On Wed, 2012-12-19 at 20:31 -0500, Steven Rostedt wrote:

Talking with Thomas, the proper solution is:

Then we have this lovely code:

block/blk-ioc.c: put_io_context_active()

retry:
        spin_lock_irqsave_nested(&ioc->lock, flags, 1);
        hlist_for_each_entry(icq, n, &ioc->icq_list, ioc_node) {
                if (icq->flags & ICQ_EXITED)
                        continue;
                if (spin_trylock(icq->q->queue_lock)) {
                        ioc_exit_icq(icq);
                        spin_unlock(icq->q->queue_lock);
                } else {
                        spin_unlock_irqrestore(&ioc->lock, flags);
                        cpu_relax();

s/cpu_relax/cpu_chill/

-- Steve

                        goto retry;
                }
        }