Re: [PATCH 3/3] workqueue: Add workqueue_bh_budget_yield tracepoint

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

Hi Aaron,

kernel test robot noticed the following build errors:

[auto build test ERROR on tj-wq/for-next]
[also build test ERROR on linus/master v7.3-rc1 next-20260831]
[cannot apply to trace/for-next]
[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/Aaron-Tomlin/workqueue-Add-workqueue_cpu_intensive-tracepoint/20260829-190515
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git for-next
patch link:    https://lore.kernel.org/r/20260829230517.42468-4-atomlin%40atomlin.com
patch subject: [PATCH 3/3] workqueue: Add workqueue_bh_budget_yield tracepoint
config: i386-allnoconfig-bpf (https://download.01.org/0day-ci/archive/20260831/202608311949.TSPVREg4-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260831/202608311949.TSPVREg4-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/202608311949.TSPVREg4-lkp@intel.com/

All errors (new ones prefixed by >>):

   ld: kernel/workqueue.o: in function `wq_worker_tick':
>> kernel/workqueue.c:1561:(.text+0xa0b6): undefined reference to `__udivdi3'


vim +1561 kernel/workqueue.c

  1522	
  1523	/**
  1524	 * wq_worker_tick - a scheduler tick occurred while a kworker is running
  1525	 * @task: task currently running
  1526	 *
  1527	 * Called from sched_tick(). We're in the IRQ context and the current
  1528	 * worker's fields which follow the 'K' locking rule can be accessed safely.
  1529	 */
  1530	void wq_worker_tick(struct task_struct *task)
  1531	{
  1532		struct worker *worker = kthread_data(task);
  1533		struct pool_workqueue *pwq = worker->current_pwq;
  1534		struct worker_pool *pool = worker->pool;
  1535		u64 dur;
  1536	
  1537		if (!pwq)
  1538			return;
  1539	
  1540		/*
  1541		 * @pwq is shared across CPUs for unbound wqs and this advisory stat is
  1542		 * bumped outside pool->lock, so the update is intentionally racy.
  1543		 */
  1544		data_race(pwq->stats[PWQ_STAT_CPU_TIME] += TICK_USEC);
  1545	
  1546		if (!wq_cpu_intensive_thresh_us)
  1547			return;
  1548	
  1549		/*
  1550		 * If the current worker is concurrency managed and hogged the CPU for
  1551		 * longer than wq_cpu_intensive_thresh_us, it's automatically marked
  1552		 * CPU_INTENSIVE to avoid stalling other concurrency-managed work items.
  1553		 *
  1554		 * Set @worker->sleeping means that @worker is in the process of
  1555		 * switching out voluntarily and won't be contributing to
  1556		 * @pool->nr_running until it wakes up. As wq_worker_sleeping() also
  1557		 * decrements ->nr_running, setting CPU_INTENSIVE here can lead to
  1558		 * double decrements. The task is releasing the CPU anyway. Let's skip.
  1559		 * We probably want to make this prettier in the future.
  1560		 */
> 1561		dur = (READ_ONCE(worker->task->se.sum_exec_runtime) - worker->current_at) /
  1562		      NSEC_PER_USEC;
  1563		if ((worker->flags & WORKER_NOT_RUNNING) || READ_ONCE(worker->sleeping) ||
  1564		    dur < wq_cpu_intensive_thresh_us)
  1565			return;
  1566	
  1567		raw_spin_lock(&pool->lock);
  1568	
  1569		worker_set_flags(worker, WORKER_CPU_INTENSIVE);
  1570		wq_cpu_intensive_report(worker->current_func);
  1571		pwq->stats[PWQ_STAT_CPU_INTENSIVE]++;
  1572	
  1573		if (kick_pool(pool))
  1574			pwq->stats[PWQ_STAT_CM_WAKEUP]++;
  1575	
  1576		raw_spin_unlock(&pool->lock);
  1577	
  1578		trace_workqueue_cpu_intensive(pwq, worker->current_work,
  1579					      worker->current_func, dur);
  1580	}
  1581	

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