linux-kernel - [PATCH v2 4/5] mm/huge_memory.c: remove unnecessary tlb_remove_page

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Date:   Thu, 29 Apr 2021 21:26:47 +0800
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     <akpm@...ux-foundation.org>
CC:     <ziy@...dia.com>, <william.kucharski@...cle.com>,
        <willy@...radead.org>, <yang.shi@...ux.alibaba.com>,
        <aneesh.kumar@...ux.ibm.com>, <rcampbell@...dia.com>,
        <songliubraving@...com>, <kirill.shutemov@...ux.intel.com>,
        <riel@...riel.com>, <hannes@...xchg.org>, <minchan@...nel.org>,
        <linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>,
        <linmiaohe@...wei.com>
Subject: [PATCH v2 4/5] 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.

Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
---
 mm/huge_memory.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index e24a96de2e37..af30338ac49c 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1680,12 +1680,9 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		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;
-- 
2.23.0