Thomas Huth <thuth@xxxxxxxxxxxxxxxxxx> writes: > On Thu, 26 Feb 2015 11:50:42 +1030 > Rusty Russell <rusty@xxxxxxxxxxxxxxx> wrote: > >> Thomas Huth <thuth@xxxxxxxxxxxxxxxxxx> writes: >> > Hi all, >> > >> > with the recent kernel 3.19, I get a kernel warning when I start my >> > KVM guest on s390 with virtio balloon enabled: >> >> The deeper problem is that virtio_ccw_get_config just silently fails on >> OOM. >> >> Neither get_config nor set_config are expected to fail. > > AFAIK this is currently not a problem. According to > http://lwn.net/Articles/627419/ these kmalloc calls never > fail because they allocate less than a page. I strongly suggest you unlearn that fact. The fix for this is in two parts: 1) Annotate using sched_annotate_sleep() and add a comment: we may spin a few times in low memory situations, but this isn't a high performance path. 2) Handle get_config (and other) failure in some more elegant way. Cheers, Rusty. -- 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
