linux-kernel - [v2 PATCH 6/8] mm: khugepaged: move some khugepaged

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Date:   Thu, 17 Mar 2022 16:48:25 -0700
From:   Yang Shi <shy828301@...il.com>
To:     vbabka@...e.cz, kirill.shutemov@...ux.intel.com,
        linmiaohe@...wei.com, songliubraving@...com, riel@...riel.com,
        willy@...radead.org, ziy@...dia.com, akpm@...ux-foundation.org,
        tytso@....edu, adilger.kernel@...ger.ca, darrick.wong@...cle.com
Cc:     shy828301@...il.com, linux-mm@...ck.org,
        linux-fsdevel@...r.kernel.org, linux-ext4@...r.kernel.org,
        linux-xfs@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [v2 PATCH 6/8] mm: khugepaged: move some khugepaged_* functions to khugepaged.c

This move also makes the following patches easier.  The following patches
will call khugepaged_enter() for regular filesystems to make readonly FS
THP collapse more consistent.  They need to use some macros defined in
huge_mm.h, for example, HPAGE_PMD_*, but it seems not preferred to
polute filesystems code with including unnecessary header files.  With
this move the filesystems code just need include khugepaged.h, which is
quite small and the use is quite specific, to call khugepaged_enter()
to hook mm with khugepaged.

And the khugepaged_* functions actually are wrappers for some non-inline
functions, so it seems the benefits are not too much to keep them inline.

This also helps to reuse hugepage_vma_check() for khugepaged_enter() so
that we could remove some duplicate checks.

Signed-off-by: Yang Shi <shy828301@...il.com>
---
 include/linux/khugepaged.h | 33 ++++++---------------------------
 mm/khugepaged.c            | 20 ++++++++++++++++++++
 2 files changed, 26 insertions(+), 27 deletions(-)

diff --git a/include/linux/khugepaged.h b/include/linux/khugepaged.h
index 0423d3619f26..54e169116d49 100644
--- a/include/linux/khugepaged.h
+++ b/include/linux/khugepaged.h
@@ -16,6 +16,12 @@ 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_fork(struct mm_struct *mm,
+			    struct mm_struct *oldmm);
+extern void khugepaged_exit(struct mm_struct *mm);
+extern void khugepaged_enter(struct vm_area_struct *vma,
+			     unsigned long vm_flags);
+
 extern void khugepaged_min_free_kbytes_update(void);
 #ifdef CONFIG_SHMEM
 extern void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr);
@@ -33,36 +39,9 @@ static inline void collapse_pte_mapped_thp(struct mm_struct *mm,
 #define khugepaged_always()				\
 	(transparent_hugepage_flags &			\
 	 (1<<TRANSPARENT_HUGEPAGE_FLAG))
-#define khugepaged_req_madv()					\
-	(transparent_hugepage_flags &				\
-	 (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG))
 #define khugepaged_defrag()					\
 	(transparent_hugepage_flags &				\
 	 (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG))
-
-static inline void khugepaged_fork(struct mm_struct *mm, struct mm_struct *oldmm)
-{
-	if (test_bit(MMF_VM_HUGEPAGE, &oldmm->flags))
-		__khugepaged_enter(mm);
-}
-
-static inline void khugepaged_exit(struct mm_struct *mm)
-{
-	if (test_bit(MMF_VM_HUGEPAGE, &mm->flags))
-		__khugepaged_exit(mm);
-}
-
-static inline void khugepaged_enter(struct vm_area_struct *vma,
-				   unsigned long vm_flags)
-{
-	if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags))
-		if ((khugepaged_always() ||
-		     (shmem_file(vma->vm_file) && shmem_huge_enabled(vma)) ||
-		     (khugepaged_req_madv() && (vm_flags & VM_HUGEPAGE))) &&
-		    !(vm_flags & VM_NOHUGEPAGE) &&
-		    !test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
-			__khugepaged_enter(vma->vm_mm);
-}
 #else /* CONFIG_TRANSPARENT_HUGEPAGE */
 static inline void khugepaged_fork(struct mm_struct *mm, struct mm_struct *oldmm)
 {
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index b87af297e652..4cb4379ecf25 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -557,6 +557,26 @@ void __khugepaged_exit(struct mm_struct *mm)
 	}
 }
 
+void khugepaged_fork(struct mm_struct *mm, struct mm_struct *oldmm)
+{
+	if (test_bit(MMF_VM_HUGEPAGE, &oldmm->flags))
+		__khugepaged_enter(mm);
+}
+
+void khugepaged_exit(struct mm_struct *mm)
+{
+	if (test_bit(MMF_VM_HUGEPAGE, &mm->flags))
+		__khugepaged_exit(mm);
+}
+
+void khugepaged_enter(struct vm_area_struct *vma, unsigned long vm_flags)
+{
+	if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
+	    khugepaged_enabled())
+		if (hugepage_vma_check(vma, vm_flags))
+			__khugepaged_enter(vma->vm_mm);
+}
+
 static void release_pte_page(struct page *page)
 {
 	mod_node_page_state(page_pgdat(page),
-- 
2.26.3