powerpc: Convert RTAS event scan from kernel thread to workqueue
RTAS event scan has to run across all cpus. Right now we use a kernel thread and set_cpus_allowed but in doing so we wake up the previous cpu unnecessarily. Some ftrace output shows this: previous cpu (2): [002] 7.022331: sched_switch: task swapper:0 [140] ==> rtasd:194 [120] [002] 7.022338: sched_switch: task rtasd:194 [120] ==> migration/2:9 [0] [002] 7.022344: sched_switch: task migration/2:9 [0] ==> swapper:0 [140] next cpu (3): [003] 7.022345: sched_switch: task swapper:0 [140] ==> rtasd:194 [120] [003] 7.022371: sched_switch: task rtasd:194 [120] ==> swapper:0 [140] We can use schedule_delayed_work_on and avoid the unnecessary wakeup. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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