Re: [RFC PATCH 4/5] sched/core: Push current task when cpu is parked

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

Hi Shrikanth,

[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 powerpc/next powerpc/fixes peterz-queue/sched/core linus/master tip/smp/core v6.15-rc7 next-20250523]
[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/Shrikanth-Hegde/cpumask-Introduce-cpu-parked-mask/20250524-021851
base:   tip/sched/core
patch link:    https://lore.kernel.org/r/20250523181448.3777233-5-sshegde%40linux.ibm.com
patch subject: [RFC PATCH 4/5] sched/core: Push current task when cpu is parked
config: x86_64-allnoconfig (https://download.01.org/0day-ci/archive/20250524/202505241517.5L95fW8h-lkp@intel.com/config)
compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250524/202505241517.5L95fW8h-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/202505241517.5L95fW8h-lkp@intel.com/

All errors (new ones prefixed by >>):

>> kernel/sched/core.c:5660:6: error: call to undeclared function 'cpu_parked'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    5660 |         if (cpu_parked(cpu))
         |             ^
   kernel/sched/core.c:7667:12: warning: array index -1 is before the beginning of the array [-Warray-bounds]
    7667 |                                        preempt_modes[preempt_dynamic_mode] : "undef",
         |                                        ^             ~~~~~~~~~~~~~~~~~~~~
   kernel/sched/core.c:7642:1: note: array 'preempt_modes' declared here
    7642 | const char *preempt_modes[] = {
         | ^
   1 warning and 1 error generated.


vim +/cpu_parked +5660 kernel/sched/core.c

  5639	
  5640	/*
  5641	 * This function gets called by the timer code, with HZ frequency.
  5642	 * We call it with interrupts disabled.
  5643	 */
  5644	void sched_tick(void)
  5645	{
  5646		int cpu = smp_processor_id();
  5647		struct rq *rq = cpu_rq(cpu);
  5648		/* accounting goes to the donor task */
  5649		struct task_struct *donor;
  5650		struct rq_flags rf;
  5651		unsigned long hw_pressure;
  5652		u64 resched_latency;
  5653	
  5654		if (housekeeping_cpu(cpu, HK_TYPE_KERNEL_NOISE))
  5655			arch_scale_freq_tick();
  5656	
  5657		sched_clock_tick();
  5658	
  5659		/* push the current task out if cpu is parked */
> 5660		if (cpu_parked(cpu))
  5661			push_current_task(rq);
  5662	
  5663		rq_lock(rq, &rf);
  5664		donor = rq->donor;
  5665	
  5666		psi_account_irqtime(rq, donor, NULL);
  5667	
  5668		update_rq_clock(rq);
  5669		hw_pressure = arch_scale_hw_pressure(cpu_of(rq));
  5670		update_hw_load_avg(rq_clock_task(rq), rq, hw_pressure);
  5671	
  5672		if (dynamic_preempt_lazy() && tif_test_bit(TIF_NEED_RESCHED_LAZY))
  5673			resched_curr(rq);
  5674	
  5675		donor->sched_class->task_tick(rq, donor, 0);
  5676		if (sched_feat(LATENCY_WARN))
  5677			resched_latency = cpu_resched_latency(rq);
  5678		calc_global_load_tick(rq);
  5679		sched_core_tick(rq);
  5680		task_tick_mm_cid(rq, donor);
  5681		scx_tick(rq);
  5682	
  5683		rq_unlock(rq, &rf);
  5684	
  5685		if (sched_feat(LATENCY_WARN) && resched_latency)
  5686			resched_latency_warn(cpu, resched_latency);
  5687	
  5688		perf_event_task_tick();
  5689	
  5690		if (donor->flags & PF_WQ_WORKER)
  5691			wq_worker_tick(donor);
  5692	

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