lru_cache_add() -> deactivate_page_nolock()?

Few questions on aging & deactivation:

Suppose a page has to be freshly allocated
(no cache hit) in __grab_cache_page() in generic_file_write(). What is the age of the page at the time of its lru_cache_add? Won't the age be zero?
If so, won't it be the case that deactive_page_nolock() will be called _every_ time such a page is lru_cache_add'ed, and that this call will be the one from here:

--------
void lru_cache_add(struct page * page)

{
	[ ... ]
	/* This should be relatively rare */
        if (!page->age)
                deactivate_page_nolock(page);
	[ ... ]
}

----------

If so, I fail to understand the motivation behind
the "relatively rare" comment ...

--------------------------------------------------------------------------
Rajagopal Ananthanarayanan ("ananth")
Member Technical Staff, SGI.
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