* possible_cpus broken in linux-next
@ 2013-05-29 17:10 Dave Hansen
2013-05-29 18:35 ` Toshi Kani
0 siblings, 1 reply; 6+ messages in thread
From: Dave Hansen @ 2013-05-29 17:10 UTC (permalink / raw)
To: Rafael J. Wysocki, Stephen Rothwell, Greg Kroah-Hartman,
Toshi Kani, LKML
If I boot with: maxcpus=2 possible_cpus=4, I get
# grep . /sys/devices/system/cpu/cpu[0-9]*/online'
/sys/devices/system/cpu/cpu1/online:1
/sys/devices/system/cpu/cpu2/online:1
/sys/devices/system/cpu/cpu3/online:1
on bad kernels, and this on working ones:
/sys/devices/system/cpu/cpu1/online:1
/sys/devices/system/cpu/cpu2/online:0
/sys/devices/system/cpu/cpu3/online:0
I also get -EINVAL if I try to re-offline them in this state. 2 and 3
don't show up in /proc/cpuinfo, so sysfs just looks broken here. This
happens in a KVM guest, so it should be dirt-simple for anyone to reproduce.
I bisected it down to:
> commit 0902a9044fa5b7a0456ea4daacec2c2b3189ba8c
> Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Date: Fri May 3 00:25:49 2013 +0200
>
> Driver core: Use generic offline/online for CPU offline/online
>
> Rework the CPU hotplug code in drivers/base/cpu.c to use the
> generic offline/online support introduced previously instead of
> its own CPU-specific code.
>
> For this purpose, modify cpu_subsys to provide offline and online
> callbacks for CONFIG_HOTPLUG_CPU set and remove the code handling
> the CPU-specific 'online' sysfs attribute.
>
> This modification is not supposed to change the user-observable
> behavior of the kernel (i.e. the 'online' attribute will be present
> in exactly the same place in sysfs and should trigger exactly the
> same actions as before).
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Toshi Kani <toshi.kani@hp.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: possible_cpus broken in linux-next
2013-05-29 17:10 possible_cpus broken in linux-next Dave Hansen
@ 2013-05-29 18:35 ` Toshi Kani
2013-05-29 18:50 ` Toshi Kani
0 siblings, 1 reply; 6+ messages in thread
From: Toshi Kani @ 2013-05-29 18:35 UTC (permalink / raw)
To: Dave Hansen
Cc: Rafael J. Wysocki, Stephen Rothwell, Greg Kroah-Hartman, LKML,
linux-acpi
On Wed, 2013-05-29 at 10:10 -0700, Dave Hansen wrote:
> If I boot with: maxcpus=2 possible_cpus=4, I get
>
> # grep . /sys/devices/system/cpu/cpu[0-9]*/online'
> /sys/devices/system/cpu/cpu1/online:1
> /sys/devices/system/cpu/cpu2/online:1
> /sys/devices/system/cpu/cpu3/online:1
>
> on bad kernels, and this on working ones:
>
> /sys/devices/system/cpu/cpu1/online:1
> /sys/devices/system/cpu/cpu2/online:0
> /sys/devices/system/cpu/cpu3/online:0
>
>
> I also get -EINVAL if I try to re-offline them in this state. 2 and 3
> don't show up in /proc/cpuinfo, so sysfs just looks broken here. This
> happens in a KVM guest, so it should be dirt-simple for anyone to reproduce.
>
> I bisected it down to:
>
> > commit 0902a9044fa5b7a0456ea4daacec2c2b3189ba8c
> > Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > Date: Fri May 3 00:25:49 2013 +0200
> >
> > Driver core: Use generic offline/online for CPU offline/online
> >
> > Rework the CPU hotplug code in drivers/base/cpu.c to use the
> > generic offline/online support introduced previously instead of
> > its own CPU-specific code.
> >
> > For this purpose, modify cpu_subsys to provide offline and online
> > callbacks for CONFIG_HOTPLUG_CPU set and remove the code handling
> > the CPU-specific 'online' sysfs attribute.
> >
> > This modification is not supposed to change the user-observable
> > behavior of the kernel (i.e. the 'online' attribute will be present
> > in exactly the same place in sysfs and should trigger exactly the
> > same actions as before).
> >
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Thanks for the report. The following patch fixes the problem.
-Toshi
====
From: Toshi Kani <toshi.kani@hp.com>
Subject: [PATCH] ACPI: Fix sysfs cpu/online of offlined cpus
As reported by Dave Hansen, sysfs cpu/online shows 1 for
offlined cpus at boot.
https://lkml.org/lkml/2013/5/29/403
Fix this problem by initializing dev.offline with cpu_online()
when registering a cpu.
Reported-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
---
drivers/base/cpu.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 130ba0b..b9f0eec 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -281,6 +281,7 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
cpu->dev.bus = &cpu_subsys;
cpu->dev.release = cpu_device_release;
cpu->dev.offline_disabled = !cpu->hotpluggable;
+ cpu->dev.offline = !cpu_online(num);
#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
cpu->dev.bus->uevent = arch_cpu_uevent;
#endif
--
1.8.1.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: possible_cpus broken in linux-next
2013-05-29 18:35 ` Toshi Kani
@ 2013-05-29 18:50 ` Toshi Kani
2013-05-29 19:02 ` Rafael J. Wysocki
0 siblings, 1 reply; 6+ messages in thread
From: Toshi Kani @ 2013-05-29 18:50 UTC (permalink / raw)
To: Dave Hansen
Cc: Rafael J. Wysocki, Stephen Rothwell, Greg Kroah-Hartman, LKML,
linux-acpi
On Wed, 2013-05-29 at 12:35 -0600, Toshi Kani wrote:
> On Wed, 2013-05-29 at 10:10 -0700, Dave Hansen wrote:
:
> Thanks for the report. The following patch fixes the problem.
> -Toshi
>
> ====
> From: Toshi Kani <toshi.kani@hp.com>
> Subject: [PATCH] ACPI: Fix sysfs cpu/online of offlined cpus
Typo. The subject needs to be:
Subject: [PATCH] cpu: Fix sysfs cpu/online of offlined cpus
-Toshi
> As reported by Dave Hansen, sysfs cpu/online shows 1 for
> offlined cpus at boot.
> https://lkml.org/lkml/2013/5/29/403
>
> Fix this problem by initializing dev.offline with cpu_online()
> when registering a cpu.
>
> Reported-by: Dave Hansen <dave.hansen@intel.com>
> Signed-off-by: Toshi Kani <toshi.kani@hp.com>
> ---
> drivers/base/cpu.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
> index 130ba0b..b9f0eec 100644
> --- a/drivers/base/cpu.c
> +++ b/drivers/base/cpu.c
> @@ -281,6 +281,7 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
> cpu->dev.bus = &cpu_subsys;
> cpu->dev.release = cpu_device_release;
> cpu->dev.offline_disabled = !cpu->hotpluggable;
> + cpu->dev.offline = !cpu_online(num);
> #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
> cpu->dev.bus->uevent = arch_cpu_uevent;
> #endif
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: possible_cpus broken in linux-next
2013-05-29 18:50 ` Toshi Kani
@ 2013-05-29 19:02 ` Rafael J. Wysocki
2013-05-29 22:14 ` Dave Hansen
0 siblings, 1 reply; 6+ messages in thread
From: Rafael J. Wysocki @ 2013-05-29 19:02 UTC (permalink / raw)
To: Toshi Kani, Dave Hansen
Cc: Stephen Rothwell, Greg Kroah-Hartman, LKML, linux-acpi
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="utf-8"; format="flowed", Size: 2199 bytes --]
On 5/29/2013 8:50 PM, Toshi Kani wrote:
> On Wed, 2013-05-29 at 12:35 -0600, Toshi Kani wrote:
>> On Wed, 2013-05-29 at 10:10 -0700, Dave Hansen wrote:
> :
>
>> Thanks for the report. The following patch fixes the problem.
>> -Toshi
>>
>> ====
>> From: Toshi Kani <toshi.kani@hp.com>
>> Subject: [PATCH] ACPI: Fix sysfs cpu/online of offlined cpus
> Typo. The subject needs to be:
>
> Subject: [PATCH] cpu: Fix sysfs cpu/online of offlined cpus
>
> -Toshi
>
>> As reported by Dave Hansen, sysfs cpu/online shows 1 for
>> offlined cpus at boot.
>> https://lkml.org/lkml/2013/5/29/403
>>
>> Fix this problem by initializing dev.offline with cpu_online()
>> when registering a cpu.
>>
>> Reported-by: Dave Hansen <dave.hansen@intel.com>
>> Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Thanks Toshi!
Dave, can you please confirm that the problem is fixed by this patch?
Rafael
>> ---
>> drivers/base/cpu.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
>> index 130ba0b..b9f0eec 100644
>> --- a/drivers/base/cpu.c
>> +++ b/drivers/base/cpu.c
>> @@ -281,6 +281,7 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
>> cpu->dev.bus = &cpu_subsys;
>> cpu->dev.release = cpu_device_release;
>> cpu->dev.offline_disabled = !cpu->hotpluggable;
>> + cpu->dev.offline = !cpu_online(num);
>> #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
>> cpu->dev.bus->uevent = arch_cpu_uevent;
>> #endif
>
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: possible_cpus broken in linux-next
2013-05-29 19:02 ` Rafael J. Wysocki
@ 2013-05-29 22:14 ` Dave Hansen
2013-05-29 22:46 ` Rafael J. Wysocki
0 siblings, 1 reply; 6+ messages in thread
From: Dave Hansen @ 2013-05-29 22:14 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: Toshi Kani, Dave Hansen, Stephen Rothwell, Greg Kroah-Hartman,
LKML, linux-acpi
On 05/29/2013 12:02 PM, Rafael J. Wysocki wrote:
>>> diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
>>> index 130ba0b..b9f0eec 100644
>>> --- a/drivers/base/cpu.c
>>> +++ b/drivers/base/cpu.c
>>> @@ -281,6 +281,7 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
>>> cpu->dev.bus = &cpu_subsys;
>>> cpu->dev.release = cpu_device_release;
>>> cpu->dev.offline_disabled = !cpu->hotpluggable;
>>> + cpu->dev.offline = !cpu_online(num);
>>> #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
>>> cpu->dev.bus->uevent = arch_cpu_uevent;
>>> #endif
This gets things working for me again. Thanks for the quick response!
Tested-by: Dave Hansen <dave.hansen@intel.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: possible_cpus broken in linux-next
2013-05-29 22:14 ` Dave Hansen
@ 2013-05-29 22:46 ` Rafael J. Wysocki
0 siblings, 0 replies; 6+ messages in thread
From: Rafael J. Wysocki @ 2013-05-29 22:46 UTC (permalink / raw)
To: Dave Hansen
Cc: Rafael J. Wysocki, Toshi Kani, Dave Hansen, Stephen Rothwell,
Greg Kroah-Hartman, LKML, linux-acpi
On Wednesday, May 29, 2013 03:14:12 PM Dave Hansen wrote:
> On 05/29/2013 12:02 PM, Rafael J. Wysocki wrote:
> >>> diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
> >>> index 130ba0b..b9f0eec 100644
> >>> --- a/drivers/base/cpu.c
> >>> +++ b/drivers/base/cpu.c
> >>> @@ -281,6 +281,7 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
> >>> cpu->dev.bus = &cpu_subsys;
> >>> cpu->dev.release = cpu_device_release;
> >>> cpu->dev.offline_disabled = !cpu->hotpluggable;
> >>> + cpu->dev.offline = !cpu_online(num);
> >>> #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
> >>> cpu->dev.bus->uevent = arch_cpu_uevent;
> >>> #endif
>
> This gets things working for me again. Thanks for the quick response!
>
> Tested-by: Dave Hansen <dave.hansen@intel.com>
Applied.
Thanks,
Rafael
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
^ permalink raw reply [flat|nested] 6+ messages in thread
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2013-05-29 17:10 possible_cpus broken in linux-next Dave Hansen
2013-05-29 18:35 ` Toshi Kani
2013-05-29 18:50 ` Toshi Kani
2013-05-29 19:02 ` Rafael J. Wysocki
2013-05-29 22:14 ` Dave Hansen
2013-05-29 22:46 ` Rafael J. Wysocki
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