From afdfe394e3fad10d5edd79dab662f9a36abf1592 Mon Sep 17 00:00:00 2001
From: Weizhen Wang <wangweizhen@pingcap.com>
Date: Mon, 13 Feb 2023 19:36:01 +0800
Subject: [PATCH] cgroup: improve test to find cgroup compatibility issues
 (#41347)

close pingcap/tidb#39786
---
 util/cgroup/cgroup_cpu.go      |  4 +++-
 util/cgroup/cgroup_cpu_test.go | 10 +++++++---
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/util/cgroup/cgroup_cpu.go b/util/cgroup/cgroup_cpu.go
index bafa319f5ad62..fdfdf2c9f979d 100644
--- a/util/cgroup/cgroup_cpu.go
+++ b/util/cgroup/cgroup_cpu.go
@@ -21,6 +21,8 @@ import (
 	"github.com/pingcap/errors"
 )
 
+var errNoCPUControllerDetected = errors.New("no cpu controller detected")
+
 // Helper function for getCgroupCPU. Root is always "/", except in tests.
 func getCgroupCPU(root string) (CPUUsage, error) {
 	path, err := detectControlPath(filepath.Join(root, procPathCGroup), "cpu,cpuacct")
@@ -30,7 +32,7 @@ func getCgroupCPU(root string) (CPUUsage, error) {
 
 	// No CPU controller detected
 	if path == "" {
-		return CPUUsage{}, errors.New("no cpu controller detected")
+		return CPUUsage{}, errNoCPUControllerDetected
 	}
 
 	mount, ver, err := getCgroupDetails(filepath.Join(root, procPathMountInfo), path, "cpu,cpuacct")
diff --git a/util/cgroup/cgroup_cpu_test.go b/util/cgroup/cgroup_cpu_test.go
index 481ed3e32ccf8..7c74994a7dbb0 100644
--- a/util/cgroup/cgroup_cpu_test.go
+++ b/util/cgroup/cgroup_cpu_test.go
@@ -42,9 +42,13 @@ func TestGetCgroupCPU(t *testing.T) {
 		}()
 	}
 	cpu, err := GetCgroupCPU()
-	require.NoError(t, err)
-	require.NotZero(t, cpu.Period)
-	require.Less(t, int64(1), cpu.Period)
+	if err == errNoCPUControllerDetected {
+		require.False(t, InContainer(), "Please check linux version > v4.7.x. This is related to cgroup compatibility.")
+	} else {
+		require.NoError(t, err)
+		require.NotZero(t, cpu.Period)
+		require.Less(t, int64(1), cpu.Period)
+	}
 	close(exit)
 	wg.Wait()
 }