[PATCH 00/10] mm/damon: improve readability, clarity and test coverage

[PATCH 00/10] mm/damon: improve readability, clarity and test coverage

[SJ Park]

Yet another batch of miscellaneous DAMON minor improvements.  Mostly
focused on readability and clarity of code and document, and unit/self
test coverage.  No user-visible behavioral change is intended.

Changes from RFC v2
- RFC v2: https://lore.kernel.org/20260917040537.107341-1-sj@kernel.org
- Drop RFC tag.
- Rebase to the latest mm-new.
Changes from RFC
- RFC: https://lore.kernel.org/20260912200814.145612-1-sj@kernel.org
- Fix a typo in the selftest warning message.
- Collect A-b: from Randy.
- Split out damos_adjust_quota() fix to an individual hotfix patch.
- Add a patch for initializing walk_control_obsolete in damon_new_ctx().
- Add a patch for probe_hits_wsum damos filter commit kunit test.
- Trivial patch sequence update.
- Rebase to the latest mm-new.

SJ Park (10):
  mm/damon/api: remove NR_DAMOS_FILTER_TYPES
  mm/damon/core: use abs_diff() in damon_feed_loop_next_input()
  mm/damon/core: use mult_frac() in damon_feed_loop_next_input()
  mm/damon/core: set damon_ctx->walk_control_obsolete in damon_new_ctx()
  mm/damon/core: document damon_call()/damon_start() race hang issue
  mm/damon/paddr: remove pa parameter from damon_pa_filter_pass()
  mm/damon/tests/core-kunit: test eligible_mem_bp commitment
  mm/damon/tests/core-kunit: add probe_hits_wsum damos filter commit
    test
  selftests/damon/sysfs_memcg_path_leak: fail only for real DAMON leak
  Docs/mm/damon/design: clarify bp is basis point

 Documentation/mm/damon/design.rst             |  5 ++--
 include/linux/damon.h                         |  2 --
 mm/damon/core.c                               | 19 ++++--------
 mm/damon/paddr.c                              |  5 ++--
 mm/damon/tests/core-kunit.h                   | 30 +++++++++++++++++++
 .../selftests/damon/sysfs_memcg_path_leak.sh  |  7 +++++
 6 files changed, 48 insertions(+), 20 deletions(-)


base-commit: 942682790e570c9422a389bf34097e74c4777fe9
-- 
2.47.3

[PATCH 10/10] Docs/mm/damon/design: clarify bp is basis point

[SJ Park]

DAMON design document uses "bp" for "basis point" in multiple places.
Because it is not clearly mentioned, it is difficult to understand what
"bp" stands for.  Add the clarification.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Closes: https://lore.kernel.org/107dc6ba-697e-4b25-ba3e-8ce2499cac9a@infradead.org
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: SJ Park <sj@kernel.org>
---
 Documentation/mm/damon/design.rst | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst
index 0a86792f90a18..e82390e77a70a 100644
--- a/Documentation/mm/damon/design.rst
+++ b/Documentation/mm/damon/design.rst
@@ -445,7 +445,7 @@ users to set the aimed amount of access events to observe via DAMON within
 given time interval.  The target can be specified by the user as a ratio of
 DAMON-observed access events to the theoretical maximum amount of the events
 (``access_bp``) that measured within a given number of aggregations
-(``aggrs``).
+(``aggrs``).  The ratio is in basis point (bp or 1/10,000).
 
 The DAMON-observed access events are calculated in byte granularity based on
 DAMON :ref:`region assumption <damon_design_region_based_sampling>`.  For
@@ -717,7 +717,8 @@ mechanism tries to make ``current_value`` of ``target_metric`` be same to
   in microseconds that measured from last quota reset to next quota reset.
   DAMOS does the measurement on its own, so only ``target_value`` need to be
   set by users at the initial time.  In other words, DAMOS does self-feedback.
-- ``node_mem_used_bp``: Specific NUMA node's used memory ratio in bp (1/10,000).
+- ``node_mem_used_bp``: Specific NUMA node's used memory ratio in basis point
+  (bp or 1/10,000).
 - ``node_mem_free_bp``: Specific NUMA node's free memory ratio in bp (1/10,000).
 - ``node_memcg_used_bp``: Specific cgroup's node used memory ratio for a
   specific NUMA node, in bp (1/10,000).
-- 
2.47.3

Re: [PATCH 10/10] Docs/mm/damon/design: clarify bp is basis point

[Zenghui Yu]

On 9/17/26 10:22 PM, SJ Park wrote:
> DAMON design document uses "bp" for "basis point" in multiple places.
> Because it is not clearly mentioned, it is difficult to understand what
> "bp" stands for.  Add the clarification.

Exactly ;-)  I had such confusion when I was reading the doc.

> 
> Reported-by: Randy Dunlap <rdunlap@infradead.org>
> Closes: https://lore.kernel.org/107dc6ba-697e-4b25-ba3e-8ce2499cac9a@infradead.org
> Acked-by: Randy Dunlap <rdunlap@infradead.org>
> Signed-off-by: SJ Park <sj@kernel.org>

Acked-by: Zenghui Yu (Huawei) <zenghui.yu@linux.dev>

Thanks,
Zenghui

Re: [PATCH 00/10] mm/damon: improve readability, clarity and test coverage

[SJ Park]

On Thu, 17 Sep 2026 07:21:58 -0700 SJ Park <sj@kernel.org> wrote:

> Yet another batch of miscellaneous DAMON minor improvements.  Mostly
> focused on readability and clarity of code and document, and unit/self
> test coverage.  No user-visible behavioral change is intended.

Sashiko found no blocker for this series.  Sashiko send its findings to damon@
mailing list [1], and I reply those if anything needs to be clarified.  Please
refer to those for details.

[1] https://lore.kernel.org/damon/


Thanks,
SJ

Re: [PATCH 00/10] mm/damon: improve readability, clarity and test coverage

[Andrew Morton]

On Thu, 17 Sep 2026 07:21:58 -0700 SJ Park <sj@kernel.org> wrote:

> Yet another batch of miscellaneous DAMON minor improvements.  Mostly
> focused on readability and clarity of code and document, and unit/self
> test coverage.  No user-visible behavioral change is intended.

Thanks, all queued up in mm-new.