Re: [PATCH v2 2/2] sched/fair: optimize and simplify rq leaf_cfs_rq_list

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

Hi Chengming,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on tip/sched/core]
[also build test ERROR on tip/master linus/master v5.18 next-20220525]
[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/intel-lab-lkp/linux/commits/Chengming-Zhou/sched-fair-optimize-and-simplify-rq-leaf_cfs_rq_list/20220526-151850
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 991d8d8142cad94f9c5c05db25e67fa83d6f772a
config: powerpc-allnoconfig (https://download.01.org/0day-ci/archive/20220526/202205261617.YUT1ixQ8-lkp@intel.com/config)
compiler: powerpc-linux-gcc (GCC) 11.3.0
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/intel-lab-lkp/linux/commit/cb2b1810aeb3f8f290a932f3e625ab9df1110054
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Chengming-Zhou/sched-fair-optimize-and-simplify-rq-leaf_cfs_rq_list/20220526-151850
        git checkout cb2b1810aeb3f8f290a932f3e625ab9df1110054
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash kernel/sched/

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

All errors (new ones prefixed by >>):

   kernel/sched/fair.c:645:5: warning: no previous prototype for 'sched_update_scaling' [-Wmissing-prototypes]
     645 | int sched_update_scaling(void)
         |     ^~~~~~~~~~~~~~~~~~~~
   kernel/sched/fair.c: In function 'enqueue_entity':
>> kernel/sched/fair.c:4343:22: error: implicit declaration of function 'throttled_hierarchy' [-Werror=implicit-function-declaration]
    4343 |                 if (!throttled_hierarchy(cfs_rq))
         |                      ^~~~~~~~~~~~~~~~~~~
   kernel/sched/fair.c: At top level:
>> kernel/sched/fair.c:5484:19: error: static declaration of 'throttled_hierarchy' follows non-static declaration
    5484 | static inline int throttled_hierarchy(struct cfs_rq *cfs_rq)
         |                   ^~~~~~~~~~~~~~~~~~~
   kernel/sched/fair.c:4343:22: note: previous implicit declaration of 'throttled_hierarchy' with type 'int()'
    4343 |                 if (!throttled_hierarchy(cfs_rq))
         |                      ^~~~~~~~~~~~~~~~~~~
   kernel/sched/fair.c:5495:6: warning: no previous prototype for 'init_cfs_bandwidth' [-Wmissing-prototypes]
    5495 | void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
         |      ^~~~~~~~~~~~~~~~~~
   kernel/sched/fair.c:11654:6: warning: no previous prototype for 'free_fair_sched_group' [-Wmissing-prototypes]
   11654 | void free_fair_sched_group(struct task_group *tg) { }
         |      ^~~~~~~~~~~~~~~~~~~~~
   kernel/sched/fair.c:11656:5: warning: no previous prototype for 'alloc_fair_sched_group' [-Wmissing-prototypes]
   11656 | int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
         |     ^~~~~~~~~~~~~~~~~~~~~~
   kernel/sched/fair.c:11661:6: warning: no previous prototype for 'online_fair_sched_group' [-Wmissing-prototypes]
   11661 | void online_fair_sched_group(struct task_group *tg) { }
         |      ^~~~~~~~~~~~~~~~~~~~~~~
   kernel/sched/fair.c:11663:6: warning: no previous prototype for 'unregister_fair_sched_group' [-Wmissing-prototypes]
   11663 | void unregister_fair_sched_group(struct task_group *tg) { }
         |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/throttled_hierarchy +4343 kernel/sched/fair.c

  4263	
  4264	/*
  4265	 * MIGRATION
  4266	 *
  4267	 *	dequeue
  4268	 *	  update_curr()
  4269	 *	    update_min_vruntime()
  4270	 *	  vruntime -= min_vruntime
  4271	 *
  4272	 *	enqueue
  4273	 *	  update_curr()
  4274	 *	    update_min_vruntime()
  4275	 *	  vruntime += min_vruntime
  4276	 *
  4277	 * this way the vruntime transition between RQs is done when both
  4278	 * min_vruntime are up-to-date.
  4279	 *
  4280	 * WAKEUP (remote)
  4281	 *
  4282	 *	->migrate_task_rq_fair() (p->state == TASK_WAKING)
  4283	 *	  vruntime -= min_vruntime
  4284	 *
  4285	 *	enqueue
  4286	 *	  update_curr()
  4287	 *	    update_min_vruntime()
  4288	 *	  vruntime += min_vruntime
  4289	 *
  4290	 * this way we don't have the most up-to-date min_vruntime on the originating
  4291	 * CPU and an up-to-date min_vruntime on the destination CPU.
  4292	 */
  4293	
  4294	static void
  4295	enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
  4296	{
  4297		bool renorm = !(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_MIGRATED);
  4298		bool curr = cfs_rq->curr == se;
  4299	
  4300		/*
  4301		 * If we're the current task, we must renormalise before calling
  4302		 * update_curr().
  4303		 */
  4304		if (renorm && curr)
  4305			se->vruntime += cfs_rq->min_vruntime;
  4306	
  4307		update_curr(cfs_rq);
  4308	
  4309		/*
  4310		 * Otherwise, renormalise after, such that we're placed at the current
  4311		 * moment in time, instead of some random moment in the past. Being
  4312		 * placed in the past could significantly boost this task to the
  4313		 * fairness detriment of existing tasks.
  4314		 */
  4315		if (renorm && !curr)
  4316			se->vruntime += cfs_rq->min_vruntime;
  4317	
  4318		/*
  4319		 * When enqueuing a sched_entity, we must:
  4320		 *   - Update loads to have both entity and cfs_rq synced with now.
  4321		 *   - Add its load to cfs_rq->runnable_avg
  4322		 *   - For group_entity, update its weight to reflect the new share of
  4323		 *     its group cfs_rq
  4324		 *   - Add its new weight to cfs_rq->load.weight
  4325		 */
  4326		update_load_avg(cfs_rq, se, UPDATE_TG | DO_ATTACH);
  4327		se_update_runnable(se);
  4328		update_cfs_group(se);
  4329		account_entity_enqueue(cfs_rq, se);
  4330	
  4331		if (flags & ENQUEUE_WAKEUP)
  4332			place_entity(cfs_rq, se, 0);
  4333	
  4334		check_schedstat_required();
  4335		update_stats_enqueue_fair(cfs_rq, se, flags);
  4336		check_spread(cfs_rq, se);
  4337		if (!curr)
  4338			__enqueue_entity(cfs_rq, se);
  4339		se->on_rq = 1;
  4340	
  4341		if (cfs_rq->nr_running == 1) {
  4342			check_enqueue_throttle(cfs_rq);
> 4343			if (!throttled_hierarchy(cfs_rq))
  4344				list_add_leaf_cfs_rq(cfs_rq);
  4345		}
  4346	}
  4347	

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