In article <[EMAIL PROTECTED]>, David Greenman
> >I will add that this is the pattern that Kirk teaches in his kernel
> >internals class.
>    If that's true,

Do you want me to fax you a copy of page 15 of his class notes from
the course he gave at last year's FreeBSDCon, or will you just take my
word for it?

> then he should practice what he preaches. Some of the code that I'm
> refering to (e.g. lockf) was apparantly written by him.

Whether Kirk practices what he preaches is irrelevant to this
discussion.  Instead of focusing on a 1-sentence "I will add ..." from
my posting, why not respond to the main thrust of it -- the paragraph
I quoted from the Birrell paper?

>    I'll say again, however, that some of the cases that rely on the
> historical symantics would become very expensive if they had to go
> through a series of complex checks (perhaps list traversals, etc),
> in order to verify that the wakeup wasn't bogus. I personally don't
> think this is an improvement.

Some of them might be expensive, but most of them would not.
Obviously the waker-upper knows that the condition is true.  Otherwise
the existing code which doesn't check wouldn't work.  In the expensive
cases the waker-upper could simply set a flag for the sleeper to

Note, I am not expressing an opinion about whether the sleeps should
be terminated prematurely during shutdown.  But I am expressing a
strong opinion about whether sleepers should do a reality check before

  John Polstra                                               [EMAIL PROTECTED]
  John D. Polstra & Co., Inc.                        Seattle, Washington USA
  "Disappointment is a good sign of basic intelligence."  -- Chögyam Trungpa

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