[PATCHv6 29/30] khugepaged: move up_read(mmap_sem) out of khugepaged_alloc_page()

[Kirill A. Shutemov]

Both variants of khugepaged_alloc_page() do up_read(&mm->mmap_sem)
first: no point keep it inside the function.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
 mm/khugepaged.c | 25 ++++++++++---------------
 1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index ef229cdfe5b7..c4693fd12f76 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -736,19 +736,10 @@ static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
 }
 
 static struct page *
-khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm,
-		       unsigned long address, int node)
+khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node)
 {
 	VM_BUG_ON_PAGE(*hpage, *hpage);
 
-	/*
-	 * Before allocating the hugepage, release the mmap_sem read lock.
-	 * The allocation can take potentially a long time if it involves
-	 * sync compaction, and we do not need to hold the mmap_sem during
-	 * that. We will recheck the vma after taking it again in write mode.
-	 */
-	up_read(&mm->mmap_sem);
-
 	*hpage = __alloc_pages_node(node, gfp, HPAGE_PMD_ORDER);
 	if (unlikely(!*hpage)) {
 		count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
@@ -809,10 +800,8 @@ static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
 }
 
 static struct page *
-khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm,
-		       unsigned long address, int node)
+khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node)
 {
-	up_read(&mm->mmap_sem);
 	VM_BUG_ON(!*hpage);
 
 	return  *hpage;
@@ -896,8 +885,14 @@ static void collapse_huge_page(struct mm_struct *mm,
 	/* Only allocate from the target node */
 	gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_OTHER_NODE | __GFP_THISNODE;
 
-	/* release the mmap_sem read lock. */
-	new_page = khugepaged_alloc_page(hpage, gfp, mm, address, node);
+	/*
+	 * Before allocating the hugepage, release the mmap_sem read lock.
+	 * The allocation can take potentially a long time if it involves
+	 * sync compaction, and we do not need to hold the mmap_sem during
+	 * that. We will recheck the vma after taking it again in write mode.
+	 */
+	up_read(&mm->mmap_sem);
+	new_page = khugepaged_alloc_page(hpage, gfp, node);
 	if (!new_page) {
 		result = SCAN_ALLOC_HUGE_PAGE_FAIL;
 		goto out_nolock;
-- 
2.8.0.rc3