;
continue;
}
+ if (PageHuge(page)) {
+ pfn = page_to_pfn(head) + compound_nr(head) - 1;
+ isolate_hugetlb(folio, &source);
+ continue;
+ } else if (PageTransHuge(page))
If the page is a tail page, we will BUG_ON(DEBUG_VM enabled) here, but
it seems that we don't guarantee the page won't be a tail page.
+ pfn = page_to_pfn(head) + thp_nr_pages(page) - 1;
thp_nr_pages() need a head page, I think it should use head here, so we
can directly use folio_nr_pages().
If we can use a folio in the PageHWPoison() case, can we use one here
as well? I know that it's all unreliable when not holding a folio
reference, and we have to be a bit careful.
Using a folio here is part of patch4, I want to unify hugetlb/thp(or
large folio) with "pfn = folio_pfn(folio) + folio_nr_pages(folio) - 1"
when large folio after get a ref.
Think it again, even the folio don't hold a ref(splitting concurrently
or something else), folio_nr_pages return incorrect, it won't cause
issue since we will loop and find movable pages again in
scan_movable_pages() and try to isolate pages, so directly use
if (folio_test_large(folio)) {
pfn = folio_pfn(folio) + folio_nr_pages(folio) - 1;
if (folio_test_hugetlb(folio))
isolate_hugetlb(folio, &source);
}
Correct me if I am wrong, thanks.
It feels like using folios here would mostly be fine, because things
like PageHuge() already use folios internally.
And using it in the PageHWPoison() but not here looks a bit odd.
We will convert to use folio in the following patch.
The important part is that we don't segfault if we'd overshoot our
target.
