sched_ext: Mark racy bitfields to prevent adding fields that can't tolerate races

The warned bitfields in struct scx_sched are updated racily from concurrent
CPUs causing RMW races, which is fine for these boolean warning flags. Add a
comment marking this area to prevent future fields that can't tolerate racy
updates from being added here.

Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/kernel/sched/ext_internal.h b/kernel/sched/ext_internal.h
index fb161fc35328cbcde007d36df5c7bf3cde947d73..dd6f25fb6159cc860260870de13b154ea39a746d 100644 (file)
--- a/kernel/sched/ext_internal.h
+++ b/kernel/sched/ext_internal.h
@@ -895,6 +895,10 @@ struct scx_sched {
        struct scx_dispatch_q   **global_dsqs;
        struct scx_sched_pcpu __percpu *pcpu;
 
+       /*
+        * Updates to the following warned bitfields can race causing RMW issues
+        * but it doesn't really matter.
+        */
        bool                    warned_zero_slice:1;
        bool                    warned_deprecated_rq:1;