>>> On 19.03.15 at 11:03, <dario.faggi...@citrix.com> wrote: > OTOH, CPU_STARTING callbacks run: > - on the cpu being brought up; > - with interrupt disabled (see how the call to local_irq_enable(), in > start_secondary(), is *after* the invocation of > notify_cpu_starting()). > > Here we are. And the reason why things works ok in Credit2, is that > csched2_alloc_pdata() doesn't really allocate anything! In fact, in > general, handling alloc_pdata() during CPU_STARTING would mean that we > can't allocate any memory which, given the name of the function, would > look rather odd. :-) > > Nevertheless I see the value of doing so, and hence I think what we > could do would be to introduce a new hook in the scheduler interface, > called .init_pdata or .init_pcpu, and, in sched_*.c, split the > allocation and the initialization parts. The former will be handled > during CPU_UP_PREPARE, when allocation is possible, the latter during > CPU_STARTING, when we have more info available to perform actual > initializations.
Another alternative would be a new CPU_ALIVE (name subject to change) notification after interrupts got enabled. That would (as a follow-up cleanup) also allow the MTRR and microcode setup on the CPU to no longer need explicit calls (which look reversed anyway - surely we should update microcode before fiddling with MTRRs). Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
