Commit 8bb78442 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Linus Torvalds
Browse files

Add suspend-related notifications for CPU hotplug 



Since nonboot CPUs are now disabled after tasks and devices have been
frozen and the CPU hotplug infrastructure is used for this purpose, we need
special CPU hotplug notifications that will help the CPU-hotplug-aware
subsystems distinguish normal CPU hotplug events from CPU hotplug events
related to a system-wide suspend or resume operation in progress.  This
patch introduces such notifications and causes them to be used during
suspend and resume transitions.  It also changes all of the
CPU-hotplug-aware subsystems to take these notifications into consideration
(for now they are handled in the same way as the corresponding "normal"
ones).

[oleg@tv-sign.ru: cleanups]
Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f37bc271

Documentation/cpu-hotplug.txt

+7 −2
Original line number Diff line number Diff line
@@ -217,14 +217,17 @@ Q: What happens when a CPU is being logically offlined? 
A: The following happen, listed in no particular order :-)



- A notification is sent to in-kernel registered modules by sending an event

  CPU_DOWN_PREPARE

  CPU_DOWN_PREPARE or CPU_DOWN_PREPARE_FROZEN, depending on whether or not the

  CPU is being offlined while tasks are frozen due to a suspend operation in

  progress

- All process is migrated away from this outgoing CPU to a new CPU

- All interrupts targeted to this CPU is migrated to a new CPU

- timers/bottom half/task lets are also migrated to a new CPU

- Once all services are migrated, kernel calls an arch specific routine

  __cpu_disable() to perform arch specific cleanup.

- Once this is successful, an event for successful cleanup is sent by an event

  CPU_DEAD.

  CPU_DEAD (or CPU_DEAD_FROZEN if tasks are frozen due to a suspend while the

  CPU is being offlined).



  "It is expected that each service cleans up when the CPU_DOWN_PREPARE

  notifier is called, when CPU_DEAD is called its expected there is nothing
@@ -242,9 +245,11 @@ A: This is what you would need in your kernel code to receive notifications. 


		switch (action) {

		case CPU_ONLINE:

		case CPU_ONLINE_FROZEN:

			foobar_online_action(cpu);

			break;

		case CPU_DEAD:

		case CPU_DEAD_FROZEN:

			foobar_dead_action(cpu);

			break;

		}

arch/i386/kernel/cpu/intel_cacheinfo.c

+2 −0
Original line number Diff line number Diff line
@@ -733,9 +733,11 @@ static int __cpuinit cacheinfo_cpu_callback(struct notifier_block *nfb, 
	sys_dev = get_cpu_sysdev(cpu);

	switch (action) {

	case CPU_ONLINE:

	case CPU_ONLINE_FROZEN:

		cache_add_dev(sys_dev);

		break;

	case CPU_DEAD:

	case CPU_DEAD_FROZEN:

		cache_remove_dev(sys_dev);

		break;

	}

arch/i386/kernel/cpu/mcheck/therm_throt.c

+2 −0
Original line number Diff line number Diff line
@@ -137,10 +137,12 @@ static __cpuinit int thermal_throttle_cpu_callback(struct notifier_block *nfb, 
	mutex_lock(&therm_cpu_lock);

	switch (action) {

	case CPU_ONLINE:

	case CPU_ONLINE_FROZEN:

		err = thermal_throttle_add_dev(sys_dev);

		WARN_ON(err);

		break;

	case CPU_DEAD:

	case CPU_DEAD_FROZEN:

		thermal_throttle_remove_dev(sys_dev);

		break;

	}

arch/i386/kernel/cpuid.c

+2 −0
Original line number Diff line number Diff line
@@ -169,9 +169,11 @@ static int cpuid_class_cpu_callback(struct notifier_block *nfb, unsigned long ac 


	switch (action) {

	case CPU_ONLINE:

	case CPU_ONLINE_FROZEN:

		cpuid_device_create(cpu);

		break;

	case CPU_DEAD:

	case CPU_DEAD_FROZEN:

		device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));

		break;

	}

arch/i386/kernel/microcode.c

+3 −0
Original line number Diff line number Diff line
@@ -775,10 +775,13 @@ mc_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu) 
	sys_dev = get_cpu_sysdev(cpu);

	switch (action) {

	case CPU_ONLINE:

	case CPU_ONLINE_FROZEN:

	case CPU_DOWN_FAILED:

	case CPU_DOWN_FAILED_FROZEN:

		mc_sysdev_add(sys_dev);

		break;

	case CPU_DOWN_PREPARE:

	case CPU_DOWN_PREPARE_FROZEN:

		mc_sysdev_remove(sys_dev);

		break;

	}

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