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| author | Manfred Spraul <manfred@colorfullife.com> | 2008-09-07 16:57:22 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-09-08 19:25:24 +0200 |
| commit | e545a6140b698b2494daf0b32107bdcc5e901390 (patch) | |
| tree | 63f302e25ba7a0705bbf051f3817fac8f8b98aba /kernel/cpu.c | |
| parent | 7686ad5606f08d9dfb33a2087a36c8366366015b (diff) | |
| download | lwn-e545a6140b698b2494daf0b32107bdcc5e901390.tar.gz lwn-e545a6140b698b2494daf0b32107bdcc5e901390.zip | |
kernel/cpu.c: create a CPU_STARTING cpu_chain notifier
Right now, there is no notifier that is called on a new cpu, before the new
cpu begins processing interrupts/softirqs.
Various kernel function would need that notification, e.g. kvm works around
by calling smp_call_function_single(), rcu polls cpu_online_map.
The patch adds a CPU_STARTING notification. It also adds a helper function
that sends the message to all cpu_chain handlers.
Tested on x86-64.
All other archs are untested. Especially on sparc, I'm not sure if I got
it right.
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index f17e9854c246..dc45f2459efb 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -453,6 +453,25 @@ out: } #endif /* CONFIG_PM_SLEEP_SMP */ +/** + * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers + * @cpu: cpu that just started + * + * This function calls the cpu_chain notifiers with CPU_STARTING. + * It must be called by the arch code on the new cpu, before the new cpu + * enables interrupts and before the "boot" cpu returns from __cpu_up(). + */ +void notify_cpu_starting(unsigned int cpu) +{ + unsigned long val = CPU_STARTING; + +#ifdef CONFIG_PM_SLEEP_SMP + if (cpu_isset(cpu, frozen_cpus)) + val = CPU_STARTING_FROZEN; +#endif /* CONFIG_PM_SLEEP_SMP */ + raw_notifier_call_chain(&cpu_chain, val, (void *)(long)cpu); +} + #endif /* CONFIG_SMP */ /* |