From: Nick Piggin <nickpiggin-/E1597aS9LT0CCvOHzKKcA@public.gmane.org>
To: Matthew Wilcox <matthew-Ztpu424NOJ8@public.gmane.org>
Cc: "Luck, Tony" <tony.luck-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
Stephen Rothwell <sfr-3FnU+UHB4dNDw9hX6IcOSA@public.gmane.org>,
linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: down_spin() implementation
Date: Sat, 29 Mar 2008 12:04:36 +1100 [thread overview]
Message-ID: <200803291204.36855.nickpiggin@yahoo.com.au> (raw)
In-Reply-To: <20080328124517.GQ16721-6jwH94ZQLHl74goWV3ctuw@public.gmane.org>
On Friday 28 March 2008 23:45, Matthew Wilcox wrote:
> I think we can do better here with:
>
> atomic_set(max);
>
> and
>
> while (unlikely(!atomic_add_unless(&ss->cur, -1, 0)))
> while (atomic_read(&ss->cur) == 0)
> cpu_relax();
Yeah of course! That's much better ;)
I'd say Tony could just open code it for now, which would get him
up and running quickly... although if anybody gets keen to add it
as a generic API then I wouldn't object.
next prev parent reply other threads:[~2008-03-29 1:04 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-25 20:49 What if a TLB flush needed to sleep? Luck, Tony
2008-03-25 21:47 ` Alan Cox
2008-03-26 12:32 ` Matthew Wilcox
2008-03-26 20:29 ` Luck, Tony
2008-03-27 8:09 ` Jens Axboe
2008-03-27 14:15 ` down_spin() implementation Matthew Wilcox
2008-03-28 0:01 ` Nick Piggin
2008-03-28 12:45 ` Matthew Wilcox
2008-03-28 21:16 ` Luck, Tony
2008-03-28 23:48 ` Arnd Bergmann
[not found] ` <20080328124517.GQ16721-6jwH94ZQLHl74goWV3ctuw@public.gmane.org>
2008-03-29 1:04 ` Nick Piggin [this message]
2008-03-28 4:51 ` Stephen Rothwell
2008-03-28 5:03 ` Nick Piggin
2008-03-28 12:46 ` Matthew Wilcox
2008-03-28 12:51 ` Jens Axboe
2008-03-28 13:17 ` Matthew Wilcox
2008-03-28 13:24 ` Jens Axboe
2008-03-26 19:25 ` What if a TLB flush needed to sleep? Christoph Lameter
2008-03-26 20:29 ` Thomas Gleixner
2008-03-27 1:19 ` Christoph Lameter
2008-03-27 13:20 ` Peter Zijlstra
2008-03-27 18:44 ` Christoph Lameter
2008-03-28 9:59 ` Peter Zijlstra
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