[PATCH v4 0/3] introduce kernel file mapped folios

[Boris Burkov <boris@bur.io>]

I would like to revisit Qu's proposal to not charge btrfs extent_buffer
allocations to the user's cgroup.

https://lore.kernel.org/linux-mm/b5fef5372ae454a7b6da4f2f75c427aeab6a07d6.1727498749.git.wqu@suse.com/

I believe it is detrimental to account these global pages to the cgroup
using them, basically at random. A bit more justification and explanation
in the patches themselves.

---
Changelog:
v4:
- change the concept from "uncharged" to "kernel_file"
- no longer violates the invariant that each mapped folio has a memcg
  when CONFIG_MEMCG=y
- no longer really tied to memcg conceptually, so simplify build/helpers
v3:
- use mod_node_page_state since we will never count cgroup stats
- include Shakeel's patch that removes a WARNING triggered by this series
v2:
- switch from filemap_add_folio_nocharge() to AS_UNCHARGED on the
  address_space.
- fix an interrupt safety bug in the vmstat patch.
- fix some foolish build errors for CONFIG_MEMCG=n



Boris Burkov (3):
  mm/filemap: add AS_KERNEL_FILE
  mm: add vmstat for kernel_file pages
  btrfs: set AS_KERNEL_FILE on the btree_inode

 fs/btrfs/disk-io.c      |  1 +
 include/linux/mmzone.h  |  1 +
 include/linux/pagemap.h |  2 ++
 mm/filemap.c            | 13 +++++++++++++
 mm/vmstat.c             |  1 +
 5 files changed, 18 insertions(+)

-- 
2.50.1