src/patches/suse-2.6.27.25/patches.arch/s390-12-08-kernel_appldata_vtimer.patch

   1 From: Gerald Schaefer <geraldsc@de.ibm.com>
   2 Subject: kernel: appldata vtimer bug with cpu hotplug
   3 References: bnc#487755,LTC#52680
   4
   5 Symptom:     Kernel BUG on SLES 11 with cpu hotplug and appldata timer enabled.
   6              On older distributions, the appldata interval will not expire
   7              correctly instead (interval may be longer after cpu hotplug).
   8 Problem:     The mod_virt_timer() function will add a one-shot timer for new
   9              cpus, not an interval timer. Also, on SLES 11 there is a misplaced
  10              BUG_ON() statement in that function.
  11 Solution:    Work around by adding a new vtimer for cpus that get online,
  12              before modifying it.
  13
  14 Acked-by: John Jolly <jjolly@suse.de>
  15 ---
  16  arch/s390/appldata/appldata_base.c |   11 ++++++++++-
  17  1 file changed, 10 insertions(+), 1 deletion(-)
  18
  19 Index: linux-sles11/arch/s390/appldata/appldata_base.c
  20 ===================================================================
  21 --- linux-sles11.orig/arch/s390/appldata/appldata_base.c
  22 +++ linux-sles11/arch/s390/appldata/appldata_base.c
  23 @@ -478,13 +478,22 @@ void appldata_unregister_ops(struct appl
  24
  25  static void __cpuinit appldata_online_cpu(int cpu)
  26  {
  27 +       u64 per_cpu_interval;
  28 +
  29         init_virt_timer(&per_cpu(appldata_timer, cpu));
  30         per_cpu(appldata_timer, cpu).function = appldata_timer_function;
  31         per_cpu(appldata_timer, cpu).data = (unsigned long)
  32                 &appldata_work;
  33         atomic_inc(&appldata_expire_count);
  34         spin_lock(&appldata_timer_lock);
  35 -       __appldata_vtimer_setup(APPLDATA_MOD_TIMER);
  36 +       if (appldata_timer_active) {
  37 +               per_cpu_interval = (u64) (appldata_interval * 1000 /
  38 +                                         num_online_cpus()) * TOD_MICRO;
  39 +               per_cpu(appldata_timer, cpu).expires = per_cpu_interval;
  40 +               smp_call_function_single(cpu, add_virt_timer_periodic,
  41 +                                        &per_cpu(appldata_timer, cpu), 1);
  42 +               __appldata_vtimer_setup(APPLDATA_MOD_TIMER);
  43 +       }
  44         spin_unlock(&appldata_timer_lock);
  45  }
  46