On Tue, Jun 14, 2022 at 06:40:53PM +0200, Peter Zijlstra wrote:
On Tue, Jun 14, 2022 at 01:41:13PM +0100, Mark Rutland wrote:
On Wed, Jun 08, 2022 at 04:27:37PM +0200, Peter Zijlstra wrote:
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -622,9 +622,13 @@ struct cpumask *tick_get_broadcast_onesh
* to avoid a deep idle transition as we are about to get the
* broadcast IPI right away.
*/
-int tick_check_broadcast_expired(void)
+noinstr int tick_check_broadcast_expired(void)
{
+#ifdef _ASM_GENERIC_BITOPS_INSTRUMENTED_NON_ATOMIC_H
+ return arch_test_bit(smp_processor_id(), cpumask_bits(tick_broadcast_force_mask));
+#else
return cpumask_test_cpu(smp_processor_id(), tick_broadcast_force_mask);
+#endif
}
This is somewhat not-ideal. :/
I'll say.
Could we unconditionally do the arch_test_bit() variant, with a comment, or
does that not exist in some cases?
Loads of build errors ensued, which is how I ended up with this mess ...
Yaey :(
I see the same is true for the thread flag manipulation too.
I'll take a look and see if we can layer things so that we can use the arch_*()
helpers and wrap those consistently so that we don't have to check the CPP
guard.
Ideally we'd have a a better language that allows us to make some
context-senstive decisions, then we could hide all this gunk in the lower
levels with somethin like:
if (!THIS_IS_A_NOINSTR_FUNCTION()) {
explicit_instrumentation(...);
}
... ho hum.
Mark.
