On Tue, Sep 24, 2019 at 05:52:11PM -0700, Matthew Wilcox wrote: > From: William Kucharski <william.kucharski@xxxxxxxxxx> > > __remove_mapping() assumes that pages can only be either base pages > or HPAGE_PMD_SIZE. Ask the page what size it is. You also fixes the issue CONFIG_READ_ONLY_THP_FOR_FS=y with this patch. The new feature makes the refcount calculation relevant not only for PageSwapCache(). It should go to v5.4. > > Signed-off-by: William Kucharski <william.kucharski@xxxxxxxxxx> > Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> > --- > mm/vmscan.c | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index a7f9f379e523..9f44868e640b 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -932,10 +932,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page, > * Note that if SetPageDirty is always performed via set_page_dirty, > * and thus under the i_pages lock, then this ordering is not required. > */ > - if (unlikely(PageTransHuge(page)) && PageSwapCache(page)) > - refcount = 1 + HPAGE_PMD_NR; > - else > - refcount = 2; > + refcount = 1 + compound_nr(page); > if (!page_ref_freeze(page, refcount)) > goto cannot_free; > /* note: atomic_cmpxchg in page_ref_freeze provides the smp_rmb */ > -- > 2.23.0 > > -- Kirill A. Shutemov
