+ samples-damon-mtier-use-damon_initialized.patch added to mm-new branch

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

The patch titled
     Subject: samples/damon/mtier: use damon_initialized()
has been added to the -mm mm-new branch.  Its filename is
     samples-damon-mtier-use-damon_initialized.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/samples-damon-mtier-use-damon_initialized.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
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------------------------------------------------------
From: SeongJae Park <sj@kernel.org>
Subject: samples/damon/mtier: use damon_initialized()
Date: Mon, 15 Sep 2025 20:35:11 -0700

damon_sample_mtier is assuming DAMON is ready to use in module_init time,
and uses its own hack to see if it is the time.  Use damon_initialized(),
which is a way for seeing if DAMON is ready to be used that is more
reliable and better to maintain instead of the hack.

Link: https://lkml.kernel.org/r/20250916033511.116366-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 samples/damon/mtier.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

--- a/samples/damon/mtier.c~samples-damon-mtier-use-damon_initialized
+++ a/samples/damon/mtier.c
@@ -193,8 +193,6 @@ static void damon_sample_mtier_stop(void
 	damon_destroy_ctx(ctxs[1]);
 }
 
-static bool init_called;
-
 static int damon_sample_mtier_enable_store(
 		const char *val, const struct kernel_param *kp)
 {
@@ -208,7 +206,7 @@ static int damon_sample_mtier_enable_sto
 	if (enabled == is_enabled)
 		return 0;
 
-	if (!init_called)
+	if (!damon_initialized())
 		return 0;
 
 	if (enabled) {
@@ -225,7 +223,12 @@ static int __init damon_sample_mtier_ini
 {
 	int err = 0;
 
-	init_called = true;
+	if (!damon_initialized()) {
+		if (enabled)
+			enabled = false;
+		return -ENOMEM;
+	}
+
 	if (enabled) {
 		err = damon_sample_mtier_start();
 		if (err)
_

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

mm-damon-lru_sort-use-param_ctx-for-damon_attrs-staging.patch
mm-damon-core-reset-age-if-nr_accesses-changes-between-non-zero-and-zero.patch
mm-damon-core-set-effective-quota-on-first-charge-window.patch
docs-mm-damon-maintainer-profile-update-community-meetup-for-reservation-requirements.patch
docs-admin-guide-mm-damon-start-add-target_pid-to-damos-example-command.patch
maintainers-rename-damon-section.patch
mm-damon-core-implement-damon_initialized-function.patch
mm-damon-stat-use-damon_initialized.patch
mm-damon-reclaim-use-damon_initialized.patch
mm-damon-lru_sort-use-damon_initialized.patch
samples-damon-wsse-use-damon_initialized.patch
samples-damon-prcl-use-damon_initialized.patch
samples-damon-mtier-use-damon_initialized.patch