On 8/4/25 13:54, Michal Hocko wrote:
> On Wed 30-07-25 16:04:28, David Hildenbrand wrote:
>> On 30.07.25 15:57, Eugen Hristev wrote:
> [...]
>>> Yes, registering after is also an option. Initially this is how I
>>> designed the kmemdump API, I also had in mind to add a flag, but, after
>>> discussing with Thomas Gleixner, he came up with the macro wrapper idea
>>> here:
>>> https://lore.kernel.org/lkml/87ikkzpcup.ffs@tglx/
>>> Do you think we can continue that discussion , or maybe start it here ?
>>
>> Yeah, I don't like that, but I can see how we ended up here.
>>
>> I also don't quite like the idea that we must encode here what to include in
>> a dump and what not ...
>>
>> For the vmcore we construct it at runtime in crash_save_vmcoreinfo_init(),
>> where we e.g., have
>>
>> VMCOREINFO_STRUCT_SIZE(pglist_data);
>>
>> Could we similar have some place where we construct what to dump similarly,
>> just not using the current values, but the memory ranges?
>
> All those symbols are part of kallsyms, right? Can we just use kallsyms
> infrastructure and a list of symbols to get what we need from there?
>
> In other words the list of symbols to be completely external to the code
> that is defining them?
Some static symbols are indeed part of kallsyms. But some symbols are
not exported, for example patch 20/29, where printk related symbols are
not to be exported. Another example is with static variables, like in
patch 17/29 , not exported as symbols, but required for the dump.
Dynamic memory regions are not have to also be considered, have a look
for example at patch 23/29 , where dynamically allocated memory needs to
be registered.
Do you think that I should move all kallsyms related symbols annotation
into a separate place and keep it for the static/dynamic regions in place ?
Thanks for looking into my patch,
Eugen
