On 2/11/19 2:37 AM, Dongli Zhang wrote: > > On 2/10/19 12:35 AM, Samuel Thibault wrote: >> >> Hans van Kranenburg, le sam. 09 févr. 2019 17:01:55 +0100, a ecrit: >>>> I have forwarded the original mail: all VM I/O get stuck, and thus the >>>> VM becomes unusable. >>> >>> These are in many cases the symptoms of running out of "grant frames". >> >> Oh! That could be it indeed. I'm wondering what could be monopolizing >> them, though, and why +deb9u11 is affected while +deb9u10 is not. I'm >> afraid increasing the gnttab max size to 32 might just defer filling it >> up. >> >>> -# ./xen-diag gnttab_query_size 5 >>> domid=5: nr_frames=11, max_nr_frames=32 >> >> The current value is 31 over max 32 indeed. > > Assuming this is grant v1, there are still 4096/8=512 grant references > available > (32-31=1 frame available). I do not think the I/O hang can be affected by the > lack of grant entry.
I suspect that 31 measurement was taken when the domU was not hanging yet. > If to increase the max frame to 64 takes effect, it is weird why the I/O would > hang when there are still 512 entries available. > >>> With Xen 4.8, you can add gnttab_max_frames=64 (or another number, but >>> higher than the default 32) to the xen hypervisor command line and reboot. >> >> admin@: I made the modification in the grub config. We can probably try >> to reboot with the newer hypervisor, and monitor that value. K _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
