From 343b288834e84d0b175b20b4f48277bc33260986 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Sat, 15 Aug 2020 19:28:51 -0400 Subject: [PATCH] mm/vmscan: Optimise shrink_page_list for non-PMD-sized folios A large folio which is smaller than a PMD does not need to do the extra work in try_to_unmap() of trying to split a PMD entry. Signed-off-by: Matthew Wilcox (Oracle) --- mm/vmscan.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index d15a9f08caab..8243437e5c5f 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1765,7 +1765,8 @@ static unsigned int shrink_page_list(struct list_head *page_list, enum ttu_flags flags = TTU_BATCH_FLUSH; bool was_swapbacked = PageSwapBacked(page); - if (unlikely(PageTransHuge(page))) + if (PageTransHuge(page) && + thp_order(page) >= HPAGE_PMD_ORDER) flags |= TTU_SPLIT_HUGE_PMD; try_to_unmap(folio, flags);