On Fri, 2011-04-29 at 18:34 +0300, Michael S. Tsirkin wrote: > On Fri, Apr 29, 2011 at 05:29:06PM +0200, Jan Kiszka wrote: > > On 2011-04-29 17:06, Michael S. Tsirkin wrote: > > > On Thu, Apr 28, 2011 at 09:15:23PM -0600, Alex Williamson wrote: > > >> When we're trying to get a newly registered phys memory client updated > > >> with the current page mappings, we end up passing the region offset > > >> (a ram_addr_t) as the start address rather than the actual guest > > >> physical memory address (target_phys_addr_t). If your guest has less > > >> than 3.5G of memory, these are coincidentally the same thing. If > > > > I think this broke even with < 3.5G as phys_offset also encodes the > > memory type while region_offset does not. So everything became RAMthis > > way, no MMIO was announced. > > > > >> there's more, the region offset for the memory above 4G starts over > > >> at 0, so the set_memory client will overwrite it's lower memory entries. > > >> > > >> Instead, keep track of the guest phsyical address as we're walking the > > >> tables and pass that to the set_memory client. > > >> > > >> Signed-off-by: Alex Williamson <alex.william...@redhat.com> > > > > > > Acked-by: Michael S. Tsirkin <m...@redhat.com> > > > > > > Given all this, can yo tell how much time does > > > it take to hotplug a device with, say, a 40G RAM guest? > > > > Why not collect pages of identical types and report them as one chunk > > once the type changes? > > Sure, but before we bother to optimize this, is this too slow?
At a set_memory call per 4k page, it's probably worthwhile to factor in some simply optimizations. My set_memory callback was being hit 10^6 times. Thanks, Alex
