Messages in this thread Patch in this message | | | From | Ming Lei <> | Subject | [PATCH] lib/group_cpus.c: simplify grp_spread_init_one() | Date | Sat, 20 Jan 2024 14:55:43 +0800 |
| |
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 <yury.norov@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> ---
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
| |