Re: [PATCH] Migration cache

[Marcelo Tosatti <marcelo.tosatti@cyclades.com>]

On Thu, Oct 21, 2004 at 08:09:35PM +0100, Hugh Dickins wrote:
> On Thu, 21 Oct 2004, Marcelo Tosatti wrote:
> > On Thu, Oct 21, 2004 at 02:10:44AM +0900, Hirokazu Takahashi wrote:
> > > 
> > > I guess it would be better to reserve one swap type for the migration
> > > cache instead of reserving the bit to reduce the impact of the maximum
> > > number of swap types.
> 
> I thought the same ...
> 
> > By reserving one swap type we would also use a bit. Using a swap type is 
> > the same thing as using a bit in the swap pagetableentry. (the swap type 
> > has 5 bits reserved for swap devices, 2^5 = 32 swap devices).
> 
> ... and don't understand your response.
> 
> Reserving a swap type leaves 31 swap devices for normal use, okay;
> but reserving a bit leaves only 16 swap devices for normal use.

Oh stupid idiot I am! Of course, we can then remove "pte_is_migration" 
(and all the related pte handling code). 

Added to TODO list. 

If anyone wants to contribute that it would be cool cause I'm 
quite busy with other stuff right now.

Thanks guys!
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