Re: [patch] page aging and deferred swapping for 2.4.0-test1

[Roger Larsson <roger.larsson@norran.net>]

Rik van Riel wrote:
> 
> Hi,
> 
> the attached patch attempts to implement the following two
> things (which we'll probably want in the active/inactive
> design later on):
> - page aging (for active pages)
> - deferred swap IO, with only unmapping in try_to_swap_out()
> 
> The patch still crashes, but maybe one of you has an idea
> on what's wrong and/or even how to fix it ;)
> 
> regards,
> 
> Rik
> --
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> 
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> 


The aging code can not be correct.
		if (PageTestandClearReferenced(page)) {
			page->age += 3;
			if (page->age > 10)
				page->age = 0;
			goto dispose_continue;
		}
		page->age--;

		if (page->age)
			goto dispose_continue;

I would say it should be:

		if (PageTestandClearReferenced(page)) {
			page->age += 3;
			if (page->age > 10)
				page->age = 10;
			goto dispose_continue;
		}

		if (page->age && priority)  // at zero priority ignore age
			goto dispose_continue;

		page->age--;

/RogerL


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