+ mm-damon-core-set-damon_ctx-walk_control_obsolete-in-damon_new_ctx.patch added to mm-new branch

+ mm-damon-core-set-damon_ctx-walk_control_obsolete-in-damon_new_ctx.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm/damon/core: set damon_ctx->walk_control_obsolete in damon_new_ctx()
has been added to the -mm mm-new branch.  Its filename is
     mm-damon-core-set-damon_ctx-walk_control_obsolete-in-damon_new_ctx.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-core-set-damon_ctx-walk_control_obsolete-in-damon_new_ctx.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/core: set damon_ctx->walk_control_obsolete in damon_new_ctx()
Date: Thu, 17 Sep 2026 07:22:02 -0700

damos_walk() should be called for a damon_ctx context that has
successfully started at least once.  That's because
damon_ctx->walk_control_obsolete is initialized when kdamond starts.  If
the rule is violated, an indefinite wait can happen.  There is no
existing violation of the rule.

damon_call() had a similar rule, and it turned out keeping the rule is
not easy for damon_call()'s case.  Hence, commit 8023b5f47e09
("mm/damon/core: set ctx->call_controls_obsolete in damon_new_ctx()")
added the initialization in damon_new_ctx() and removed the rule.

Keeping the rule for damos_walk() is relatively easier.  But having
slightly different rules for similar functions could be confusing.
Sashiko, for example, repeatedly asked questions about this.  Do the
initialization of walk_control_obsolete in damon_new_ctx() for
consistency.

Link: https://lore.kernel.org/20260917142210.90829-5-sj@kernel.org
Link: https://lore.kernel.org/20260915011614.102342-1-sj@kernel.org [1]
Signed-off-by: SJ Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Asier Gutierrez <gutierrez.asier@huawei-partners.com>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@davidgow.net>
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: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
---

 mm/damon/core.c |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

--- a/mm/damon/core.c~mm-damon-core-set-damon_ctx-walk_control_obsolete-in-damon_new_ctx
+++ a/mm/damon/core.c
@@ -939,6 +939,7 @@ struct damon_ctx *damon_new_ctx(void)
 	INIT_LIST_HEAD(&ctx->schemes);
 
 	ctx->call_controls_obsolete = true;
+	ctx->walk_control_obsolete = true;
 	prandom_seed_state(&ctx->rnd_state, get_random_u64());
 
 	return ctx;
@@ -2308,10 +2309,6 @@ canceled:
  * passed at least one &damos->apply_interval_us, kdamond marks the request as
  * completed so that damos_walk() can wakeup and return.
  *
- * Note that this function should be called only after damon_start() with the
- * @ctx has succeeded.  Otherwise, this function could fall into an indefinite
- * wait.
- *
  * Return: 0 on success, negative error code otherwise.
  */
 int damos_walk(struct damon_ctx *ctx, struct damos_walk_control *control)
_

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

mm-damon-vaddr-avoid-hw-driven-pte-updates-during-damon_hugetlb_mkold.patch
mm-damon-core-reset-invalid-quota-charge_target_from.patch
mm-damon-core-dont-skip-damos_adjust_quota-while-esz-is-not-zero.patch
mm-damon-core-skip-applying-scheme-if-region-split-for-quota-fails.patch
mm-damon-paddr-respect-folio-end-for-damos_stat.patch
mm-damon-paddr-respect-folio-end-for-damos-actions-except-stat.patch
mm-damon-vaddr-respect-folio-end-for-damos_stat.patch
mm-damon-vaddr-respect-folio-end-for-damos_migrate_hotcold.patch
mm-damon-core-handle-extreme-memory-state-in-damon_get_node_mem_bp.patch
mm-damon-core-handle-extreme-memory-state-in-get_node_memcg_used_bp.patch
mm-damon-core-handle-extreme-memory-state-in-get_in_active_mem_bp.patch
mm-damon-core-introduce-damon_filter_type_pgidle_unset.patch
mm-damon-paddr-support-pgidle_unset-probe-filter-type.patch
mm-damon-sysfs-support-pgidle_unset-probe-filter-type.patch
docs-mm-damon-design-document-pgidle_unset-probe-filter-type.patch
mm-damon-core-introduce-damon_prep-struct.patch
mm-damon-core-commit-preps.patch
mm-damon-core-introduce-damon_operations-prep_probes.patch
mm-damon-paddr-support-damon_prep.patch
mm-damon-sysfs-implement-preps-directory.patch
mm-damon-sysfs-implement-preps-nr_preps-file.patch
mm-damon-sysfs-create-directories-for-nr_preps-writes.patch
mm-damon-sysfs-implement-prep_action-file.patch
mm-damon-sysfs-pass-preps-to-damon-core.patch
selftests-damon-sysfssh-test-probe-prep-sysfs-files.patch
docs-mm-damon-design-document-probe-preps.patch
docs-admin-guide-mm-damon-usage-document-probe-preps-sysfs-files.patch
docs-abi-damon-document-probe-prep-sysfs-files.patch
mm-damon-tests-core-kunit-test-committing-psi-goal-to-psi-goal.patch
mm-damon-core-handle-uninitialized-damos_quota_goal-last_psi_total.patch
mm-damon-core-copy-nid-for-eligible_mem_bp-damos-quota-goal-commit.patch
mm-damon-sysfs-set-next-refresh-jiffies-per-sysfs-context.patch
mm-damon-tests-core-kunit-test-damon_commit_filter.patch
mm-damon-tests-core-kunit-add-damon_commit_probes-test.patch
selftests-damon-_damon_sysfs-implement-damonprobes.patch
selftests-damon-drgn_dump_damon_status-dump-probes.patch
selftests-damon-sysfspy-extend-commit-assertion-function-for-probes.patch
selftests-damon-sysfspy-test-damon-probes.patch
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