On 02/12/2019 06:10 AM, Samuel Thibault wrote: > Hans van Kranenburg, le lun. 11 févr. 2019 22:59:11 +0100, a ecrit: >> 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. > > Indeed, I didn't have the hanging VM offhand. I have looked again, it's > now at 33. We'll have to monitor to check that it doesn't continue just > increasing.
If the max used to be 32 and the current is already 33, this indicates the grant entries might be used up in the past before the max_nr_frames is tuned. Dongli ZHang > > Samuel > _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel