Messages in this thread Patch in this message | | | Date | Sun, 21 Apr 2013 11:56:09 -0700 | From | "Paul E. McKenney" <> | Subject | Re: irq 16: nobody cared |
| |
On Sun, Apr 21, 2013 at 08:10:35PM +0200, Borislav Petkov wrote: > On Sun, Apr 21, 2013 at 06:56:54PM +0200, Borislav Petkov wrote: > > Ok, let me try to disable the soundcard in the BIOS. > > Ok, there's no warning message anymore but maybe a dozen of seconds > delay before the machine is actually powered off.
That is not so good...
> "... > ACPI: Preparing to enter system sleep state S5 > [Firmware Bug]: ACPI: BIOS _OSI(Linux) query ignored > <a bunch of seconds of doing nothing> > ... > <machine powers off>" > > So could it be that some RCU cleanup stuff is going on during that time?
CONFIG_RCU_FAST_NO_HZ will definitely change the timing, for example, increasing grace-period durations by up to a factor of four.
One way to figure out if this is the problem would be to either (1) apply the following patch (assuming you have no more than a few tens of CPUs) or (2) setting the sysfs rcutree.rcu_expedited variable to 1 just before suspending the system.
Either approach will force RCU to always use the faster expedited grace periods for synchronize_rcu() and friends. They will -not- help if someone has open-coded synchronize_rcu() in terms of call_rcu(), though.
> I mean, the issue is not that big of a deal - when the box resumes, the > sound card works just fine so...
Fair point. perhaps we should wait for Takashi to weigh in.
Thanx, Paul
> Thanks. > > -- > Regards/Gruss, > Boris. > > Sent from a fat crate under my desk. Formatting is fine. > --
------------------------------------------------------------------------
rcu: Not for inclusion: Force expedited grace periods
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcutree.c b/kernel/rcutree.c index a9610d1..55c5ef6 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -2420,7 +2420,7 @@ void synchronize_sched(void) "Illegal synchronize_sched() in RCU-sched read-side critical section"); if (rcu_blocking_is_gp()) return; - if (rcu_expedited) + if (1) synchronize_sched_expedited(); else wait_rcu_gp(call_rcu_sched); @@ -2447,7 +2447,7 @@ void synchronize_rcu_bh(void) "Illegal synchronize_rcu_bh() in RCU-bh read-side critical section"); if (rcu_blocking_is_gp()) return; - if (rcu_expedited) + if (1) synchronize_rcu_bh_expedited(); else wait_rcu_gp(call_rcu_bh); diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 46b93b0..190a199 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -711,7 +711,7 @@ void synchronize_rcu(void) "Illegal synchronize_rcu() in RCU read-side critical section"); if (!rcu_scheduler_active) return; - if (rcu_expedited) + if (1) synchronize_rcu_expedited(); else wait_rcu_gp(call_rcu);
| |