Re: [PATCH] sched: Make select_idle_sibling search domain configurable

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

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Hi Xi,

I love your patch! Yet something to improve:

[auto build test ERROR on tip/sched/core]
[also build test ERROR on tip/auto-latest linus/master v5.8-rc7]
[cannot apply to block/for-next cgroup/for-next next-20200727]
[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/0day-ci/linux/commits/Xi-Wang/sched-Make-select_idle_sibling-search-domain-configurable/20200728-150328
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 13efa616124f7eec7d6a58adeeef31864aa03879
config: arc-allyesconfig (attached as .config)
compiler: arc-elf-gcc (GCC) 9.3.0
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
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arc 

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

All error/warnings (new ones prefixed by >>):

   kernel/sched/fair.c: In function 'select_idle_sibling':
>> kernel/sched/fair.c:6285:27: error: passing argument 2 of 'select_idle_core' from incompatible pointer type [-Werror=incompatible-pointer-types]
    6285 |   r = select_idle_core(p, cpus, target);
         |                           ^~~~
         |                           |
         |                           struct cpumask *
   kernel/sched/fair.c:6096:80: note: expected 'struct sched_domain *' but argument is of type 'struct cpumask *'
    6096 | static inline int select_idle_core(struct task_struct *p, struct sched_domain *sd, int target)
         |                                                           ~~~~~~~~~~~~~~~~~~~~~^~
   kernel/sched/fair.c: At top level:
>> kernel/sched/fair.c:6754:5: warning: no previous prototype for 'proc_sched_wake_idle_domain_handler' [-Wmissing-prototypes]
    6754 | int proc_sched_wake_idle_domain_handler(struct ctl_table *table,
         |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   In file included from include/linux/perf_event.h:25,
                    from include/linux/trace_events.h:10,
                    from include/trace/syscall.h:7,
                    from include/linux/syscalls.h:85,
                    from kernel/sched/sched.h:65,
                    from kernel/sched/fair.c:23:
   arch/arc/include/asm/perf_event.h:126:23: warning: 'arc_pmu_cache_map' defined but not used [-Wunused-const-variable=]
     126 | static const unsigned 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[] = {
         |                           ^~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors
--
>> kernel/cgroup/cpuset.c:1018:6: warning: no previous prototype for '__rebuild_sched_domains' [-Wmissing-prototypes]
    1018 | void __rebuild_sched_domains(int force_update)
         |      ^~~~~~~~~~~~~~~~~~~~~~~

vim +/select_idle_core +6285 kernel/sched/fair.c

  6196	
  6197	/*
  6198	 * Try and locate an idle core/thread in the sis domain.
  6199	 */
  6200	static int select_idle_sibling(struct task_struct *p, int prev, int target)
  6201	{
  6202		struct sched_domain *sd_asym;
  6203		struct sched_domain *sd[2];
  6204		struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_idle_mask);
  6205		int i, r, recent_used_cpu;
  6206	
  6207		/*
  6208		 * For asymmetric CPU capacity systems, our domain of interest is
  6209		 * sd_asym_cpucapacity rather than sd_sis.
  6210		 */
  6211		if (static_branch_unlikely(&sched_asym_cpucapacity)) {
  6212			sd_asym = rcu_dereference(per_cpu(sd_asym_cpucapacity, target));
  6213			/*
  6214			 * On an asymmetric CPU capacity system where an exclusive
  6215			 * cpuset defines a symmetric island (i.e. one unique
  6216			 * capacity_orig value through the cpuset), the key will be set
  6217			 * but the CPUs within that cpuset will not have a domain with
  6218			 * SD_ASYM_CPUCAPACITY. These should follow the usual symmetric
  6219			 * capacity path.
  6220			 */
  6221			if (!sd_asym)
  6222				goto symmetric;
  6223	
  6224			i = select_idle_capacity(p, sd_asym, target);
  6225			return ((unsigned)i < nr_cpumask_bits) ? i : target;
  6226		}
  6227	
  6228	symmetric:
  6229		if (available_idle_cpu(target) || sched_idle_cpu(target))
  6230			return target;
  6231	
  6232		/*
  6233		 * If the previous CPU is cache affine and idle, don't be stupid:
  6234		 */
  6235		if (prev != target && cpus_share_sis(prev, target) &&
  6236		    (available_idle_cpu(prev) || sched_idle_cpu(prev)))
  6237			return prev;
  6238	
  6239		/*
  6240		 * Allow a per-cpu kthread to stack with the wakee if the
  6241		 * kworker thread and the tasks previous CPUs are the same.
  6242		 * The assumption is that the wakee queued work for the
  6243		 * per-cpu kthread that is now complete and the wakeup is
  6244		 * essentially a sync wakeup. An obvious example of this
  6245		 * pattern is IO completions.
  6246		 */
  6247		if (is_per_cpu_kthread(current) &&
  6248		    prev == smp_processor_id() &&
  6249		    this_rq()->nr_running <= 1) {
  6250			return prev;
  6251		}
  6252	
  6253		/* Check a recently used CPU as a potential idle candidate: */
  6254		recent_used_cpu = p->recent_used_cpu;
  6255		if (recent_used_cpu != prev &&
  6256		    recent_used_cpu != target &&
  6257		    cpus_share_sis(recent_used_cpu, target) &&
  6258		    (available_idle_cpu(recent_used_cpu) || sched_idle_cpu(recent_used_cpu)) &&
  6259		    cpumask_test_cpu(p->recent_used_cpu, p->cpus_ptr)) {
  6260			/*
  6261			 * Replace recent_used_cpu with prev as it is a potential
  6262			 * candidate for the next wake:
  6263			 */
  6264			p->recent_used_cpu = prev;
  6265			return recent_used_cpu;
  6266		}
  6267	
  6268		for (i = 0; ; i++) {
  6269			if (i == 0) {
  6270				sd[0] = rcu_dereference(per_cpu(sd_sis_pre, target));
  6271				if (!sd[0])
  6272					continue;
  6273				cpumask_and(cpus, sched_domain_span(sd[0]), p->cpus_ptr);
  6274			} else if (i == 1) {
  6275				sd[1] = rcu_dereference(per_cpu(sd_sis, target));
  6276				if (!sd[1])
  6277					continue;
  6278				cpumask_and(cpus, sched_domain_span(sd[1]), p->cpus_ptr);
  6279				if (sd[0])
  6280					cpumask_andnot(cpus, cpus, sched_domain_span(sd[0]));
  6281			} else {
  6282				break;
  6283			}
  6284	
> 6285			r = select_idle_core(p, cpus, target);
  6286			if ((unsigned)r < nr_cpumask_bits)
  6287				return r;
  6288	
  6289			r = select_idle_cpu(p, cpus, (i == 1), sd[i]->span_weight, target);
  6290			if ((unsigned)r < nr_cpumask_bits)
  6291				return r;
  6292	
  6293			r = select_idle_smt(p, target);
  6294			if ((unsigned)r < nr_cpumask_bits)
  6295				return r;
  6296		}
  6297	
  6298		return target;
  6299	}
  6300	

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

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