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

kernel test robot
2020-07-28T10:39:29Z

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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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