On Mon, 15 Jun 2015, Peter Zijlstra wrote:
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.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..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.
ok , Will fix.
+
+ 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.
I saw the cpumask_any_but but wanted to avoid the
for loop in the cpumask_any_but , but now i see why from your previous comment.
Without the cpumask_t I will have to use the cpumask_any_but .. the two were
related.
Thanks,
Vikas
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