On 24/02/2015 00:27, Scott Wood wrote: > This isn't a host PIC driver. It's guest PIC emulation, some of which > is indeed not suitable for a rawlock (in particular, openpic_update_irq > which loops on the number of vcpus, with a loop body that calls > IRQ_check() which loops over all pending IRQs).
The question is what behavior is wanted of code that isn't quite RT-ready. What is preferred, bugs or bad latency? If the answer is bad latency (which can be avoided simply by not running KVM on a RT kernel in production), patch 1 can be applied. If the answer is bugs, patch 1 is not upstream material. I myself prefer to have bad latency; if something takes a spinlock in atomic context, that spinlock should be raw. If it hurts (latency), don't do it (use the affected code). Paolo > The vcpu limits are a > temporary bandaid to avoid the worst latencies, but I'm still skeptical > about this being upstream material. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
