Re: [PATCH] sched/core: forced idle accounting

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

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Hi Josh,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on tip/sched/core]
[also build test ERROR on tip/master next-20211011]
[cannot apply to linux/master linus/master v5.15-rc5]
[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/Josh-Don/sched-core-forced-idle-accounting/20211008-095615
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 769fdf83df57b373660343ef4270b3ada91ef434
config: i386-randconfig-a004-20210930 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/b2e2ae116ab03285ca899a48b9d23cbedab5ad0a
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Josh-Don/sched-core-forced-idle-accounting/20211008-095615
        git checkout b2e2ae116ab03285ca899a48b9d23cbedab5ad0a
        # save the attached .config to linux build tree
        mkdir build_dir
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash

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

All errors (new ones prefixed by >>):

   ld: kernel/sched/core_sched.o: in function `sched_core_account_forceidle':
>> kernel/sched/core_sched.c:282: undefined reference to `__udivdi3'


vim +282 kernel/sched/core_sched.c

   235	
   236	/* REQUIRES: rq->core's clock recently updated. */
   237	void sched_core_account_forceidle(struct rq *rq)
   238	{
   239		const struct cpumask *smt_mask = cpu_smt_mask(cpu_of(rq));
   240		unsigned int smt_count;
   241		u64 delta, now = rq_clock(rq->core);
   242		struct rq *rq_i;
   243		struct task_struct *p;
   244		int i;
   245	
   246		lockdep_assert_rq_held(rq);
   247	
   248		WARN_ON_ONCE(!rq->core->core_forceidle);
   249	
   250		if (rq->core->core_forceidle_start == 0)
   251			return;
   252	
   253		delta = now - rq->core->core_forceidle_start;
   254		if (unlikely((s64)delta <= 0))
   255			return;
   256	
   257		rq->core->core_forceidle_start = now;
   258	
   259		/*
   260		 * For larger SMT configurations, we need to scale the charged
   261		 * forced idle amount since there can be more than one forced idle
   262		 * sibling and more than one running cookied task.
   263		 */
   264		smt_count = cpumask_weight(smt_mask);
   265		if (smt_count > 2) {
   266			unsigned int nr_forced_idle = 0, nr_running = 0;
   267	
   268			for_each_cpu(i, smt_mask) {
   269				rq_i = cpu_rq(i);
   270				p = rq_i->core_pick ?: rq_i->curr;
   271	
   272				if (p != rq_i->idle)
   273					nr_running++;
   274				else if (rq_i->nr_running)
   275					nr_forced_idle++;
   276			}
   277	
   278			if (WARN_ON_ONCE(!nr_running)) {
   279				/* can't be forced idle without a running task */
   280			} else {
   281				delta *= nr_forced_idle;
 > 282				delta /= nr_running;
   283			}
   284		}
   285	
   286		for_each_cpu(i, smt_mask) {
   287			rq_i = cpu_rq(i);
   288			p = rq_i->core_pick ?: rq_i->curr;
   289	
   290			if (!p->core_cookie)
   291				continue;
   292	
   293			p->core_forceidle_sum += delta;
   294	
   295			/* Optimize for common case. */
   296			if (smt_count == 2)
   297				break;
   298		}
   299	}
   300	

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

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