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| author | Avi Kivity <avi@qumranet.com> | 2007-05-24 13:23:10 +0400 |
|---|---|---|
| committer | Avi Kivity <avi@qumranet.com> | 2007-07-16 13:05:49 +0400 |
| commit | db912f963909b3cbc3a059b7528f6a1a1eb6ffae (patch) | |
| tree | 85d112b2879782fda2b2ca77413ac73361d0d3b0 | |
| parent | e495606dd09d79f9fa496334ac3958f6ff179d82 (diff) | |
| download | linux-db912f963909b3cbc3a059b7528f6a1a1eb6ffae.tar.xz | |
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>
| -rw-r--r-- | include/linux/notifier.h | 3 | ||||
| -rw-r--r-- | kernel/cpu.c | 16 |
2 files changed, 17 insertions, 2 deletions
diff --git a/include/linux/notifier.h b/include/linux/notifier.h index 9431101bf876..576f2bb34cc8 100644 --- a/include/linux/notifier.h +++ b/include/linux/notifier.h @@ -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 */ diff --git a/kernel/cpu.c b/kernel/cpu.c index 208cf3497c10..181ae7086029 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -103,11 +103,19 @@ static inline void check_for_tasks(int cpu) write_unlock_irq(&tasklist_lock); } +struct take_cpu_down_param { + unsigned long mod; + void *hcpu; +}; + /* Take this CPU down. */ -static int take_cpu_down(void *unused) +static int take_cpu_down(void *_param) { + struct take_cpu_down_param *param = _param; int err; + raw_notifier_call_chain(&cpu_chain, CPU_DYING | param->mod, + param->hcpu); /* Ensure this CPU doesn't handle any more interrupts. */ err = __cpu_disable(); if (err < 0) @@ -127,6 +135,10 @@ static int _cpu_down(unsigned int cpu, int tasks_frozen) cpumask_t old_allowed, tmp; void *hcpu = (void *)(long)cpu; unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0; + struct take_cpu_down_param tcd_param = { + .mod = mod, + .hcpu = hcpu, + }; if (num_online_cpus() == 1) return -EBUSY; @@ -153,7 +165,7 @@ static int _cpu_down(unsigned int cpu, int tasks_frozen) set_cpus_allowed(current, tmp); mutex_lock(&cpu_bitmask_lock); - p = __stop_machine_run(take_cpu_down, NULL, cpu); + p = __stop_machine_run(take_cpu_down, &tcd_param, cpu); mutex_unlock(&cpu_bitmask_lock); if (IS_ERR(p) || cpu_online(cpu)) { |