From 7115936ac10abd0997f2937e4305cb679d47b592 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Tue, 9 Apr 2024 21:22:53 +0200 Subject: mm/page_alloc: use folio_mapped() in __alloc_contig_migrate_range() We want to limit the use of page_mapcount() to the places where it is absolutely necessary. For tracing purposes, we use page_mapcount() in __alloc_contig_migrate_range(). Adding that mapcount to total_mapped sounds strange: total_migrated and total_reclaimed would count each page only once, not multiple times. But then, isolate_migratepages_range() adds each folio only once to the list. So for large folios, we would query the mapcount of the first page of the folio, which doesn't make too much sense for large folios. Let's simply use folio_mapped() * folio_nr_pages(), which makes more sense as nr_migratepages is also incremented by the number of pages in the folio in case of successful migration. Link: https://lkml.kernel.org/r/20240409192301.907377-11-david@redhat.com Signed-off-by: David Hildenbrand Cc: Chris Zankel Cc: Hugh Dickins Cc: John Paul Adrian Glaubitz Cc: Jonathan Corbet Cc: Matthew Wilcox (Oracle) Cc: Max Filippov Cc: Miaohe Lin Cc: Muchun Song Cc: Naoya Horiguchi Cc: Peter Xu Cc: Richard Chang Cc: Rich Felker Cc: Ryan Roberts Cc: Yang Shi Cc: Yin Fengwei Cc: Yoshinori Sato Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/page_alloc.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'mm/page_alloc.c') diff --git a/mm/page_alloc.c b/mm/page_alloc.c index dd4265c760ff..45fccbcda763 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6347,8 +6347,12 @@ int __alloc_contig_migrate_range(struct compact_control *cc, if (trace_mm_alloc_contig_migrate_range_info_enabled()) { total_reclaimed += nr_reclaimed; - list_for_each_entry(page, &cc->migratepages, lru) - total_mapped += page_mapcount(page); + list_for_each_entry(page, &cc->migratepages, lru) { + struct folio *folio = page_folio(page); + + total_mapped += folio_mapped(folio) * + folio_nr_pages(folio); + } } ret = migrate_pages(&cc->migratepages, alloc_migration_target, -- cgit v1.2.3