diff options
Diffstat (limited to 'Documentation/cpu-hotplug.txt')
| -rw-r--r-- | Documentation/cpu-hotplug.txt | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt index cc60d29b954..b6d24c22274 100644 --- a/Documentation/cpu-hotplug.txt +++ b/Documentation/cpu-hotplug.txt @@ -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; } |