DAMOS filters are categorized into two groups based on their handling layers, namely core and operations layers. The categorization affects when each filter is evaluated. Core layer handled filters are evaluated first. The order meant nothing before, but introduction of allow filters changed that. DAMOS sysfs interface provides single directory for filters, namely 'filters'. Users can install any filters in any order there. DAMON will internally categorize those into core and operations layer handled ones, and apply the evaluation order rule. The ordering rule is clearly documented. But the interface could still confuse users since it is allowed to install filters on the directory in mixed ways. Add two sysfs directories for managing filters by handling layers, namely 'core_filters' and 'ops_filters' for filters that handled by core and operations layer, respectively. Those are avoided to be used for installing filters that not handled by the assumed layers. For backward compatibility, keep 'filters' directory with its curernt behavior. Filters installed in the directory will be added to DAMON after those of 'core_filters' and 'ops_filters' directories, with the automatic categorizations. Also recommend users to use the new directories while noticing 'filters' directory could be deprecated in future on the usage documents. Note that new directories provide all features that were provided with 'filters', but just in a more clear way. Deprecating 'filters' in future will hence not make an irreversal feature loss. Changes from RFC (https://lore.kernel.org/20250220194646.37726-1-sj@xxxxxxxxxx) - Fix sphinx error on usage doc change - Wrodsmith commit messages - Rebase on latest mm-unstable SeongJae Park (8): mm/damon/sysfs-schemes: let damon_sysfs_scheme_set_filters() be used for different named directories mm/damon/sysfs-schemes: implement core_filters and ops_filters directories mm/damon/sysfs-schemes: commit filters in {core,ops}_filters directories mm/damon/core: expose damos_filter_for_ops() to DAMON kernel API callers mm/damon/sysfs-schemes: record filters of which layer should be added to the given filters directory mm/damon/sysfs-schemes: return error when for attempts to install filters on wrong sysfs directory Docs/ABI/damon: document {core,ops}_filters directories Docs/admin-guide/mm/damon/usage: update for {core,ops}_filters directories .../ABI/testing/sysfs-kernel-mm-damon | 16 +++ Documentation/admin-guide/mm/damon/usage.rst | 31 +++-- include/linux/damon.h | 1 + mm/damon/core.c | 9 +- mm/damon/sysfs-schemes.c | 119 ++++++++++++++++-- 5 files changed, 153 insertions(+), 23 deletions(-) base-commit: d5ce0f2fd108557fb138adccb203441d0d70f1c4 -- 2.39.5
