[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] xen: remove on-stack cpumask from stop_machine_run()
>>> On 28.05.19 at 15:08, <jgross@xxxxxxxx> wrote: > --- a/xen/common/stop_machine.c > +++ b/xen/common/stop_machine.c > @@ -69,8 +69,8 @@ static void stopmachine_wait_state(void) > > int stop_machine_run(int (*fn)(void *), void *data, unsigned int cpu) > { > - cpumask_t allbutself; > unsigned int i, nr_cpus; > + unsigned int my_cpu = smp_processor_id(); Variables starting with my_ being commonly used in introductory examples, I'd prefer to avoid such names. Elsewhere we use "this_cpu", "me", or maybe "this" if plain "cpu" is already taken. > @@ -79,9 +79,7 @@ int stop_machine_run(int (*fn)(void *), void *data, > unsigned int cpu) > if ( !get_cpu_maps() ) > return -EBUSY; > > - cpumask_andnot(&allbutself, &cpu_online_map, > - cpumask_of(smp_processor_id())); > - nr_cpus = cpumask_weight(&allbutself); > + nr_cpus = cpumask_weight(&cpu_online_map) - 1; Having looked at a lot of CPU offlining code recently, I notice this isn't strictly correct: You imply cpu_online(my_cpu) to produce "true". I think at present this will always hold, but I'd prefer if we could avoid gaining such a dependency. And it doesn't look overly difficult to avoid it. Also please don't open-code num_online_cpus(). > @@ -100,8 +98,9 @@ int stop_machine_run(int (*fn)(void *), void *data, > unsigned int cpu) > > smp_wmb(); > > - for_each_cpu ( i, &allbutself ) > - tasklet_schedule_on_cpu(&per_cpu(stopmachine_tasklet, i), i); > + for_each_cpu ( i, &cpu_online_map ) Same here for for_each_online_cpu(). Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel
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