[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] map memory holes with same page

At 09:42 +0100 on 23 May (1306143771), Paul Durrant wrote:
> > -----Original Message-----
> [snip]
> > 
> > Should there be a performance impact if Windows tries to touch a
> > page that I have previously given pack with decrease_reservation?
> > Will that invoke the PoD sweep?
> > 
> No. The p2m entry will be 'invalid', not 'PoD'. IIRC the sweep should
> only be invoked if the cache is exhausted when trying to fix up a PoD
> entry.

But yes, there will be a performance impact because all accesses to the
missing page will be emulated by sending an ioreq to qemu, so it will
run _very_ slowly. 


Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, Xen Platform Team
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.