On 04.08.25 13:06, Eugen Hristev wrote:
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 ?
If you want to use a symbol from kmemdump, then make that symbol
available to kmemdump.
IOW, if we were to rip out kmemdump tomorrow, we wouldn't have to touch
any non-kmemdump-specific files.
--
Cheers,
David / dhildenb
