Re: [RFC] atomic highmem kmap page pinning

[Nicolas Pitre]

On Thu, 5 Mar 2009, Minchan Kim wrote:

> On Wed, 04 Mar 2009 21:37:43 -0500 (EST)
> Nicolas Pitre <nico@xxxxxxx> wrote:
> 
> > My assertion is that the cost is negligible.  This is why I'm asking you 
> > why you think this is a big cost.
> 
> Of course, I am not sure whether it's big cost or not. 
> But I thought it already is used in many fs, driver.
> so, whether it's big cost depends on workload type .
> 
> However, This patch is needed for VIVT and no coherent cache.
> Is right ?
> 
> If it is right, it will add unnessary overhead in other architecture 
> which don't have this problem.
> 
> I think it's not desirable although it is small cost.
> If we have a other method which avoids unnessary overhead, It would be better.
> Unfortunately, I don't have any way to solve this, now. 

OK.  What about this patch then: