On 2024/8/17 16:49, Kefeng Wang wrote:
> The commit b15c87263a69 ("hwpoison, memory_hotplug: allow hwpoisoned
> pages to be offlined") don't handle the hugetlb pages, the endless
> loop still occur if offline a hwpoison hugetlb, luckly, with the
> commit e591ef7d96d6 ("mm,hwpoison,hugetlb,memory_hotplug: hotremove
> memory section with hwpoisoned hugepage") section with hwpoisoned
> hugepage"), the HPageMigratable of hugetlb page will be clear, and
It should be commit e591ef7d96d6 ("mm,hwpoison,hugetlb,memory_hotplug: hotremove memory section
with hwpoisoned hugepage")? Above "section with hwpoisoned")" is duplicated.
Also s/be clear/be cleared/ ?
> the hwpoison hugetlb page will be skipped in scan_movable_pages(),
> so the endless loop issue is fixed.
>
> However if the HPageMigratable() check passed(without reference and
> lock), the hugetlb page may be hwpoisoned, it won't cause issue since
> the hwpoisoned page will be handled correctly in the next movable
> pages scan loop, and it will be isolated in do_migrate_range() but
> fails to migrate. In order to avoid the unnecessary isolation and
> unify all hwpoisoned page handling, let's unconditionally check hwpoison
> firstly, and if it is a hwpoisoned hugetlb page, try to unmap it as
> the catch all safety net like normal page does.
>
> Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
> ---
> mm/memory_hotplug.c | 17 +++++++++--------
> 1 file changed, 9 insertions(+), 8 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index dc19b0e28fbc..02a0d4fbc3fe 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1793,13 +1793,8 @@ static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
> * but out loop could handle that as it revisits the split
> * folio later.
> */
> - if (folio_test_large(folio)) {
> + if (folio_test_large(folio))
> pfn = folio_pfn(folio) + folio_nr_pages(folio) - 1;
> - if (folio_test_hugetlb(folio)) {
> - isolate_hugetlb(folio, &source);
> - continue;
> - }
> - }
>
> /*
> * HWPoison pages have elevated reference counts so the migration would
> @@ -1808,11 +1803,17 @@ static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
> * (e.g. current hwpoison implementation doesn't unmap KSM pages but keep
> * the unmap as the catch all safety net).
> */
> - if (PageHWPoison(page)) {
> + if (folio_test_hwpoison(folio) ||
> + (folio_test_large(folio) && folio_test_has_hwpoisoned(folio))) {
> 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);
> + continue;
> + }
> +
> + if (folio_test_hugetlb(folio)) {
> + isolate_hugetlb(folio, &source);
While you're here, should we pr_warn "failed to isolate pfn xx" for hugetlb folios too as
we already done for raw pages and thp folios?
Thanks.
.
