+ mm-damon-ops-common-use-nr_accesses-moving-sum-for-quota-score.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/damon/ops-common: use nr_accesses moving sum for quota score
has been added to the -mm mm-new branch.  Its filename is
     mm-damon-ops-common-use-nr_accesses-moving-sum-for-quota-score.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-ops-common-use-nr_accesses-moving-sum-for-quota-score.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: SJ Park <sj@kernel.org>
Subject: mm/damon/ops-common: use nr_accesses moving sum for quota score
Date: Sun, 19 Jul 2026 09:11:33 -0700

Since commit 42f994b71404 ("mm/damon/core: implement scheme-specific apply
interval"), DAMOS scheme can be applied at any time.  At that time,
nr_accesses may not be fully aggregated.  But the quota prioritization
score is calculated using the not fully aggregated count.  As a result,
the performance of DAMOS could be degraded.  Fix by using
damon_nr_accesses_mvsum() instead.

The user impact of the issue is suboptimum DAMOS performance under certain
setups.  Nonetheless, the bug was there from the beginning of the setup
availability.  In other words, the suboptimum performance is the baseline
of the setup and hence it didn't cause regression.  Also the extent of the
suboptimality was not big enough to be found from users and testers. 
Still, this is a clear bug that is better to be fixed, and can be easily
fixed.

Link: https://lore.kernel.org/20260719161136.90191-1-sj@kernel.org
Fixes: 42f994b71404 ("mm/damon/core: implement scheme-specific apply interval")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 6.7.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/damon/ops-common.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/mm/damon/ops-common.c~mm-damon-ops-common-use-nr_accesses-moving-sum-for-quota-score
+++ a/mm/damon/ops-common.c
@@ -111,8 +111,9 @@ int damon_hot_score(struct damon_ctx *c,
 	unsigned int age_weight = s->quota.weight_age;
 	int hotness;
 
-	freq_subscore = r->nr_accesses * DAMON_MAX_SUBSCORE /
-		damon_nr_samples_per_aggr(&c->attrs);
+	freq_subscore = mult_frac(damon_nr_accesses_mvsum(r, c),
+			DAMON_MAX_SUBSCORE,
+			damon_nr_samples_per_aggr(&c->attrs));
 
 	age_in_sec = (unsigned long)r->age * c->attrs.aggr_interval / 1000000;
 	if (age_in_sec)
_

Patches currently in -mm which might be from sj@kernel.org are

samples-damon-wsse-handle-damon_start-failure.patch
samples-damon-prcl-handle-damon_start-failure.patch
samples-damon-mtier-handle-damon_start-failure.patch
samples-damon-mtier-handle-damon_stop-failure.patch
samples-damon-wsse-stop-and-free-damon-ctx-when-damon_call-fails.patch
samples-damon-prcl-stop-and-free-damon-ctx-when-damon_call-fails.patch
mm-damon-sysfs-kobject_del-target-normal-context-and-kdamond-dirs.patch
mm-damon-sysfs-kobject_del-region-and-target-error-dirs.patch
mm-damon-sysfs-schemes-kobject_del-scheme-dirs.patch
mm-damon-sysfs-schemes-kobject_del-scheme-region-dirs.patch
mm-damon-sysfs-schemes-kobject_del-scheme-filter-dirs.patch
mm-damon-sysfs-schemes-kobject_del-scheme-quota-goal-dirs.patch
mm-damon-sysfs-schemes-kobject_del-scheme-action-destination-dirs.patch
mm-damon-sysfs-kobject_del-probe-dirs.patch
mm-damon-sysfs-kobject_del-probe-filter-dirs.patch
mm-damon-sysfs-kobject_del-probe-dirs-in-probes_addd_dir-error-path.patch
mm-damon-sysfs-schemes-kobject_del-region-for-populate_region-error.patch
docs-mm-damon-design-update-for-damos_quota_node_eligible_mem_bp.patch
docs-abi-damon-document-probe-files.patch
mm-damon-tests-core-kunit-test-damon_rand.patch
selftests-damon-sysfssh-test-multiple-probe-dirs-creation.patch
selftests-damon-sysfssh-test-coreops_filters-directories.patch
selftests-damon-sysfssh-test-dests-dir.patch
selftests-damon-sysfssh-test-all-files-in-quota-goal-dir.patch
mm-damon-core-reduce-range-setup-in-damon_commit_target_regions.patch
mm-damon-sysfs-split-probe-setup-function-out.patch
mm-damon-sysfs-split-out-filters-setup-function.patch
mm-damon-sysfs-fix-typos-in-probe_addrm_dirs-s-attr-probe.patch
mm-damon-core-introduce-damon_nr_accesses_mvsum.patch
mm-damon-tests-core-kunit-test-damon_mvsum.patch
mm-damon-core-always-update-last_nr_accesses-for-intervals-change.patch
mm-damon-core-handle-unreset-nr_accesses-in-damon_nr_accesses_mvsum.patch
mm-damon-core-use-damon_nr_accesses_mvsum-in-__damos_valid_target.patch
mm-damon-core-use-damon_nr_accesses_mvsum-for-damos-region-tracing.patch
mm-damon-sysfs-schemes-use-damon_nr_accesses_mvsum-for-damo-regions.patch
mm-damon-core-remove-damon_warn_fix_nr_accesses_corruption.patch
mm-damon-core-remove-damon_verify_reset_aggregated.patch
mm-damon-core-remove-damon_verify_merge_regions_of.patch
mm-damon-tests-core-kunit-remove-nr_accesses_bp-setup-and-tests.patch
selftests-damon-drgn_dump_damon_status-do-not-dump-nr_accesses_bp.patch
mm-damon-core-remove-nr_accesses_bp-setups-and-updates.patch
mm-damon-core-remove-attrs-param-from-damon_update_region_access_rate.patch
mm-damon-paddr-remove-attrs-param-from-__damon_pa_check_access.patch
mm-damon-vaddr-remove-attrs-param-from-__damon_va_check_access.patch
mm-damon-core-remove-damon_moving_sum-and-its-unit-test.patch
mm-damon-core-remove-damon_region-nr_accesses_bp.patch
mm-damon-add-damon_region-last_probe_hits.patch
mm-damon-core-introduce-damon_probe_hits_mvsum.patch
mm-damon-sysfs-schemes-set-probe-hits-as-pseudo-moving-sums.patch
mm-damon-core-safely-validate-src-on-damon_commit_ctx.patch
mm-damon-core-do-parameter-testing-commit-on-damon_start.patch
mm-damon-sysfs-remove-duplicated-commit-input-validity-check.patch
mm-damon-reclaim-remove-duplicated-min_region_sz-power-of-2-check.patch
mm-damon-lru_sort-remove-duplicated-min_region_sz-power_of_2-check.patch
mm-damon-document-region-size-validation-in-damon_set_regions.patch
mm-damon-core-remove-start-end-check-in-damon_set_region_system_rams.patch
mm-damon-sysfs-remove-region-size-validation.patch
mm-damon-core-stop-ctxs-in-damon_start-before-returning-an-error.patch
samples-damon-mtier-do-not-stop-first-context-for-damon_start-failure.patch
mm-damon-core-make-damon_stop-never-fails.patch
mm-damon-sysfs-ignore-damon_stop-return-value.patch
mm-damon-reclaaim-ignore-damon_stop-return-value.patch
mm-damon-lru_sort-ignore-damon_stop-return-value.patch
mm-damon-core-change-damon_stop-return-type-to-void.patch
samples-damon-mtier-stop-all-contexts-with-single-damon_stop-call.patch
mm-damon-core-wait-ctx-stop-in-damon_call-before-reruning-an-error.patch
samples-damon-wsse-do-not-stop-ctx-for-damon_call-failure.patch
samples-damon-prcl-do-not-stop-damon-for-damon_call-failure.patch
mm-damon-core-remove-comment-and-test-for-nr_to_bp-divide-by-zero.patch
mm-damon-core-s-damon_max_nr_accesses-damon_nr_samples_per_aggr.patch
mm-damon-core-s-accesses_bp_to_nr_accesses-sample_bp_to_count.patch
mm-damon-core-s-nr_accesses_to_accesses_bp-sample_count_to_bp.patch
mm-damon-core-s-nr_accesses_for_new_attrs-nr_samples_for_new_attrs.patch
mm-damon-core-update-probe-hits-for-new-parameter-commit.patch
mm-damon-core-handle-unreset-probe_hits-in-probe_hits_mvsum.patch
mm-damon-core-introduce-damon_probe-weight.patch
mm-damon-core-ask-apply_probes-ops-callback-to-set-sampling-address.patch
mm-damon-paddr-set-samples-in-apply_probes-if-requested.patch
mm-damon-core-ask-apply_probe-to-return-max-probe-hits-weighted-sum.patch
mm-damon-core-implement-damon_probe_hits_wsum.patch
mm-damon-paddr-respect-return_max_wsum.patch
mm-damon-core-use-abs_diff-instead-of-abs.patch
mm-damon-core-extend-merge-function-to-work-with-probe-hits.patch
mm-damon-core-disallow-probe_hits-overflow-on-attrs-only-monitoring.patch
mm-damon-core-validate-params-for-probe-hits-weighted-sum-overflow.patch
mm-damon-core-disable-access-monitoring-when-probe-weights-are-set.patch
mm-damon-core-set-samples-in-apply_probes-if-probe-weights-are-set.patch
mm-damon-core-s-max_nr_accesses-max_merge_score-in-kdamond_fn.patch
mm-damon-core-get-merge-threshold-from-probe-hits-when-weights-are-set.patch
mm-damon-core-implement-damon_has_probe_weight.patch
mm-damon-sysfs-implement-probe-weight-file.patch
docs-mm-damon-design-document-attrs-only-monitoring.patch
docs-admin-guide-mm-damon-usage-document-weight-sysfs-file.patch
docs-abi-damon-document-probe-weight-file.patch
mm-damon-core-skip-aging-from-repeated-aggressive-merging.patch
mm-damon-core-hide-private-damon_region-fields.patch
mm-damon-core-hide-private-damon_target-fields.patch
mm-damon-core-hide-private-damos_quota_goal-fields.patch
mm-damon-core-hide-private-damos_quota-fields.patch
mm-damon-core-hide-private-damos_filter-fields.patch
mm-damon-core-hide-private-damos-fields.patch
mm-damon-core-hide-private-damon_filter-fields.patch
mm-damon-core-hide-private-damon_probe-fields.patch
mm-damon-sysfs-do-not-directly-access-damon_ctx-ops.patch
mm-damon-core-hide-core-private-damon_ctx-fields.patch
mm-damon-core-avoid-infinite-kdamond_merge_regions-internal-loop.patch
mm-damon-tests-core-kunit-catch-test-failure-in-test_merge_regions_of.patch
mm-damon-vaddr-drop-last-same-folio-access-check-optimization.patch
mm-damon-paddr-drop-last-same-folio-access-check-reuse-optimization.patch
mm-damon-sysfs-read-addr_unit-only-once-in-damon_sysfs_apply_inputs.patch
mm-damon-sysfs-read-ops_id-only-once-in-damon_sysfs_apply_inputs.patch
mm-damon-core-initialize-damos-last_applied.patch
mm-damon-core-kunit-check-region-count-before-testing-in-split_at.patch
mm-damon-vaddr-kunit-check-region-count-in-three_regions-test.patch
mm-damon-core-kunit-handle-region-split-failure-in-filter_out.patch
mm-damon-core-kunit-skip-wrong-dest-walk-in-commit_dests_for.patch
mm-damon-core-kunit-skip-wrong-quota-goal-walk-in-commit_quota_goals.patch
mm-damon-core-kunit-skip-wrong-region-walk-in-commit_target_regions.patch
mm-damon-ops-common-use-nr_accesses-moving-sum-for-quota-score.patch