Re: [PATCH] generalized spin_lock_bit

[Robert Love]

On Sat, 2002-07-20 at 15:27, David S. Miller wrote:
>    From: Robert Love <[e-mail]>
>    Date: 20 Jul 2002 13:21:51 -0700
>    
>    Thanks to Christoph Hellwig for prodding to make it per-architecture,
>    Ben LaHaise for the loop optimization, and William Irwin for the
>    original bit locking.
> 
> Just note that the implementation of these bit spinlocks will be
> extremely expensive on some platforms that lack "compare and swap"
> type instructions (or something similar like "load locked, store
> conditional" as per mips/alpha).

That is what they do use, but the code is pushed into the architecture
headers so you can do something else if you choose.

I originally just had a single generic version, but people representing
the greater good of SPARC and PA-RISC argued otherwise.  It should be
simple enough to just paste the generic implementations into your
asm/spinlock.h if you do not want to do any hand-tuning.

	Robert Love