Documentation/core-api/cpu_hotplug.rst

139 Once a CPU has been logically shutdown the teardown callbacks of registered
164 When a CPU is onlined, the startup callbacks are invoked sequentially until
166 callbacks of a state are set up or an instance is added to a multi-instance
169 When a CPU is offlined the teardown callbacks are invoked in the reverse
171 be invoked when the callbacks of a state are removed or an instance is
185   The startup callbacks in this section are invoked before the CPU is
186   started during a CPU online operation. The teardown callbacks are invoked
189   The callbacks are invoked on a control CPU as they can't obviously run on
193   The startup callbacks are used to setup resources which are required to
194   bring a CPU successfully online. The teardown callbacks are used to free
198   The startup callbacks are allowed to fail. If a callback fails, the CPU
202   The teardown callbacks in this section are not allowed to fail.
209   The startup callbacks in this section are invoked on the hotplugged CPU
211   setup code. The teardown callbacks are invoked with interrupts disabled
215   The callbacks in this section are not allowed to fail.
217   The callbacks are used for low level hardware initialization/shutdown and
225   The startup callbacks in this section are invoked on the hotplugged CPU
226   during a CPU online operation. The teardown callbacks are invoked on the
229   The callbacks are invoked in the context of the per CPU hotplug thread,
230   which is pinned on the hotplugged CPU. The callbacks are invoked with
233   The callbacks are allowed to fail. When a callback fails the hotplug
354   callbacks during a CPU online operation. During a CPU offline operation
355   the driver teardown callbacks have to be invoked before the core teardown
363   Static allocation is also required when the state callbacks are not set
369   When there are no ordering requirements for the state callbacks then
374   range. The STARTING section does not as most of the callbacks in that
388 CPU hotplug state callbacks need to be invoked for each instance, the CPU
392 invocations of the state callbacks on add and removal. To set up such a
438 The functions differ in the way how the installed callbacks are treated:
441     and cpuhp_setup_state_multi() only install the callbacks
444     callbacks and invoke the @startup callback (if not NULL) for all online
452     the callbacks for the state are not installed and in case of dynamic
458 used. These functions cannot be used from within CPU hotplug callbacks.
467            the state callbacks have to be removed later, e.g. module
492 The functions differ in the way how the installed callbacks are treated:
495     and cpuhp_remove_multi_state() only remove the callbacks.
497   * cpuhp_remove_state() removes the callbacks and invokes the teardown
509 used. These functions cannot be used from within CPU hotplug callbacks.
528 state callbacks and can be used by the callback to retrieve the instance
531 The functions differ in the way how the installed callbacks are treated:
557 The functions differ in the way how the installed callbacks are treated:
574 from within CPU hotplug callbacks and CPU hotplug read locked regions.
598 for notifications on online operations without invoking the callbacks::
696 95.552. All invoked callbacks including their return codes are visible in the