[merged mm-stable] mm-damon-sysfs-set-next-refresh-jiffies-per-sysfs-context.patch removed from -mm tree

[merged mm-stable] mm-damon-sysfs-set-next-refresh-jiffies-per-sysfs-context.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm/damon/sysfs: set next refresh jiffies per sysfs context
has been removed from the -mm tree.  Its filename was
     mm-damon-sysfs-set-next-refresh-jiffies-per-sysfs-context.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: SJ Park <sj@kernel.org>
Subject: mm/damon/sysfs: set next refresh jiffies per sysfs context
Date: Tue, 1 Sep 2026 17:27:23 -0700

When 'refresh_ms' is set, DAMON sysfs interface periodically updates
auto-tuned parameters and DAMOS stats.  The timestamp for the next refresh
is initialized when a DAMON context starts, and updated in its
damon_call() callback function.  That is, each DAMON context updates it. 
However, the timestamp is a global variable that is shared with all the
contexts.  When there are multiple DAMON contexts having different
refresh_ms, the update frequency will be changed, depending on the order
of the contexts.  When there are multiple kdamonds, it will be even more
chaotic.  Fix the problem by having the timestamp per each context.

The user impact is not very critical.  It does not leak, corrupt or crash.
The update will not be faster or slower than the lowest and largest
refresh_ms values of the contexts, respectively.  The user can also
manually ask the updates on demand using kdamond state commands.  That
said, clearly this is a bug and can easily be reproduced.

Link: https://lore.kernel.org/20260902002725.108635-5-sj@kernel.org
Fixes: 9fd7bb5083d1 ("mm/damon/sysfs: change next_update_jiffies to a global variable")
Signed-off-by: SJ Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Lian Wang <lianux.mm@gmail.com>
Tested-by: Lian Wang <lianux.mm@gmail.com>
Reviewed-by: Kunwu Chan <kunwu.chan@gmail.com>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@davidgow.net>
Cc: Quanmin Yan <yanquanmin1@huawei.com>
Cc: <stable@vger.kernel.org> # 6.18.x
---

 mm/damon/sysfs.c |   11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

--- a/mm/damon/sysfs.c~mm-damon-sysfs-set-next-refresh-jiffies-per-sysfs-context
+++ a/mm/damon/sysfs.c
@@ -2034,6 +2034,7 @@ struct damon_sysfs_kdamond {
 	struct damon_sysfs_contexts *contexts;
 	struct damon_ctx *damon_ctx;
 	unsigned int refresh_ms;
+	unsigned long next_refresh_jiffies;
 };
 
 static struct damon_sysfs_kdamond *damon_sysfs_kdamond_alloc(void)
@@ -2484,17 +2485,15 @@ static struct damon_ctx *damon_sysfs_bui
 	return ctx;
 }
 
-static unsigned long damon_sysfs_next_update_jiffies;
-
 static int damon_sysfs_repeat_call_fn(void *data)
 {
 	struct damon_sysfs_kdamond *sysfs_kdamond = data;
 
 	if (!sysfs_kdamond->refresh_ms)
 		return 0;
-	if (time_before(jiffies, damon_sysfs_next_update_jiffies))
+	if (time_before(jiffies, sysfs_kdamond->next_refresh_jiffies))
 		return 0;
-	damon_sysfs_next_update_jiffies = jiffies +
+	sysfs_kdamond->next_refresh_jiffies = jiffies +
 		msecs_to_jiffies(sysfs_kdamond->refresh_ms);
 
 	if (!mutex_trylock(&damon_sysfs_lock))
@@ -2542,8 +2541,8 @@ static int damon_sysfs_turn_damon_on(str
 	}
 	kdamond->damon_ctx = ctx;
 
-	damon_sysfs_next_update_jiffies =
-		jiffies + msecs_to_jiffies(kdamond->refresh_ms);
+	kdamond->next_refresh_jiffies = jiffies +
+		msecs_to_jiffies(kdamond->refresh_ms);
 
 	repeat_call_control->fn = damon_sysfs_repeat_call_fn;
 	repeat_call_control->data = kdamond;
_

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

mm-damon-core-use-damon_nr_samples_per_aggr-for-max-merge-threshold.patch
mm-damon-core-remove-debug-messages.patch
mm-damon-core-remove-debug-messages-fix.patch
mm-damon-vaddr-remove-a-debug-message.patch
mm-damon-core-validate-number-of-probes-in-valid_probe_params.patch
mm-damon-sysfs-remove-probes-number-validation.patch
mm-damon-tests-core-kunit-extend-set_regions-test-for-error-case.patch
mm-damon-tests-core-kunit-test-=0-size-damon_set_regions-inputs.patch
mm-damon-tests-core-kunit-test-overlapping-ranges-for-set_regions.patch
mm-damon-tests-core-kunit-test-damon_nr_samples_per_aggr.patch
selftests-damon-sysfssh-test-hugepage_mem_bp-quota-goal.patch
docs-mm-damon-maintainer-profile-update-ai-review-for-sashiko-replies.patch
docs-abi-damon-recommend-subsystem-doc-instead-of-admin-guide.patch
mm-damon-core-error-damos_commit_quota_goal-for-zero-target_value.patch
revert-mm-damon-lru_sort-error-out-for-10000-active_mem_bp.patch
revert-samples-damon-mtier-error-out-for-zero-quota-goal-target-values.patch
mm-damon-core-handle-null-ctx-parameter-in-damon_call.patch
mm-damon-core-set-ctx-call_controls_obsolete-in-damon_new_ctx.patch
mm-damon-reclaim-remove-unnecessary-damon_call-param-validation.patch
mm-damon-lru_sort-remove-unnecessary-damon_call-param-validation.patch
mm-damon-vaddr-support-prep_probes.patch
mm-damon-paddr-move-probe-filter-handling-to-ops-common.patch
mm-damon-vaddr-support-apply_probe.patch
mm-damon-vaddr-extend-apply_probes-for-hugetlb.patch
mm-damon-vaddr-support-pgidle_unset-probe-filter-type.patch
mm-damon-api-introduce-damon_filter_type_pgidle_set.patch
mm-damon-paddr-support-damon_filter_type_pgidle_set.patch
mm-damon-vaddr-support-damon_filter_type_pgidle_set.patch
mm-damon-sysfs-support-damon_filter_type_pgidle_set.patch
docs-mm-damon-design-update-for-pgidle_set-probe-filter.patch
mm-damon-api-introduce-damos_filter_type_probe_hits_wsum.patch
mm-damon-api-introduce-damos_filter_type_probe_hits_wsum-fix.patch
mm-damon-core-extend-probe_hits_wsum-for-moving-sum-based-calculation.patch
mm-damon-core-support-probe_hits_wsum-damos-core-filter.patch
mm-damon-sysfs-schemes-rename-sysfs_filter-sz_range-to-range_minmax.patch
mm-damon-sysfs-schemes-support-probe_hits_wsum-damos-core-filter.patch
docs-mm-damon-design-update-for-probe_hits_wsum-damos-core-filter.patch
docs-admin-guide-mm-damon-usage-update-for-probe_hits_wsum-damos-filter.patch
mm-damon-sysfs-schemes-read-sysfs_filter-addr_range-only-once.patch
mm-damon-sysfs-schemes-read-sysfs_filter-sz_range-only-once.patch
mm-damon-core-return-an-error-from-damos_commit_filter_arg.patch
mm-damon-core-disallow-max-min-damos-filter-range-arguments-commit.patch
mm-damon-sysfs-schemes-drop-centralized-filter-range-arg-validations.patch
mm-damon-sysfs-schemes-use-switch-case-in-add_scheme_filters.patch
mm-damon-core-kunit-extend-damos_commit_filter_for-for-wrong-input.patch
mm-damon-core-kunit-test-invalid-damos-filter-commits.patch
mm-damon-api-introduce-damon_filter_type_hugepage_size.patch
mm-damon-core-commit-hugepage_size-type-damon-filter.patch
mm-damon-ops-common-support-hugepage_size-damon-filter-matching.patch
mm-damon-sysfs-add-minmax-files-under-probe-filter-directory.patch
mm-damon-sysfs-support-hugepage_size-probe-filter.patch
docs-mm-damon-design-update-for-hugepage_size-probe-filter.patch
docs-admin-guide-mm-damon-usage-update-for-hugepage_size.patch
docs-abi-damon-update-for-hugepage_size-probe-filter.patch
mm-damon-api-remove-nr_damos_filter_types.patch
mm-damon-core-use-abs_diff-in-damon_feed_loop_next_input.patch
mm-damon-core-use-mult_frac-in-damon_feed_loop_next_input.patch
mm-damon-core-set-damon_ctx-walk_control_obsolete-in-damon_new_ctx.patch
mm-damon-core-document-damon_call-damon_start-race-hang-issue.patch
mm-damon-paddr-remove-pa-parameter-from-damon_pa_filter_pass.patch
mm-damon-tests-core-kunit-test-eligible_mem_bp-commitment.patch
mm-damon-tests-core-kunit-add-probe_hits_wsum-damos-filter-commit-test.patch
selftests-damon-sysfs_memcg_path_leak-fail-only-for-real-damon-leak.patch
docs-mm-damon-design-clarify-bp-is-basis-point.patch
mm-damon-core-introduce-damos_quota_goal-complement.patch
mm-damon-core-add-complement-argument-to-damos_new_quota_goal.patch
mm-damon-sysfs-schemes-support-quota-goal-complement-flag.patch
mm-damon-tests-core-kunit-test-quota_goal-complement-commit.patch
selftests-damon-sysfssh-test-quota-goal-complement-flag-file.patch
docs-mm-damon-design-document-damos-quota-goal-complement-flag.patch
docs-admin-guide-mm-damon-usage-update-for-quota-goal-complement-file.patch
docs-abi-damon-update-for-quota-goal-metric-complement-sysfs-file.patch