On Tue, Jan 03, 2006 at 07:39:42PM +0530, Dipankar Sarma wrote:
> On Sat, Dec 31, 2005 at 12:14:26PM -0800, Paul E. McKenney wrote:
> > So it seems to me that Linus's patch is part of the solution, but
> > needs to also have a global component, perhaps as follows:
> >
> > if (unlikely(rdp->count > 100)) {
> > set_need_resched();
> > if (unlikely(rdp->count - rdp->last_rs_count > 1000)) {
> > int cpu;
> >
> > rdp->last_rs_count = rdp->count;
> > spin_lock_bh(&rcu_bh_state.lock);
> > for_each_cpu_mask(cpu, rdp->rcu_bh_state.cpumask)
> > smp_send_reschedule(cpu);
> > spin_unlock_bh(&rcu_bh_state.lock);
> > }
> > }
>
> Yes, something like this that covers corner cases and forces
> queiscent state in all cpus, would be ideal.
>
> > I am sure that I am missing some interaction or another with tickless
> > idle and CPU hotplug covered.
>
> It would be safe to miss a cpu or two while sending the resched
> interrupt. So, I don't think we need to worry about tickless
> idle and cpu hotplug.
OK, does that also mean that the spin_lock_bh/spin_unlock_bh are also
unnecessary? ;-)
> > There also needs to be some adjustment in rcu_do_batch(), which will
> > have to somehow get back to a quiescent state periodically. Dipankar,
> > Vatsa, thoughts?
>
> My original thought was to make maxbatch dynamic and automatically
> adjust it depending on the situation. I can try that approach.
Makes sense to me!
Thanx, Paul
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
