From fac1c2040203363eab6c6e86ce883cb71390418f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 20 Sep 2017 19:00:15 +0200 Subject: [PATCH] smp/hotplug: Add state diagram Add a state diagram to clarify when which states are ran where. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Cc: bigeasy@linutronix.de Cc: efault@gmx.de Cc: rostedt@goodmis.org Cc: max.byungchul.park@gmail.com Link: https://lkml.kernel.org/r/20170920170546.661598270@infradead.org --- include/linux/cpuhotplug.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index f24bfb2..477b2e6 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -3,6 +3,24 @@ #include +/* + * CPU-up CPU-down + * + * BP AP BP AP + * + * OFFLINE OFFLINE + * | ^ + * v | + * BRINGUP_CPU->AP_OFFLINE BRINGUP_CPU <- AP_IDLE_DEAD (idle thread/play_dead) + * | AP_OFFLINE + * v (IRQ-off) ,---------------^ + * AP_ONLNE | (stop_machine) + * | TEARDOWN_CPU <- AP_ONLINE_IDLE + * | ^ + * v | + * AP_ACTIVE AP_ACTIVE + */ + enum cpuhp_state { CPUHP_OFFLINE, CPUHP_CREATE_THREADS, -- 2.7.4