[1.4] Add memory policy support

Implement support for Linux memory policy in OCI spec PR:
https://github.com/opencontainers/runtime-spec/pull/1282

Signed-off-by: Antti Kervinen <antti.kervinen@intel.com>
(cherry picked from commit eda7bdf80c)
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>

internal/linux/linux.go

@@ -2,6 +2,7 @@ package linux
 
 import (
 	"os"
+	"unsafe"
 
 	"golang.org/x/sys/unix"
 )
@@ -72,3 +73,15 @@ func Sendmsg(fd int, p, oob []byte, to unix.Sockaddr, flags int) error {
 	})
 	return os.NewSyscallError("sendmsg", err)
 }
+
+// SetMempolicy wraps set_mempolicy.
+func SetMempolicy(mode uint, mask *unix.CPUSet) error {
+	err := retryOnEINTR(func() error {
+		_, _, errno := unix.Syscall(unix.SYS_SET_MEMPOLICY, uintptr(mode), uintptr(unsafe.Pointer(mask)), unsafe.Sizeof(*mask)*8)
+		if errno != 0 {
+			return errno
+		}
+		return nil
+	})
+	return os.NewSyscallError("set_mempolicy", err)
+}