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cpu/hotplug: Document states better 

Requested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2016-03-08 10:36:13 +01:00
parent 2a58c527bb
commit d10ef6f938
1 changed files with 46 additions and 1 deletions
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47
kernel/cpu.c
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@ -1172,6 +1172,10 @@ static struct cpuhp_step cpuhp_bp_states[] = {
.teardown = NULL,
.cant_stop = true,
},
/*
* Preparatory and dead notifiers. Will be replaced once the notifiers
* are converted to states.
*/
[CPUHP_NOTIFY_PREPARE] = {
.name = "notify:prepare",
.startup = notify_prepare,
@ -1179,12 +1183,17 @@ static struct cpuhp_step cpuhp_bp_states[] = {
.skip_onerr = true,
.cant_stop = true,
},
/* Kicks the plugged cpu into life */
[CPUHP_BRINGUP_CPU] = {
.name = "cpu:bringup",
.startup = bringup_cpu,
.teardown = NULL,
.cant_stop = true,
},
/*
* Handled on controll processor until the plugged processor manages
* this itself.
*/
[CPUHP_TEARDOWN_CPU] = {
.name = "cpu:teardown",
.startup = NULL,
@ -1197,6 +1206,23 @@ static struct cpuhp_step cpuhp_bp_states[] = {
/* Application processor state steps */
static struct cpuhp_step cpuhp_ap_states[] = {
#ifdef CONFIG_SMP
/* Final state before CPU kills itself */
[CPUHP_AP_IDLE_DEAD] = {
.name = "idle:dead",
},
/*
* Last state before CPU enters the idle loop to die. Transient state
* for synchronization.
*/
[CPUHP_AP_OFFLINE] = {
.name = "ap:offline",
.cant_stop = true,
},
/*
* Low level startup/teardown notifiers. Run with interrupts
* disabled. Will be removed once the notifiers are converted to
* states.
*/
[CPUHP_AP_NOTIFY_STARTING] = {
.name = "notify:starting",
.startup = notify_starting,
@ -1204,17 +1230,32 @@ static struct cpuhp_step cpuhp_ap_states[] = {
.skip_onerr = true,
.cant_stop = true,
},
/* Entry state on starting. Interrupts enabled from here on. Transient
* state for synchronsization */
[CPUHP_AP_ONLINE] = {
.name = "ap:online",
},
/* Handle smpboot threads park/unpark */
[CPUHP_AP_SMPBOOT_THREADS] = {
.name = "smpboot:threads",
.startup = smpboot_unpark_threads,
.teardown = NULL,
},
/*
* Online/down_prepare notifiers. Will be removed once the notifiers
* are converted to states.
*/
[CPUHP_AP_NOTIFY_ONLINE] = {
.name = "notify:online",
.startup = notify_online,
.teardown = notify_down_prepare,
},
#endif
/*
* The dynamically registered state space is here
*/
/* CPU is fully up and running. */
[CPUHP_ONLINE] = {
.name = "online",
.startup = NULL,
@ -1232,7 +1273,11 @@ static int cpuhp_cb_check(enum cpuhp_state state)
static bool cpuhp_is_ap_state(enum cpuhp_state state)
{
return state > CPUHP_BRINGUP_CPU;
/*
* The extra check for CPUHP_TEARDOWN_CPU is only for documentation
* purposes as that state is handled explicitely in cpu_down.
*/
return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU;
}
static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state)