On Fri, Mar 03, 2017 at 01:35:11PM +0800, Hillf Danton wrote:
>
> On March 02, 2017 11:11 PM Kirill A. Shutemov wrote:
> >
> > Basically the same race as with numa balancing in change_huge_pmd(), but
> > a bit simpler to mitigate: we don't need to preserve dirty/young flags
> > here due to MADV_FREE functionality.
> >
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> > Cc: Minchan Kim <minchan@xxxxxxxxxx>
> > ---
> > mm/huge_memory.c | 2 --
> > 1 file changed, 2 deletions(-)
> >
> > diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> > index bb2b3646bd78..324217c31ec9 100644
> > --- a/mm/huge_memory.c
> > +++ b/mm/huge_memory.c
> > @@ -1566,8 +1566,6 @@ bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
> > deactivate_page(page);
> >
> > if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) {
> > - orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd,
> > - tlb->fullmm);
> > orig_pmd = pmd_mkold(orig_pmd);
> > orig_pmd = pmd_mkclean(orig_pmd);
> >
> $ grep -n set_pmd_at linux-4.10/arch/powerpc/mm/pgtable-book3s64.c
>
> /*
> * set a new huge pmd. We should not be called for updating
> * an existing pmd entry. That should go via pmd_hugepage_update.
> */
> void set_pmd_at(struct mm_struct *mm, unsigned long addr,
+Aneesh.
Urgh... Power is special again.
I think this should work fine.
>From 056914fa025992c0a2212aee057c26307ce60238 Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Date: Thu, 2 Mar 2017 16:47:45 +0300
Subject: [PATCH] thp: fix MADV_DONTNEED vs. MADV_FREE race
Basically the same race as with numa balancing in change_huge_pmd(), but
a bit simpler to mitigate: we don't need to preserve dirty/young flags
here due to MADV_FREE functionality.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
---
mm/huge_memory.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index bb2b3646bd78..23c1b3d58cf4 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1566,8 +1566,7 @@ bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
deactivate_page(page);
if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) {
- orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd,
- tlb->fullmm);
+ pmdp_invalidate(vma, addr, pmd);
orig_pmd = pmd_mkold(orig_pmd);
orig_pmd = pmd_mkclean(orig_pmd);
--
Kirill A. Shutemov
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