On 16/07/16 15:12, Dario Faggioli wrote: > On Fri, 2016-07-15 at 19:07 +0100, Andrew Cooper wrote: > >> None of the scheduler-accounting functions should be disabling >> interrupts. >> > They don't. But you can't keep irq disabled for some operations and > enabled for others, on the same lock (because of the irq-safety > spinlock checks/enforcement). > > So you have to always keep IRQ enabled, for all scheduling operations, > which is ok for _almost_ all of them, with the only exception of the > wakeup of a vcpu.
I know that it is all or nothing. What specific action about waking a vcpu requires holding a lock? If it is simply re-queueing the vcpu onto the runable queue, there are a number of lockless queuing algorithms which can be used. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
