Re: [PATCH/RFC 0/8] numa - Migrate-on-Fault

> On Sun, 14 Nov 2010, KOSAKI Motohiro wrote:
> 
> > Nice!
> 
> Lets not get overenthused. There has been no conclusive proof that the
> overhead introduced by automatic migration schemes is consistently less
> than the benefit obtained by moving the data. Quite to the contrary. We
> have over a decades worth of research and attempts on this issue and there
> was no general improvement to be had that way.
> 
> The reason that the manual placement interfaces exist is because there was
> no generally beneficial migration scheme available. The manual interfaces
> allow the writing of various automatic migrations schemes in user space.
> 
> If wecan come up with something that is an improvement then lets go
> this way but I am skeptical.

Ah, I thought this series only has manua migration (i.e. MPOL_MF_LAZY),
but it also has automatic migration if a page is not mapped. So my standpoint
is, manual lazy migration has certinally usecase. but I have no opinion against
automatic one.