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author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2008-12-22 12:36:30 +0100 |
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committer | Rusty Russell <rusty@rustcorp.com.au> | 2009-01-04 23:10:14 +0100 |
commit | 9ea09af3bd3090e8349ca2899ca2011bd94cda85 (patch) | |
tree | 36396347bb750a6aecb0771cfebf9887aaaae492 /kernel/cpu.c | |
parent | parisc: fix module loading failure of large kernel modules (diff) | |
download | linux-9ea09af3bd3090e8349ca2899ca2011bd94cda85.tar.xz linux-9ea09af3bd3090e8349ca2899ca2011bd94cda85.zip |
stop_machine: introduce stop_machine_create/destroy.
Introduce stop_machine_create/destroy. With this interface subsystems
that need a non-failing stop_machine environment can create the
stop_machine machine threads before actually calling stop_machine.
When the threads aren't needed anymore they can be killed with
stop_machine_destroy again.
When stop_machine gets called and the threads aren't present they
will be created and destroyed automatically. This restores the old
behaviour of stop_machine.
This patch also converts cpu hotplug to the new interface since it
is special: cpu_down calls __stop_machine instead of stop_machine.
However the kstop threads will only be created when stop_machine
gets called.
Changing the code so that the threads would be created automatically
on __stop_machine is currently not possible: when __stop_machine gets
called we hold cpu_add_remove_lock, which is the same lock that
create_rt_workqueue would take. So the workqueue needs to be created
before the cpu hotplug code locks cpu_add_remove_lock.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'kernel/cpu.c')
-rw-r--r-- | kernel/cpu.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 47fff3b63cbf..30e74dd6d01b 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -269,8 +269,11 @@ out_release: int __ref cpu_down(unsigned int cpu) { - int err = 0; + int err; + err = stop_machine_create(); + if (err) + return err; cpu_maps_update_begin(); if (cpu_hotplug_disabled) { @@ -297,6 +300,7 @@ int __ref cpu_down(unsigned int cpu) out: cpu_maps_update_done(); + stop_machine_destroy(); return err; } EXPORT_SYMBOL(cpu_down); |