On Fri, May 17, 2013 at 10:49:16PM +0200, Arend van Spriel wrote:
> On 05/14/2013 10:38 PM, Arend van Spriel wrote:
> >On 05/14/2013 10:34 PM, Rafael J. Wysocki wrote:
> >>On Tuesday, May 14, 2013 03:03:58 PM Arend van Spriel wrote:
> >>>Laptop hangs pretty soon after booting. Workaround for me was to turn
> >>>off ACPI on kernel command line, ie. acpi=off
> >>>
> >>>Attached is my kernel configuration.
> >>
> >>Well, I have no idea what may be the source of this.
> >
> >Me neither.
> >
> >>Any chance to bisect?
> >
> >can try. Rebuilding kernels can be a drag :-p
> >
> >Regards,
> >Arend
>
> Hi Rafael,
>
> The bisect result found commit c0f4dfd4f as culprit. I also verified
> that the merge into Linus' tree introduced the issue upstream, ie.
> 6c24499 works and 1f889ec does not. I tried to revert the commit,
> but that was a bit risky (conflict to resolve) and did not give me a
> stable kernel. The only thing that works is selecting acpi=off. I
> tried also nohz=off but that resulted in /init failure.
>
> Regards,
> Arend
>
> ---8<----------------------------------------------------------------
>
> commit 1f889ec62c3f0d8913f3c32f9aff2a1e15099346
> Merge: 6c24499 8fcfae3
>
> commit 8fcfae31719c0a6c03f2cf63f815b46d378d8be4
> Merge: d02a9a8 6d87669
>
> commit 6d87669357936bffa1e8fea7a4e7743e76905736
> Merge: 3f944ad 81e5949 910ee45
>
> commit c0f4dfd4f90f1667d234d21f15153ea09a2eaa66
> Author: Paul E. McKenney <paul.mckenney@xxxxxxxxxx>
> Date: Fri Dec 28 11:30:36 2012 -0800
>
> rcu: Make RCU_FAST_NO_HZ take advantage of numbered callbacks
>
> Because RCU callbacks are now associated with the number
> of the grace period that they must wait for, CPUs can now
> take advance callbacks corresponding to grace periods that
> ended while a given CPU was in dyntick-idle mode. This
> eliminates the need to try forcing the RCU state machine
> while entering idle, thus reducing the CPU intensiveness
> of RCU_FAST_NO_HZ, which should increase its energy
> efficiency.
>
> Signed-off-by: Paul E. McKenney <paul.mckenney@xxxxxxxxxx>
> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Hello, Arend,
Thank you for tracking this down! Could you please try out the following
patch?
Thanx, Paul
------------------------------------------------------------------------
rcu: Fix comparison sense in rcu_needs_cpu()
Commit c0f4dfd4f (rcu: Make RCU_FAST_NO_HZ take advantage of numbered
callbacks) introduced a bug that can result in excessively long grace
periods. This bug reverse the senes of the "if" statement checking
for lazy callbacks, so that RCU takes a lazy approach when there are
in fact non-lazy callbacks. This can result in excessive boot, suspend,
and resume times.
This commit therefore fixes the sense of this "if" statement.
Reported-by: Borislav Petkov <bp@xxxxxxxxx>
Reported-by: Bjørn Mork <bjorn@xxxxxxx>
Reported-by: Joerg Roedel <joro@xxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Tested-by: Bjørn Mork <bjorn@xxxxxxx>
Tested-by: Joerg Roedel <joro@xxxxxxxxxx>
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 170814d..6d939a6 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -1667,7 +1667,7 @@ int rcu_needs_cpu(int cpu, unsigned long *dj)
rdtp->last_accelerate = jiffies;
/* Request timer delay depending on laziness, and round. */
- if (rdtp->all_lazy) {
+ if (!rdtp->all_lazy) {
*dj = round_up(rcu_idle_gp_delay + jiffies,
rcu_idle_gp_delay) - jiffies;
} else {
--
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