On Fri, 30 Dec 2022 17:30:20 +0800 Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> wrote:
> Straightforwardly convert split_huge_pages_all() to use a folio.
>
> ...
>
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -2932,6 +2932,7 @@ static void split_huge_pages_all(void)
> {
> struct zone *zone;
> struct page *page;
> + struct folio *folio;
> unsigned long pfn, max_zone_pfn;
> unsigned long total = 0, split = 0;
>
> @@ -2944,24 +2945,32 @@ static void split_huge_pages_all(void)
> int nr_pages;
>
> page = pfn_to_online_page(pfn);
> - if (!page || !get_page_unless_zero(page))
> + if (!page || PageTail(page))
> + continue;
> + folio = page_folio(page);
> + if (!folio_try_get(folio))
> continue;
>
> - if (zone != page_zone(page))
> + if (unlikely(page_folio(page) != folio))
> + goto next;
> +
> + if (zone != folio_zone(folio))
> goto next;
I'm still not understanding the above hunk. Why is the
"page_folio(page) != folio" check added? Should it be commented?
> - if (!PageHead(page) || PageHuge(page) || !PageLRU(page))
> + if (!folio_test_large(folio) ||
> + folio_test_hugetlb(folio) ||
> + !folio_test_lru(folio))
> goto next;
>
> total++;
> - lock_page(page);
> - nr_pages = thp_nr_pages(page);
> - if (!split_huge_page(page))
> + folio_lock(folio);
> + nr_pages = folio_nr_pages(folio);
> + if (!split_folio(folio))
> split++;
> pfn += nr_pages - 1;
> - unlock_page(page);
> + folio_unlock(folio);
> next:
> - put_page(page);
> + folio_put(folio);
> cond_resched();
> }
> }
> --
> 2.35.3
