Re: [RESEND PATCH v2 1/2] update mem= option's spec according to its implementation

From: KOSAKI Motohiro
Date: Sat Oct 20 2012 - 00:24:01 EST


On Fri, Oct 19, 2012 at 8:52 PM, Wen Congyang <wency@xxxxxxxxxxxxxx> wrote:
> At 10/20/2012 02:11 AM, KOSAKI Motohiro Wrote:
>> On Fri, Oct 19, 2012 at 6:16 AM, <wency@xxxxxxxxxxxxxx> wrote:
>>> From: Wen Congyang <wency@xxxxxxxxxxxxxx>
>>>
>>> Current mem= implementation seems buggy because specification and
>>> implementation doesn't match. Current mem= has been working
>>> for many years and it's not buggy, it works as expected. So
>>> we should update the specification.
>>>
>>> Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
>>> Sort-of-tentatively-acked-by: Rob Landley <rob@xxxxxxxxxxx>
>>> ---
>>> Documentation/kernel-parameters.txt | 7 ++++---
>>> 1 files changed, 4 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
>>> index 9776f06..85b911a 100644
>>> --- a/Documentation/kernel-parameters.txt
>>> +++ b/Documentation/kernel-parameters.txt
>>> @@ -1481,9 +1481,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
>>> mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
>>> Amount of memory to be used when the kernel is not able
>>> to see the whole system memory or for test.
>>> - [X86-32] Use together with memmap= to avoid physical
>>> - address space collisions. Without memmap= PCI devices
>>> - could be placed at addresses belonging to unused RAM.
>>> + [X86-32] Work as limiting max address. Use together
>>> + with memmap= to avoid physical address space collisions.
>>> + Without memmap= PCI devices could be placed at addresses
>>> + belonging to unused RAM.
>>
>> If my remember is correct, x86-64 also specify maximum address.
>> but my remember is not clear.
>
> Do you mean max_addr option? It is only for ia64 box.

No.
Your patch say x86-32 and x86-64 have different mem parameter
semantics. and I doubt it.
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