Re: broken VM in 2.4.10-pre9

[Jan Harkes <jaharkes@cs.cmu.edu>]

On Mon, Sep 17, 2001 at 02:33:12PM +0200, Daniel Phillips wrote:
> The inactive queues have always had both mapped and unmapped pages on
> them. The reason for unmapping a swap cache page page when putting it

So the following code in refill_inactive_scan only exists in my
imagination?

	    if (page_count(page) <= (page->buffers ? 2 : 1)) {
		    deactivate_page_nolock(page);
		    page_active = 0;
	    } else {
		    page_active = 1;
	    }

We only move pages to the inactive list when they have one reference
from the page cache and one from buffers. Since all mapped pte's also
keep a reference, this means that there cannot be any pte's that point
to this page by the time we decide to deactivate the page.

> any choice.  The point where we place it on the inactive queue is the
> last point where we're able to find its userspace page table entry.

And that is because we only move it after all pte's have been unmapped.

Jan