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// +build linux
package fs
import (
"encoding/binary"
"fmt"
"syscall"
"testing"
"time"
)
func TestNotifyOnOOM(t *testing.T) {
helper := NewCgroupTestUtil("memory", t)
defer helper.cleanup()
helper.writeFileContents(map[string]string{
"memory.oom_control": "",
"cgroup.event_control": "",
})
var eventFd, oomControlFd int
ooms, err := notifyOnOOM(helper.CgroupData)
if err != nil {
t.Fatal("expected no error, got:", err)
}
memoryPath, _ := helper.CgroupData.path("memory")
data, err := readFile(memoryPath, "cgroup.event_control")
if err != nil {
t.Fatal("couldn't read event control file:", err)
}
if _, err := fmt.Sscanf(data, "%d %d", &eventFd, &oomControlFd); err != nil {
t.Fatalf("invalid control data %q: %s", data, err)
}
// re-open the eventfd
efd, err := syscall.Dup(eventFd)
if err != nil {
t.Fatal("unable to reopen eventfd:", err)
}
defer syscall.Close(efd)
if err != nil {
t.Fatal("unable to dup event fd:", err)
}
buf := make([]byte, 8)
binary.LittleEndian.PutUint64(buf, 1)
if _, err := syscall.Write(efd, buf); err != nil {
t.Fatal("unable to write to eventfd:", err)
}
select {
case <-ooms:
case <-time.After(100 * time.Millisecond):
t.Fatal("no notification on oom channel after 100ms")
}
// simulate what happens when a cgroup is destroyed by cleaning up and then
// writing to the eventfd.
helper.cleanup()
if _, err := syscall.Write(efd, buf); err != nil {
t.Fatal("unable to write to eventfd:", err)
}
// give things a moment to shut down
select {
case _, ok := <-ooms:
if ok {
t.Fatal("expected no oom to be triggered")
}
case <-time.After(100 * time.Millisecond):
}
if _, _, err := syscall.Syscall(syscall.SYS_FCNTL, uintptr(oomControlFd), syscall.F_GETFD, 0); err != syscall.EBADF {
t.Error("expected oom control to be closed")
}
if _, _, err := syscall.Syscall(syscall.SYS_FCNTL, uintptr(eventFd), syscall.F_GETFD, 0); err != syscall.EBADF {
t.Error("expected event fd to be closed")
}
}
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