Date: Mon, 18 Aug 2008 17:54:18 +0200 From: Max Laier <max@love2party.net> To: freebsd-hackers@freebsd.org Cc: Ryan Stone <rysto32@gmail.com> Subject: Re: Acquiring a mtx after an sx lock Message-ID: <200808181754.18812.max@love2party.net> In-Reply-To: <bc2d970808180814ue926d43s7966b36ffa3c9699@mail.gmail.com> References: <bc2d970808180814ue926d43s7966b36ffa3c9699@mail.gmail.com>
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On Monday 18 August 2008 17:14:01 Ryan Stone wrote:
> Are there any problems acquiring a sleep mutex after acquiring an sx lock?
> man 9 locking says that you can't, but doesn't provide any reasons.
> Obviously while you're holding the mutex you have to abide by the rules
> applying to mutexes, but as long as you do that, I can't see why acquiring
> a mutex after an sx lock would cause an issue. Is the locking man page
> wrong about this?
Where does it say so? The interaction table clearly shows:
You have: You want: Spin_mtx Slp_mtx sx_lock rw_lock rm_locksleep
SPIN mutex ok-1 no no no no no-3
Sleep mutex ok ok-1 no ok ok no-3
|
V
sx_lock ok -->ok<-- ok-2 ok ok ok-4
^
|
rw_lock ok ok no ok-2 ok no-3
rm_lock ok ok no ok ok-2 no
--
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