mm: thp: kill transparent_hugepage_active()

The transparent_hugepage_active() was introduced to show THP eligibility
bit in smaps in proc, smaps is the only user.  But it actually does the
similar check as hugepage_vma_check() which is used by khugepaged.  We
definitely don't have to maintain two similar checks, so kill
transparent_hugepage_active().

This patch also fixed the wrong behavior for VM_NO_KHUGEPAGED vmas.

Also move hugepage_vma_check() to huge_memory.c and huge_mm.h since it
is not only for khugepaged anymore.

[akpm@linux-foundation.org: check vma->vm_mm, per Zach]
[akpm@linux-foundation.org: add comment to vdso check]
Link: https://lkml.kernel.org/r/20220616174840.1202070-5-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zach O'Keefe <zokeefe@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 4 insertions, 44 deletions

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 67e144e64b7f..6bbf3adac534 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -430,46 +430,6 @@ static inline int khugepaged_test_exit(struct mm_struct *mm)
 	return atomic_read(&mm->mm_users) == 0;
 }
 
-bool hugepage_vma_check(struct vm_area_struct *vma,
-			unsigned long vm_flags)
-{
-	if (!transhuge_vma_enabled(vma, vm_flags))
-		return false;
-
-	if (vm_flags & VM_NO_KHUGEPAGED)
-		return false;
-
-	/* Don't run khugepaged against DAX vma */
-	if (vma_is_dax(vma))
-		return false;
-
-	/* Check alignment for file vma and size for both file and anon vma */
-	if (!transhuge_vma_suitable(vma, (vma->vm_end - HPAGE_PMD_SIZE)))
-		return false;
-
-	/* Enabled via shmem mount options or sysfs settings. */
-	if (shmem_file(vma->vm_file))
-		return shmem_huge_enabled(vma);
-
-	if (!khugepaged_enabled())
-		return false;
-
-	/* THP settings require madvise. */
-	if (!(vm_flags & VM_HUGEPAGE) && !khugepaged_always())
-		return false;
-
-	/* Only regular file is valid */
-	if (file_thp_enabled(vma))
-		return true;
-
-	if (!vma->anon_vma || !vma_is_anonymous(vma))
-		return false;
-	if (vma_is_temporary_stack(vma))
-		return false;
-
-	return true;
-}
-
 void __khugepaged_enter(struct mm_struct *mm)
 {
 	struct mm_slot *mm_slot;
@@ -506,7 +466,7 @@ void khugepaged_enter_vma(struct vm_area_struct *vma,
 {
 	if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
 	    khugepaged_enabled()) {
-		if (hugepage_vma_check(vma, vm_flags))
+		if (hugepage_vma_check(vma, vm_flags, false))
 			__khugepaged_enter(vma->vm_mm);
 	}
 }
@@ -956,7 +916,7 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address,
 
 	if (!transhuge_vma_suitable(vma, address))
 		return SCAN_ADDRESS_RANGE;
-	if (!hugepage_vma_check(vma, vma->vm_flags))
+	if (!hugepage_vma_check(vma, vma->vm_flags, false))
 		return SCAN_VMA_CHECK;
 	/*
 	 * Anon VMA expected, the address may be unmapped then
@@ -1441,7 +1401,7 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
 	 * the valid THP. Add extra VM_HUGEPAGE so hugepage_vma_check()
 	 * will not fail the vma for missing VM_HUGEPAGE
 	 */
-	if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE))
+	if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE, false))
 		return;
 
 	/* Keep pmd pgtable for uffd-wp; see comment in retract_page_tables() */
@@ -2131,7 +2091,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
 			progress++;
 			break;
 		}
-		if (!hugepage_vma_check(vma, vma->vm_flags)) {
+		if (!hugepage_vma_check(vma, vma->vm_flags, false)) {
 skip:
 			progress++;
 			continue;