[PATCH v6] mm/hugetlb: ignore hugepage kernel args if hugepages are unsupported

[Ritesh Harjani (IBM)]

"David Hildenbrand (Red Hat)" <david at kernel.org> writes:

>> Coming back to the fixes tag. I did mention a bit of a history [2] of
>> whatever I could find while reviewing this patch. I am not sure whether
>> you have looked into the links shared in that email or not. Here [2]:
>> 
>> [2]: https://lore.kernel.org/linuxppc-dev/875xa3ksz9.ritesh.list@gmail.com/
>> 
>> Where I am coming from is.. The current patch is acutally a partial
>> revert of the patch mentioned in the fixes tag. That means if this patch
>> gets applied to the older stable kernels, it would end up bringing the
>> same problem back, which the "Fixes" tagged patch is fixing in the 1st
>> place, isnt' it? See this discussion [3]...
>> 
>> [3]: https://lore.kernel.org/all/b1f04f9f-fa46-c2a0-7693-4a0679d2a1ee@oracle.com/T/#m0eee87b458d93559426b8b0e78dc6ebcd26ad3ae
>> 
>> ... So, IMO - the right fixes tag, if we have to add, it should be the
>> patch which moved the hpage_shift initialization to happen early i.e. in
>> mmu_early_init_devtree. That would be this patch [4]:
>> 
>> [4]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2354ad252b66695be02f4acd18e37bf6264f0464
>> 
>> Now, it's not really that the patch [4] had any issue as such. But it
>> seems like, that the current fix can only be applied after patch [4] is
>> taken.
>> 
>> Do we agree?
> I think we should document all that in the cover letter, an describe 
> that this partial revert is only possible after [4],

Yes, I agree. Let's add the above details in the commit msg.

> and that that must 
> be considered when attempting any kind of stable backports.

Sure. I would prefer if we change the Fixes tag to the one which I
pointed in above [4] (with explaination in the commit msg). However I am
still ok if we would like to retain the existing fixes tag and show [4]
as a dependency.


-ritesh