Hi Scott,

I love your patch! Yet something to improve:

[auto build test ERROR on linux/master]
[also build test ERROR on v5.12]
[cannot apply to tip/sched/core tip/master linus/master next-20210428]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Scott-Wood/newidle_balance-PREEMPT_RT-latency-mitigations/20210429-073033
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 1fe5501ba1abf2b7e78295df73675423bd6899a0
config: arc-allyesconfig (attached as .config)
compiler: arceb-elf-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/a88b1e73d8edba9a004ca170d136eccc8bcf7e9f
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Scott-Wood/newidle_balance-PREEMPT_RT-latency-mitigations/20210429-073033
        git checkout a88b1e73d8edba9a004ca170d136eccc8bcf7e9f
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross W=1 ARCH=arc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   kernel/sched/fair.c: In function 'stop_balance_early':
>> kernel/sched/fair.c:9507:40: error: implicit declaration of function 'rq_has_higher_tasks' [-Werror=implicit-function-declaration]
    9507 |  return env->idle == CPU_NEWLY_IDLE && rq_has_higher_tasks(env->dst_rq);
         |                                        ^~~~~~~~~~~~~~~~~~~
   In file included from include/linux/perf_event.h:25,
                    from include/linux/trace_events.h:10,
                    from include/trace/syscall.h:7,
                    from include/linux/syscalls.h:85,
                    from kernel/sched/sched.h:65,
                    from kernel/sched/fair.c:23:
   At top level:
   arch/arc/include/asm/perf_event.h:126:23: warning: 'arc_pmu_cache_map' defined but not used [-Wunused-const-variable=]
     126 | static const unsigned arc_pmu_cache_map[C(MAX)][C(OP_MAX)][C(RESULT_MAX)] = {
         |                       ^~~~~~~~~~~~~~~~~
   arch/arc/include/asm/perf_event.h:91:27: warning: 'arc_pmu_ev_hw_map' defined but not used [-Wunused-const-variable=]
      91 | static const char * const arc_pmu_ev_hw_map[] = {
         |                           ^~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/rq_has_higher_tasks +9507 kernel/sched/fair.c

  9504	
  9505	static bool stop_balance_early(struct lb_env *env)
  9506	{
> 9507		return env->idle == CPU_NEWLY_IDLE && rq_has_higher_tasks(env->dst_rq);
  9508	}
  9509	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org