Re: Zoned CART

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

On Fri, 2005-08-12 at 20:08 -0300, Marcelo Tosatti wrote:

> +/* The replace function. This function serches the active and longterm
> +lists and looks for a candidate for replacement. This function selects
> +the candidate and returns the corresponding structpage or returns
> +NULL in case no page can be freed. The *where argument is used to
> +indicate the parent list of the page so that, in case it cannot be
> +written back, it can be placed back on the correct list */ 
> +struct page *replace(struct zone *zone, int *where)
> 
> +	list = list->next;
> +	while (list !=&zone->active_longterm) {
> +		page = list_entry(list, struct page, lru);
> +
> +		if (!PageReferenced(page))
> +			break;
> +		
> +		ClearPageReferenced(page);
> +		del_page_from_active_longterm(zone, page);
> +		add_page_to_active_list_tail(zone, page);
> 
> This sounds odd. If a page is referenced you remove it from the longterm list
> "unpromoting" it to the active list? Shouldnt be the other way around?

This is correct, the longterm list (T2) is essentially a FIFO. All it
does is delay the re-evaluation of the page.

-- 
Peter Zijlstra <a.p.zijlstra@chello.nl>

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