From: David Mosberger <davidm@napali.hpl.hp.com>
To: linux-ia64@vger.kernel.org
Subject: Re: [Linux-ia64] spin_unlock() problem
Date: Mon, 07 Apr 2003 21:09:24 +0000 [thread overview]
Message-ID: <marc-linux-ia64-105590723705426@msgid-missing> (raw)
In-Reply-To: <marc-linux-ia64-105590723705414@msgid-missing>
>>>>> On Thu, 3 Apr 2003 23:51:04 -0500, Jes Sorensen <jes@wildopensource.com> said:
Jes> Hi, I have been tracing a problem with tty->count hitting an
Jes> unidenfied state and I am starting to ponder if our current
Jes> spin_unlock() implementation is sufficient.
Jes> Currently the spin_unlock() implementation looks like this:
Jes> #define spin_unlock(x) do { barrier(); ((spinlock_t *) x)->lock
Jes> = 0;} while (0)
Jes> barrier() doesn't guarantee memory ordering, in other words, we
Jes> are not guaranteed that writes have been flushed to physical
Jes> memory on exit.
Note that "lock" is declared as "volatile", so clearing it will use
"release" semantics. (Since I know you have a copy of the ia64 linux
kernel book: this is described in detail starting on page 302).
--david
next prev parent reply other threads:[~2003-04-07 21:09 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-04 4:51 [Linux-ia64] spin_unlock() problem Jes Sorensen
2003-04-04 5:04 ` Jes Sorensen
2003-04-04 14:43 ` Van Maren, Kevin
2003-04-04 14:49 ` Van Maren, Kevin
2003-04-04 15:13 ` Jes Sorensen
2003-04-07 21:09 ` David Mosberger [this message]
2003-04-07 21:14 ` David Mosberger
2003-04-07 22:09 ` Jes Sorensen
2003-04-07 22:18 ` Luck, Tony
2003-04-07 22:58 ` David Mosberger
2003-04-07 23:13 ` Jes Sorensen
2003-04-07 23:30 ` Jim Hull
2003-04-07 23:38 ` Chen, Kenneth W
2003-04-08 0:14 ` David Mosberger
2003-04-08 0:15 ` David Mosberger
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