yep. Or when we extend a zone/node via hotplug.
The only thing I am worried about is that by doing that, the system
will account spanned_pages incorrectly.
As long as end_pfn - start_pfn matches then I do not see what would be
incorrect.
If by end_pfn - start_pfn you mean zone_end_pfn - zone_start_pfn,
then we would still need to change zone_start_pfn when removing
the first section, and adjust spanned_pages in case we remove the last
section,
would not we?
Let us say we have a zone with 3 sections:
zone_start_pfn = 0
zone_end_pfn = 98304
If we hot-remove the last section, zone_end_pfn should be adjusted to
65536.
Otherwise zone_end_pfn - zone_start_pfn will give us more.
The same goes when we hot-remove the first section.
Of course, we should not care when removing a section which is not
either
the first one or the last one.
Having said that, I will check the uses we have for spanned_pages.
