+ mm-huge_memory-fix-page_trans_huge_mapcount-assumption-of-thp-size.patch added to -mm tree

+ mm-huge_memory-fix-page_trans_huge_mapcount-assumption-of-thp-size.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm/huge_memory: fix page_trans_huge_mapcount assumption of THP size
has been added to the -mm tree.  Its filename is
     mm-huge_memory-fix-page_trans_huge_mapcount-assumption-of-thp-size.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-huge_memory-fix-page_trans_huge_mapcount-assumption-of-thp-size.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-huge_memory-fix-page_trans_huge_mapcount-assumption-of-thp-size.patch

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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: mm/huge_memory: fix page_trans_huge_mapcount assumption of THP size

Ask the page what size it is instead of assuming it's PMD size.

Link: https://lkml.kernel.org/r/20200908195539.25896-7-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/huge_memory.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/mm/huge_memory.c~mm-huge_memory-fix-page_trans_huge_mapcount-assumption-of-thp-size
+++ a/mm/huge_memory.c
@@ -2529,14 +2529,14 @@ int page_trans_huge_mapcount(struct page
 	page = compound_head(page);
 
 	_total_mapcount = ret = 0;
-	for (i = 0; i < HPAGE_PMD_NR; i++) {
+	for (i = 0; i < thp_nr_pages(page); i++) {
 		mapcount = atomic_read(&page[i]._mapcount) + 1;
 		ret = max(ret, mapcount);
 		_total_mapcount += mapcount;
 	}
 	if (PageDoubleMap(page)) {
 		ret -= 1;
-		_total_mapcount -= HPAGE_PMD_NR;
+		_total_mapcount -= thp_nr_pages(page);
 	}
 	mapcount = compound_mapcount(page);
 	ret += mapcount;
_

Patches currently in -mm which might be from willy@infradead.org are

mm-debug-do-not-dereference-i_ino-blindly.patch
mm-account-pmd-tables-like-pte-tables.patch
mm-move-pagedoublemap-bit.patch
mm-simplify-pagedoublemap-with-pf_second-policy.patch
xarray-add-xa_get_order.patch
xarray-add-xas_split.patch
mm-filemap-fix-storing-to-a-thp-shadow-entry.patch
mm-filemap-fix-page-cache-removal-for-arbitrary-sized-thps.patch
mm-memory-remove-page-fault-assumption-of-compound-page-size.patch
mm-page_owner-change-split_page_owner-to-take-a-count.patch
mm-huge_memory-fix-page_trans_huge_mapcount-assumption-of-thp-size.patch
mm-huge_memory-fix-can_split_huge_page-assumption-of-thp-size.patch
mm-rmap-fix-assumptions-of-thp-size.patch
mm-truncate-fix-truncation-for-pages-of-arbitrary-size.patch
mm-page-writeback-support-tail-pages-in-wait_for_stable_page.patch
mm-vmscan-allow-arbitrary-sized-pages-to-be-paged-out.patch
mm-readahead-add-define_readahead.patch
mm-readahead-make-page_cache_ra_unbounded-take-a-readahead_control.patch
mm-readahead-make-do_page_cache_ra-take-a-readahead_control.patch
mm-readahead-add-page_cache_sync_ra-and-page_cache_async_ra.patch
harden-autofs-ioctl-table.patch