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* [PATCH] Fix preempt imbalance in kvm_timer_init()
@ 2010-12-09 18:42 Thomas Meyer
  2010-12-12  9:28 ` Avi Kivity
  0 siblings, 1 reply; 2+ messages in thread
From: Thomas Meyer @ 2010-12-09 18:42 UTC (permalink / raw)
  To: linux-kernel
  Cc: zamsden, Avi Kivity, Marcelo Tosatti, Thomas Gleixner,
	Ingo Molnar, H. Peter Anvin, x86, kvm

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
---
 arch/x86/kvm/x86.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cdac9e5..2609c3d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4561,7 +4561,7 @@ static struct notifier_block kvmclock_cpu_notifier_block = {
 
 static void kvm_timer_init(void)
 {
-	int cpu;
+	int cpu = get_cpu();
 
 	max_tsc_khz = tsc_khz;
 	register_hotcpu_notifier(&kvmclock_cpu_notifier_block);
@@ -4569,13 +4569,14 @@ static void kvm_timer_init(void)
 #ifdef CONFIG_CPU_FREQ
 		struct cpufreq_policy policy;
 		memset(&policy, 0, sizeof(policy));
-		cpufreq_get_policy(&policy, get_cpu());
+		cpufreq_get_policy(&policy, cpu);
 		if (policy.cpuinfo.max_freq)
 			max_tsc_khz = policy.cpuinfo.max_freq;
 #endif
 		cpufreq_register_notifier(&kvmclock_cpufreq_notifier_block,
 					  CPUFREQ_TRANSITION_NOTIFIER);
 	}
+	put_cpu();
 	pr_debug("kvm: max_tsc_khz = %ld\n", max_tsc_khz);
 	for_each_online_cpu(cpu)
 		smp_call_function_single(cpu, tsc_khz_changed, NULL, 1);
-- 
1.7.3.3



^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] Fix preempt imbalance in kvm_timer_init()
  2010-12-09 18:42 [PATCH] Fix preempt imbalance in kvm_timer_init() Thomas Meyer
@ 2010-12-12  9:28 ` Avi Kivity
  0 siblings, 0 replies; 2+ messages in thread
From: Avi Kivity @ 2010-12-12  9:28 UTC (permalink / raw)
  To: Thomas Meyer
  Cc: linux-kernel, zamsden, Marcelo Tosatti, Thomas Gleixner,
	Ingo Molnar, H. Peter Anvin, x86, kvm

On 12/09/2010 08:42 PM, Thomas Meyer wrote:
> Signed-off-by: Thomas Meyer<thomas@m3y3r.de>
> ---
>   arch/x86/kvm/x86.c |    5 +++--
>   1 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index cdac9e5..2609c3d 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -4561,7 +4561,7 @@ static struct notifier_block kvmclock_cpu_notifier_block = {
>
>   static void kvm_timer_init(void)
>   {
> -	int cpu;
> +	int cpu = get_cpu();
>
>   	max_tsc_khz = tsc_khz;
>   	register_hotcpu_notifier(&kvmclock_cpu_notifier_block);

This eventually takes a mutex (in cpu_maps_update_begin()), so it can't 
be called with preemption disabled.

> @@ -4569,13 +4569,14 @@ static void kvm_timer_init(void)
>   #ifdef CONFIG_CPU_FREQ
>   		struct cpufreq_policy policy;
>   		memset(&policy, 0, sizeof(policy));
> -		cpufreq_get_policy(&policy, get_cpu());
> +		cpufreq_get_policy(&policy, cpu);
>   		if (policy.cpuinfo.max_freq)
>   			max_tsc_khz = policy.cpuinfo.max_freq;
>   #endif
>   		cpufreq_register_notifier(&kvmclock_cpufreq_notifier_block,
>   					  CPUFREQ_TRANSITION_NOTIFIER);
>   	}
> +	put_cpu();
>   	pr_debug("kvm: max_tsc_khz = %ld\n", max_tsc_khz);
>   	for_each_online_cpu(cpu)
>   		smp_call_function_single(cpu, tsc_khz_changed, NULL, 1);


-- 
error compiling committee.c: too many arguments to function


^ permalink raw reply	[flat|nested] 2+ messages in thread

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