Re: [Lhms-devel] [RFC] consistency of zone->zone_start_pfn, spanned_pages

[Yasunori Goto <y-goto@jp.fujitsu.com>]

> Hi,
> Dave Hansen wrote:
> > The zone struct has a few important members which explicitly define the
> > range of pages that it manages: zone_start_pfn and spanned_pages.
> > 
> > The current memory hotplug coded has concentrated on appending memory to
> > existing zones, which means just increasing spanned_pages.  There is
> > currently no code that breaks at runtime if this value is simply
> > incremented.
> > 
> 
> How about removing zone_start_pfn and spanned_pages ?
> 
> I found they are used in
>     bad_range() in page_alloc.c
>     mark_free_page() in CONFIG_PM.
> 
> And I think we can remove them with section-range-ops when CONFIG_SPARSEMEM=y.
> They are used in some another places ?

Hmm, spanned_pages is used at build_zonelists_node() 
in page_alloc.c.
It looks like still useful for me to initialize and update zonelists
which is hot-added.


Bye.
-- 
Yasunori Goto 


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