try_to_swap_out() return value problem?

[Marcelo Tosatti]

Hi Linus,

Your latest changes to try_to_swap_out() does not seem to be obviously
correct.

	-   if (mm->swap_cnt)
	-       mm->swap_cnt--;
	+   if (!mm->swap_cnt)
	+       return 1;
	+
	+   mm->swap_cnt--;

Having swap_cnt == 0 does not necessarily mean that we successfully freed
a page (look at the page aging and locking checks in try_to_swap_out).

Now refill_inactive() relies on the assumption that swap_out() returning 
1 means we successfully freed a page:

                while (swap_out(priority, gfp_mask)) {
                        made_progress = 1;
                        if (--count <= 0)
                                goto done;
                }