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    SubjectRe: [patch 1/19] writeback tunables
    On Mon, 17 Jun 2002, Andrew Morton wrote:

    > Russell King wrote:
    > >
    > > On Mon, Jun 17, 2002 at 12:33:18PM +0200, Martin Dalecki wrote:
    > > ...
    > > > > +int dirty_expire_centisecs = 30 * 100;
    > > > > +
    > > >
    > > > Blind guess - didn't the 100 wan't to be HZ?!
    > >
    > > The units are centiseconds (as the name suggests). 5 * 100 centiseconds = 5
    > > seconds, so the dirty writeback timeout is 5 seconds. Check the code a
    > > little further and you'll see HZ gets factored into them on use.
    > >
    >
    > Yup. Sorry about the "_centisecs" thing. That's a bit anal, but
    > I tend to think that it's best to be really explicit about the
    > units, make it a bit easier to use. I don't know how many times
    > I've had to peer in fs/buffer.c to remember what those dang numbers do.
    >
    > Possibly, "seconds" may be sufficiently high resolution for
    > these things. But I wasn't sure - maybe someone wants to
    > run the kupdate function five times per second? Dunno.

    Possibly, we should just concede that anywhere where we're measuring time,
    we'll eventually want to use a non-integer external representation just so
    we're not building in obsolescense. With a couple simple wrappers like
    atoif(".667",HZ)=67, this could be pretty painless.

    --
    "Love the dolphins," she advised him. "Write by W.A.S.T.E.."

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