HOTPLUG: Add CPU_DYING notifier

KVM wants a notification when a cpu is about to die, so it can disable
hardware extensions, but at a time when user processes cannot be scheduled
on the cpu, so it doesn't try to use virtualization extensions after they
have been disabled.

This adds a CPU_DYING notification.  The notification is called in atomic
context on the doomed cpu.

Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Avi Kivity 2007-05-24 12:23:10 +03:00
parent e495606dd0
commit db912f9639
2 changed files with 17 additions and 2 deletions

View file

@ -196,6 +196,8 @@ extern int __srcu_notifier_call_chain(struct srcu_notifier_head *nh,
#define CPU_DEAD 0x0007 /* CPU (unsigned)v dead */
#define CPU_LOCK_ACQUIRE 0x0008 /* Acquire all hotcpu locks */
#define CPU_LOCK_RELEASE 0x0009 /* Release all hotcpu locks */
#define CPU_DYING 0x000A /* CPU (unsigned)v not running any task,
* not handling interrupts, soon dead */
/* Used for CPU hotplug events occuring while tasks are frozen due to a suspend
* operation in progress
@ -208,6 +210,7 @@ extern int __srcu_notifier_call_chain(struct srcu_notifier_head *nh,
#define CPU_DOWN_PREPARE_FROZEN (CPU_DOWN_PREPARE | CPU_TASKS_FROZEN)
#define CPU_DOWN_FAILED_FROZEN (CPU_DOWN_FAILED | CPU_TASKS_FROZEN)
#define CPU_DEAD_FROZEN (CPU_DEAD | CPU_TASKS_FROZEN)
#define CPU_DYING_FROZEN (CPU_DYING | CPU_TASKS_FROZEN)
#endif /* __KERNEL__ */
#endif /* _LINUX_NOTIFIER_H */