rt-patches/0099-stop_machine-convert-stop_machine_run-to-PREEMPT_RT.patch

   1 From 54139dfd773a22677e9a8f1e49c4123ed3a55f0b Mon Sep 17 00:00:00 2001
   2 From: Ingo Molnar <mingo@elte.hu>
   3 Date: Fri, 3 Jul 2009 08:30:27 -0500
   4 Subject: [PATCH 099/366] stop_machine: convert stop_machine_run() to
   5  PREEMPT_RT
   6
   7 Instead of playing with non-preemption, introduce explicit
   8 startup serialization. This is more robust and cleaner as
   9 well.
  10
  11 Signed-off-by: Ingo Molnar <mingo@elte.hu>
  12 Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
  13 [bigeasy: XXX: stopper_lock -> stop_cpus_lock]
  14 ---
  15  kernel/stop_machine.c | 10 ++++++++++
  16  1 file changed, 10 insertions(+)
  17
  18 diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
  19 index a3bbaee..4ef69a3 100644
  20 --- a/kernel/stop_machine.c
  21 +++ b/kernel/stop_machine.c
  22 @@ -450,6 +450,16 @@ repeat:
  23                 struct cpu_stop_done *done = work->done;
  24                 char ksym_buf[KSYM_NAME_LEN] __maybe_unused;
  25
  26 +               /*
  27 +                * Wait until the stopper finished scheduling on all
  28 +                * cpus
  29 +                */
  30 +               lg_global_lock(&stop_cpus_lock);
  31 +               /*
  32 +                * Let other cpu threads continue as well
  33 +                */
  34 +               lg_global_unlock(&stop_cpus_lock);
  35 +
  36                 /* cpu stop callbacks are not allowed to sleep */
  37                 preempt_disable();
  38
  39 --
  40 1.9.1
  41