mm/damon/api: introduce DAMOS_FILTER_TYPE_PROBE_HITS_WSUM

Patch series "mm/damon: introduce probe_hits_wsum DAMOS core filter", v2.

DAMON can do flexible data attributes monitoring.  The classical data
access monitoring can also be done using the attributes monitoring.  The
access event is just one of the data attributes that DAMON supports. 
Users do monitoring to make some actions based on it.  DAMOS is a feature
for automating that.  However, DAMOS cannot utilize the data attributes
monitoring results.  It is still Data "Access" Monitoring-based Operation
Schemes.  It requires users to set the target "access" pattern.

DAMOS core filter is effectively the same as the target access pattern. 
It is just a more generalized and flexible way of describing the operation
action target region.  Introduce a new DAMOS core filter type,
probe_hits_wsum.  It specifies the filter target based on a range of the
probe hits weighted sum.  Using this, users can apply DAMOS actions to
regions of specific data attributes pattern.

Note that the classic target access pattern still works.  Hence the target
nr_accesses range should still be properly configured.  The new filter
would be used in only data attributes-only mode.  In the mode, classic
access monitoring is just turned off, and therefore nr_accesses of regions
are always zero.  Users could simply set the target nr_accesses range to
include the zero nr_Accesses regions.

Patches Sequence
================

Patch 1 updates the DAMON kernel API for the new filter type.  Patch 2
extends damon_probe_hits_wsum() to do the calculation based on moving sum.
Patch 3 implements the filter type in the core layer.  Patch 4 refactors
DAMON sysfs interface internal data structure for efficient reuse of data
structure for the probe hits weighted sum range user inputs.  Patch 5
updates DAMON sysfs interface to support the new filter type.  Patches 6
and 7 update design and usage documents for the new filter type,
respectively.


This patch (of 7):

Update DAMON kernel API to introduce new DAMOS core filter type,
PROBE_HITS_WSUM.  It will allow API callers to describe the DAMOS action
target regions based on their probe_hits weighted sum.  For describing the
filtering target weighted sum range, add two type-dependent union fields
to damos_filter.

[sj@kernel.org: clarify DAMOS_FILTER_TYPE_PROBE_HITS_WSUM behavior]
  Link: https://lore.kernel.org/20260911142522.98013-1-sj@kernel.org
Link: https://lore.kernel.org/20260911135510.96914-1-sj@kernel.org
Link: https://lore.kernel.org/20260911135510.96914-2-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>

0 files changed, 0 insertions, 0 deletions