2013-06-20 08:59:07

by Hanjun Guo

[permalink] [raw]
Subject: [PATCH] Documentation / cpu hotplug: remove outdated description for MADT entries

More than 256 entries in ACPI MADT is supported from ACPI 3.0 Specification,
So the outdated description for MADT entries should be removed.

Signed-off-by: Hanjun Guo <[email protected]>
---
Documentation/cpu-hotplug.txt | 3 ---
1 file changed, 3 deletions(-)

diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt
index 9f40135..2e36e40 100644
--- a/Documentation/cpu-hotplug.txt
+++ b/Documentation/cpu-hotplug.txt
@@ -370,9 +370,6 @@ A: There is no clear spec defined way from ACPI that can give us that
CPUs in MADT as hotpluggable CPUS. In the case there are no disabled CPUS
we assume 1/2 the number of CPUs currently present can be hotplugged.

- Caveat: Today's ACPI MADT can only provide 256 entries since the apicid field
- in MADT is only 8 bits.
-
User Space Notification

Hotplug support for devices is common in Linux today. Its being used today to
--
1.7.9.5


2013-06-20 19:43:31

by Rafael J. Wysocki

[permalink] [raw]
Subject: Re: [PATCH] Documentation / cpu hotplug: remove outdated description for MADT entries

On Thursday, June 20, 2013 04:54:42 PM Hanjun Guo wrote:
> More than 256 entries in ACPI MADT is supported from ACPI 3.0 Specification,
> So the outdated description for MADT entries should be removed.

Well, it kind of is still valid for systems pre-dating ACPI 3.0, isn't it?

So perhaps instead of simply removing that information it would be better to
rephrase it?

Thanks,
Rafael


> Signed-off-by: Hanjun Guo <[email protected]>
> ---
> Documentation/cpu-hotplug.txt | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt
> index 9f40135..2e36e40 100644
> --- a/Documentation/cpu-hotplug.txt
> +++ b/Documentation/cpu-hotplug.txt
> @@ -370,9 +370,6 @@ A: There is no clear spec defined way from ACPI that can give us that
> CPUs in MADT as hotpluggable CPUS. In the case there are no disabled CPUS
> we assume 1/2 the number of CPUs currently present can be hotplugged.
>
> - Caveat: Today's ACPI MADT can only provide 256 entries since the apicid field
> - in MADT is only 8 bits.
> -
> User Space Notification
>
> Hotplug support for devices is common in Linux today. Its being used today to
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.

2013-06-21 02:17:18

by Hanjun Guo

[permalink] [raw]
Subject: Re: [PATCH] Documentation / cpu hotplug: remove outdated description for MADT entries

On 2013-6-21 3:52, Rafael J. Wysocki wrote:
> On Thursday, June 20, 2013 04:54:42 PM Hanjun Guo wrote:
>> More than 256 entries in ACPI MADT is supported from ACPI 3.0 Specification,
>> So the outdated description for MADT entries should be removed.
>
> Well, it kind of is still valid for systems pre-dating ACPI 3.0, isn't it?

Yes, it is.

>
> So perhaps instead of simply removing that information it would be better to
> rephrase it?

Good idea, I will update my patch and send out soon.

Thanks
Hanjun

>
> Thanks,
> Rafael
>
>
>> Signed-off-by: Hanjun Guo <[email protected]>
>> ---
>> Documentation/cpu-hotplug.txt | 3 ---
>> 1 file changed, 3 deletions(-)
>>
>> diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt
>> index 9f40135..2e36e40 100644
>> --- a/Documentation/cpu-hotplug.txt
>> +++ b/Documentation/cpu-hotplug.txt
>> @@ -370,9 +370,6 @@ A: There is no clear spec defined way from ACPI that can give us that
>> CPUs in MADT as hotpluggable CPUS. In the case there are no disabled CPUS
>> we assume 1/2 the number of CPUs currently present can be hotplugged.
>>
>> - Caveat: Today's ACPI MADT can only provide 256 entries since the apicid field
>> - in MADT is only 8 bits.
>> -
>> User Space Notification
>>
>> Hotplug support for devices is common in Linux today. Its being used today to
>>

2013-06-21 04:30:31

by Rob Landley

[permalink] [raw]
Subject: Re: [PATCH] Documentation / cpu hotplug: remove outdated description for MADT entries

On 06/20/2013 03:54:42 AM, Hanjun Guo wrote:
> More than 256 entries in ACPI MADT is supported from ACPI 3.0
> Specification,
> So the outdated description for MADT entries should be removed.
>
> Signed-off-by: Hanjun Guo <[email protected]>
> ---
> Documentation/cpu-hotplug.txt | 3 ---
> 1 file changed, 3 deletions(-)

Acked-by: Rob Landley <[email protected]>

> diff --git a/Documentation/cpu-hotplug.txt
> b/Documentation/cpu-hotplug.txt
> index 9f40135..2e36e40 100644
> --- a/Documentation/cpu-hotplug.txt
> +++ b/Documentation/cpu-hotplug.txt
> @@ -370,9 +370,6 @@ A: There is no clear spec defined way from ACPI
> that can give us that
> CPUs in MADT as hotpluggable CPUS. In the case there are no
> disabled CPUS
> we assume 1/2 the number of CPUs currently present can be
> hotplugged.
>
> - Caveat: Today's ACPI MADT can only provide 256 entries since the
> apicid field
> - in MADT is only 8 bits.
> -
> User Space Notification
>
> Hotplug support for devices is common in Linux today. Its being used
> today to
> --
> 1.7.9.5
>
>

2013-06-26 09:21:47

by Jiri Kosina

[permalink] [raw]
Subject: Re: [PATCH] Documentation / cpu hotplug: remove outdated description for MADT entries

On Thu, 20 Jun 2013, Rob Landley wrote:

> On 06/20/2013 03:54:42 AM, Hanjun Guo wrote:
> > More than 256 entries in ACPI MADT is supported from ACPI 3.0 Specification,
> > So the outdated description for MADT entries should be removed.
> >
> > Signed-off-by: Hanjun Guo <[email protected]>
> > ---
> > Documentation/cpu-hotplug.txt | 3 ---
> > 1 file changed, 3 deletions(-)
>
> Acked-by: Rob Landley <[email protected]>

I am not taking this one, as I think the information should be kept there
to reflect the state on systems that are not 3.0-compliant.

--
Jiri Kosina
SUSE Labs