Re: [Invitation] Linux MM Alignment Session on kmemdump on Wednesday

[Eugen Hristev <eugen.hristev@linaro.org>]

On 9/16/25 15:07, Matthew Wilcox wrote:
> On Tue, Sep 16, 2025 at 11:49:35AM +0300, Eugen Hristev wrote:
>> On 9/15/25 21:53, Matthew Wilcox wrote:
>>> On Mon, Sep 15, 2025 at 08:58:35AM -0700, David Rientjes wrote:
>>>> This week's topic will be kmemdump led by Eugen Hristev.  See the latest
>>>> proposal at https://lwn.net/Articles/1031319/.
>>>
>>> I don't understand what this has to do with mm, to be honest.
>>> It looks like a debugging aid.
>>
>> It was suggested to move it to mm/ :
>>
>> https://lore.kernel.org/all/0fa9e4e7-1247-4c82-8c0b-fa65b7fbb56d@infradead.org/
> 
> I feel like you should be able to explain this rather better than
> "somebody else told me to move it".  As of this moment, I still don't
> know what kmemdump even is.
> 
>>>
>>> https://lore.kernel.org/lkml/20250422113156.575971-2-eugen.hristev@linaro.org/
>>>
>>> is a great example of how to write a lot of documentation that doesn't
>>> actually tell the reader what anything is.
>>>
>>>
>>
>> Here is a link to the v3 where I changed it a little bit :
>>
>> https://lore.kernel.org/all/20250912150855.2901211-1-eugen.hristev@linaro.org/
>>
>> I am eager to improve the documentation to make more sense out of it, I
>> am happy with suggestions.
> 
> Start by telling me what it is.

A way to select memory areas from the kernel that can be used to debug
the kernel, instead of saving the whole memory dump which is mostly not
of interest and takes a lot of space.
Anyone can register a pointer and a size, these are placed into a list,
and a dedicated firmware can parse it and save it in case of a crash.
Does this make sense ?