From: erik quanstrom <quanstro@quanstro.net>
To: 9fans@9fans.net
Subject: Re: [9fans] sleep/wakeup bug?
Date: Fri, 25 Feb 2011 00:26:44 -0500 [thread overview]
Message-ID: <11da45046fa8267e7445128ed00724cd@ladd.quanstro.net> (raw)
> assuming a tight 1:1 coupling between sleep and
> wakeup is a recipe for trouble. even if your change
> fixes one possible race (i didn't bother to see what changed),
> you still have to deal with
the point of sleep/rendezvous is tight coupling, no?
the change was to move the ready() to after the rendezvous
lock was dropped. therefore the sleeper knows the rendezvous
is not locked by the event that woke him. if one can assert
that each sleep has exactly one wakeup (as is often the case
for rpc-style programming), then that is enough to know
the rendezvous can be retired.
> these races are inherent to the definition of sleep and
> wakeup. it doesn't mean what you need it to mean
> to free memory immediately after sleeping on it.
if not a tight coupling, what kind of coupling would you
think is appropriate? when would you think it would be
fair to recycle the rendezvous? 10s? :-) what idiom do
you think would be appropriate for such a case?
- erik
next reply other threads:[~2011-02-25 5:26 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-25 5:26 erik quanstrom [this message]
2011-02-25 5:47 ` Russ Cox
2011-02-25 5:53 ` erik quanstrom
2011-02-25 6:01 ` Russ Cox
2011-02-25 6:12 ` erik quanstrom
[not found] ` <2808a9fa079bea86380a8d52be67b980@coraid.com>
[not found] ` <AANLkTi=4_=++Tm2a9Jq9jSzqUSexkW-ZjM-38oD_bS1y@mail.gmail.com>
[not found] ` <40925e8f64489665bd5bd6ca743400ea@coraid.com>
2011-02-25 6:51 ` Russ Cox
2011-02-25 7:13 ` erik quanstrom
2011-02-25 14:44 ` Russ Cox
2011-02-25 8:37 ` Sape Mullender
2011-02-25 9:18 ` Bakul Shah
2011-02-25 14:57 ` Charles Forsyth
2011-02-25 16:09 ` Venkatesh Srinivas
-- strict thread matches above, loose matches on Subject: below --
2011-02-24 22:01 erik quanstrom
2011-02-25 4:46 ` Russ Cox
2011-02-25 9:46 ` Richard Miller
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