* [BUG] Description for memmap in kernel-parameters.txt is wrong
@ 2014-01-30 16:52 Andiry Xu
2014-01-30 19:25 ` Randy Dunlap
0 siblings, 1 reply; 8+ messages in thread
From: Andiry Xu @ 2014-01-30 16:52 UTC (permalink / raw)
To: linux-kernel; +Cc: Andiry Xu
Hi,
In kernel-parameters.txt, there is following description:
memmap=nn[KMG]$ss[KMG]
[KNL,ACPI] Mark specific memory as reserved.
Region of memory to be used, from ss to ss+nn.
Unfortunately this is incorrect. The meaning of nn and ss is reversed.
For example:
Command Expected Result
memmap 2G$6G 6G - 8G reserved 2G - 8G reserved
memmap 6G$2G 2G - 8G reserved 6G - 8G reserved
Test kernel version 3.13, but I believe the issue has been there long ago.
I'm not sure whether the description or implementation should be
fixed, but apparently they do not match.
Thanks,
Andiry
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [BUG] Description for memmap in kernel-parameters.txt is wrong
2014-01-30 16:52 [BUG] Description for memmap in kernel-parameters.txt is wrong Andiry Xu
@ 2014-01-30 19:25 ` Randy Dunlap
2014-01-30 19:33 ` Andiry Xu
0 siblings, 1 reply; 8+ messages in thread
From: Randy Dunlap @ 2014-01-30 19:25 UTC (permalink / raw)
To: Andiry Xu, linux-kernel; +Cc: Andiry Xu, Linux MM
[adding linux-mm mailing list]
On 01/30/2014 08:52 AM, Andiry Xu wrote:
> Hi,
>
> In kernel-parameters.txt, there is following description:
>
> memmap=nn[KMG]$ss[KMG]
> [KNL,ACPI] Mark specific memory as reserved.
> Region of memory to be used, from ss to ss+nn.
Should be:
Region of memory to be reserved, from ss to ss+nn.
but that doesn't help with the problem that you describe, does it?
> Unfortunately this is incorrect. The meaning of nn and ss is reversed.
> For example:
>
> Command Expected Result
> memmap 2G$6G 6G - 8G reserved 2G - 8G reserved
> memmap 6G$2G 2G - 8G reserved 6G - 8G reserved
Are you testing on x86?
The code in arch/x86/kernel/e820.c always parses mem_size followed by start address.
I don't (yet) see where it goes wrong...
> Test kernel version 3.13, but I believe the issue has been there long ago.
>
> I'm not sure whether the description or implementation should be
> fixed, but apparently they do not match.
I prefer to change the documentation and leave the implementation as is.
--
~Randy
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [BUG] Description for memmap in kernel-parameters.txt is wrong
2014-01-30 19:25 ` Randy Dunlap
@ 2014-01-30 19:33 ` Andiry Xu
2014-01-30 20:26 ` Randy Dunlap
0 siblings, 1 reply; 8+ messages in thread
From: Andiry Xu @ 2014-01-30 19:33 UTC (permalink / raw)
To: Randy Dunlap; +Cc: linux-kernel, Andiry Xu, Linux MM
On Thu, Jan 30, 2014 at 11:25 AM, Randy Dunlap <rdunlap@infradead.org> wrote:
> [adding linux-mm mailing list]
>
> On 01/30/2014 08:52 AM, Andiry Xu wrote:
>> Hi,
>>
>> In kernel-parameters.txt, there is following description:
>>
>> memmap=nn[KMG]$ss[KMG]
>> [KNL,ACPI] Mark specific memory as reserved.
>> Region of memory to be used, from ss to ss+nn.
>
> Should be:
> Region of memory to be reserved, from ss to ss+nn.
>
> but that doesn't help with the problem that you describe, does it?
>
Actually it should be:
Region of memory to be reserved, from nn to nn+ss.
That is, exchange nn and ss.
>
>> Unfortunately this is incorrect. The meaning of nn and ss is reversed.
>> For example:
>>
>> Command Expected Result
>> memmap 2G$6G 6G - 8G reserved 2G - 8G reserved
>> memmap 6G$2G 2G - 8G reserved 6G - 8G reserved
>
> Are you testing on x86?
> The code in arch/x86/kernel/e820.c always parses mem_size followed by start address.
> I don't (yet) see where it goes wrong...
>
Yes, it's a x86 machine.
>
>> Test kernel version 3.13, but I believe the issue has been there long ago.
>>
>> I'm not sure whether the description or implementation should be
>> fixed, but apparently they do not match.
>
> I prefer to change the documentation and leave the implementation as is.
>
That's fine. memmap itself works OK, it's just the description is
wrong and people like me get confused.
Thanks,
Andiry
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [BUG] Description for memmap in kernel-parameters.txt is wrong
2014-01-30 19:33 ` Andiry Xu
@ 2014-01-30 20:26 ` Randy Dunlap
2014-01-30 22:17 ` David Rientjes
0 siblings, 1 reply; 8+ messages in thread
From: Randy Dunlap @ 2014-01-30 20:26 UTC (permalink / raw)
To: Andiry Xu; +Cc: linux-kernel, Andiry Xu, Linux MM
On 01/30/2014 11:33 AM, Andiry Xu wrote:
> On Thu, Jan 30, 2014 at 11:25 AM, Randy Dunlap <rdunlap@infradead.org> wrote:
>> [adding linux-mm mailing list]
>>
>> On 01/30/2014 08:52 AM, Andiry Xu wrote:
>>> Hi,
>>>
>>> In kernel-parameters.txt, there is following description:
>>>
>>> memmap=nn[KMG]$ss[KMG]
>>> [KNL,ACPI] Mark specific memory as reserved.
>>> Region of memory to be used, from ss to ss+nn.
>>
>> Should be:
>> Region of memory to be reserved, from ss to ss+nn.
>>
>> but that doesn't help with the problem that you describe, does it?
>>
>
> Actually it should be:
> Region of memory to be reserved, from nn to nn+ss.
>
> That is, exchange nn and ss.
Yes, I understand that that's what you are reporting. I just haven't yet
worked out how the code manages to exchange those 2 values.
>>
>>> Unfortunately this is incorrect. The meaning of nn and ss is reversed.
>>> For example:
>>>
>>> Command Expected Result
>>> memmap 2G$6G 6G - 8G reserved 2G - 8G reserved
>>> memmap 6G$2G 2G - 8G reserved 6G - 8G reserved
>>
>> Are you testing on x86?
>> The code in arch/x86/kernel/e820.c always parses mem_size followed by start address.
>> I don't (yet) see where it goes wrong...
>>
>
> Yes, it's a x86 machine.
>
>>
>>> Test kernel version 3.13, but I believe the issue has been there long ago.
>>>
>>> I'm not sure whether the description or implementation should be
>>> fixed, but apparently they do not match.
>>
>> I prefer to change the documentation and leave the implementation as is.
>>
>
> That's fine. memmap itself works OK, it's just the description is
> wrong and people like me get confused.
>
> Thanks,
> Andiry
--
~Randy
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [BUG] Description for memmap in kernel-parameters.txt is wrong
2014-01-30 20:26 ` Randy Dunlap
@ 2014-01-30 22:17 ` David Rientjes
2014-01-30 22:54 ` Randy Dunlap
0 siblings, 1 reply; 8+ messages in thread
From: David Rientjes @ 2014-01-30 22:17 UTC (permalink / raw)
To: Randy Dunlap; +Cc: Andiry Xu, linux-kernel, Andiry Xu, Linux MM
On Thu, 30 Jan 2014, Randy Dunlap wrote:
> >>> Hi,
> >>>
> >>> In kernel-parameters.txt, there is following description:
> >>>
> >>> memmap=nn[KMG]$ss[KMG]
> >>> [KNL,ACPI] Mark specific memory as reserved.
> >>> Region of memory to be used, from ss to ss+nn.
> >>
> >> Should be:
> >> Region of memory to be reserved, from ss to ss+nn.
> >>
> >> but that doesn't help with the problem that you describe, does it?
> >>
> >
> > Actually it should be:
> > Region of memory to be reserved, from nn to nn+ss.
> >
> > That is, exchange nn and ss.
>
> Yes, I understand that that's what you are reporting. I just haven't yet
> worked out how the code manages to exchange those 2 values.
>
It doesn't, the documentation is correct as written and could be improved
by your suggestion of "Region of memory to be reserved, from ss to ss+nn."
I think Andiry probably is having a problem with his bootloader
interpreting the '$' incorrectly (or variable expansion if coming from the
shell) or interpreting the resulting user-defined e820 map incorrectly.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [BUG] Description for memmap in kernel-parameters.txt is wrong
2014-01-30 22:17 ` David Rientjes
@ 2014-01-30 22:54 ` Randy Dunlap
2014-01-30 23:43 ` Andiry Xu
0 siblings, 1 reply; 8+ messages in thread
From: Randy Dunlap @ 2014-01-30 22:54 UTC (permalink / raw)
To: David Rientjes; +Cc: Andiry Xu, linux-kernel, Andiry Xu, Linux MM
On 01/30/2014 02:17 PM, David Rientjes wrote:
> On Thu, 30 Jan 2014, Randy Dunlap wrote:
>
>>>>> Hi,
>>>>>
>>>>> In kernel-parameters.txt, there is following description:
>>>>>
>>>>> memmap=nn[KMG]$ss[KMG]
>>>>> [KNL,ACPI] Mark specific memory as reserved.
>>>>> Region of memory to be used, from ss to ss+nn.
>>>>
>>>> Should be:
>>>> Region of memory to be reserved, from ss to ss+nn.
>>>>
>>>> but that doesn't help with the problem that you describe, does it?
>>>>
>>>
>>> Actually it should be:
>>> Region of memory to be reserved, from nn to nn+ss.
>>>
>>> That is, exchange nn and ss.
>>
>> Yes, I understand that that's what you are reporting. I just haven't yet
>> worked out how the code manages to exchange those 2 values.
>>
>
> It doesn't, the documentation is correct as written and could be improved
> by your suggestion of "Region of memory to be reserved, from ss to ss+nn."
> I think Andiry probably is having a problem with his bootloader
> interpreting the '$' incorrectly (or variable expansion if coming from the
> shell) or interpreting the resulting user-defined e820 map incorrectly.
> --
Yeah, I certainly don't see a problem with the code and I would want to
see/understand that before I exchanged the 2 values in the documentation.
I'll submit a patch to make the wording a bit better.
Thanks.
--
~Randy
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [BUG] Description for memmap in kernel-parameters.txt is wrong
2014-01-30 22:54 ` Randy Dunlap
@ 2014-01-30 23:43 ` Andiry Xu
2014-01-30 23:49 ` Randy Dunlap
0 siblings, 1 reply; 8+ messages in thread
From: Andiry Xu @ 2014-01-30 23:43 UTC (permalink / raw)
To: Randy Dunlap; +Cc: David Rientjes, Andiry Xu, linux-kernel, Linux MM
On Thu, Jan 30, 2014 at 2:54 PM, Randy Dunlap <rdunlap@infradead.org> wrote:
> On 01/30/2014 02:17 PM, David Rientjes wrote:
>> On Thu, 30 Jan 2014, Randy Dunlap wrote:
>>
>>>>>> Hi,
>>>>>>
>>>>>> In kernel-parameters.txt, there is following description:
>>>>>>
>>>>>> memmap=nn[KMG]$ss[KMG]
>>>>>> [KNL,ACPI] Mark specific memory as reserved.
>>>>>> Region of memory to be used, from ss to ss+nn.
>>>>>
>>>>> Should be:
>>>>> Region of memory to be reserved, from ss to ss+nn.
>>>>>
>>>>> but that doesn't help with the problem that you describe, does it?
>>>>>
>>>>
>>>> Actually it should be:
>>>> Region of memory to be reserved, from nn to nn+ss.
>>>>
>>>> That is, exchange nn and ss.
>>>
>>> Yes, I understand that that's what you are reporting. I just haven't yet
>>> worked out how the code manages to exchange those 2 values.
>>>
>>
>> It doesn't, the documentation is correct as written and could be improved
>> by your suggestion of "Region of memory to be reserved, from ss to ss+nn."
>> I think Andiry probably is having a problem with his bootloader
>> interpreting the '$' incorrectly (or variable expansion if coming from the
>> shell) or interpreting the resulting user-defined e820 map incorrectly.
>> --
>
> Yeah, I certainly don't see a problem with the code and I would want to
> see/understand that before I exchanged the 2 values in the documentation.
>
> I'll submit a patch to make the wording a bit better.
>
I'm using Ubuntu 13.04 with GRUB2. If it's a bootloader issue, what should I do?
Thanks,
Andiry
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [BUG] Description for memmap in kernel-parameters.txt is wrong
2014-01-30 23:43 ` Andiry Xu
@ 2014-01-30 23:49 ` Randy Dunlap
0 siblings, 0 replies; 8+ messages in thread
From: Randy Dunlap @ 2014-01-30 23:49 UTC (permalink / raw)
To: Andiry Xu; +Cc: David Rientjes, Andiry Xu, linux-kernel, Linux MM
On 01/30/2014 03:43 PM, Andiry Xu wrote:
> On Thu, Jan 30, 2014 at 2:54 PM, Randy Dunlap <rdunlap@infradead.org> wrote:
>> On 01/30/2014 02:17 PM, David Rientjes wrote:
>>> On Thu, 30 Jan 2014, Randy Dunlap wrote:
>>>
>>>>>>> Hi,
>>>>>>>
>>>>>>> In kernel-parameters.txt, there is following description:
>>>>>>>
>>>>>>> memmap=nn[KMG]$ss[KMG]
>>>>>>> [KNL,ACPI] Mark specific memory as reserved.
>>>>>>> Region of memory to be used, from ss to ss+nn.
>>>>>>
>>>>>> Should be:
>>>>>> Region of memory to be reserved, from ss to ss+nn.
>>>>>>
>>>>>> but that doesn't help with the problem that you describe, does it?
>>>>>>
>>>>>
>>>>> Actually it should be:
>>>>> Region of memory to be reserved, from nn to nn+ss.
>>>>>
>>>>> That is, exchange nn and ss.
>>>>
>>>> Yes, I understand that that's what you are reporting. I just haven't yet
>>>> worked out how the code manages to exchange those 2 values.
>>>>
>>>
>>> It doesn't, the documentation is correct as written and could be improved
>>> by your suggestion of "Region of memory to be reserved, from ss to ss+nn."
>>> I think Andiry probably is having a problem with his bootloader
>>> interpreting the '$' incorrectly (or variable expansion if coming from the
>>> shell) or interpreting the resulting user-defined e820 map incorrectly.
>>> --
>>
>> Yeah, I certainly don't see a problem with the code and I would want to
>> see/understand that before I exchanged the 2 values in the documentation.
>>
>> I'll submit a patch to make the wording a bit better.
>>
>
> I'm using Ubuntu 13.04 with GRUB2. If it's a bootloader issue, what should I do?
See https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/448413
i.e., use shell escape '\' character.
--
~Randy
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2014-01-30 23:50 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
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2014-01-30 16:52 [BUG] Description for memmap in kernel-parameters.txt is wrong Andiry Xu
2014-01-30 19:25 ` Randy Dunlap
2014-01-30 19:33 ` Andiry Xu
2014-01-30 20:26 ` Randy Dunlap
2014-01-30 22:17 ` David Rientjes
2014-01-30 22:54 ` Randy Dunlap
2014-01-30 23:43 ` Andiry Xu
2014-01-30 23:49 ` Randy Dunlap
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