From: James Bottomley <James.Bottomley@SteelEye.com>
To: John David Anglin <dave@hiauly1.hia.nrc.ca>
Cc: parisc-linux@parisc-linux.org
Subject: Re: [parisc-linux] coherent ops and mb() revisited
Date: 05 Sep 2004 10:36:43 -0400 [thread overview]
Message-ID: <1094395005.1690.1.camel@mulgrave> (raw)
In-Reply-To: <200409050627.i856RWW3027615@hiauly1.hia.nrc.ca>
On Sun, 2004-09-05 at 02:27, John David Anglin wrote:
> > I think the best implementation is probably
> >
> > barrier();
> > a = __ldcw_align(x);
>
> I don't understand why you put the barrier before the __ldcw_align
> operation. The alignment operation is non-critical and could be done
> much earlier if that's desireable from a scheduling standpoint.
Actually, you're right. I think all we need is the mb() after the
spin_lock code and another mb before the spin_unlock code. How the
taking or releasing of the lock is optimised by gcc should be irrelevant
as long as it's locked when we cross the barrier.
James
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next prev parent reply other threads:[~2004-09-05 14:36 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-05 1:38 [parisc-linux] coherent ops and mb() revisited Grant Grundler
2004-09-05 2:56 ` James Bottomley
2004-09-05 6:27 ` John David Anglin
2004-09-05 14:36 ` James Bottomley [this message]
2004-09-06 4:19 ` Grant Grundler
2004-09-06 9:24 ` John David Anglin
2004-09-06 14:15 ` James Bottomley
2004-09-07 15:17 ` Grant Grundler
2004-09-07 15:30 ` James Bottomley
2004-09-08 16:52 ` Grant Grundler
2004-09-08 17:11 ` James Bottomley
2004-09-10 16:11 ` Grant Grundler
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