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

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

[Andrew Morton]

The patch titled
     Subject: mm/damon/stat: use damon_initialized()
has been added to the -mm mm-new branch.  Its filename is
     mm-damon-stat-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/mm-damon-stat-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
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: SeongJae Park <sj@kernel.org>
Subject: mm/damon/stat: use damon_initialized()
Date: Mon, 15 Sep 2025 20:35:06 -0700

DAMON_STAT 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/20250916033511.116366-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/damon/stat.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

--- a/mm/damon/stat.c~mm-damon-stat-use-damon_initialized
+++ a/mm/damon/stat.c
@@ -214,8 +214,6 @@ static void damon_stat_stop(void)
 	damon_destroy_ctx(damon_stat_context);
 }
 
-static bool damon_stat_init_called;
-
 static int damon_stat_enabled_store(
 		const char *val, const struct kernel_param *kp)
 {
@@ -229,7 +227,7 @@ static int damon_stat_enabled_store(
 	if (is_enabled == enabled)
 		return 0;
 
-	if (!damon_stat_init_called)
+	if (!damon_initialized())
 		/*
 		 * probably called from command line parsing (parse_args()).
 		 * Cannot call damon_new_ctx().  Let damon_stat_init() handle.
@@ -250,12 +248,16 @@ static int __init damon_stat_init(void)
 {
 	int err = 0;
 
-	damon_stat_init_called = true;
+	if (!damon_initialized()) {
+		err = -ENOMEM;
+		goto out;
+	}
 
 	/* probably set via command line */
 	if (enabled)
 		err = damon_stat_start();
 
+out:
 	if (err && enabled)
 		enabled = false;
 	return 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