From 3669686b475d32c439c104241775c3f5625d844a Mon Sep 17 00:00:00 2001
From: David Hildenbrand <david@redhat.com>
Date: Fri, 7 Jun 2024 14:23:52 +0200
Subject: [PATCH] fs/proc/task_mmu: indicate PM_FILE for PMD-mapped file THP
[ 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 a954305fbc31b..484886cdd272c 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1513,6 +1513,8 @@ 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;
--
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