Re: Subtle MM bug

[Marcelo Tosatti <marcelo@conectiva.com.br>]

On Tue, 9 Jan 2001, Linus Torvalds wrote:

> 
> 
> On Tue, 9 Jan 2001, Marcelo Tosatti wrote:
> > 
> > The "while (!inactive_shortage())" should be "while (inactive_shortage())"
> > as Benjamin noted on lk.
> 
> Yes. Also, it does need something to make sure that it doesn't end up
> being an endless loop. 

Ok, I'll send another patch which fixes this later today.

> > The second problem is that background scanning is being done
> > unconditionally, and it should not. You end up getting all pages with the
> > same age if the system is idle. Look at this example (2.4.1-pre1):
> 
> I agree. However, I think that we do want to do some background scanning
> to push out dirty pages in the background, kind of like bdflush. It just
> shouldn't age the pages (and thus not move them to the inactive list).

Actually it must age the pages, but aging should not be unconditional. 

Stephen has some thoughts on this. Stephen? 


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