On Tue, Nov 24, 2015 at 01:29:41PM +0900, Sergey Senozhatsky wrote:
> Hello,
>
> On (11/20/15 12:31), Vladimir Davydov wrote:
> [..]
> > - if (ptep_clear_flush_young_notify(vma, address, pte)) {
> > - /*
> > - * Don't treat a reference through a sequentially read
> > - * mapping as such. If the page has been used in
> > - * another mapping, we will catch it; if this other
> > - * mapping is already gone, the unmap path will have
> > - * set PG_referenced or activated the page.
> > - */
> > - if (likely(!(vma->vm_flags & VM_SEQ_READ)))
> > + if (pte) {
> > + if (ptep_clear_flush_young_notify(vma, address, pte)) {
> > + /*
> > + * Don't treat a reference through a sequentially read
> > + * mapping as such. If the page has been used in
> > + * another mapping, we will catch it; if this other
> > + * mapping is already gone, the unmap path will have
> > + * set PG_referenced or activated the page.
> > + */
> > + if (likely(!(vma->vm_flags & VM_SEQ_READ)))
> > + referenced++;
> > + }
> > + pte_unmap(pte);
> > + } else {
> > + if (pmdp_clear_flush_young_notify(vma, address, pmd))
> > referenced++;
> > }
>
> # CONFIG_TRANSPARENT_HUGEPAGE is not set
>
> x86_64, 4.4.0-rc2-mm1
>
>
> mm/built-in.o: In function `page_referenced_one':
> rmap.c:(.text+0x32070): undefined reference to `pmdp_clear_flush_young'
Something like this?
diff --git a/mm/page_idle.c b/mm/page_idle.c
index 374931f32ebc..4ea9c4ef5146 100644
--- a/mm/page_idle.c
+++ b/mm/page_idle.c
@@ -66,8 +66,12 @@ static int page_idle_clear_pte_refs_one(struct page *page,
if (pte) {
referenced = ptep_clear_young_notify(vma, addr, pte);
pte_unmap(pte);
- } else
+ } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
referenced = pmdp_clear_young_notify(vma, addr, pmd);
+ } else {
+ /* unexpected pmd-mapped page? */
+ WARN_ON_ONCE(1);
+ }
spin_unlock(ptl);
diff --git a/mm/rmap.c b/mm/rmap.c
index 27916086ac50..499b24511b1f 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -929,9 +929,12 @@ static int page_referenced_one(struct page *page, struct vm_area_struct *vma,
referenced++;
}
pte_unmap(pte);
- } else {
+ } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
if (pmdp_clear_flush_young_notify(vma, address, pmd))
referenced++;
+ } else {
+ /* unexpected pmd-mapped page? */
+ WARN_ON_ONCE(1);
}
spin_unlock(ptl);
--
Kirill A. Shutemov
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