[015/192] mm/huge_memory.c: remove unnecessary tlb_remove_page_size() for huge zero pmd

Commit Message

Andrew Morton July 1, 2021, 1:47 a.m. UTC

From: Miaohe Lin <[e-mail]>
Subject: mm/huge_memory.c: remove unnecessary tlb_remove_page_size() for huge zero pmd

Commit aa88b68c3b1d ("thp: keep huge zero page pinned until tlb flush")
introduced tlb_remove_page() for huge zero page to keep it pinned until
flush is complete and prevents the page from being split under us.  But
huge zero page is kept pinned until all relevant mm_users reach zero since
the commit 6fcb52a56ff6 ("thp: reduce usage of huge zero page's atomic
counter").  So tlb_remove_page_size() for huge zero pmd is unnecessary
now.

Link: https://lkml.kernel.org/r/[e-mail]
Reviewed-by: Yang Shi <[e-mail]>
Acked-by: David Hildenbrand <[e-mail]>
Signed-off-by: Miaohe Lin <[e-mail]>
Cc: Alexey Dobriyan <[e-mail]>
Cc: "Aneesh Kumar K . V" <[e-mail]>
Cc: Anshuman Khandual <[e-mail]>
Cc: Hugh Dickins <[e-mail]>
Cc: Johannes Weiner <[e-mail]>
Cc: Kirill A. Shutemov <[e-mail]>
Cc: Matthew Wilcox <[e-mail]>
Cc: Minchan Kim <[e-mail]>
Cc: Ralph Campbell <[e-mail]>
Cc: Rik van Riel <[e-mail]>
Cc: Song Liu <[e-mail]>
Cc: William Kucharski <[e-mail]>
Cc: Zi Yan <[e-mail]>
Cc: Mike Kravetz <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/huge_memory.c |    3 ---
 1 file changed, 3 deletions(-)

Patch

--- a/mm/huge_memory.c~mm-huge_memoryc-remove-unnecessary-tlb_remove_page_size-for-huge-zero-pmd
+++ a/mm/huge_memory.c
@@ -1686,12 +1686,9 @@  int zap_huge_pmd(struct mmu_gather *tlb,
 		if (arch_needs_pgtable_deposit())
 			zap_deposited_table(tlb->mm, pmd);
 		spin_unlock(ptl);
-		if (is_huge_zero_pmd(orig_pmd))
-			tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE);
 	} else if (is_huge_zero_pmd(orig_pmd)) {
 		zap_deposited_table(tlb->mm, pmd);
 		spin_unlock(ptl);
-		tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE);
 	} else {
 		struct page *page = NULL;
 		int flush_needed = 1;