What the inner loop needs to do is to assign each cpu in `siblmsk & nmsk`.
Clean it by using cpumask_next_and(), meantime add helper of grp_assign_cpu().
So grp_spread_init_one() becomes more readable now.
Cc: Yury Norov <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Ming Lei <[email protected]>
---
Hello Andrew,
Please consider to use this one to replace the 1st, 2nd & 4th patches
in Yury's V5:
- avoid to add new kernel API
- avoid to update iterator variable inside loop, which is tricky
- fix bug in the 4th patch
- add grp_assign_cpu() to make code more readable & clean
lib/group_cpus.c | 34 +++++++++++++++++++---------------
1 file changed, 19 insertions(+), 15 deletions(-)
diff --git a/lib/group_cpus.c b/lib/group_cpus.c
index ee272c4cefcc..6cbc7379d954 100644
--- a/lib/group_cpus.c
+++ b/lib/group_cpus.c
@@ -11,32 +11,36 @@
#ifdef CONFIG_SMP
+static bool grp_assign_cpu(int cpu, struct cpumask *irqmsk,
+ struct cpumask *nmsk)
+{
+ if (cpu >= nr_cpu_ids)
+ return false;
+
+ cpumask_clear_cpu(cpu, nmsk);
+ cpumask_set_cpu(cpu, irqmsk);
+ return true;
+}
+
static void grp_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk,
unsigned int cpus_per_grp)
{
const struct cpumask *siblmsk;
- int cpu, sibl;
-
- for ( ; cpus_per_grp > 0; ) {
- cpu = cpumask_first(nmsk);
+ int cpu = -1, sibl;
- /* Should not happen, but I'm too lazy to think about it */
- if (cpu >= nr_cpu_ids)
+ while (cpus_per_grp > 0) {
+ cpu = cpumask_next(cpu, nmsk);
+ if (!grp_assign_cpu(cpu, irqmsk, nmsk))
return;
-
- cpumask_clear_cpu(cpu, nmsk);
- cpumask_set_cpu(cpu, irqmsk);
cpus_per_grp--;
/* If the cpu has siblings, use them first */
siblmsk = topology_sibling_cpumask(cpu);
- for (sibl = -1; cpus_per_grp > 0; ) {
- sibl = cpumask_next(sibl, siblmsk);
- if (sibl >= nr_cpu_ids)
+ sibl = cpu;
+ while (cpus_per_grp > 0) {
+ sibl = cpumask_next_and(sibl, siblmsk, nmsk);
+ if (!grp_assign_cpu(sibl, irqmsk, nmsk))
break;
- if (!cpumask_test_and_clear_cpu(sibl, nmsk))
- continue;
- cpumask_set_cpu(sibl, irqmsk);
cpus_per_grp--;
}
}
--
2.41.0