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

[Dave Hansen <haveblue@us.ibm.com>]

On Fri, 2005-05-13 at 13:24 -0500, Robin Holt wrote:
> On Fri, May 13, 2005 at 09:00:19AM -0700, Dave Hansen wrote:
> > Any other ideas?
> 
> Not necessarily a good idea but how about...
> 
> static int bad_range(struct zone *zone, struct page *page)
> {
> 	unsigned long start_pfn;
> 	unsigned long spanned_pages;
> 
> 	do {
> 		start_pfn = zone->zone_start_pfn;
> 		spanned_pages = zone->spanned_pages;
> 	while (unlikely(start_pfn != zone->zone_start_pfn));
> 
> 	if (page_to_pfn(page) >= start_pfn + spanned_pages;
> 		return 1;
> }

I think that's a similar idea to using a seq_lock, right?

I have the feeling that also open-coding this for shrinking zones would
make it a bit more complex.  It's a good idea, though.

-- Dave

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