I''ve been recently testing the Xendemo CD and I can say that Xen is awesome. I''d like to start deploying it initially in some development/testing servers. However the limitation of the max memory of 800MB or so per virtual machine is a show stopper for many applications. Are there plans to raise the limit to something higher (like 2GB or so)? How difficult would it be? Another feature that would be very nice (and I''ve seen other requests for it in this list too) is the possibility of sharing readonly (and possibly executable only) memory among different domains, which would reduce the total memory utilization. Regards and thanks, Flavio Villanustre
> I''ve been recently testing the Xendemo CD and I can say that Xen is awesome. > > I''d like to start deploying it initially in some development/testing servers. > > However the limitation of the max memory of 800MB or so per virtual machine is > a show stopper for many applications. > > Are there plans to raise the limit to something higher (like 2GB or so)? > How difficult would it be?The 800MB limit is a limitation of XenoLinux, not Xen. This limitation is fixed in the latest version of Xen/XenoLinux (v1.3), as XenoLinux now supports CONFIG_HIGHMEM allowing each guest OS to be allocated up to 4GB of memory.> Another feature that would be very nice (and I''ve seen other requests for it in > this list too) is the possibility of sharing readonly (and possibly executable > only) memory among different domains, which would reduce the total memory > utilization.We are considering implementing a shared buffer cache, but haven''t fully worked out the details. Another thing we''re looking at is using shadow page tables to allow translation of memory addresses without guest-OS knowledge -- this could be used to quite easily implement shared read-only pages entirely within Xen, with no guest OS modifications. -- Keir ------------------------------------------------------- This SF.Net email is sponsored by the new InstallShield X.>From Windows to Linux, servers to mobile, InstallShield X is the oneinstallation-authoring solution that does it all. Learn more and evaluate today! http://www.installshield.com/Dev2Dev/0504 _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
" XenoLinux now supports CONFIG_HIGHMEM and HIGHMEM works great! Thanks for adding that back to xenolinux. " We are considering implementing a shared buffer cache, but haven''t A memory management scheme that would be useful here is a lowater/hiwater setting for memory allocatation to each domain. This would allow phys memory to be oversubscribed by the domains. Then xen could slosh memory between domains based on demand. It seems like the balloon driver system would have had the groundwork for this. I know that bit of things has rotted, but when it worked it ought to have demonstrated the mechansisms needed for a lowater/hiwater policy. ------------------------------------------------------- This SF.Net email is sponsored by the new InstallShield X.>From Windows to Linux, servers to mobile, InstallShield X is the oneinstallation-authoring solution that does it all. Learn more and evaluate today! http://www.installshield.com/Dev2Dev/0504 _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
> " We are considering implementing a shared buffer cache, but haven''t > > A memory management scheme that would be useful here is a lowater/hiwater > setting for memory allocatation to each domain. > This would allow phys memory to be oversubscribed by the domains. > Then xen could slosh memory between domains based on demand. > > It seems like the balloon driver system would have had the groundwork for this. > I know that bit of things has rotted, but when it worked it ought to have > demonstrated the mechansisms needed for a lowater/hiwater policy.The balloon driver enables a domain to give back physical memory pages or request new memory. Unlike e.g. vmware this isn''t transparent to the guest OS, but there are actually good reasons why you don''t want it to be transparent (the guest OS is in a much better position to make sensible paging decisions than the VMM). Fixing the balloon driver should be very straight forward. We then need to add a control interface so that domain0 can tell other domains what their current memory allocation target is (when reducing a domain''s target dom0 should give them a few hundred milliseconds to hand back the pages, then kill the domain if it doesn''t comply). It would be really nice to get this in the 2.0 release. Any volunteers to help out? ;-) Thanks, Ian ------------------------------------------------------- This SF.Net email is sponsored by the new InstallShield X.>From Windows to Linux, servers to mobile, InstallShield X is the oneinstallation-authoring solution that does it all. Learn more and evaluate today! http://www.installshield.com/Dev2Dev/0504 _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel