5.15-stable review patch. If anyone has any objections, please let me know.
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From: David Hildenbrand david@redhat.com
[ Upstream commit 3f9f022e975d930709848a86a1c79775b0585202 ]
Patch series "fs/proc: move page_mapcount() to fs/proc/internal.h".
With all other page_mapcount() users in the tree gone, move page_mapcount() to fs/proc/internal.h, rename it and extend the documentation to prevent future (ab)use.
... of course, I find some issues while working on that code that I sort first ;)
We'll now only end up calling page_mapcount() [now folio_precise_page_mapcount()] on pages mapped via present page table entries. Except for /proc/kpagecount, that still does questionable things, but we'll leave that legacy interface as is for now.
Did a quick sanity check. Likely we would want some better selfestest for /proc/$/pagemap + smaps. I'll see if I can find some time to write some more.
This patch (of 6):
Looks like we never taught pagemap_pmd_range() about the existence of PMD-mapped file THPs. Seems to date back to the times when we first added support for non-anon THPs in the form of shmem THP.
Link: https://lkml.kernel.org/r/20240607122357.115423-1-david@redhat.com Link: https://lkml.kernel.org/r/20240607122357.115423-2-david@redhat.com Signed-off-by: David Hildenbrand david@redhat.com Fixes: 800d8c63b2e9 ("shmem: add huge pages support") Acked-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Reviewed-by: Lance Yang ioworker0@gmail.com Reviewed-by: Oscar Salvador osalvador@suse.de Cc: David Hildenbrand david@redhat.com Cc: Jonathan Corbet corbet@lwn.net Cc: Alexey Dobriyan adobriyan@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/proc/task_mmu.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 705a41f4d6b36..b255e3dfded14 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1471,6 +1471,8 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end, } #endif
+ if (page && !PageAnon(page)) + flags |= PM_FILE; if (page && !migration && page_mapcount(page) == 1) flags |= PM_MMAP_EXCLUSIVE;