mm: shmem: fix ShmemHugePages at swapout

/proc/meminfo ShmemHugePages has been showing overlarge amounts (more than
Shmem) after swapping out THPs: we forgot to update NR_SHMEM_THPS.

Add shmem_update_stats(), to avoid repetition, and risk of making that
mistake again: the call from shmem_delete_from_page_cache() is the bugfix;
the call from shmem_replace_folio() is reassuring, but not really a bugfix
(replace corrects misplaced swapin readahead, but huge swapin readahead
would be a mistake).

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 809bc86517cc ("mm: shmem: support large folio swap out")
Signed-off-by: Hugh Dickins <[email protected]>
Reviewed-by: Shakeel Butt <[email protected]>
Reviewed-by: Yosry Ahmed <[email protected]>
Reviewed-by: Baolin Wang <[email protected]>
Tested-by: Baolin Wang <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions