rcu: Make RCU_FAST_NO_HZ respect nohz= boot parameter
If the nohz= boot parameter disables nohz, then RCU_FAST_NO_HZ needs to
also disable itself. This commit therefore checks for tick_nohz_enabled
being zero, disabling rcu_prepare_for_idle() if so. This commit assumes
that tick_nohz_enabled can change at runtime: If this is not the case,
then a simpler approach suffices.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index 19b61ac..e978845 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -97,6 +97,7 @@
/* # times non-lazy CBs posted to CPU. */
unsigned long nonlazy_posted_snap;
/* idle-period nonlazy_posted snapshot. */
+ int tick_nohz_enabled_snap; /* Previously seen value from sysfs. */
#endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */
};