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From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Matthew Wilcox <matthew@wil.cx>
Subject: Re: down_spin() implementation
Date: Sat, 29 Mar 2008 12:04:36 +1100
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Cc: "Luck, Tony" <tony.luck@intel.com>,
       Stephen Rothwell <sfr@canb.auug.org.au>, linux-arch@vger.kernel.org,
       linux-mm@kvack.org, linux-kernel@vger.kernel.org
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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.

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