lkml.org 
[lkml]   [2009]   [Aug]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: CONFIG_PREEMPT_RCU in next/mmotm
On Sun, 9 Aug 2009, Hugh Dickins wrote:
>
> filp 13343 objects:
>
> CPU last cur F M
> 0 1 0 0 0
> 1 0 0 0 0
> 2 -1 0 0 0
> 3 0 0 0 0
> ggp = 35124, state = waitzero

Interesting that rcu_try_flip_waitzero() doesn't see 1 + 0 + -1 + 0 == 0.

That's because rcu_cpu_online_map is 0x1 instead of the 0xf it should be.

Which is because I don't have CONFIG_HOTPLUG_CPU=y on that PPC machine
(unlike the x86s), and I think you've made some recent mods which
accidentally made the rcu cpu initialization dependent on hotplug
cpu notifiers? CONFIG_HOTPLUG_CPU=y and it works properly again.

And TREE_RCU doesn't use an rcu_cpu_online_map (though it does expect
some per-cpu initialization, but seems to get away without it).

So I think that's the mystery solved - I'll let you decide the right fix!

Hugh


\
 
 \ /
  Last update: 2009-08-09 15:09    [from the cache]
©2003-2011 Jasper Spaans