On Wed, Aug 10, 2022 at 02:24:33PM +0800, Huang, Ying wrote: > Peter Xu <peterx@xxxxxxxxxx> writes: > > > Carry over the dirty bit from pmd to pte when a huge pmd splits. It > > shouldn't be a correctness issue since when pmd_dirty() we'll have the page > > marked dirty anyway, however having dirty bit carried over helps the next > > initial writes of split ptes on some archs like x86. > > > > Signed-off-by: Peter Xu <peterx@xxxxxxxxxx> > > --- > > mm/huge_memory.c | 6 +++++- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > > index 0611b2fd145a..e8e78d1bac5f 100644 > > --- a/mm/huge_memory.c > > +++ b/mm/huge_memory.c > > @@ -2005,7 +2005,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, > > pgtable_t pgtable; > > pmd_t old_pmd, _pmd; > > bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; > > - bool anon_exclusive = false; > > + bool anon_exclusive = false, dirty = false; > > unsigned long addr; > > int i; > > > > @@ -2098,6 +2098,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, > > SetPageDirty(page); > > write = pmd_write(old_pmd); > > young = pmd_young(old_pmd); > > + dirty = pmd_dirty(old_pmd); > > Nitpick: This can be put under > > if (pmd_dirty(old_pmd)) > SetPageDirty(page); > > Not a big deal. > > Reviewed-by: "Huang, Ying" <ying.huang@xxxxxxxxx> Yeah will do, thanks. -- Peter Xu
