On Wed, 24 Jun 2015, Thomas Gleixner wrote:
On Tue, 23 Jun 2015, 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.shiva...@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..ea63b65 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) +{ + static cpumask_t tmp;How is that supposed to work? You cannot expect, that all potential users of this function are magically serialized.
I am trying do something wierd with this API. trying to do cpumask_and_any_but. But anything with 'and' operation, usually the caller supplies the dst. Guess I can remove this API altogether and 'and' the online and package cpu masks during hot cpu notifications.
Thanks, Vikas
+ + cpumask_and(&tmp, cpu_online_mask, mask); + cpumask_clear_cpu(cpu, &tmp); + return cpumask_any(&tmp);Thanks, tglx
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