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| author | David Hildenbrand <david@redhat.com> | 2024-06-07 14:23:54 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-08-03 08:54:09 +0200 |
| commit | 8acbcc5067acbd3cdd22efcbb58f451d1a32918c (patch) | |
| tree | 4f94059663f1f690929e7d745b40431e989a5b21 /fs/nilfs2/segment.c | |
| parent | cdeba6d1cfb100c58162eb0e9634ad8fbf5ae24b (diff) | |
fs/proc/task_mmu: properly detect PM_MMAP_EXCLUSIVE per page of PMD-mapped THPs
[ Upstream commit 2c1f057e5be63e890f2dd89e4c25ab5eef084a91 ]
We added PM_MMAP_EXCLUSIVE in 2015 via commit 77bb499bb60f ("pagemap: add
mmap-exclusive bit for marking pages mapped only here"), when THPs could
not be partially mapped and page_mapcount() returned something that was
true for all pages of the THP.
In 2016, we added support for partially mapping THPs via commit
53f9263baba6 ("mm: rework mapcount accounting to enable 4k mapping of
THPs") but missed to determine PM_MMAP_EXCLUSIVE as well per page.
Checking page_mapcount() on the head page does not tell the whole story.
We should check each individual page. In a future without per-page
mapcounts it will be different, but we'll change that to be consistent
with PTE-mapped THPs once we deal with that.
Link: https://lkml.kernel.org/r/20240607122357.115423-4-david@redhat.com
Fixes: 53f9263baba6 ("mm: rework mapcount accounting to enable 4k mapping of THPs")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <ioworker0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs/nilfs2/segment.c')
0 files changed, 0 insertions, 0 deletions