Re: + memory-hotplug-fix-kswapd-looping-forever-problem-fix-fix.patch added to -mm tree

[Minchan Kim <minchan@kernel.org>]

On Mon, Jul 23, 2012 at 08:42:47AM -0700, Tejun Heo wrote:
> Hello, Minchan.
> 
> On Mon, Jul 23, 2012 at 01:58:55PM +0900, Minchan Kim wrote:
> > I would like to know what fields you are concerning because most of field
> 
> The above question itself is a problem.  It's subtle to hell.  Some
> fields of this data structure is used during early boot but at some
> point all are reset to zero, so we have to be careful about how those
> fields are used before and after.
> 
> This might seem clear now but things like this are likely to make
> people later working on the code go WTF.  Let's say for whatever
> reason ->bdata needs to be accessed after free_area_init - e.g.
> arch_add_memory() needs some info from bdata, what then?
> 
> What if we end up having to add a new property field which is
> determined by platform code but used by generic code.  I would add a
> field to pgdat, init it from numa.c and then later use it in generic
> code.  If the field gets zeroed inbetween, I would get pretty annoyed.
> 
> I really don't think this subject is worth the amount of discussion we
> had in this thread.  Just make the archs clear the data structure on
> creation.  Anything else is silly.

I sent patchset and will wait of akpm's opinion.
Thanks for the comment, Tejun.

-- 
Kind regards,
Minchan Kim

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