* AP_ACTIVE AP_ACTIVE
*/
+/*
+ * CPU hotplug states. The state machine invokes the installed state
+ * startup callbacks sequentially from CPUHP_OFFLINE + 1 to CPUHP_ONLINE
+ * during a CPU online operation. During a CPU offline operation the
+ * installed teardown callbacks are invoked in the reverse order from
+ * CPU_ONLINE - 1 down to CPUHP_OFFLINE.
+ *
+ * The state space has three sections: PREPARE, STARTING and ONLINE.
+ *
+ * PREPARE: The callbacks are invoked on a control CPU before the
+ * hotplugged CPU is started up or after the hotplugged CPU has died.
+ *
+ * STARTING: The callbacks are invoked on the hotplugged CPU from the low level
+ * hotplug startup/teardown code with interrupts disabled.
+ *
+ * ONLINE: The callbacks are invoked on the hotplugged CPU from the per CPU
+ * hotplug thread with interrupts and preemption enabled.
+ *
+ * Adding explicit states to this enum is only necessary when:
+ *
+ * 1) The state is within the STARTING section
+ *
+ * 2) The state has ordering constraints vs. other states in the
+ * same section.
+ *
+ * If neither #1 nor #2 apply, please use the dynamic state space when
+ * setting up a state by using CPUHP_PREPARE_DYN or CPUHP_PREPARE_ONLINE
+ * for the @state argument of the setup function.
+ *
+ * See Documentation/core-api/cpu_hotplug.rst for further information and
+ * examples.
+ */
enum cpuhp_state {
CPUHP_INVALID = -1,
+
+ /* PREPARE section invoked on a control CPU */
CPUHP_OFFLINE = 0,
CPUHP_CREATE_THREADS,
CPUHP_PERF_PREPARE,
CPUHP_BP_PREPARE_DYN,
CPUHP_BP_PREPARE_DYN_END = CPUHP_BP_PREPARE_DYN + 20,
CPUHP_BRINGUP_CPU,
+
+ /*
+ * STARTING section invoked on the hotplugged CPU in low level
+ * bringup and teardown code.
+ */
CPUHP_AP_IDLE_DEAD,
CPUHP_AP_OFFLINE,
CPUHP_AP_SCHED_STARTING,
CPUHP_AP_ARM_CACHE_B15_RAC_DYING,
CPUHP_AP_ONLINE,
CPUHP_TEARDOWN_CPU,
+
+ /* Online section invoked on the hotplugged CPU from the hotplug thread */
CPUHP_AP_ONLINE_IDLE,
CPUHP_AP_SCHED_WAIT_EMPTY,
CPUHP_AP_SMPBOOT_THREADS,
int (*teardown)(unsigned int cpu),
bool multi_instance);
/**
- * cpuhp_setup_state - Setup hotplug state callbacks with calling the callbacks
+ * cpuhp_setup_state - Setup hotplug state callbacks with calling the @startup
+ * callback
* @state: The state for which the calls are installed
* @name: Name of the callback (will be used in debug output)
- * @startup: startup callback function
- * @teardown: teardown callback function
+ * @startup: startup callback function or NULL if not required
+ * @teardown: teardown callback function or NULL if not required
*
- * Installs the callback functions and invokes the startup callback on
- * the present cpus which have already reached the @state.
+ * Installs the callback functions and invokes the @startup callback on
+ * the online cpus which have already reached the @state.
*/
static inline int cpuhp_setup_state(enum cpuhp_state state,
const char *name,
return __cpuhp_setup_state(state, name, true, startup, teardown, false);
}
+/**
+ * cpuhp_setup_state_cpuslocked - Setup hotplug state callbacks with calling
+ * @startup callback from a cpus_read_lock()
+ * held region
+ * @state: The state for which the calls are installed
+ * @name: Name of the callback (will be used in debug output)
+ * @startup: startup callback function or NULL if not required
+ * @teardown: teardown callback function or NULL if not required
+ *
+ * Same as cpuhp_setup_state() except that it must be invoked from within a
+ * cpus_read_lock() held region.
+ */
static inline int cpuhp_setup_state_cpuslocked(enum cpuhp_state state,
const char *name,
int (*startup)(unsigned int cpu),
/**
* cpuhp_setup_state_nocalls - Setup hotplug state callbacks without calling the
- * callbacks
+ * @startup callback
* @state: The state for which the calls are installed
* @name: Name of the callback.
- * @startup: startup callback function
- * @teardown: teardown callback function
+ * @startup: startup callback function or NULL if not required
+ * @teardown: teardown callback function or NULL if not required
*
- * Same as @cpuhp_setup_state except that no calls are executed are invoked
- * during installation of this callback. NOP if SMP=n or HOTPLUG_CPU=n.
+ * Same as cpuhp_setup_state() except that the @startup callback is not
+ * invoked during installation. NOP if SMP=n or HOTPLUG_CPU=n.
*/
static inline int cpuhp_setup_state_nocalls(enum cpuhp_state state,
const char *name,
false);
}
+/**
+ * cpuhp_setup_state_nocalls_cpuslocked - Setup hotplug state callbacks without
+ * invoking the @startup callback from
+ * a cpus_read_lock() held region
+ * callbacks
+ * @state: The state for which the calls are installed
+ * @name: Name of the callback.
+ * @startup: startup callback function or NULL if not required
+ * @teardown: teardown callback function or NULL if not required
+ *
+ * Same as cpuhp_setup_state_nocalls() except that it must be invoked from
+ * within a cpus_read_lock() held region.
+ */
static inline int cpuhp_setup_state_nocalls_cpuslocked(enum cpuhp_state state,
const char *name,
int (*startup)(unsigned int cpu),
* cpuhp_setup_state_multi - Add callbacks for multi state
* @state: The state for which the calls are installed
* @name: Name of the callback.
- * @startup: startup callback function
- * @teardown: teardown callback function
+ * @startup: startup callback function or NULL if not required
+ * @teardown: teardown callback function or NULL if not required
*
* Sets the internal multi_instance flag and prepares a state to work as a multi
* instance callback. No callbacks are invoked at this point. The callbacks are
* invoked once an instance for this state are registered via
- * @cpuhp_state_add_instance or @cpuhp_state_add_instance_nocalls.
+ * cpuhp_state_add_instance() or cpuhp_state_add_instance_nocalls()
*/
static inline int cpuhp_setup_state_multi(enum cpuhp_state state,
const char *name,
* @state: The state for which the instance is installed
* @node: The node for this individual state.
*
- * Installs the instance for the @state and invokes the startup callback on
- * the present cpus which have already reached the @state. The @state must have
- * been earlier marked as multi-instance by @cpuhp_setup_state_multi.
+ * Installs the instance for the @state and invokes the registered startup
+ * callback on the online cpus which have already reached the @state. The
+ * @state must have been earlier marked as multi-instance by
+ * cpuhp_setup_state_multi().
*/
static inline int cpuhp_state_add_instance(enum cpuhp_state state,
struct hlist_node *node)
* @state: The state for which the instance is installed
* @node: The node for this individual state.
*
- * Installs the instance for the @state The @state must have been earlier
- * marked as multi-instance by @cpuhp_setup_state_multi.
+ * Installs the instance for the @state. The @state must have been earlier
+ * marked as multi-instance by cpuhp_setup_state_multi. NOP if SMP=n or
+ * HOTPLUG_CPU=n.
*/
static inline int cpuhp_state_add_instance_nocalls(enum cpuhp_state state,
struct hlist_node *node)
return __cpuhp_state_add_instance(state, node, false);
}
+/**
+ * cpuhp_state_add_instance_nocalls_cpuslocked - Add an instance for a state
+ * without invoking the startup
+ * callback from a cpus_read_lock()
+ * held region.
+ * @state: The state for which the instance is installed
+ * @node: The node for this individual state.
+ *
+ * Same as cpuhp_state_add_instance_nocalls() except that it must be
+ * invoked from within a cpus_read_lock() held region.
+ */
static inline int
cpuhp_state_add_instance_nocalls_cpuslocked(enum cpuhp_state state,
struct hlist_node *node)
* @state: The state for which the calls are removed
*
* Removes the callback functions and invokes the teardown callback on
- * the present cpus which have already reached the @state.
+ * the online cpus which have already reached the @state.
*/
static inline void cpuhp_remove_state(enum cpuhp_state state)
{
/**
* cpuhp_remove_state_nocalls - Remove hotplug state callbacks without invoking
- * teardown
+ * the teardown callback
* @state: The state for which the calls are removed
*/
static inline void cpuhp_remove_state_nocalls(enum cpuhp_state state)
__cpuhp_remove_state(state, false);
}
+/**
+ * cpuhp_remove_state_nocalls_cpuslocked - Remove hotplug state callbacks without invoking
+ * teardown from a cpus_read_lock() held region.
+ * @state: The state for which the calls are removed
+ *
+ * Same as cpuhp_remove_state nocalls() except that it must be invoked
+ * from within a cpus_read_lock() held region.
+ */
static inline void cpuhp_remove_state_nocalls_cpuslocked(enum cpuhp_state state)
{
__cpuhp_remove_state_cpuslocked(state, false);
* @state: The state from which the instance is removed
* @node: The node for this individual state.
*
- * Removes the instance and invokes the teardown callback on the present cpus
- * which have already reached the @state.
+ * Removes the instance and invokes the teardown callback on the online cpus
+ * which have already reached @state.
*/
static inline int cpuhp_state_remove_instance(enum cpuhp_state state,
struct hlist_node *node)
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