From: Linus Torvalds <torvalds@transmeta.com>
To: "Stephen C. Tweedie" <sct@dcs.ed.ac.uk>
Cc: linux-mm@kvack.org, linux-smp@vger.rutgers.edu
Subject: Re: Lazy page reclamation on SMP machines: memory barriers
Date: Tue, 24 Mar 1998 16:11:56 -0800 (PST) [thread overview]
Message-ID: <Pine.LNX.3.95.980324161015.5682I-100000@penguin.transmeta.com> (raw)
In-Reply-To: <199803242254.WAA03274@dax.dcs.ed.ac.uk>
On Tue, 24 Mar 1998, Stephen C. Tweedie wrote:
> > Intel guarantees total ordering around any locked instruction, so the
> > spinlocks themselves act as the barriers.
>
> Fine. Can we assume that spinlocks and atomic set/clear_bit
> instructions have the same semantics on other CPUs?
We can certainly guarantee that a spinlock has the necessary locking
semantics - anything else would make spinlocks useless.
The other atomic instructions I'd be inclined to claim to be weakly
ordered.
Linus
next prev parent reply other threads:[~1998-03-25 0:12 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
1998-03-23 22:49 Stephen C. Tweedie
1998-03-23 23:20 ` Linus Torvalds
1998-03-24 22:54 ` Stephen C. Tweedie
1998-03-24 23:45 ` David S. Miller
1998-03-25 0:11 ` Linus Torvalds [this message]
1998-03-25 9:08 ` Rik van Riel
1998-03-23 23:37 ` Linus Torvalds
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