Re: [PATCH v3] cpuidle-haltpoll: vcpu hotplug support
On Tue, Sep 3, 2019 at 12:18 AM Marcelo Tosatti 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
> > 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
> > > Signed-off-by: Boris Ostrovsky
> > > ---
> > > 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 @@
> > > */
> > >
Re: [PATCH v3] cpuidle-haltpoll: vcpu hotplug support
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
> 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
> > Signed-off-by: Boris Ostrovsky
> > ---
> > 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
> > +#include
> > #include
> > #include
> > #include
> > #include
> > #include
> >
> > +static struct cpuidle_device __percpu *haltpoll_cpuidle_devices;
> > +static enum cpuhp_state haltpoll_hp_state;
> > +
> > static int default_enter_idle(struct cpuidle_devi
Re: [PATCH v3] cpuidle-haltpoll: vcpu hotplug support
On Mon, Sep 2, 2019 at 12:43 PM Joao Martins 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
> Signed-off-by: Boris Ostrovsky
> ---
> 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
> +#include
> #include
> #include
> #include
> #include
> #include
>
> +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(haltpol
[PATCH v3] cpuidle-haltpoll: vcpu hotplug support
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
Signed-off-by: Boris Ostrovsky
---
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(-)
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
+#include
#include
#include
#include
#include
#include
+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;
+}
+
