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From: Costa Shulyupin <costa.shul@redhat.com>
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Subject: [PATCH v1 6/7] [NOT-FOR-MERGE] test timers and hrtimers affinity adjustment
Date: Thu, 16 May 2024 22:04:36 +0300
Message-ID: <20240516190437.3545310-7-costa.shul@redhat.com>
In-Reply-To: <20240516190437.3545310-1-costa.shul@redhat.com>
References: <20240516190437.3545310-1-costa.shul@redhat.com>
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Kernel module to generate timers and hrtimers for the test
and shell commands.

Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
---
 tests/timers.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 tests/timers.c

diff --git a/tests/timers.c b/tests/timers.c
new file mode 100644
index 0000000000000..bf6ef3244bc05
--- /dev/null
+++ b/tests/timers.c
@@ -0,0 +1,58 @@
+#include <linux/timer.h>
+#include <linux/hrtimer.h>
+#include <linux/module.h>
+
+/*
+ * Testing instructions:
+ *
+ * isolate=1
+ * insmod timers.ko test_cpu=$isolate
+ * cd /sys/fs/cgroup/
+ * echo +cpuset > cgroup.subtree_control
+ * mkdir test
+ * echo isolated > test/cpuset.cpus.partition
+ * echo $isolate > test/cpuset.cpus
+ *
+ * awk "/cpu:/{y=0};/cpu: $isolate\$/{y=1};/ #[0-9]/ && y;" /proc/timer_list \
+ * 	| grep -q test_hrtimer_cb && echo FAIL || echo PASS
+ *
+ * Assure that there is no timers on the isolated cpu.
+ */
+
+static void test_timer_cb(struct timer_list *unused) { }
+
+static struct timer_list test_timer;
+
+static struct hrtimer test_hrtimer;
+
+static enum hrtimer_restart test_hrtimer_cb(struct hrtimer *hr_timer)
+{
+	return HRTIMER_NORESTART;
+}
+
+static int test_cpu = 1;
+module_param(test_cpu, int, 0444);
+
+static int timers_init(void)
+{
+	set_cpus_allowed_ptr(current, cpumask_of(test_cpu));
+	timer_setup(&test_timer, test_timer_cb, TIMER_PINNED);
+	test_timer.expires = KTIME_MAX;
+	add_timer(&test_timer);
+
+	hrtimer_init(&test_hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	test_hrtimer.function = test_hrtimer_cb;
+	hrtimer_start(&test_hrtimer, -1, HRTIMER_MODE_REL);
+	return 0;
+}
+
+static void timers_exit(void)
+{
+	del_timer(&test_timer);
+	hrtimer_cancel(&test_hrtimer);
+}
+
+module_init(timers_init);
+module_exit(timers_exit);
+
+MODULE_LICENSE("GPL");
-- 
2.45.0