On 25/08/2023 14:59, Matthew Wilcox (Oracle) wrote:
> Call folio_undo_large_rmappable() if needed. free_unref_page_prepare()
> destroys the ability to call folio_order(), so stash the order in
> folio->private for the benefit of the second loop.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---
> mm/page_alloc.c | 21 +++++++++++++++------
> 1 file changed, 15 insertions(+), 6 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index bca5c70b5576..e586d17fb7f2 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -2465,7 +2465,7 @@ void free_unref_page(struct page *page, unsigned int order)
> }
>
> /*
> - * Free a batch of 0-order pages
> + * Free a batch of folios
> */
> void free_unref_folios(struct folio_batch *folios)
> {
> @@ -2478,7 +2478,11 @@ void free_unref_folios(struct folio_batch *folios)
> for (i = 0, j = 0; i < folios->nr; i++) {
> struct folio *folio = folios->folios[i];
> unsigned long pfn = folio_pfn(folio);
> - if (!free_unref_page_prepare(&folio->page, pfn, 0))
> + unsigned int order = folio_order(folio);
Do you need to do anything special for hugetlb folios? I see that
destroy_large_folio() has:
if (folio_test_hugetlb(folio)) {
free_huge_folio(folio);
return;
}
> +
> + if (order > 0 && folio_test_large_rmappable(folio))
> + folio_undo_large_rmappable(folio);
> + if (!free_unref_page_prepare(&folio->page, pfn, order))
> continue;
>
> /*
> @@ -2486,11 +2490,13 @@ void free_unref_folios(struct folio_batch *folios)
> * comment in free_unref_page.
> */
> migratetype = get_pcppage_migratetype(&folio->page);
> - if (unlikely(is_migrate_isolate(migratetype))) {
> + if (order > PAGE_ALLOC_COSTLY_ORDER ||
Should this be `if (!pcp_allowed_order(order) ||` ? That helper includes the THP
pageblock_order too.
> + is_migrate_isolate(migratetype)) {
> free_one_page(folio_zone(folio), &folio->page, pfn,
> - 0, migratetype, FPI_NONE);
> + order, migratetype, FPI_NONE);
> continue;
> }
> + folio->private = (void *)(unsigned long)order;
> if (j != i)
> folios->folios[j] = folio;
> j++;
> @@ -2500,7 +2506,9 @@ void free_unref_folios(struct folio_batch *folios)
> for (i = 0; i < folios->nr; i++) {
> struct folio *folio = folios->folios[i];
> struct zone *zone = folio_zone(folio);
> + unsigned int order = (unsigned long)folio->private;
>
> + folio->private = NULL;
> migratetype = get_pcppage_migratetype(&folio->page);
>
> /* Different zone requires a different pcp lock */
> @@ -2519,7 +2527,7 @@ void free_unref_folios(struct folio_batch *folios)
> if (unlikely(!pcp)) {
> pcp_trylock_finish(UP_flags);
> free_one_page(zone, &folio->page,
> - folio_pfn(folio), 0,
> + folio_pfn(folio), order,
> migratetype, FPI_NONE);
> locked_zone = NULL;
> continue;
> @@ -2535,7 +2543,8 @@ void free_unref_folios(struct folio_batch *folios)
> migratetype = MIGRATE_MOVABLE;
>
> trace_mm_page_free_batched(&folio->page);
> - free_unref_page_commit(zone, pcp, &folio->page, migratetype, 0);
> + free_unref_page_commit(zone, pcp, &folio->page, migratetype,
> + order);
> }
>
> if (pcp) {
