Re: [rfc] optimise unlock_page

On Sun, 13 May 2007, Nick Piggin wrote:
On Fri, May 11, 2007 at 02:15:03PM +0100, Hugh Dickins wrote:

Hmm, well, I think that's fairly horrid, and would it even be
guaranteed to work on all architectures? Playing with one char
of an unsigned long in one way, while playing with the whole of
the unsigned long in another way (bitops) sounds very dodgy to me.

Of course not, but they can just use a regular atomic word sized
bitop. The problem with i386 is that its atomic ops also imply
memory barriers that you obviously don't need on unlock.

But is it even a valid procedure on i386?

Hugh
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