Re: [RFC PATCH] sched: fair: reset task_group.load_avg when there are no running tasks.

[kernel test robot <lkp@intel.com>]

Hi Imran,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build errors:

[auto build test ERROR on tip/sched/core]
[also build test ERROR on peterz-queue/sched/core linus/master v6.7-rc5 next-20231215]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Imran-Khan/sched-fair-reset-task_group-load_avg-when-there-are-no-running-tasks/20231215-132912
base:   tip/sched/core
patch link:    https://lore.kernel.org/r/20231215052652.917741-1-imran.f.khan%40oracle.com
patch subject: [RFC PATCH] sched: fair: reset task_group.load_avg when there are no running tasks.
config: i386-buildonly-randconfig-002-20231217 (https://download.01.org/0day-ci/archive/20231217/202312171425.MFabjrns-lkp@intel.com/config)
compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231217/202312171425.MFabjrns-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202312171425.MFabjrns-lkp@intel.com/

All errors (new ones prefixed by >>):

>> kernel/sched/fair.c:3579:43: error: incomplete definition of type 'struct task_group'
                   atomic_long_inc(&task_group(task_of(se))->cfs_nr_running);
                                    ~~~~~~~~~~~~~~~~~~~~~~~^
   include/linux/sched.h:71:8: note: forward declaration of 'struct task_group'
   struct task_group;
          ^
   kernel/sched/fair.c:3595:43: error: incomplete definition of type 'struct task_group'
                   atomic_long_dec(&task_group(task_of(se))->cfs_nr_running);
                                    ~~~~~~~~~~~~~~~~~~~~~~~^
   include/linux/sched.h:71:8: note: forward declaration of 'struct task_group'
   struct task_group;
          ^
   kernel/sched/fair.c:13091:6: warning: no previous prototype for function 'free_fair_sched_group' [-Wmissing-prototypes]
   void free_fair_sched_group(struct task_group *tg) { }
        ^
   kernel/sched/fair.c:13091:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void free_fair_sched_group(struct task_group *tg) { }
   ^
   static 
   kernel/sched/fair.c:13093:5: warning: no previous prototype for function 'alloc_fair_sched_group' [-Wmissing-prototypes]
   int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
       ^
   kernel/sched/fair.c:13093:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
   ^
   static 
   kernel/sched/fair.c:13098:6: warning: no previous prototype for function 'online_fair_sched_group' [-Wmissing-prototypes]
   void online_fair_sched_group(struct task_group *tg) { }
        ^
   kernel/sched/fair.c:13098:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void online_fair_sched_group(struct task_group *tg) { }
   ^
   static 
   kernel/sched/fair.c:13100:6: warning: no previous prototype for function 'unregister_fair_sched_group' [-Wmissing-prototypes]
   void unregister_fair_sched_group(struct task_group *tg) { }
        ^
   kernel/sched/fair.c:13100:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void unregister_fair_sched_group(struct task_group *tg) { }
   ^
   static 
   4 warnings and 2 errors generated.


vim +3579 kernel/sched/fair.c

  3568	
  3569	static void
  3570	account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
  3571	{
  3572		update_load_add(&cfs_rq->load, se->load.weight);
  3573	#ifdef CONFIG_SMP
  3574		if (entity_is_task(se)) {
  3575			struct rq *rq = rq_of(cfs_rq);
  3576	
  3577			account_numa_enqueue(rq, task_of(se));
  3578			list_add(&se->group_node, &rq->cfs_tasks);
> 3579			atomic_long_inc(&task_group(task_of(se))->cfs_nr_running);
  3580		}
  3581	#endif
  3582		cfs_rq->nr_running++;
  3583		if (se_is_idle(se))
  3584			cfs_rq->idle_nr_running++;
  3585	}
  3586	

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