Messages in this thread | | | Subject | Re: [patch 3/4] stop_machine: implement stop_machine_from_offline_cpu() | From | Peter Zijlstra <> | Date | Thu, 23 Jun 2011 11:25:19 +0200 |
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On Wed, 2011-06-22 at 15:20 -0700, Suresh Siddha wrote: > +int stop_machine_from_offline_cpu(int (*fn)(void *), void *data, > + const struct cpumask *cpus) > +{ > + struct stop_machine_data smdata = { .fn = fn, .data = data, > + .active_cpus = cpus }; > + struct cpu_stop_done done; > + int ret; > + > + /* Local CPU must be offline and CPU hotplug in progress. */ > + BUG_ON(cpu_online(raw_smp_processor_id())); > + smdata.num_threads = num_online_cpus() + 1; /* +1 for local */ > + > + /* No proper task established and can't sleep - busy wait for lock. */ > + while (!mutex_trylock(&stop_cpus_mutex)) > + cpu_relax(); > + > + /* Schedule work on other CPUs and execute directly for local CPU */ > + set_state(&smdata, STOPMACHINE_PREPARE); > + cpu_stop_init_done(&done, num_online_cpus()); > + queue_stop_cpus_work(cpu_online_mask, stop_machine_cpu_stop, &smdata, > + &done); > + ret = stop_machine_cpu_stop(&smdata); > + > + /* Busy wait for completion. */ > + while (!completion_done(&done.completion)) > + cpu_relax(); > + > + mutex_unlock(&stop_cpus_mutex); > + return ret ?: done.ret; > +}
Damn thats ugly, I sure hope you're going to make those hardware folks pay for this :-)
In commit d0af9eed5aa91b6b7b5049cae69e5ea956fd85c3 you mention that its specific to HT, wouldn't it make sense to limit the stop-machine use in the next patch to the sibling mask instead of the whole machine?
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