From: Tejun Heo Date: Tue, 23 Sep 2025 19:03:26 +0000 (-1000) Subject: sched_ext: Improve SCX_KF_DISPATCH comment X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=edf005fa274a0c224e550a52726aa7a426384e36;p=thirdparty%2Fkernel%2Fstable.git sched_ext: Improve SCX_KF_DISPATCH comment The comment for SCX_KF_DISPATCH was incomplete and didn't explain that ops.dispatch() may temporarily release the rq lock, allowing ENQUEUE and SELECT_CPU operations to be nested inside DISPATCH contexts. Update the comment to clarify this nesting behavior and provide better context for when these operations can occur within dispatch. Acked-by: Andrea Righi Signed-off-by: Tejun Heo --- diff --git a/include/linux/sched/ext.h b/include/linux/sched/ext.h index 7047101dbf587..d82b7a9b0658b 100644 --- a/include/linux/sched/ext.h +++ b/include/linux/sched/ext.h @@ -108,7 +108,11 @@ enum scx_kf_mask { SCX_KF_UNLOCKED = 0, /* sleepable and not rq locked */ /* ENQUEUE and DISPATCH may be nested inside CPU_RELEASE */ SCX_KF_CPU_RELEASE = 1 << 0, /* ops.cpu_release() */ - /* ops.dequeue (in REST) may be nested inside DISPATCH */ + /* + * ops.dispatch() may release rq lock temporarily and thus ENQUEUE and + * SELECT_CPU may be nested inside. ops.dequeue (in REST) may also be + * nested inside DISPATCH. + */ SCX_KF_DISPATCH = 1 << 1, /* ops.dispatch() */ SCX_KF_ENQUEUE = 1 << 2, /* ops.enqueue() and ops.select_cpu() */ SCX_KF_SELECT_CPU = 1 << 3, /* ops.select_cpu() */