[v3] cpuidle-haltpoll: vcpu hotplug support
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Message ID 20190902104031.9296-1-joao.m.martins@oracle.com
State Mainlined, archived
Headers show
Series
  • [v3] cpuidle-haltpoll: vcpu hotplug support
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Commit Message

Joao Martins Sept. 2, 2019, 10:40 a.m. UTC
When cpus != maxcpus cpuidle-haltpoll will fail to register all vcpus
past the online ones and thus fail to register the idle driver.
This is because cpuidle_add_sysfs() will return with -ENODEV as a
consequence from get_cpu_device() return no device for a non-existing
CPU.

Instead switch to cpuidle_register_driver() and manually register each
of the present cpus through cpuhp_setup_state() callbacks and future
ones that get onlined or offlined. This mimmics similar logic that
intel_idle does.

Fixes: fa86ee90eb11 ("add cpuidle-haltpoll driver")
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---
v3:
* register the teardown callback for correct handling of hotunplug
and error cases. In case cpuhp_setup_state calls fails (e.g. in one of
the cpus that it invoked the callback) it will then call the teardown of
the previously enabled devices; so no need to handle that manually in
haltpoll_uninit().
* use the cpuhp_setup_state() returned dyn allocated state when it
succeeds. And use that state in haltpoll_unint() to call
cpuhp_remove_state() instead of looping online cpus manually. This
is because cpuhp_remove_state() invokes the teardown/offline callback.
* fix subsystem name to 'cpuidle' instead of 'idle' in cpuhp_setup_state()

v2:
* move cpus_read_unlock() after unregistering all cpuidle_devices;
(Marcello Tosatti)
* redundant usage of cpuidle_unregister() when only
cpuidle_unregister_driver() suffices; (Marcelo Tosatti)
* cpuhp_setup_state() returns a state (> 0) for CPUHP_AP_ONLINE_DYN
---
 arch/x86/include/asm/cpuidle_haltpoll.h |  4 +-
 arch/x86/kernel/kvm.c                   | 18 +++----
 drivers/cpuidle/cpuidle-haltpoll.c      | 68 +++++++++++++++++++++++--
 include/linux/cpuidle_haltpoll.h        |  4 +-
 4 files changed, 73 insertions(+), 21 deletions(-)

Comments

Rafael J. Wysocki Sept. 2, 2019, 8:34 p.m. UTC | #1
On Mon, Sep 2, 2019 at 12:43 PM Joao Martins <joao.m.martins@oracle.com> wrote:
>
> When cpus != maxcpus cpuidle-haltpoll will fail to register all vcpus
> past the online ones and thus fail to register the idle driver.
> This is because cpuidle_add_sysfs() will return with -ENODEV as a
> consequence from get_cpu_device() return no device for a non-existing
> CPU.
>
> Instead switch to cpuidle_register_driver() and manually register each
> of the present cpus through cpuhp_setup_state() callbacks and future
> ones that get onlined or offlined. This mimmics similar logic that
> intel_idle does.
>
> Fixes: fa86ee90eb11 ("add cpuidle-haltpoll driver")
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> ---
> v3:
> * register the teardown callback for correct handling of hotunplug
> and error cases. In case cpuhp_setup_state calls fails (e.g. in one of
> the cpus that it invoked the callback) it will then call the teardown of
> the previously enabled devices; so no need to handle that manually in
> haltpoll_uninit().
> * use the cpuhp_setup_state() returned dyn allocated state when it
> succeeds. And use that state in haltpoll_unint() to call
> cpuhp_remove_state() instead of looping online cpus manually. This
> is because cpuhp_remove_state() invokes the teardown/offline callback.
> * fix subsystem name to 'cpuidle' instead of 'idle' in cpuhp_setup_state()

Marcelo, is the R-by still applicable?

Paolo, any comments?

>
> v2:
> * move cpus_read_unlock() after unregistering all cpuidle_devices;
> (Marcello Tosatti)
> * redundant usage of cpuidle_unregister() when only
> cpuidle_unregister_driver() suffices; (Marcelo Tosatti)
> * cpuhp_setup_state() returns a state (> 0) for CPUHP_AP_ONLINE_DYN
> ---
>  arch/x86/include/asm/cpuidle_haltpoll.h |  4 +-
>  arch/x86/kernel/kvm.c                   | 18 +++----
>  drivers/cpuidle/cpuidle-haltpoll.c      | 68 +++++++++++++++++++++++--
>  include/linux/cpuidle_haltpoll.h        |  4 +-
>  4 files changed, 73 insertions(+), 21 deletions(-)
>
> diff --git a/arch/x86/include/asm/cpuidle_haltpoll.h b/arch/x86/include/asm/cpuidle_haltpoll.h
> index ff8607d81526..c8b39c6716ff 100644
> --- a/arch/x86/include/asm/cpuidle_haltpoll.h
> +++ b/arch/x86/include/asm/cpuidle_haltpoll.h
> @@ -2,7 +2,7 @@
>  #ifndef _ARCH_HALTPOLL_H
>  #define _ARCH_HALTPOLL_H
>
> -void arch_haltpoll_enable(void);
> -void arch_haltpoll_disable(void);
> +void arch_haltpoll_enable(unsigned int cpu);
> +void arch_haltpoll_disable(unsigned int cpu);
>
>  #endif
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> index 8d150e3732d9..a9b6c4e2446d 100644
> --- a/arch/x86/kernel/kvm.c
> +++ b/arch/x86/kernel/kvm.c
> @@ -880,32 +880,26 @@ static void kvm_enable_host_haltpoll(void *i)
>         wrmsrl(MSR_KVM_POLL_CONTROL, 1);
>  }
>
> -void arch_haltpoll_enable(void)
> +void arch_haltpoll_enable(unsigned int cpu)
>  {
>         if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL)) {
> -               printk(KERN_ERR "kvm: host does not support poll control\n");
> -               printk(KERN_ERR "kvm: host upgrade recommended\n");
> +               pr_err_once("kvm: host does not support poll control\n");
> +               pr_err_once("kvm: host upgrade recommended\n");
>                 return;
>         }
>
> -       preempt_disable();
>         /* Enable guest halt poll disables host halt poll */
> -       kvm_disable_host_haltpoll(NULL);
> -       smp_call_function(kvm_disable_host_haltpoll, NULL, 1);
> -       preempt_enable();
> +       smp_call_function_single(cpu, kvm_disable_host_haltpoll, NULL, 1);
>  }
>  EXPORT_SYMBOL_GPL(arch_haltpoll_enable);
>
> -void arch_haltpoll_disable(void)
> +void arch_haltpoll_disable(unsigned int cpu)
>  {
>         if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL))
>                 return;
>
> -       preempt_disable();
>         /* Enable guest halt poll disables host halt poll */
> -       kvm_enable_host_haltpoll(NULL);
> -       smp_call_function(kvm_enable_host_haltpoll, NULL, 1);
> -       preempt_enable();
> +       smp_call_function_single(cpu, kvm_enable_host_haltpoll, NULL, 1);
>  }
>  EXPORT_SYMBOL_GPL(arch_haltpoll_disable);
>  #endif
> diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c
> index 9ac093dcbb01..56d8ab814466 100644
> --- a/drivers/cpuidle/cpuidle-haltpoll.c
> +++ b/drivers/cpuidle/cpuidle-haltpoll.c
> @@ -11,12 +11,16 @@
>   */
>
>  #include <linux/init.h>
> +#include <linux/cpu.h>
>  #include <linux/cpuidle.h>
>  #include <linux/module.h>
>  #include <linux/sched/idle.h>
>  #include <linux/kvm_para.h>
>  #include <linux/cpuidle_haltpoll.h>
>
> +static struct cpuidle_device __percpu *haltpoll_cpuidle_devices;
> +static enum cpuhp_state haltpoll_hp_state;
> +
>  static int default_enter_idle(struct cpuidle_device *dev,
>                               struct cpuidle_driver *drv, int index)
>  {
> @@ -46,6 +50,46 @@ static struct cpuidle_driver haltpoll_driver = {
>         .state_count = 2,
>  };
>
> +static int haltpoll_cpu_online(unsigned int cpu)
> +{
> +       struct cpuidle_device *dev;
> +
> +       dev = per_cpu_ptr(haltpoll_cpuidle_devices, cpu);
> +       if (!dev->registered) {
> +               dev->cpu = cpu;
> +               if (cpuidle_register_device(dev)) {
> +                       pr_notice("cpuidle_register_device %d failed!\n", cpu);
> +                       return -EIO;
> +               }
> +               arch_haltpoll_enable(cpu);
> +       }
> +
> +       return 0;
> +}
> +
> +static int haltpoll_cpu_offline(unsigned int cpu)
> +{
> +       struct cpuidle_device *dev;
> +
> +       dev = per_cpu_ptr(haltpoll_cpuidle_devices, cpu);
> +       if (dev->registered) {
> +               arch_haltpoll_disable(cpu);
> +               cpuidle_unregister_device(dev);
> +       }
> +
> +       return 0;
> +}
> +
> +static void haltpoll_uninit(void)
> +{
> +       if (haltpoll_hp_state)
> +               cpuhp_remove_state(haltpoll_hp_state);
> +       cpuidle_unregister_driver(&haltpoll_driver);
> +
> +       free_percpu(haltpoll_cpuidle_devices);
> +       haltpoll_cpuidle_devices = NULL;
> +}
> +
>  static int __init haltpoll_init(void)
>  {
>         int ret;
> @@ -56,17 +100,31 @@ static int __init haltpoll_init(void)
>         if (!kvm_para_available())
>                 return 0;
>
> -       ret = cpuidle_register(&haltpoll_driver, NULL);
> -       if (ret == 0)
> -               arch_haltpoll_enable();
> +       ret = cpuidle_register_driver(drv);
> +       if (ret < 0)
> +               return ret;
> +
> +       haltpoll_cpuidle_devices = alloc_percpu(struct cpuidle_device);
> +       if (haltpoll_cpuidle_devices == NULL) {
> +               cpuidle_unregister_driver(drv);
> +               return -ENOMEM;
> +       }
> +
> +       ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "cpuidle/haltpoll:online",
> +                               haltpoll_cpu_online, haltpoll_cpu_offline);
> +       if (ret < 0) {
> +               haltpoll_uninit();
> +       } else {
> +               haltpoll_hp_state = ret;
> +               ret = 0;
> +       }
>
>         return ret;
>  }
>
>  static void __exit haltpoll_exit(void)
>  {
> -       arch_haltpoll_disable();
> -       cpuidle_unregister(&haltpoll_driver);
> +       haltpoll_uninit();
>  }
>
>  module_init(haltpoll_init);
> diff --git a/include/linux/cpuidle_haltpoll.h b/include/linux/cpuidle_haltpoll.h
> index fe5954c2409e..d50c1e0411a2 100644
> --- a/include/linux/cpuidle_haltpoll.h
> +++ b/include/linux/cpuidle_haltpoll.h
> @@ -5,11 +5,11 @@
>  #ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
>  #include <asm/cpuidle_haltpoll.h>
>  #else
> -static inline void arch_haltpoll_enable(void)
> +static inline void arch_haltpoll_enable(unsigned int cpu)
>  {
>  }
>
> -static inline void arch_haltpoll_disable(void)
> +static inline void arch_haltpoll_disable(unsigned int cpu)
>  {
>  }
>  #endif
> --
> 2.17.1
>
Marcelo Tosatti Sept. 2, 2019, 10:17 p.m. UTC | #2
On Mon, Sep 02, 2019 at 10:34:07PM +0200, Rafael J. Wysocki wrote:
> On Mon, Sep 2, 2019 at 12:43 PM Joao Martins <joao.m.martins@oracle.com> wrote:
> >
> > When cpus != maxcpus cpuidle-haltpoll will fail to register all vcpus
> > past the online ones and thus fail to register the idle driver.
> > This is because cpuidle_add_sysfs() will return with -ENODEV as a
> > consequence from get_cpu_device() return no device for a non-existing
> > CPU.
> >
> > Instead switch to cpuidle_register_driver() and manually register each
> > of the present cpus through cpuhp_setup_state() callbacks and future
> > ones that get onlined or offlined. This mimmics similar logic that
> > intel_idle does.
> >
> > Fixes: fa86ee90eb11 ("add cpuidle-haltpoll driver")
> > Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> > Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> > ---
> > v3:
> > * register the teardown callback for correct handling of hotunplug
> > and error cases. In case cpuhp_setup_state calls fails (e.g. in one of
> > the cpus that it invoked the callback) it will then call the teardown of
> > the previously enabled devices; so no need to handle that manually in
> > haltpoll_uninit().
> > * use the cpuhp_setup_state() returned dyn allocated state when it
> > succeeds. And use that state in haltpoll_unint() to call
> > cpuhp_remove_state() instead of looping online cpus manually. This
> > is because cpuhp_remove_state() invokes the teardown/offline callback.
> > * fix subsystem name to 'cpuidle' instead of 'idle' in cpuhp_setup_state()
> 
> Marcelo, is the R-by still applicable?
> 
> Paolo, any comments?
> 
> >
> > v2:
> > * move cpus_read_unlock() after unregistering all cpuidle_devices;
> > (Marcello Tosatti)
> > * redundant usage of cpuidle_unregister() when only
> > cpuidle_unregister_driver() suffices; (Marcelo Tosatti)
> > * cpuhp_setup_state() returns a state (> 0) for CPUHP_AP_ONLINE_DYN
> > ---
> >  arch/x86/include/asm/cpuidle_haltpoll.h |  4 +-
> >  arch/x86/kernel/kvm.c                   | 18 +++----
> >  drivers/cpuidle/cpuidle-haltpoll.c      | 68 +++++++++++++++++++++++--
> >  include/linux/cpuidle_haltpoll.h        |  4 +-
> >  4 files changed, 73 insertions(+), 21 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/cpuidle_haltpoll.h b/arch/x86/include/asm/cpuidle_haltpoll.h
> > index ff8607d81526..c8b39c6716ff 100644
> > --- a/arch/x86/include/asm/cpuidle_haltpoll.h
> > +++ b/arch/x86/include/asm/cpuidle_haltpoll.h
> > @@ -2,7 +2,7 @@
> >  #ifndef _ARCH_HALTPOLL_H
> >  #define _ARCH_HALTPOLL_H
> >
> > -void arch_haltpoll_enable(void);
> > -void arch_haltpoll_disable(void);
> > +void arch_haltpoll_enable(unsigned int cpu);
> > +void arch_haltpoll_disable(unsigned int cpu);
> >
> >  #endif
> > diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> > index 8d150e3732d9..a9b6c4e2446d 100644
> > --- a/arch/x86/kernel/kvm.c
> > +++ b/arch/x86/kernel/kvm.c
> > @@ -880,32 +880,26 @@ static void kvm_enable_host_haltpoll(void *i)
> >         wrmsrl(MSR_KVM_POLL_CONTROL, 1);
> >  }
> >
> > -void arch_haltpoll_enable(void)
> > +void arch_haltpoll_enable(unsigned int cpu)
> >  {
> >         if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL)) {
> > -               printk(KERN_ERR "kvm: host does not support poll control\n");
> > -               printk(KERN_ERR "kvm: host upgrade recommended\n");
> > +               pr_err_once("kvm: host does not support poll control\n");
> > +               pr_err_once("kvm: host upgrade recommended\n");
> >                 return;
> >         }
> >
> > -       preempt_disable();
> >         /* Enable guest halt poll disables host halt poll */
> > -       kvm_disable_host_haltpoll(NULL);
> > -       smp_call_function(kvm_disable_host_haltpoll, NULL, 1);
> > -       preempt_enable();
> > +       smp_call_function_single(cpu, kvm_disable_host_haltpoll, NULL, 1);
> >  }
> >  EXPORT_SYMBOL_GPL(arch_haltpoll_enable);
> >
> > -void arch_haltpoll_disable(void)
> > +void arch_haltpoll_disable(unsigned int cpu)
> >  {
> >         if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL))
> >                 return;
> >
> > -       preempt_disable();
> >         /* Enable guest halt poll disables host halt poll */
> > -       kvm_enable_host_haltpoll(NULL);
> > -       smp_call_function(kvm_enable_host_haltpoll, NULL, 1);
> > -       preempt_enable();
> > +       smp_call_function_single(cpu, kvm_enable_host_haltpoll, NULL, 1);
> >  }
> >  EXPORT_SYMBOL_GPL(arch_haltpoll_disable);
> >  #endif
> > diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c
> > index 9ac093dcbb01..56d8ab814466 100644
> > --- a/drivers/cpuidle/cpuidle-haltpoll.c
> > +++ b/drivers/cpuidle/cpuidle-haltpoll.c
> > @@ -11,12 +11,16 @@
> >   */
> >
> >  #include <linux/init.h>
> > +#include <linux/cpu.h>
> >  #include <linux/cpuidle.h>
> >  #include <linux/module.h>
> >  #include <linux/sched/idle.h>
> >  #include <linux/kvm_para.h>
> >  #include <linux/cpuidle_haltpoll.h>
> >
> > +static struct cpuidle_device __percpu *haltpoll_cpuidle_devices;
> > +static enum cpuhp_state haltpoll_hp_state;
> > +
> >  static int default_enter_idle(struct cpuidle_device *dev,
> >                               struct cpuidle_driver *drv, int index)
> >  {
> > @@ -46,6 +50,46 @@ static struct cpuidle_driver haltpoll_driver = {
> >         .state_count = 2,
> >  };
> >
> > +static int haltpoll_cpu_online(unsigned int cpu)
> > +{
> > +       struct cpuidle_device *dev;
> > +
> > +       dev = per_cpu_ptr(haltpoll_cpuidle_devices, cpu);
> > +       if (!dev->registered) {
> > +               dev->cpu = cpu;
> > +               if (cpuidle_register_device(dev)) {
> > +                       pr_notice("cpuidle_register_device %d failed!\n", cpu);
> > +                       return -EIO;
> > +               }
> > +               arch_haltpoll_enable(cpu);
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +static int haltpoll_cpu_offline(unsigned int cpu)
> > +{
> > +       struct cpuidle_device *dev;
> > +
> > +       dev = per_cpu_ptr(haltpoll_cpuidle_devices, cpu);
> > +       if (dev->registered) {
> > +               arch_haltpoll_disable(cpu);
> > +               cpuidle_unregister_device(dev);
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +static void haltpoll_uninit(void)
> > +{
> > +       if (haltpoll_hp_state)
> > +               cpuhp_remove_state(haltpoll_hp_state);
> > +       cpuidle_unregister_driver(&haltpoll_driver);
> > +
> > +       free_percpu(haltpoll_cpuidle_devices);
> > +       haltpoll_cpuidle_devices = NULL;
> > +}
> > +
> >  static int __init haltpoll_init(void)
> >  {
> >         int ret;
> > @@ -56,17 +100,31 @@ static int __init haltpoll_init(void)
> >         if (!kvm_para_available())
> >                 return 0;
> >
> > -       ret = cpuidle_register(&haltpoll_driver, NULL);
> > -       if (ret == 0)
> > -               arch_haltpoll_enable();
> > +       ret = cpuidle_register_driver(drv);
> > +       if (ret < 0)
> > +               return ret;
> > +
> > +       haltpoll_cpuidle_devices = alloc_percpu(struct cpuidle_device);
> > +       if (haltpoll_cpuidle_devices == NULL) {
> > +               cpuidle_unregister_driver(drv);
> > +               return -ENOMEM;
> > +       }
> > +
> > +       ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "cpuidle/haltpoll:online",
> > +                               haltpoll_cpu_online, haltpoll_cpu_offline);
> > +       if (ret < 0) {
> > +               haltpoll_uninit();
> > +       } else {
> > +               haltpoll_hp_state = ret;
> > +               ret = 0;
> > +       }
> >
> >         return ret;
> >  }
> >
> >  static void __exit haltpoll_exit(void)
> >  {
> > -       arch_haltpoll_disable();
> > -       cpuidle_unregister(&haltpoll_driver);
> > +       haltpoll_uninit();
> >  }
> >
> >  module_init(haltpoll_init);
> > diff --git a/include/linux/cpuidle_haltpoll.h b/include/linux/cpuidle_haltpoll.h
> > index fe5954c2409e..d50c1e0411a2 100644
> > --- a/include/linux/cpuidle_haltpoll.h
> > +++ b/include/linux/cpuidle_haltpoll.h
> > @@ -5,11 +5,11 @@
> >  #ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
> >  #include <asm/cpuidle_haltpoll.h>
> >  #else
> > -static inline void arch_haltpoll_enable(void)
> > +static inline void arch_haltpoll_enable(unsigned int cpu)
> >  {
> >  }
> >
> > -static inline void arch_haltpoll_disable(void)
> > +static inline void arch_haltpoll_disable(unsigned int cpu)
> >  {
> >  }
> >  #endif
> > --
> > 2.17.1
> >

Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Rafael J. Wysocki Sept. 3, 2019, 7:38 a.m. UTC | #3
On Tue, Sep 3, 2019 at 12:18 AM Marcelo Tosatti <mtosatti@redhat.com> wrote:
>
> On Mon, Sep 02, 2019 at 10:34:07PM +0200, Rafael J. Wysocki wrote:
> > On Mon, Sep 2, 2019 at 12:43 PM Joao Martins <joao.m.martins@oracle.com> wrote:
> > >
> > > When cpus != maxcpus cpuidle-haltpoll will fail to register all vcpus
> > > past the online ones and thus fail to register the idle driver.
> > > This is because cpuidle_add_sysfs() will return with -ENODEV as a
> > > consequence from get_cpu_device() return no device for a non-existing
> > > CPU.
> > >
> > > Instead switch to cpuidle_register_driver() and manually register each
> > > of the present cpus through cpuhp_setup_state() callbacks and future
> > > ones that get onlined or offlined. This mimmics similar logic that
> > > intel_idle does.
> > >
> > > Fixes: fa86ee90eb11 ("add cpuidle-haltpoll driver")
> > > Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> > > Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> > > ---
> > > v3:
> > > * register the teardown callback for correct handling of hotunplug
> > > and error cases. In case cpuhp_setup_state calls fails (e.g. in one of
> > > the cpus that it invoked the callback) it will then call the teardown of
> > > the previously enabled devices; so no need to handle that manually in
> > > haltpoll_uninit().
> > > * use the cpuhp_setup_state() returned dyn allocated state when it
> > > succeeds. And use that state in haltpoll_unint() to call
> > > cpuhp_remove_state() instead of looping online cpus manually. This
> > > is because cpuhp_remove_state() invokes the teardown/offline callback.
> > > * fix subsystem name to 'cpuidle' instead of 'idle' in cpuhp_setup_state()
> >
> > Marcelo, is the R-by still applicable?
> >
> > Paolo, any comments?
> >
> > >
> > > v2:
> > > * move cpus_read_unlock() after unregistering all cpuidle_devices;
> > > (Marcello Tosatti)
> > > * redundant usage of cpuidle_unregister() when only
> > > cpuidle_unregister_driver() suffices; (Marcelo Tosatti)
> > > * cpuhp_setup_state() returns a state (> 0) for CPUHP_AP_ONLINE_DYN
> > > ---
> > >  arch/x86/include/asm/cpuidle_haltpoll.h |  4 +-
> > >  arch/x86/kernel/kvm.c                   | 18 +++----
> > >  drivers/cpuidle/cpuidle-haltpoll.c      | 68 +++++++++++++++++++++++--
> > >  include/linux/cpuidle_haltpoll.h        |  4 +-
> > >  4 files changed, 73 insertions(+), 21 deletions(-)
> > >
> > > diff --git a/arch/x86/include/asm/cpuidle_haltpoll.h b/arch/x86/include/asm/cpuidle_haltpoll.h
> > > index ff8607d81526..c8b39c6716ff 100644
> > > --- a/arch/x86/include/asm/cpuidle_haltpoll.h
> > > +++ b/arch/x86/include/asm/cpuidle_haltpoll.h
> > > @@ -2,7 +2,7 @@
> > >  #ifndef _ARCH_HALTPOLL_H
> > >  #define _ARCH_HALTPOLL_H
> > >
> > > -void arch_haltpoll_enable(void);
> > > -void arch_haltpoll_disable(void);
> > > +void arch_haltpoll_enable(unsigned int cpu);
> > > +void arch_haltpoll_disable(unsigned int cpu);
> > >
> > >  #endif
> > > diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> > > index 8d150e3732d9..a9b6c4e2446d 100644
> > > --- a/arch/x86/kernel/kvm.c
> > > +++ b/arch/x86/kernel/kvm.c
> > > @@ -880,32 +880,26 @@ static void kvm_enable_host_haltpoll(void *i)
> > >         wrmsrl(MSR_KVM_POLL_CONTROL, 1);
> > >  }
> > >
> > > -void arch_haltpoll_enable(void)
> > > +void arch_haltpoll_enable(unsigned int cpu)
> > >  {
> > >         if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL)) {
> > > -               printk(KERN_ERR "kvm: host does not support poll control\n");
> > > -               printk(KERN_ERR "kvm: host upgrade recommended\n");
> > > +               pr_err_once("kvm: host does not support poll control\n");
> > > +               pr_err_once("kvm: host upgrade recommended\n");
> > >                 return;
> > >         }
> > >
> > > -       preempt_disable();
> > >         /* Enable guest halt poll disables host halt poll */
> > > -       kvm_disable_host_haltpoll(NULL);
> > > -       smp_call_function(kvm_disable_host_haltpoll, NULL, 1);
> > > -       preempt_enable();
> > > +       smp_call_function_single(cpu, kvm_disable_host_haltpoll, NULL, 1);
> > >  }
> > >  EXPORT_SYMBOL_GPL(arch_haltpoll_enable);
> > >
> > > -void arch_haltpoll_disable(void)
> > > +void arch_haltpoll_disable(unsigned int cpu)
> > >  {
> > >         if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL))
> > >                 return;
> > >
> > > -       preempt_disable();
> > >         /* Enable guest halt poll disables host halt poll */
> > > -       kvm_enable_host_haltpoll(NULL);
> > > -       smp_call_function(kvm_enable_host_haltpoll, NULL, 1);
> > > -       preempt_enable();
> > > +       smp_call_function_single(cpu, kvm_enable_host_haltpoll, NULL, 1);
> > >  }
> > >  EXPORT_SYMBOL_GPL(arch_haltpoll_disable);
> > >  #endif
> > > diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c
> > > index 9ac093dcbb01..56d8ab814466 100644
> > > --- a/drivers/cpuidle/cpuidle-haltpoll.c
> > > +++ b/drivers/cpuidle/cpuidle-haltpoll.c
> > > @@ -11,12 +11,16 @@
> > >   */
> > >
> > >  #include <linux/init.h>
> > > +#include <linux/cpu.h>
> > >  #include <linux/cpuidle.h>
> > >  #include <linux/module.h>
> > >  #include <linux/sched/idle.h>
> > >  #include <linux/kvm_para.h>
> > >  #include <linux/cpuidle_haltpoll.h>
> > >
> > > +static struct cpuidle_device __percpu *haltpoll_cpuidle_devices;
> > > +static enum cpuhp_state haltpoll_hp_state;
> > > +
> > >  static int default_enter_idle(struct cpuidle_device *dev,
> > >                               struct cpuidle_driver *drv, int index)
> > >  {
> > > @@ -46,6 +50,46 @@ static struct cpuidle_driver haltpoll_driver = {
> > >         .state_count = 2,
> > >  };
> > >
> > > +static int haltpoll_cpu_online(unsigned int cpu)
> > > +{
> > > +       struct cpuidle_device *dev;
> > > +
> > > +       dev = per_cpu_ptr(haltpoll_cpuidle_devices, cpu);
> > > +       if (!dev->registered) {
> > > +               dev->cpu = cpu;
> > > +               if (cpuidle_register_device(dev)) {
> > > +                       pr_notice("cpuidle_register_device %d failed!\n", cpu);
> > > +                       return -EIO;
> > > +               }
> > > +               arch_haltpoll_enable(cpu);
> > > +       }
> > > +
> > > +       return 0;
> > > +}
> > > +
> > > +static int haltpoll_cpu_offline(unsigned int cpu)
> > > +{
> > > +       struct cpuidle_device *dev;
> > > +
> > > +       dev = per_cpu_ptr(haltpoll_cpuidle_devices, cpu);
> > > +       if (dev->registered) {
> > > +               arch_haltpoll_disable(cpu);
> > > +               cpuidle_unregister_device(dev);
> > > +       }
> > > +
> > > +       return 0;
> > > +}
> > > +
> > > +static void haltpoll_uninit(void)
> > > +{
> > > +       if (haltpoll_hp_state)
> > > +               cpuhp_remove_state(haltpoll_hp_state);
> > > +       cpuidle_unregister_driver(&haltpoll_driver);
> > > +
> > > +       free_percpu(haltpoll_cpuidle_devices);
> > > +       haltpoll_cpuidle_devices = NULL;
> > > +}
> > > +
> > >  static int __init haltpoll_init(void)
> > >  {
> > >         int ret;
> > > @@ -56,17 +100,31 @@ static int __init haltpoll_init(void)
> > >         if (!kvm_para_available())
> > >                 return 0;
> > >
> > > -       ret = cpuidle_register(&haltpoll_driver, NULL);
> > > -       if (ret == 0)
> > > -               arch_haltpoll_enable();
> > > +       ret = cpuidle_register_driver(drv);
> > > +       if (ret < 0)
> > > +               return ret;
> > > +
> > > +       haltpoll_cpuidle_devices = alloc_percpu(struct cpuidle_device);
> > > +       if (haltpoll_cpuidle_devices == NULL) {
> > > +               cpuidle_unregister_driver(drv);
> > > +               return -ENOMEM;
> > > +       }
> > > +
> > > +       ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "cpuidle/haltpoll:online",
> > > +                               haltpoll_cpu_online, haltpoll_cpu_offline);
> > > +       if (ret < 0) {
> > > +               haltpoll_uninit();
> > > +       } else {
> > > +               haltpoll_hp_state = ret;
> > > +               ret = 0;
> > > +       }
> > >
> > >         return ret;
> > >  }
> > >
> > >  static void __exit haltpoll_exit(void)
> > >  {
> > > -       arch_haltpoll_disable();
> > > -       cpuidle_unregister(&haltpoll_driver);
> > > +       haltpoll_uninit();
> > >  }
> > >
> > >  module_init(haltpoll_init);
> > > diff --git a/include/linux/cpuidle_haltpoll.h b/include/linux/cpuidle_haltpoll.h
> > > index fe5954c2409e..d50c1e0411a2 100644
> > > --- a/include/linux/cpuidle_haltpoll.h
> > > +++ b/include/linux/cpuidle_haltpoll.h
> > > @@ -5,11 +5,11 @@
> > >  #ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
> > >  #include <asm/cpuidle_haltpoll.h>
> > >  #else
> > > -static inline void arch_haltpoll_enable(void)
> > > +static inline void arch_haltpoll_enable(unsigned int cpu)
> > >  {
> > >  }
> > >
> > > -static inline void arch_haltpoll_disable(void)
> > > +static inline void arch_haltpoll_disable(unsigned int cpu)
> > >  {
> > >  }
> > >  #endif
> > > --
> > > 2.17.1
> > >
>
> Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>

OK, queued for v5.4, thanks!

Patch
diff mbox series

diff --git a/arch/x86/include/asm/cpuidle_haltpoll.h b/arch/x86/include/asm/cpuidle_haltpoll.h
index ff8607d81526..c8b39c6716ff 100644
--- a/arch/x86/include/asm/cpuidle_haltpoll.h
+++ b/arch/x86/include/asm/cpuidle_haltpoll.h
@@ -2,7 +2,7 @@ 
 #ifndef _ARCH_HALTPOLL_H
 #define _ARCH_HALTPOLL_H
 
-void arch_haltpoll_enable(void);
-void arch_haltpoll_disable(void);
+void arch_haltpoll_enable(unsigned int cpu);
+void arch_haltpoll_disable(unsigned int cpu);
 
 #endif
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 8d150e3732d9..a9b6c4e2446d 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -880,32 +880,26 @@  static void kvm_enable_host_haltpoll(void *i)
 	wrmsrl(MSR_KVM_POLL_CONTROL, 1);
 }
 
-void arch_haltpoll_enable(void)
+void arch_haltpoll_enable(unsigned int cpu)
 {
 	if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL)) {
-		printk(KERN_ERR "kvm: host does not support poll control\n");
-		printk(KERN_ERR "kvm: host upgrade recommended\n");
+		pr_err_once("kvm: host does not support poll control\n");
+		pr_err_once("kvm: host upgrade recommended\n");
 		return;
 	}
 
-	preempt_disable();
 	/* Enable guest halt poll disables host halt poll */
-	kvm_disable_host_haltpoll(NULL);
-	smp_call_function(kvm_disable_host_haltpoll, NULL, 1);
-	preempt_enable();
+	smp_call_function_single(cpu, kvm_disable_host_haltpoll, NULL, 1);
 }
 EXPORT_SYMBOL_GPL(arch_haltpoll_enable);
 
-void arch_haltpoll_disable(void)
+void arch_haltpoll_disable(unsigned int cpu)
 {
 	if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL))
 		return;
 
-	preempt_disable();
 	/* Enable guest halt poll disables host halt poll */
-	kvm_enable_host_haltpoll(NULL);
-	smp_call_function(kvm_enable_host_haltpoll, NULL, 1);
-	preempt_enable();
+	smp_call_function_single(cpu, kvm_enable_host_haltpoll, NULL, 1);
 }
 EXPORT_SYMBOL_GPL(arch_haltpoll_disable);
 #endif
diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c
index 9ac093dcbb01..56d8ab814466 100644
--- a/drivers/cpuidle/cpuidle-haltpoll.c
+++ b/drivers/cpuidle/cpuidle-haltpoll.c
@@ -11,12 +11,16 @@ 
  */
 
 #include <linux/init.h>
+#include <linux/cpu.h>
 #include <linux/cpuidle.h>
 #include <linux/module.h>
 #include <linux/sched/idle.h>
 #include <linux/kvm_para.h>
 #include <linux/cpuidle_haltpoll.h>
 
+static struct cpuidle_device __percpu *haltpoll_cpuidle_devices;
+static enum cpuhp_state haltpoll_hp_state;
+
 static int default_enter_idle(struct cpuidle_device *dev,
 			      struct cpuidle_driver *drv, int index)
 {
@@ -46,6 +50,46 @@  static struct cpuidle_driver haltpoll_driver = {
 	.state_count = 2,
 };
 
+static int haltpoll_cpu_online(unsigned int cpu)
+{
+	struct cpuidle_device *dev;
+
+	dev = per_cpu_ptr(haltpoll_cpuidle_devices, cpu);
+	if (!dev->registered) {
+		dev->cpu = cpu;
+		if (cpuidle_register_device(dev)) {
+			pr_notice("cpuidle_register_device %d failed!\n", cpu);
+			return -EIO;
+		}
+		arch_haltpoll_enable(cpu);
+	}
+
+	return 0;
+}
+
+static int haltpoll_cpu_offline(unsigned int cpu)
+{
+	struct cpuidle_device *dev;
+
+	dev = per_cpu_ptr(haltpoll_cpuidle_devices, cpu);
+	if (dev->registered) {
+		arch_haltpoll_disable(cpu);
+		cpuidle_unregister_device(dev);
+	}
+
+	return 0;
+}
+
+static void haltpoll_uninit(void)
+{
+	if (haltpoll_hp_state)
+		cpuhp_remove_state(haltpoll_hp_state);
+	cpuidle_unregister_driver(&haltpoll_driver);
+
+	free_percpu(haltpoll_cpuidle_devices);
+	haltpoll_cpuidle_devices = NULL;
+}
+
 static int __init haltpoll_init(void)
 {
 	int ret;
@@ -56,17 +100,31 @@  static int __init haltpoll_init(void)
 	if (!kvm_para_available())
 		return 0;
 
-	ret = cpuidle_register(&haltpoll_driver, NULL);
-	if (ret == 0)
-		arch_haltpoll_enable();
+	ret = cpuidle_register_driver(drv);
+	if (ret < 0)
+		return ret;
+
+	haltpoll_cpuidle_devices = alloc_percpu(struct cpuidle_device);
+	if (haltpoll_cpuidle_devices == NULL) {
+		cpuidle_unregister_driver(drv);
+		return -ENOMEM;
+	}
+
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "cpuidle/haltpoll:online",
+				haltpoll_cpu_online, haltpoll_cpu_offline);
+	if (ret < 0) {
+		haltpoll_uninit();
+	} else {
+		haltpoll_hp_state = ret;
+		ret = 0;
+	}
 
 	return ret;
 }
 
 static void __exit haltpoll_exit(void)
 {
-	arch_haltpoll_disable();
-	cpuidle_unregister(&haltpoll_driver);
+	haltpoll_uninit();
 }
 
 module_init(haltpoll_init);
diff --git a/include/linux/cpuidle_haltpoll.h b/include/linux/cpuidle_haltpoll.h
index fe5954c2409e..d50c1e0411a2 100644
--- a/include/linux/cpuidle_haltpoll.h
+++ b/include/linux/cpuidle_haltpoll.h
@@ -5,11 +5,11 @@ 
 #ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
 #include <asm/cpuidle_haltpoll.h>
 #else
-static inline void arch_haltpoll_enable(void)
+static inline void arch_haltpoll_enable(unsigned int cpu)
 {
 }
 
-static inline void arch_haltpoll_disable(void)
+static inline void arch_haltpoll_disable(unsigned int cpu)
 {
 }
 #endif