linux-kernel - Re: [PATCH] sched/deadline: Remove fair-servers from real-time task's bandwidth accounting

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Message-ID: <202507220727.BmA1Osdg-lkp@intel.com>
Date: Tue, 22 Jul 2025 08:07:25 +0800
From: kernel test robot <lkp@...el.com>
To: Yuri Andriaccio <yurand2000@...il.com>, Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Juri Lelli <juri.lelli@...hat.com>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Dietmar Eggemann <dietmar.eggemann@....com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
	Valentin Schneider <vschneid@...hat.com>
Cc: oe-kbuild-all@...ts.linux.dev, linux-kernel@...r.kernel.org,
	Luca Abeni <luca.abeni@...tannapisa.it>,
	Yuri Andriaccio <yuri.andriaccio@...tannapisa.it>
Subject: Re: [PATCH] sched/deadline: Remove fair-servers from real-time
 task's bandwidth accounting

Hi Yuri,

kernel test robot noticed the following build errors:

[auto build test ERROR on tip/sched/core]
[also build test ERROR on tip/master peterz-queue/sched/core next-20250721]
[cannot apply to tip/auto-latest linus/master v6.16-rc7]
[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/Yuri-Andriaccio/sched-deadline-Remove-fair-servers-from-real-time-task-s-bandwidth-accounting/20250721-191333
base:   tip/sched/core
patch link:    https://lore.kernel.org/r/20250721111131.309388-1-yurand2000%40gmail.com
patch subject: [PATCH] sched/deadline: Remove fair-servers from real-time task's bandwidth accounting
config: i386-buildonly-randconfig-001-20250722 (https://download.01.org/0day-ci/archive/20250722/202507220727.BmA1Osdg-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14+deb12u1) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250722/202507220727.BmA1Osdg-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@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202507220727.BmA1Osdg-lkp@intel.com/

All errors (new ones prefixed by >>):

   ld: kernel/sched/build_policy.o: in function `dl_server_apply_params':
>> kernel/sched/deadline.c:1693: undefined reference to `__udivdi3'


vim +1693 kernel/sched/deadline.c

  1677	
  1678	int dl_server_apply_params(struct sched_dl_entity *dl_se, u64 runtime, u64 period, bool init)
  1679	{
  1680		u64 max_bw, new_bw = to_ratio(period, runtime);
  1681		struct rq *rq = dl_se->rq;
  1682		int cpu = cpu_of(rq);
  1683		struct dl_bw *dl_b;
  1684		unsigned long cap;
  1685		int retval = 0;
  1686		int cpus;
  1687	
  1688		dl_b = dl_bw_of(cpu);
  1689		guard(raw_spinlock)(&dl_b->lock);
  1690	
  1691		cpus = dl_bw_cpus(cpu);
  1692		cap = dl_bw_capacity(cpu);
> 1693		max_bw = cap_scale(BW_UNIT - dl_b->bw, cap) / cpus;
  1694	
  1695		if (new_bw > max_bw)
  1696			return -EBUSY;
  1697	
  1698		if (init) {
  1699			__add_rq_bw(new_bw, &rq->dl);
  1700		} else {
  1701			dl_rq_change_utilization(rq, dl_se, new_bw);
  1702		}
  1703	
  1704		dl_se->dl_runtime = runtime;
  1705		dl_se->dl_deadline = period;
  1706		dl_se->dl_period = period;
  1707	
  1708		dl_se->runtime = 0;
  1709		dl_se->deadline = 0;
  1710	
  1711		dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime);
  1712		dl_se->dl_density = to_ratio(dl_se->dl_deadline, dl_se->dl_runtime);
  1713	
  1714		return retval;
  1715	}
  1716	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki