Re: [PATCH] rcu: Fix CONFIG_RCU_NOCB_CPU_ALL panic on machines with sparse CPU mask

2013-09-23 Thread Paul E. McKenney
#ifndef CONFIG_RCU_NOCB_CPU_NONE */ > >>   if (have_rcu_nocb_mask) { > > > > Do we need a cpumask_and() within this "if" statement to handle the > > case where the kernel's rcu_nocbs= boot parameter specified a CPU > > that is not present?  (If so

Re: [PATCH] rcu: Fix CONFIG_RCU_NOCB_CPU_ALL panic on machines with sparse CPU mask

2013-09-15 Thread Kirill Tkhai
rcu_nocbs= boot parameter specified a CPU > that is not present?  (If so, probably also giving a warning about the > non-present CPUs specified.) > > I believe that the answer to both questions is "yes", and I would > welcome an updated patch that covered these cases. Yes an

Re: [PATCH] rcu: Fix CONFIG_RCU_NOCB_CPU_ALL panic on machines with sparse CPU mask

2013-09-14 Thread Paul E. McKenney
On Sat, Sep 14, 2013 at 05:03:20PM +0400, Kirill Tkhai wrote: > When a system has a sparse cpumask and CONFIG_RCU_NOCB_CPU_ALL is enabled, > rcu_spawn_nocb_kthreads() creates nocb threads for nonexistent CPUS. > > The problem is in rcu_bootup_announce_oddness(). cpumask_setall() sets all > bits fr