On Sun, 2011-12-04 at 19:34 +0200, Avi Kivity wrote: > On 12/04/2011 07:29 PM, Sasha Levin wrote: > > On Sun, 2011-12-04 at 18:53 +0200, Avi Kivity wrote: > > > On 12/02/2011 07:46 AM, Sasha Levin wrote: > > > > > Do you want to create read only memory slots for kvm tool? > > > > > > > > What KVM tool currently does is copy the kernel into guest memory and > > > > run it from there. An idea raised recently was instead of copying it we > > > > should mmap it into the memory to reduce footprint. > > > > > > > > This is why I'm looking into adding a read only memory slot. The KVM > > > > code doesn't have to know it's read only. > > > > > > The kernel will patch itself very early. You need to use MAP_PRIVATE > > > (and thus have a read/write area). It will be interesting to see what > > > fraction of the memory is modified. > > > > > > Note that mapping will remove benefits like huge page support, and that > > > you can get page sharing by using ksm. Still, it's interesting to see > > > where this goes. > > > > Why would I lose hugepage if the kernel gets it's own memory slot? > > (transparent) hugepages only work on anonymous memory. Hopefully later > it will be extended to work on mapped memory as well. So I'll lose hugepages just for the kernel memory slot, I wonder how it will matter performance-wise. -- Sasha. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
