>
mel@skynet.ie (Mel Gorman) writes:
>
> > On (16/09/07 17:08), Andrea Arcangeli didst pronounce:
> >> zooming in I see red pixels all over the squares mized with green
> >> pixels in the same square. This is exactly what happens with the
> >> variable order page cache and that's why it provides zero guarantees
> >> in terms of how much ram is really "free" (free as in "available").
> >>
> >
> > This picture is not grouping pages by mobility so that is hardly a
> > suprise. This picture is not running grouping pages by mobility. This is
> > what the normal kernel looks like. Look at the videos in
> >
http://www.skynet.ie/~mel/anti-frag/2007-02-28 and see how list-based
> > compares to vanilla. These are from February when there was less control
> > over mixing blocks than there is today.
> >
> > In the current version mixing occurs in the lower blocks as much as possible
> > not the upper ones. So there are a number of mixed blocks but the number is
> > kept to a minimum.
> >
> > The number of mixed blocks could have been enforced as 0, but I felt it was
> > better in the general case to fragment rather than regress performance.
> > That may be different for large blocks where you will want to take the
> > enforcement steps.
>
> I agree that 0 is a bad value. But so is infinity. There should be
> some mixing but not a lot. You say "kept to a minimum". Is that
> actively done or already happens by itself. Hopefully the later which
> would be just splendid.
>
