On 20/02/2015 14:45, Alexander Graf wrote: > > > On 18.02.15 10:32, Bogdan Purcareata wrote: >> This patchset enables running KVM SMP guests with external interrupts on an >> underlying RT-enabled Linux. Previous to this patch, a guest with in-kernel >> MPIC >> emulation could easily panic the kernel due to preemption when delivering >> IPIs >> and external interrupts, because of the openpic spinlock becoming a sleeping >> mutex on PREEMPT_RT_FULL Linux. >> >> 0001: converts the openpic spinlock to a raw spinlock, in order to circumvent >> this behavior. While this change is targeted for a RT enabled Linux, it has >> no >> effect on upstream kvm-ppc, so send it upstream for better future >> maintenance. >> >> 0002: introduces a limit on the maximum VCPUs a guest can have, in order to >> prevent potential DoS attack due to large system latencies. This patch is >> targeted to RT (due to CONFIG_PREEMPT_RT_FULL), but it can also be applied on >> upstream Linux, with no effect. Not sure if it's best to send it upstream and >> have a hanging CONFIG_PREEMPT_RT_FULL check there, with no effect, or send it >> against linux-stable-rt. Please apply as you consider appropriate. > > Thomas, what is the usual approach for patches like this? Do you take > them into your rt tree or should they get integrated to upstream?
Patch 1 is definitely suitable for upstream, that's the reason why we have raw_spin_lock vs. raw_spin_unlock. Paolo _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
