[v3 PATCH 7/8] mm: khugepaged: introduce khugepaged_enter_vma() helper

[Yang Shi <shy828301@gmail.com>]

The khugepaged_enter_vma_merge() actually does as the same thing as the
khugepaged_enter() section called by shmem_mmap(), so consolidate them
into one helper and rename it to khugepaged_enter_vma().

Signed-off-by: Yang Shi <shy828301@gmail.com>
---
 include/linux/khugepaged.h |  8 ++++----
 mm/khugepaged.c            | 26 +++++++++-----------------
 mm/mmap.c                  |  8 ++++----
 mm/shmem.c                 | 12 ++----------
 4 files changed, 19 insertions(+), 35 deletions(-)

diff --git a/include/linux/khugepaged.h b/include/linux/khugepaged.h
index 6acf9701151e..f4b12be155ab 100644
--- a/include/linux/khugepaged.h
+++ b/include/linux/khugepaged.h
@@ -10,8 +10,8 @@ extern void khugepaged_destroy(void);
 extern int start_stop_khugepaged(void);
 extern void __khugepaged_enter(struct mm_struct *mm);
 extern void __khugepaged_exit(struct mm_struct *mm);
-extern void khugepaged_enter_vma_merge(struct vm_area_struct *vma,
-				       unsigned long vm_flags);
+extern void khugepaged_enter_vma(struct vm_area_struct *vma,
+				 unsigned long vm_flags);
 extern void khugepaged_fork(struct mm_struct *mm,
 			    struct mm_struct *oldmm);
 extern void khugepaged_exit(struct mm_struct *mm);
@@ -49,8 +49,8 @@ static inline void khugepaged_enter(struct vm_area_struct *vma,
 				    unsigned long vm_flags)
 {
 }
-static inline void khugepaged_enter_vma_merge(struct vm_area_struct *vma,
-					      unsigned long vm_flags)
+static inline void khugepaged_enter_vma(struct vm_area_struct *vma,
+					unsigned long vm_flags)
 {
 }
 static inline void collapse_pte_mapped_thp(struct mm_struct *mm,
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index ec5b0a691d87..c5c3202d7401 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -365,7 +365,7 @@ int hugepage_madvise(struct vm_area_struct *vma,
 		 * register it here without waiting a page fault that
 		 * may not happen any time soon.
 		 */
-		khugepaged_enter_vma_merge(vma, *vm_flags);
+		khugepaged_enter_vma(vma, *vm_flags);
 		break;
 	case MADV_NOHUGEPAGE:
 		*vm_flags &= ~VM_HUGEPAGE;
@@ -505,23 +505,15 @@ void __khugepaged_enter(struct mm_struct *mm)
 		wake_up_interruptible(&khugepaged_wait);
 }
 
-void khugepaged_enter_vma_merge(struct vm_area_struct *vma,
-			       unsigned long vm_flags)
+void khugepaged_enter_vma(struct vm_area_struct *vma,
+			  unsigned long vm_flags)
 {
-	unsigned long hstart, hend;
-
-	/*
-	 * khugepaged only supports read-only files for non-shmem files.
-	 * khugepaged does not yet work on special mappings. And
-	 * file-private shmem THP is not supported.
-	 */
-	if (!hugepage_vma_check(vma, vm_flags))
-		return;
-
-	hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
-	hend = vma->vm_end & HPAGE_PMD_MASK;
-	if (hstart < hend)
-		khugepaged_enter(vma, vm_flags);
+	if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
+	    khugepaged_enabled() &&
+	    (((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) <
+	     (vma->vm_end & HPAGE_PMD_MASK)))
+		if (hugepage_vma_check(vma, vm_flags))
+			__khugepaged_enter(vma->vm_mm);
 }
 
 void __khugepaged_exit(struct mm_struct *mm)
diff --git a/mm/mmap.c b/mm/mmap.c
index 3aa839f81e63..604c8dece5dd 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1218,7 +1218,7 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
 					 end, prev->vm_pgoff, NULL, prev);
 		if (err)
 			return NULL;
-		khugepaged_enter_vma_merge(prev, vm_flags);
+		khugepaged_enter_vma(prev, vm_flags);
 		return prev;
 	}
 
@@ -1245,7 +1245,7 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
 		}
 		if (err)
 			return NULL;
-		khugepaged_enter_vma_merge(area, vm_flags);
+		khugepaged_enter_vma(area, vm_flags);
 		return area;
 	}
 
@@ -2460,7 +2460,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
 		}
 	}
 	anon_vma_unlock_write(vma->anon_vma);
-	khugepaged_enter_vma_merge(vma, vma->vm_flags);
+	khugepaged_enter_vma(vma, vma->vm_flags);
 	validate_mm(mm);
 	return error;
 }
@@ -2538,7 +2538,7 @@ int expand_downwards(struct vm_area_struct *vma,
 		}
 	}
 	anon_vma_unlock_write(vma->anon_vma);
-	khugepaged_enter_vma_merge(vma, vma->vm_flags);
+	khugepaged_enter_vma(vma, vma->vm_flags);
 	validate_mm(mm);
 	return error;
 }
diff --git a/mm/shmem.c b/mm/shmem.c
index 529c9ad3e926..92eca974771d 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2239,11 +2239,7 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
 
 	file_accessed(file);
 	vma->vm_ops = &shmem_vm_ops;
-	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
-			((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) <
-			(vma->vm_end & HPAGE_PMD_MASK)) {
-		khugepaged_enter(vma, vma->vm_flags);
-	}
+	khugepaged_enter_vma(vma, vma->vm_flags);
 	return 0;
 }
 
@@ -4136,11 +4132,7 @@ int shmem_zero_setup(struct vm_area_struct *vma)
 	vma->vm_file = file;
 	vma->vm_ops = &shmem_vm_ops;
 
-	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
-			((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) <
-			(vma->vm_end & HPAGE_PMD_MASK)) {
-		khugepaged_enter(vma, vma->vm_flags);
-	}
+	khugepaged_enter_vma(vma, vma->vm_flags);
 
 	return 0;
 }
-- 
2.26.3