+ mm-shmem-shmem_replace_page-remember-nr_shmem.patch added to mm-hotfixes-unstable branch

+ mm-shmem-shmem_replace_page-remember-nr_shmem.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm/shmem: shmem_replace_page() remember NR_SHMEM
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-shmem-shmem_replace_page-remember-nr_shmem.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-shmem-shmem_replace_page-remember-nr_shmem.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Hugh Dickins <hughd@google.com>
Subject: mm/shmem: shmem_replace_page() remember NR_SHMEM
Date: Wed, 10 Aug 2022 22:06:33 -0700 (PDT)

Elsewhere, NR_SHMEM is updated at the same time as shmem NR_FILE_PAGES;
but shmem_replace_page() was forgetting to do that - so NR_SHMEM stats
could grow too big or too small, in those unusual cases when it's used.

Link: https://lkml.kernel.org/r/cec7c09d-5874-e160-ada6-6e10ee48784@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Radoslaw Burny <rburny@google.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/shmem.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/mm/shmem.c~mm-shmem-shmem_replace_page-remember-nr_shmem
+++ a/mm/shmem.c
@@ -1659,7 +1659,9 @@ static int shmem_replace_page(struct pag
 		new = page_folio(newpage);
 		mem_cgroup_migrate(old, new);
 		__inc_lruvec_page_state(newpage, NR_FILE_PAGES);
+		__inc_lruvec_page_state(newpage, NR_SHMEM);
 		__dec_lruvec_page_state(oldpage, NR_FILE_PAGES);
+		__dec_lruvec_page_state(oldpage, NR_SHMEM);
 	}
 	xa_unlock_irq(&swap_mapping->i_pages);
 
_

Patches currently in -mm which might be from hughd@google.com are

mm-shmem-fix-chattr-fsflags-support-in-tmpfs.patch
mm-shmem-tmpfs-fallocate-use-file_modified.patch
mm-shmem-shmem_replace_page-remember-nr_shmem.patch