[RFC PATCH v2 2/7] mm: compaction: handle non-lru compound pages properly in isolate_migratepages_block().
From: Zi Yan <hidden>
Date: 2021-12-09 23:04:43
Also in:
linux-iommu, linux-mm, lkml
Subsystem:
memory management, memory management - page allocator, the rest · Maintainers:
Andrew Morton, Vlastimil Babka, Linus Torvalds
From: Zi Yan <ziy@nvidia.com> In isolate_migratepages_block(), a !PageLRU tail page can be encountered when the page is larger than a pageblock. Use compound head page for the checks inside and skip the entire compound page when isolation succeeds. Signed-off-by: Zi Yan <ziy@nvidia.com> --- mm/compaction.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/mm/compaction.c b/mm/compaction.c
index b4e94cda3019..ad9053fbbe06 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c@@ -979,19 +979,23 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, * Skip any other type of page */ if (!PageLRU(page)) { + struct page *head = compound_head(page); /* * __PageMovable can return false positive so we need * to verify it under page_lock. */ - if (unlikely(__PageMovable(page)) && - !PageIsolated(page)) { + if (unlikely(__PageMovable(head)) && + !PageIsolated(head)) { if (locked) { unlock_page_lruvec_irqrestore(locked, flags); locked = NULL; } - if (!isolate_movable_page(page, isolate_mode)) + if (!isolate_movable_page(head, isolate_mode)) { + low_pfn += (1 << compound_order(head)) - 1 - (page - head); + page = head; goto isolate_success; + } } goto isolate_fail;
--
2.33.0