Add a state diagram to clarify when which states are ran where.
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
---
include/linux/cpuhotplug.h | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -3,6 +3,24 @@
#include <linux/types.h>
+/*
+ * 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,
