Re: MM patches against 2.5.31

[Andrew Morton]

Daniel Phillips wrote:
> 
> Going right back to basics, what do you suppose is wrong with the 2.4
> strategy of always doing the lru removal in free_pages_ok?

That's equivalent to what we have at present, which is:

	if (put_page_testzero(page)) {
		/* window here */
		lru_cache_del(page);
		__free_pages_ok(page, 0);
	}

versus:

	spin_lock(lru lock);
	page = list_entry(lru, ...);
	if (page_count(page) == 0)
		continue;
	/* window here */
	page_cache_get(page);
	page_cache_release(page);	/* double-free */