Hi, I know Xenpaging is still at an experimental stage, but I still wanted to test it out. Sadly, I could not get it to work reliably. I have an AMD RVI enabled linux 3.2 host, and I am using linux 2.6.35-22 HVM guests. After booting a few guests normally upto the host RAM limit, I do the following to enable paging for a few guests: />/usr/lib/xen/bin/xenpaging -f /var/lib/xen/xenpaging/pagefile-hvm-guest -d 1 &>xenstore-write /local/domain/1/memory/target-tot_pages $((1024*512))/(here ''1'' is the dom_id and pagefile-hvm-guest is the backing paging file for the hvm guest) I am then able to boot more VMs and I can see the corresponding pagefiles increase in size for the xenpaging enabled guests. The problem is when I go back to the guests on which I enabled xenpaging, I see the following errors when I run any basic commands like vim, top, less /proc/meminfo: /xc: error: Error populating page 100: Internal error xc: error: Error loading 100 during page-in (22 = Invalid argument): Internal error/ This happens even when there is paged-out memory from other guests to be had, and the system is not out of RAM for paging in guest''s memory. It seems like a page-in error on gfn 100, but that is strange as, from I what I gathered from the xenpaging code, policy_default.c starts paging only after half of the guest''s gfns : current_gfn = max_pages / 2 (inside policy_default.c: policy_init()) I was expecting there to be other stability issues rather that this kind of an error. Could someone please help me understand this and let me know if I am doing something incorrectly. Also, there do not seem to be any interesting messages in xm dmesg or in /var/log/xen*. Thanks, Sahil Suneja Ph.D. Student University of Toronto -- View this message in context: http://xen.1045712.n5.nabble.com/Issues-with-Xenpaging-in-Xen-4-2-1-tp5714431.html Sent from the Xen - Dev mailing list archive at Nabble.com.
On Mon, Feb 25, sahilsuneja wrote:> I know Xenpaging is still at an experimental stage, but I still wanted to > test it out. Sadly, I could not get it to work reliably. > > I have an AMD RVI enabled linux 3.2 host, and I am using linux 2.6.35-22 HVMThe pvops kernel may not have all required changes to run xenpaging in dom0. Maybe 3.8 already has these changes. If in doubt try the SLES/openSuSE kernels as dom0, their backend drivers can deal with paged granttable entries. Olaf
sahilsuneja wrote> Hi, > > I know Xenpaging is still at an experimental stage, but I still wanted to > test it out. Sadly, I could not get it to work reliably. > > I have an AMD RVI enabled linux 3.2 host, and I am using linux 2.6.35-22 > HVM guests. After booting a few guests normally upto the host RAM limit, I > do the following to enable paging for a few guests:/>>/usr/lib/xen/bin/xenpaging -f /var/lib/xen/xenpaging/pagefile-hvm-guest -d1 &>>xenstore-write /local/domain/1/memory/target-tot_pages $((1024*512))/> > (here ''1'' is the dom_id and pagefile-hvm-guest is the backing paging file > for the hvm guest) > > I am then able to boot more VMs and I can see the corresponding pagefiles > increase in size for the xenpaging enabled guests. > > The problem is when I go back to the guests on which I enabled xenpaging, > I see the following errors when I run any basic commands like vim, top, > less /proc/meminfo:/> xc: error: Error populating page 100: Internal error > xc: error: Error loading 100 during page-in (22 = Invalid argument): > Internal error/> > This happens even when there is paged-out memory from other guests to be > had, and the system is not out of RAM for paging in guest''s memory. > > It seems like a page-in error on gfn 100, but that is strange as, from I > what I gathered from the xenpaging code, policy_default.c starts paging > only after half of the guest''s gfns : current_gfn = max_pages / 2 (inside > policy_default.c: policy_init()) > > I was expecting there to be other stability issues rather that this kind > of an error. > > Could someone please help me understand this and let me know if I am doing > something incorrectly. > > Also, there do not seem to be any interesting messages in xm dmesg or in > /var/log/xen*. > > Thanks, > > Sahil Suneja > Ph.D. Student > University of Toronto-- View this message in context: http://xen.1045712.n5.nabble.com/Issues-with-Xenpaging-in-Xen-4-2-1-tp5714431p5714493.html Sent from the Xen - Dev mailing list archive at Nabble.com.
> The pvops kernel may not have all required changes to run xenpaging in > dom0. Maybe 3.8 already has these changes. If in doubt try the > SLES/openSuSE kernels as dom0, their backend drivers can deal with > paged granttable entries.Thanks a lot Olaf! Confirming that linux 3.8 as dom0 still has the same xenpaging page-in error wrt gfn #100, but opensuse 12.3 rc1 kernel (linux 3.7.9-1.4-xen) has a much more stable xenpaging, and a much more rich xen-config kernel build option set. Although, I am still not clear what the error meant to begin with. Best, Sahil