Re: [rfc] optimise unlock_page

From: Hugh Dickins
Date: Sun May 13 2007 - 00:39:37 EST


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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