[kbuild-all] [mingo-tip:master 1793/2382] kernel/sched/fair.c:10758:6: warning: no previous prototype for 'nohz_balance_enter_idle'

tree: git://git.kernel.org/pub/scm/linux/kernel/git/mingo/tip.git master head: 1a880941a087613ed42f77001229edfcf75ea8a5 commit: 90af8efc5f313f5faa40d7e7bc58986a4342828a [1793/2382] headers/deps: Reorganize, clean up and optimize kernel/sched/sched.h dependencies config: x86_64-randconfig-a011 (https://download.01.org/0day-ci/archive/20220114/202201140251.J3IHIgTm-lk...) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://git.kernel.org/pub/scm/linux/kernel/git/mingo/tip.git/commit/?id=... git remote add mingo-tip git://git.kernel.org/pub/scm/linux/kernel/git/mingo/tip.git git fetch --no-tags mingo-tip master git checkout 90af8efc5f313f5faa40d7e7bc58986a4342828a # save the config file to linux build tree mkdir build_dir make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash kernel/sched/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): kernel/sched/fair.c:5486:6: warning: no previous prototype for 'init_cfs_bandwidth' [-Wmissing-prototypes] 5486 | void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {} | ^~~~~~~~~~~~~~~~~~ 10758 | void nohz_balance_enter_idle(int cpu) | ^~~~~~~~~~~~~~~~~~~~~~~ kernel/sched/fair.c:11880:6: warning: no previous prototype for 'free_fair_sched_group' [-Wmissing-prototypes] 11880 | void free_fair_sched_group(struct task_group *tg) { } | ^~~~~~~~~~~~~~~~~~~~~ kernel/sched/fair.c:11882:5: warning: no previous prototype for 'alloc_fair_sched_group' [-Wmissing-prototypes] 11882 | int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) | ^~~~~~~~~~~~~~~~~~~~~~ kernel/sched/fair.c:11887:6: warning: no previous prototype for 'online_fair_sched_group' [-Wmissing-prototypes] 11887 | void online_fair_sched_group(struct task_group *tg) { } | ^~~~~~~~~~~~~~~~~~~~~~~ kernel/sched/fair.c:11889:6: warning: no previous prototype for 'unregister_fair_sched_group' [-Wmissing-prototypes] 11889 | void unregister_fair_sched_group(struct task_group *tg) { } | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ vim +/nohz_balance_enter_idle +10758 kernel/sched/fair.c 69e1e811dcc436 kernel/sched/fair.c Suresh Siddha 2011-12-01 10753 1e3c88bdeb1260 kernel/sched_fair.c Peter Zijlstra 2009-12-17 10754 /* 97fb7a0a8944bd kernel/sched/fair.c Ingo Molnar 2018-03-03 10755 * This routine will record that the CPU is going idle with tick stopped. 0b005cf54eac17 kernel/sched/fair.c Suresh Siddha 2011-12-01 10756 * This info will be used in performing idle load balancing in the future. 1e3c88bdeb1260 kernel/sched_fair.c Peter Zijlstra 2009-12-17 10757 */ c1cc017c59c44d kernel/sched/fair.c Alex Shi 2012-09-10 @10758 void nohz_balance_enter_idle(int cpu) 1e3c88bdeb1260 kernel/sched_fair.c Peter Zijlstra 2009-12-17 10759 { 00357f5ec5d67a kernel/sched/fair.c Peter Zijlstra 2017-12-21 10760 struct rq *rq = cpu_rq(cpu); 00357f5ec5d67a kernel/sched/fair.c Peter Zijlstra 2017-12-21 10761 00357f5ec5d67a kernel/sched/fair.c Peter Zijlstra 2017-12-21 10762 SCHED_WARN_ON(cpu != smp_processor_id()); 00357f5ec5d67a kernel/sched/fair.c Peter Zijlstra 2017-12-21 10763 97fb7a0a8944bd kernel/sched/fair.c Ingo Molnar 2018-03-03 10764 /* If this CPU is going down, then nothing needs to be done: */ 71325960d16cd6 kernel/sched/fair.c Suresh Siddha 2012-01-19 10765 if (!cpu_active(cpu)) 71325960d16cd6 kernel/sched/fair.c Suresh Siddha 2012-01-19 10766 return; 71325960d16cd6 kernel/sched/fair.c Suresh Siddha 2012-01-19 10767 387bc8b5536eeb kernel/sched/fair.c Frederic Weisbecker 2017-06-19 10768 /* Spare idle load balancing on CPUs that don't want to be disturbed: */ de201559df872f kernel/sched/fair.c Frederic Weisbecker 2017-10-27 10769 if (!housekeeping_cpu(cpu, HK_FLAG_SCHED)) 387bc8b5536eeb kernel/sched/fair.c Frederic Weisbecker 2017-06-19 10770 return; 387bc8b5536eeb kernel/sched/fair.c Frederic Weisbecker 2017-06-19 10771 f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10772 /* f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10773 * Can be set safely without rq->lock held f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10774 * If a clear happens, it will have evaluated last additions because f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10775 * rq->lock is held during the check and the clear f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10776 */ f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10777 rq->has_blocked_load = 1; f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10778 f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10779 /* f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10780 * The tick is still stopped but load could have been added in the f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10781 * meantime. We set the nohz.has_blocked flag to trig a check of the f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10782 * *_avg. The CPU is already part of nohz.idle_cpus_mask so the clear f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10783 * of nohz.has_blocked can only happen after checking the new load f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10784 */ 00357f5ec5d67a kernel/sched/fair.c Peter Zijlstra 2017-12-21 10785 if (rq->nohz_tick_stopped) f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10786 goto out; 1e3c88bdeb1260 kernel/sched_fair.c Peter Zijlstra 2009-12-17 10787 97fb7a0a8944bd kernel/sched/fair.c Ingo Molnar 2018-03-03 10788 /* If we're a completely isolated CPU, we don't play: */ 00357f5ec5d67a kernel/sched/fair.c Peter Zijlstra 2017-12-21 10789 if (on_null_domain(rq)) d987fc7f3228bf kernel/sched/fair.c Mike Galbraith 2011-12-05 10790 return; d987fc7f3228bf kernel/sched/fair.c Mike Galbraith 2011-12-05 10791 00357f5ec5d67a kernel/sched/fair.c Peter Zijlstra 2017-12-21 10792 rq->nohz_tick_stopped = 1; 00357f5ec5d67a kernel/sched/fair.c Peter Zijlstra 2017-12-21 10793 83cd4fe27ad844 kernel/sched_fair.c Venkatesh Pallipadi 2010-05-21 10794 cpumask_set_cpu(cpu, nohz.idle_cpus_mask); 0b005cf54eac17 kernel/sched/fair.c Suresh Siddha 2011-12-01 10795 atomic_inc(&nohz.nr_cpus); 00357f5ec5d67a kernel/sched/fair.c Peter Zijlstra 2017-12-21 10796 f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10797 /* f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10798 * Ensures that if nohz_idle_balance() fails to observe our f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10799 * @idle_cpus_mask store, it must observe the @has_blocked 7fd7a9e0caba10 kernel/sched/fair.c Valentin Schneider 2021-08-23 10800 * and @needs_update stores. f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10801 */ f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10802 smp_mb__after_atomic(); f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10803 00357f5ec5d67a kernel/sched/fair.c Peter Zijlstra 2017-12-21 10804 set_cpu_sd_state_idle(cpu); f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10805 7fd7a9e0caba10 kernel/sched/fair.c Valentin Schneider 2021-08-23 10806 WRITE_ONCE(nohz.needs_update, 1); f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10807 out: f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10808 /* f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10809 * Each time a cpu enter idle, we assume that it has blocked load and f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10810 * enable the periodic update of the load of idle cpus f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10811 */ f643ea2207010d kernel/sched/fair.c Vincent Guittot 2018-02-13 10812 WRITE_ONCE(nohz.has_blocked, 1); 1e3c88bdeb1260 kernel/sched_fair.c Peter Zijlstra 2009-12-17 10813 } 1e3c88bdeb1260 kernel/sched_fair.c Peter Zijlstra 2009-12-17 10814 :::::: The code at line 10758 was first introduced by commit :::::: c1cc017c59c44d9ede7003631c43adc0cfdce2f9 sched/nohz: Clean up select_nohz_load_balancer() :::::: TO: Alex Shi <alex.shi(a)intel.com&gt; :::::: CC: Ingo Molnar <mingo(a)kernel.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org