RFC mm/damon/sysfs: add a file for efficiently get total size of DAMOS tried regions

The tried_regions directory of DAMON sysfs interface is useful for retrieving monitoring results snapshot or DAMOS debugging. However, for common use case that need to monitor only the total size of the scheme tried regions (e.g., monitoring working set size), the kernel overhead for directory construction and user overhead for reading the content could be high if the number of monitoring region is not small. This patchset implements DAMON sysfs files for efficient support of the use case.

The first patch implements the sysfs file to reduce the user space overhead, and the second patch implements a command for reducing the kernel space overhead.

The third patch adds a selftest for the new file, and following two patches update documents.

SeongJae Park (5):
mm/damon/sysfs-schemes: implement DAMOS tried total bytes file mm/damon/sysfs: implement a command for updating only schemes tried
total bytes
selftests/damon/sysfs: test tried_regions/total_bytes file Docs/ABI/damon: update for tried_regions/total_bytes Docs/admin-guide/mm/damon/usage: update for tried_regions/total_bytes

 .../ABI/testing/sysfs-kernel-mm-damon         | 13 +++++-
 Documentation/admin-guide/mm/damon/usage.rst  | 42 ++++++++++++-------
 mm/damon/sysfs-common.h                       |  2 +-
 mm/damon/sysfs-schemes.c                      | 24 ++++++++++-
 mm/damon/sysfs.c                              | 26 +++++++++---
 tools/testing/selftests/damon/sysfs.sh        |  1 +
 6 files changed, 83 insertions(+), 25 deletions(-)

2.25.1