Messages in this thread Patch in this message | | | Date | Fri, 30 Sep 2011 09:28:15 -0700 | From | Jeremy Fitzhardinge <> | Subject | [PATCH RFC] stop_machine: make stop_machine safe and efficient to call early |
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Make stop_machine() safe to call early in boot, before SMP has been set up, by simply calling the callback function directly if there's only one CPU online.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Tejun Heo <tj@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: H. Peter Anvin <hpa@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index ba5070c..2df15ca 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -485,6 +485,9 @@ int __stop_machine(int (*fn)(void *), void *data, const struct cpumask *cpus) .num_threads = num_online_cpus(), .active_cpus = cpus }; + if (smdata.num_threads == 1) + return (*fn)(data); + /* Set the initial state and stop all online cpus. */ set_state(&smdata, STOPMACHINE_PREPARE); return stop_cpus(cpu_online_mask, stop_machine_cpu_stop, &smdata);
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