The patch titled
Subject: mm/huge_memory: fix total_mapcount assumption of page size
has been added to the -mm tree. Its filename is
mm-huge_memory-fix-total_mapcount-assumption-of-page-size.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-huge_memory-fix-total_mapcount-assumption-of-page-size.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-huge_memory-fix-total_mapcount-assumption-of-page-size.patch
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------------------------------------------------------
From: "Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx>
Subject: mm/huge_memory: fix total_mapcount assumption of page size
File THPs may now be of arbitrary order.
Link: https://lkml.kernel.org/r/20200908195539.25896-5-willy@xxxxxxxxxxxxx
Signed-off-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Huang Ying <ying.huang@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
--- a/mm/huge_memory.c~mm-huge_memory-fix-total_mapcount-assumption-of-page-size
+++ a/mm/huge_memory.c
@@ -2465,7 +2465,7 @@ static void __split_huge_page(struct pag
int total_mapcount(struct page *page)
{
- int i, compound, ret;
+ int i, compound, nr, ret;
VM_BUG_ON_PAGE(PageTail(page), page);
@@ -2473,16 +2473,17 @@ int total_mapcount(struct page *page)
return atomic_read(&page->_mapcount) + 1;
compound = compound_mapcount(page);
+ nr = compound_nr(page);
if (PageHuge(page))
return compound;
ret = compound;
- for (i = 0; i < HPAGE_PMD_NR; i++)
+ for (i = 0; i < nr; i++)
ret += atomic_read(&page[i]._mapcount) + 1;
/* File pages has compound_mapcount included in _mapcount */
if (!PageAnon(page))
- return ret - compound * HPAGE_PMD_NR;
+ return ret - compound * nr;
if (PageDoubleMap(page))
- ret -= HPAGE_PMD_NR;
+ ret -= nr;
return ret;
}
_
Patches currently in -mm which might be from kirill@xxxxxxxxxxxxx are
mm-huge_memory-fix-total_mapcount-assumption-of-page-size.patch
mm-huge_memory-fix-split-assumption-of-page-size.patch
