thp: keep highpte mapped until it is no longer needed

[platform/adaptation/renesas_rcar/renesas_kernel.git] / mm / huge_memory.c

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index fce667c..c4f634b 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1389,7 +1389,8 @@ out:
        return ret;
 }
 
-int hugepage_madvise(unsigned long *vm_flags, int advice)
+int hugepage_madvise(struct vm_area_struct *vma,
+                    unsigned long *vm_flags, int advice)
 {
        switch (advice) {
        case MADV_HUGEPAGE:
@@ -1404,6 +1405,13 @@ int hugepage_madvise(unsigned long *vm_flags, int advice)
                        return -EINVAL;
                *vm_flags &= ~VM_NOHUGEPAGE;
                *vm_flags |= VM_HUGEPAGE;
+               /*
+                * If the vma become good for khugepaged to scan,
+                * register it here without waiting a page fault that
+                * may not happen any time soon.
+                */
+               if (unlikely(khugepaged_enter_vma_merge(vma)))
+                       return -ENOMEM;
                break;
        case MADV_NOHUGEPAGE:
                /*
@@ -1417,6 +1425,11 @@ int hugepage_madvise(unsigned long *vm_flags, int advice)
                        return -EINVAL;
                *vm_flags &= ~VM_HUGEPAGE;
                *vm_flags |= VM_NOHUGEPAGE;
+               /*
+                * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning
+                * this vma even if we leave the mm registered in khugepaged if
+                * it got registered before VM_NOHUGEPAGE was set.
+                */
                break;
        }
 
@@ -1784,7 +1797,8 @@ static void collapse_huge_page(struct mm_struct *mm,
        if (address < hstart || address + HPAGE_PMD_SIZE > hend)
                goto out;
 
-       if (!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always())
+       if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) ||
+           (vma->vm_flags & VM_NOHUGEPAGE))
                goto out;
 
        /* VM_PFNMAP vmas may have vm_ops null but vm_file set */
@@ -1823,9 +1837,9 @@ static void collapse_huge_page(struct mm_struct *mm,
        spin_lock(ptl);
        isolated = __collapse_huge_page_isolate(vma, address, pte);
        spin_unlock(ptl);
-       pte_unmap(pte);
 
        if (unlikely(!isolated)) {
+               pte_unmap(pte);
                spin_lock(&mm->page_table_lock);
                BUG_ON(!pmd_none(*pmd));
                set_pmd_at(mm, address, pmd, _pmd);
@@ -1842,6 +1856,7 @@ static void collapse_huge_page(struct mm_struct *mm,
        anon_vma_unlock(vma->anon_vma);
 
        __collapse_huge_page_copy(pte, new_page, vma, address, ptl);
+       pte_unmap(pte);
        __SetPageUptodate(new_page);
        pgtable = pmd_pgtable(_pmd);
        VM_BUG_ON(page_count(pgtable) != 1);
@@ -2007,8 +2022,9 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
                        break;
                }
 
-               if (!(vma->vm_flags & VM_HUGEPAGE) &&
-                   !khugepaged_always()) {
+               if ((!(vma->vm_flags & VM_HUGEPAGE) &&
+                    !khugepaged_always()) ||
+                   (vma->vm_flags & VM_NOHUGEPAGE)) {
                        progress++;
                        continue;
                }