diff --git a/src/core/support/cpu_linux.c b/src/core/support/cpu_linux.c
index eab8b7fbd05f470120eaedac00ea95fa18fe3161..ad82174894b574b1f08c4e35ab6adaae34081905 100644
--- a/src/core/support/cpu_linux.c
+++ b/src/core/support/cpu_linux.c
@@ -31,44 +31,17 @@
  *
  */
 
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif  /* _GNU_SOURCE */
+
 #include <grpc/support/port_platform.h>
 
 #ifdef GPR_CPU_LINUX
 
 #include "src/core/support/cpu.h"
 
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE
-#define GRPC_GNU_SOURCE
-#endif
-
-#ifndef __USE_GNU
-#define __USE_GNU
-#define GRPC_USE_GNU
-#endif
-
-#ifndef __USE_MISC
-#define __USE_MISC
-#define GRPC_USE_MISC
-#endif
-
 #include <sched.h>
-
-#ifdef GRPC_GNU_SOURCE
-#undef _GNU_SOURCE
-#undef GRPC_GNU_SOURCE
-#endif
-
-#ifdef GRPC_USE_GNU
-#undef __USE_GNU
-#undef GRPC_USE_GNU
-#endif
-
-#ifdef GRPC_USE_MISC
-#undef __USE_MISC
-#undef GRPC_USE_MISC
-#endif
-
 #include <errno.h>
 #include <unistd.h>
 #include <string.h>