Re: [PATCH] Section mismatch contig_page_data and bootmem_node_data

[Marcin Slusarz <marcin.slusarz@gmail.com>]

On Wed, Aug 20, 2008 at 11:45:00PM +0200, Johannes Weiner wrote:
> Hi,
> 
> > On Wed, 20 Aug 2008 21:05:41 +0200
> > Marcin Slusarz <marcin.slusarz@gmail.com> wrote:
> >
> >> I thought about this warning today and found 2 other solutions:
> >> 1) Mark contig_page_data as __ref (but it might hide real bugs).
> >> 2) Remove bdata from struct pglist_data and access it directly through
> >>    bootmem_node_data. It requires passing node number to all functions
> >>    which use bdata, but unfortunately arch/ia64/mm/discontig.c handles
> >>    node numbering its own way. I'm still investigating it.
> 
> Yeah, I gave it a shot once too but dropped it again after I looked at
> ia64 code.
> 
> Perhaps we can just remove the static assignment and do it at boot up?

That won't work - modpost will warn at different place about section
mismatch. But even if it would work, we lose potentially useful
analysis of all uses of pglist_data->bdata.

But I think I found better solution - replace "struct bootmem_data *bdata"
in struct pglist_data with "int bootmem_node;" and change all uses of bdata
to &bootmem_node_data[struct pglist_data *->bootmem_node].

What do you think about it? Would it be acceptable?

PS: restored cc'ing LKML

Marcin