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From: Charles Forsyth <forsyth@terzarima.net>
To: 9fans@9fans.net
Subject: Re: [9fans] double wakeup disallowed
Date: Wed, 28 Oct 2009 15:45:18 +0000	[thread overview]
Message-ID: <dddea78fb97715c0e589cc1639d1b804@terzarima.net> (raw)
In-Reply-To: <dd6fe68a0910280829s1110fd5dr301a9d422deeb67d@mail.gmail.com>

>however the invarient that there is exactly one wakeup for
>every sleep requires some careful accounting that
>can be equally error prone.care not to double-interrupt.

if a process p sleeps on r for condition f, and there are two wakeup(r), only
the first wakeup does anything because by the time of the second,
r doesn't refer to p any more. were you wanting r to retain memory of p so
the second wakeup would ... presumably still not do anything? (because
p wouldn't be in the right state.) if so, i don't see what you've gained.
i must be missing something.



  reply	other threads:[~2009-10-28 15:45 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <<d73c6a7a4b7a22bffde73a5b0ec7a0b7@terzarima.net>
2009-10-28 13:24 ` erik quanstrom
2009-10-28 15:29   ` Russ Cox
2009-10-28 15:45     ` Charles Forsyth [this message]
2009-10-28 16:14       ` erik quanstrom
2009-10-30  5:45         ` Russ Cox
     [not found] <<dd6fe68a0910292245x70f83d7bl8957356abda38201@mail.gmail.com>
2009-10-30 14:11 ` erik quanstrom
2009-10-27 23:38 erik quanstrom
2009-10-28  9:43 ` Charles Forsyth

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