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| author |   Avi Kivity <avi@qumranet.com> | 2007-05-24 12:23:10 +0300 |
|---|---|---|
| committer | Avi Kivity <avi@qumranet.com> | 2007-07-16 12:05:49 +0300 |
| commit | db912f963909b3cbc3a059b7528f6a1a1eb6ffae (patch) | |
| tree | 85d112b2879782fda2b2ca77413ac73361d0d3b0 /kernel/cpu.c | |
| parent | KVM: Clean up #includes (diff) | |
| download | linux-dev-db912f963909b3cbc3a059b7528f6a1a1eb6ffae.tar.xz linux-dev-db912f963909b3cbc3a059b7528f6a1a1eb6ffae.zip | |
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.c | 16 |
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)) { |