:> For some reason banning you from the irc channel hasn't convinced
:> you that complaining without providing patches isn't the way we do
:> things around here.
:How about first analysing the problem in detail and
:trying to fix it after we understand the problem ?
:The current stage is that I've pretty much figured out
:the problem and know why the code in FreeBSD and NetBSD
:doesn't currently work (while it would have worked in
:the original Mach VM).
:A next stage is getting some smart people together
:and coming up with a thorough solution.
:"Patch first, think later" is definately not the
:attitude I'm used to seeing in the FreeBSD world,
:no matter how often you and phk have shouted this at
:me yesterday ;)

    Well, we'll see what you have to say in your paper.  VM/Swap is a
    tough nut to crack... remember when I thought I had optimized the
    pageout daemon to not launder dirty pages unnecessarily?  And then it
    turned out that, in fact, the pageouts were necessary to maintain
    stability in certain environments (like USENET news servers).  That was
    somewhat embarassing because I waxed poetic to you and Linus and then
    had to correct myself and revert part of the optimization after real-life
    problems started cropping up.

    About 8 months ago I introduce code that would prevent sequential
    reads of large files from blowing away the rest of the system's VM
    page cache, to reduce the impact sequential reads would have 
    in a heavily loaded system.  It's a wonderful idea and I had thought
    up a great algorithm... too bad it didn't work in real life.  It took
    a month to find all the edge cases and change the algorithm to be
    more of a heuristic to handle them all.  I'm still not completely happy
    with it so at the moment it's only used by madvise().  At some point
    soon I am going to make the buffer cache use it, though.

    In anycase... insofar as VM goes, A theory doesn't usually last beyond
    the first implementation.  So "we'll see".


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