hs-test: fix cpu allocator

Effective CPUs file is different between cgroups v1 and v2.

Type: test

Change-Id: Ic1b9059435b3f0944624120f57e72da45adca223
Signed-off-by: Matus Fabian <matfabia@cisco.com>

diff --git a/extras/hs-test/cpu.go b/extras/hs-test/cpu.go
index 9a034ed..a976f47 100644 (file)
--- a/extras/hs-test/cpu.go
+++ b/extras/hs-test/cpu.go
@@ -2,11 +2,14 @@ package main
 
 import (
        "bufio"
+       "errors"
        "fmt"
        "os"
+       "os/exec"
+       "strings"
 )
 
-var CPU_PATH = "/sys/fs/cgroup/cpuset.cpus.effective"
+var CgroupPath = "/sys/fs/cgroup/"
 
 type CpuContext struct {
        cpuAllocator *CpuAllocatorT
@@ -38,7 +41,25 @@ func (c *CpuAllocatorT) Allocate(nCpus int) (*CpuContext, error) {
 
 func (c *CpuAllocatorT) readCpus() error {
        var first, last int
-       file, err := os.Open(CPU_PATH)
+
+       // Path depends on cgroup version. We need to check which version is in use.
+       // For that following command can be used: 'stat -fc %T /sys/fs/cgroup/'
+       // In case the output states 'cgroup2fs' then cgroups v2 is used, 'tmpfs' in case cgroups v1.
+       cmd := exec.Command("stat", "-fc", "%T", "/sys/fs/cgroup/")
+       byteOutput, err := cmd.CombinedOutput()
+       if err != nil {
+               return err
+       }
+       CpuPath := CgroupPath
+       if strings.Contains(string(byteOutput), "tmpfs") {
+               CpuPath += "cpuset/cpuset.effective_cpus"
+       } else if strings.Contains(string(byteOutput), "cgroup2fs") {
+               CpuPath += "cpuset.cpus.effective"
+       } else {
+               return errors.New("cgroup unknown fs: " + string(byteOutput))
+       }
+
+       file, err := os.Open(CpuPath)
        if err != nil {
                return err
        }