Re: [PATCH v2 0/7] mm/hotplug: Only use subsection map in VMEMMAP case

David Hildenbrand
2020-02-25T09:10:57Z

>>> include/linux/mmzone.h | 2 +
>>> mm/sparse.c | 178 +++++++++++++++++++++++++++++------------
>>> 2 files changed, 127 insertions(+), 53 deletions(-)
>>
>> Why do we need to add so much code to remove a functionality from one
>> memory model?
>
> Hmm, Dan also asked this before.
>
> The adding mainly happens in patch 2, 3, 4, including the two newly
> added function defitions, the code comments above them, and those added
> dummy functions for !VMEMMAP.

AFAIKS, it's mostly a bunch of newly added comments on top of functions.
E.g., the comment for fill_subsection_map() alone spans 12 LOC in total.
I do wonder if we have to be that verbose. We are barely that verbose on
MM code (and usually I don't see much benefit unless it's a function
with many users from many different places).

--
Thanks,

David / dhildenb