From: miller@hamnavoe.demon.co.uk
To: 9fans@cse.psu.edu
Subject: Re: [9fans] Kernel question: i386 test-and-set problem
Date: Mon, 10 Jul 2000 17:21:41 +0100 [thread overview]
Message-ID: <E13BgOG-000Lm9-0U@anchor-post-30.mail.demon.net> (raw)
Russ Cox <rsc@plan9.bell-labs.com> writes:
> ... Since we don't
> play funny games with lock-free data structures, ...
A notable exception is the funny game which sleep() and wakeup()
play with the Rendez structure, which no longer has the lock
which protected it in the original 2nd edition kernel. This game
is not just funny but dangerous, as evidenced by the new coherence()
calls introduced to counteract the resulting vulnerability to weakly
coherent memory on some multiprocessors, and the long explanatory
comment.
Kids, don't try this at home ... practise the discipline of Safe
Sharing (always use a lock) and you won't need to worry about
memory coherence.
-- Richard Miller
next reply other threads:[~2000-07-10 16:21 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-07-10 16:21 miller [this message]
-- strict thread matches above, loose matches on Subject: below --
2000-08-03 9:56 miller
2000-08-02 16:24 presotto
2000-08-02 15:43 jmk
2000-08-02 14:51 miller
2000-08-02 13:20 presotto
2000-08-02 8:32 miller
2000-07-31 17:26 presotto
2000-07-23 14:41 miller
2000-07-21 13:15 presotto
2000-07-21 9:10 miller
2000-07-20 17:09 presotto
2000-07-20 13:54 miller
2000-07-20 2:03 jmk
2000-07-10 12:40 Russ Cox
2000-07-11 8:51 ` Jakub Jermar
2000-07-10 9:57 Jakub Jermar
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