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authorAvi Kivity <avi@qumranet.com>2007-05-24 12:23:10 +0300
committerAvi Kivity <avi@qumranet.com>2007-07-16 12:05:49 +0300
commitdb912f963909b3cbc3a059b7528f6a1a1eb6ffae (patch)
tree85d112b2879782fda2b2ca77413ac73361d0d3b0 /kernel/cpu.c
parente495606dd09d79f9fa496334ac3958f6ff179d82 (diff)
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>
Diffstat (limited to 'kernel/cpu.c')
-rw-r--r--kernel/cpu.c16
1 files changed, 14 insertions, 2 deletions
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)) {

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