linux-kernel - [PATCH 4/9] huge tmpfs: revert shmem's use of transhuge_vma

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Date:   Tue, 17 Aug 2021 01:12:34 -0700 (PDT)
From:   Hugh Dickins <hughd@...gle.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
cc:     Hugh Dickins <hughd@...gle.com>,
        Shakeel Butt <shakeelb@...gle.com>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Yang Shi <shy828301@...il.com>,
        Miaohe Lin <linmiaohe@...wei.com>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Michal Hocko <mhocko@...e.com>,
        Rik van Riel <riel@...riel.com>,
        Matthew Wilcox <willy@...radead.org>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH 4/9] huge tmpfs: revert shmem's use of
 transhuge_vma_enabled()

5.14 commit e6be37b2e7bd ("mm/huge_memory.c: add missing read-only THP
checking in transparent_hugepage_enabled()") added transhuge_vma_enabled()
as a wrapper for two very different checks (one check is whether the app
has marked its address range not to use THPs, the other check is whether
the app is running in a hierarchy that has been marked never to use THPs).
shmem_huge_enabled() prefers to show those two checks explicitly,
as before.

Signed-off-by: Hugh Dickins <hughd@...gle.com>
Reviewed-by: Yang Shi <shy828301@...il.com>
---
 mm/shmem.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index ce3ccaac54d6..c6fa6f4f2db8 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -4003,7 +4003,8 @@ bool shmem_huge_enabled(struct vm_area_struct *vma)
 	loff_t i_size;
 	pgoff_t off;
 
-	if (!transhuge_vma_enabled(vma, vma->vm_flags))
+	if ((vma->vm_flags & VM_NOHUGEPAGE) ||
+	    test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
 		return false;
 	if (shmem_huge == SHMEM_HUGE_FORCE)
 		return true;
-- 
2.26.2