From: Matthew Wilcox <matthew@wil.cx>
To: David Howells <dhowells@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>,
linux-arch@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [rfc] io memory barriers, and getting rid of mmiowb
Date: Tue, 20 Nov 2007 09:58:12 -0700 [thread overview]
Message-ID: <20071120165812.GH12494@parisc-linux.org> (raw)
In-Reply-To: <4680.1195577182@redhat.com>
On Tue, Nov 20, 2007 at 04:46:22PM +0000, David Howells wrote:
> > The best way to do this is with
> > +io_lock and io_unlock barriers, which directs the critical section to order
> > +IO access as well. For example:
>
> Should there be a spin_lock_io() for example?
Then we need ...
spin_lock_irqsave_io()
spin_lock_irq_io()
spin_lock_bh_io()
spin_trylock_io()
spin_trylock_irqsave_io()
spin_trylock_irq_io()
spin_trylock_bh_io()
ditto with write_ and read_. Maybe double_spin_lock_io too. That's an
extra 25 primitives (oh, plus the unlocks; 28).
--
Intel are signing my paycheques ... these opinions are still mine
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
next prev parent reply other threads:[~2007-11-20 16:58 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-20 16:02 [rfc] io memory barriers, and getting rid of mmiowb Nick Piggin
2007-11-20 16:46 ` David Howells
2007-11-20 16:58 ` Matthew Wilcox [this message]
2007-11-20 17:04 ` David Howells
2007-11-21 0:30 ` Nick Piggin
2007-11-21 1:53 ` David Howells
2007-11-22 8:23 ` Nick Piggin
2007-11-21 13:50 ` Ralf Baechle
2007-11-22 8:04 ` Nick Piggin
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