Messages in this thread | | | Date | Tue, 30 Jan 2007 19:32:27 +0530 | From | Gautham R Shenoy <> | Subject | Re: Fw: Re: [mm PATCH 4/6] RCU: (now) CPU hotplug |
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On Mon, Jan 29, 2007 at 06:45:49PM -0800, Paul E. McKenney wrote: > > static int _cpu_down(unsigned int cpu) > { > int err; > struct task_struct *p; > cpumask_t old_allowed, tmp; > > if (num_online_cpus() == 1) > return -EBUSY; > > if (!cpu_online(cpu)) > return -EINVAL; > > if (freeze_processes()) { > err = -EBUSY; > goto out_freeze_notify_failed; > } > err = raw_notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE, > (void *)(long)cpu); > if (err == NOTIFY_BAD) { > printk("%s: attempt to take down CPU %u failed\n", > __FUNCTION__, cpu); > err = -EINVAL; > goto out_freeze_notify_failed; > } > > /* Ensure that we are not runnable on dying cpu */ > old_allowed = current->cpus_allowed; > tmp = CPU_MASK_ALL; > cpu_clear(cpu, tmp); > set_cpus_allowed(current, tmp); > > mutex_lock(&cpu_bitmask_lock);
We won't be needing this lock either, since it forms the core of the unpopular lock_cpu_hotplug :-)
> p = __stop_machine_run(take_cpu_down, NULL, cpu); > mutex_unlock(&cpu_bitmask_lock);
Looks good.
I'm wondering if we'll need to try_to_freeze in the fork and exit code as well :?
Thanks and Regards gautham. -- Gautham R Shenoy Linux Technology Center IBM India. "Freedom comes with a price tag of responsibility, which is still a bargain, because Freedom is priceless!" - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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