Re: [PATCH v2 04/11] sched: Simplify wake_up_*idle*()

On Tue, Oct 19, 2021 at 03:22:43PM -0400, Qian Cai wrote:

On 10/19/21 11:50 AM, Peter Zijlstra wrote:

quoted

quoted

quoted

diff --git a/kernel/smp.c b/kernel/smp.c
index ad0b68a3a3d3..61ddc7a3bafa 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c

@@ -1170,14 +1170,12 @@ void wake_up_all_idle_cpus(void)
 {
 	int cpu;
 
-	cpus_read_lock();
-	for_each_online_cpu(cpu) {
-		if (cpu == raw_smp_processor_id())
-			continue;
-
-		wake_up_if_idle(cpu);
+	for_each_cpu(cpu) {
+		preempt_disable();
+		if (cpu != smp_processor_id() && cpu_online(cpu))
+			wake_up_if_idle(cpu);
+		preempt_enable();
 	}
-	cpus_read_unlock();
 }
 EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus);

This does not compile.

kernel/smp.c:1173:18: error: macro "for_each_cpu" requires 2 arguments, but only 1 given

Bah, for_each_possible_cpu(), lemme update the patch, I'm sure the
robots will scream bloody murder on that too.

This survived the regression tests here.

Thanks!