diff options
| author | Boris Burkov <boris@bur.io> | 2025-08-21 14:55:36 -0700 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-09-13 16:55:20 -0700 |
| commit | e3a9ac4e866ea746475b4026819a8c08ec1142e6 (patch) | |
| tree | 56ebc8ed1f9d68fbe783b5a907a45b9cd7977b27 /mm/filemap.c | |
| parent | cf1dec76ba8a00b20e51d205f3c9f5c45bc96df2 (diff) | |
| download | linux-e3a9ac4e866ea746475b4026819a8c08ec1142e6.tar.gz | |
mm: add vmstat for kernel_file pages
Kernel file pages are tricky to track because they are indistinguishable
from files whose usage is accounted to the root cgroup.
To maintain good accounting, introduce a vmstat counter tracking kernel
file pages.
Confirmed that these work as expected at a high level by mounting a btrfs
using AS_KERNEL_FILE for metadata pages, and seeing the counter rise with
fs usage then go back to a minimal level after drop_caches and finally
down to 0 after unmounting the fs.
Link: https://lkml.kernel.org/r/08ff633e3a005ed5f7691bfd9f58a5df8e474339.1755812945.git.boris@bur.io
Signed-off-by: Boris Burkov <boris@bur.io>
Suggested-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Tested-by: syzbot@syzkaller.appspotmail.com
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qu Wenruo <wqu@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/filemap.c')
| -rw-r--r-- | mm/filemap.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 92ea20356f227d..cd9387b0a5b500 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -190,6 +190,9 @@ static void filemap_unaccount_folio(struct address_space *mapping, __lruvec_stat_mod_folio(folio, NR_FILE_THPS, -nr); filemap_nr_thps_dec(mapping); } + if (test_bit(AS_KERNEL_FILE, &folio->mapping->flags)) + mod_node_page_state(folio_pgdat(folio), + NR_KERNEL_FILE_PAGES, -nr); /* * At this point folio must be either written or cleaned by @@ -989,6 +992,10 @@ int filemap_add_folio(struct address_space *mapping, struct folio *folio, if (!(gfp & __GFP_WRITE) && shadow) workingset_refault(folio, shadow); folio_add_lru(folio); + if (kernel_file) + mod_node_page_state(folio_pgdat(folio), + NR_KERNEL_FILE_PAGES, + folio_nr_pages(folio)); } return ret; } |