Shrink task_struct if CONFIG_FUTEX=n

robust_list, compat_robust_list, pi_state_list, pi_state_cache are
really used if futexes are on.

Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 87f2eb2..5716658 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1132,13 +1132,14 @@
 	int cpuset_mems_generation;
 	int cpuset_mem_spread_rotor;
 #endif
+#ifdef CONFIG_FUTEX
 	struct robust_list_head __user *robust_list;
 #ifdef CONFIG_COMPAT
 	struct compat_robust_list_head __user *compat_robust_list;
 #endif
 	struct list_head pi_state_list;
 	struct futex_pi_state *pi_state_cache;
-
+#endif
 	atomic_t fs_excl;	/* holding fs exclusive resources */
 	struct rcu_head rcu;