Piteball/android_kernel_google_msm
1
0
Fork 0
mirror of https://github.com/followmsi/android_kernel_google_msm.git synced 2024-09-20 19:51:42 +00:00
Code Issues Projects Releases Wiki Activity

rcu: Add warning for RCU_FAST_NO_HZ timer firing

Browse source 
RCU_FAST_NO_HZ uses a timer to limit the time that a CPU with callbacks
can remain in dyntick-idle mode.  This timer is cancelled when the CPU
exits idle, and therefore should never fire.  However, if the timer
were migrated to some other CPU for whatever reason (1) the timer could
actually fire and (2) firing on some other CPU would fail to wake up the
CPU with callbacks, possibly resulting in sluggishness or a system hang.

This commit therfore adds a WARN_ON_ONCE() to the timer handler in order
to detect this condition.

CRs-fixed: 657837
Change-Id: Ie667bd7ee157668b2f0fca7eaf67cb746be1d674
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Git-commit: 79b9a75fb7
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Ramesh Gupta Guntha <rggupt@codeaurora.org>
This commit is contained in:
Paul E. McKenney 2012-04-23 10:06:39 -07:00 committed by Zhao Wei Liew
parent fd7133ac3c
commit c0c7fc6063
1 changed files with 1 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

1
kernel/rcutree_plugin.h
View file

@ -2068,6 +2068,7 @@ static bool rcu_cpu_has_nonlazy_callbacks(int cpu)
*/
static void rcu_idle_gp_timer_func(unsigned long unused)
{
WARN_ON_ONCE(1); /* Getting here can hang the system... */
trace_rcu_prep_idle("Timer");
}