Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 15 Jun 2015 14:36:14 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 01/10] cpumask: Introduce cpumask_any_online_but |
| |
On Fri, Jun 12, 2015 at 11:17:08AM -0700, Vikas Shivappa wrote: > There is currently no cpumask helper function to pick a "random" cpu > from a mask which is also online. > > cpumask_any_online_but() does that which is similar to cpumask_any_but() > but also returns a cpu that is online. > > Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com> > --- > include/linux/cpumask.h | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h > index 27e285b..f2d7e8a 100644 > --- a/include/linux/cpumask.h > +++ b/include/linux/cpumask.h > @@ -548,6 +548,24 @@ static inline void cpumask_copy(struct cpumask *dstp, > #define cpumask_of(cpu) (get_cpu_mask(cpu)) > > /** > + * cpumask_any_online_but - return a "random" and online cpu in a cpumask, > + * but not this one > + * @mask: the input mask to search > + * @cpu: the cpu to ignore > + * > + * Returns >= nr_cpu_ids if no cpus set. > +*/ > +static inline unsigned int cpumask_any_online_but(const struct cpumask *mask, > + unsigned int cpu) > +{ > + cpumask_t tmp;
No, you cannot put a cpumask_t on stack like that. Those things can be massive.
> + > + cpumask_and(&tmp, cpu_online_mask, mask); > + cpumask_clear_cpu(cpu, &tmp); > + return cpumask_any(&tmp); > +}
You had a good example in cpumask_any_but() copy that.
| ![\](/images/icornerr.gif) |