Hi Daniel,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on 7d2a07b769330c34b4deabeed939325c77a7ec2f]

url:    https://github.com/0day-ci/linux/commits/Daniel-Jordan/padata-vfio-sched-Multithreaded-VFIO-page-pinning/20220106-084934
base:   7d2a07b769330c34b4deabeed939325c77a7ec2f
config: arc-allyesconfig (https://download.01.org/0day-ci/archive/20220106/202201061409.pRp9ULXe-lkp(a)intel.com/config)
compiler: arceb-elf-gcc (GCC) 11.2.0
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/44b2a69264d6505d97cd115e781a10437a6dc90d
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Daniel-Jordan/padata-vfio-sched-Multithreaded-VFIO-page-pinning/20220106-084934
        git checkout 44b2a69264d6505d97cd115e781a10437a6dc90d
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arc SHELL=/bin/bash kernel/sched/

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

All warnings (new ones prefixed by >>):

   kernel/sched/core.c:3216:6: warning: no previous prototype for 'sched_set_stop_task' [-Wmissing-prototypes]
    3216 | void sched_set_stop_task(int cpu, struct task_struct *stop)
         |      ^~~~~~~~~~~~~~~~~~~
>> kernel/sched/core.c:10025:5: warning: no previous prototype for 'max_cfs_bandwidth_cpus' [-Wmissing-prototypes]
   10025 | int max_cfs_bandwidth_cpus(struct cgroup_subsys_state *css)
         |     ^~~~~~~~~~~~~~~~~~~~~~
   In file included from include/linux/perf_event.h:25,
                    from include/linux/trace_events.h:10,
                    from include/trace/trace_events.h:21,
                    from include/trace/define_trace.h:102,
                    from include/trace/events/sched.h:738,
                    from kernel/sched/core.c:10:
   arch/arc/include/asm/perf_event.h:126:27: warning: 'arc_pmu_cache_map' defined but not used [-Wunused-const-variable=]
     126 | static const unsigned int 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[] = {
         |                           ^~~~~~~~~~~~~~~~~


vim +/max_cfs_bandwidth_cpus +10025 kernel/sched/core.c

 10023	
 10024	/* Returns the max whole number of CPUs that @css's bandwidth settings allow. */
 10025	int max_cfs_bandwidth_cpus(struct cgroup_subsys_state *css)
 10026	{
 10027		struct task_group *tg = css_tg(css);
 10028		u64 quota_us, period_us;
 10029	
 10030		if (tg == &root_task_group)
 10031			return nr_cpu_ids;
 10032	
 10033		quota_us = tg_get_cfs_quota(tg);
 10034	
 10035		if (quota_us == RUNTIME_INF)
 10036			return nr_cpu_ids;
 10037	
 10038		period_us = tg_get_cfs_period(tg);
 10039	
 10040		return quota_us / period_us;
 10041	}
 10042	

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