Re: [PATCH v5 15/19] sched: Add proxy deactivate helper

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

Hi John,

kernel test robot noticed the following build warnings:

[auto build test WARNING on tip/locking/core]
[also build test WARNING on linus/master tip/auto-latest v6.5-rc7]
[cannot apply to tip/sched/core tip/master next-20230824]
[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/John-Stultz/sched-Unify-runtime-accounting-across-classes/20230821-121604
base:   tip/locking/core
patch link:    https://lore.kernel.org/r/20230819060915.3001568-16-jstultz%40google.com
patch subject: [PATCH v5 15/19] sched: Add proxy deactivate helper
config: loongarch-allmodconfig (https://download.01.org/0day-ci/archive/20230824/202308241905.goxohVDL-lkp@intel.com/config)
compiler: loongarch64-linux-gcc (GCC) 13.2.0
reproduce: (https://download.01.org/0day-ci/archive/20230824/202308241905.goxohVDL-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/202308241905.goxohVDL-lkp@intel.com/

All warnings (new ones prefixed by >>):

   kernel/sched/core.c:6565:6: warning: no previous prototype for 'try_to_deactivate_task' [-Wmissing-prototypes]
    6565 | bool try_to_deactivate_task(struct rq *rq, struct task_struct *p,
         |      ^~~~~~~~~~~~~~~~~~~~~~
>> kernel/sched/core.c:6603:6: warning: no previous prototype for 'proxy_deactivate' [-Wmissing-prototypes]
    6603 | bool proxy_deactivate(struct rq *rq, struct task_struct *next)
         |      ^~~~~~~~~~~~~~~~


vim +/proxy_deactivate +6603 kernel/sched/core.c

  6564	
> 6565	bool try_to_deactivate_task(struct rq *rq, struct task_struct *p,
  6566				    unsigned long state, bool deactivate_cond)
  6567	{
  6568		if (signal_pending_state(state, p)) {
  6569			WRITE_ONCE(p->__state, TASK_RUNNING);
  6570		} else if (deactivate_cond) {
  6571			p->sched_contributes_to_load =
  6572				(state & TASK_UNINTERRUPTIBLE) &&
  6573				!(state & TASK_NOLOAD) &&
  6574				!(state & TASK_FROZEN);
  6575	
  6576			if (p->sched_contributes_to_load)
  6577				rq->nr_uninterruptible++;
  6578	
  6579			/*
  6580			 * __schedule()			ttwu()
  6581			 *   prev_state = prev->state;    if (p->on_rq && ...)
  6582			 *   if (prev_state)		    goto out;
  6583			 *     p->on_rq = 0;		  smp_acquire__after_ctrl_dep();
  6584			 *				  p->state = TASK_WAKING
  6585			 *
  6586			 * Where __schedule() and ttwu() have matching control dependencies.
  6587			 *
  6588			 * After this, schedule() must not care about p->state any more.
  6589			 */
  6590			deactivate_task(rq, p, DEQUEUE_SLEEP | DEQUEUE_NOCLOCK);
  6591	
  6592			if (p->in_iowait) {
  6593				atomic_inc(&rq->nr_iowait);
  6594				delayacct_blkio_start();
  6595			}
  6596			return true;
  6597		}
  6598		return false;
  6599	}
  6600	
  6601	#ifdef CONFIG_PROXY_EXEC
  6602	
> 6603	bool proxy_deactivate(struct rq *rq, struct task_struct *next)
  6604	{
  6605		unsigned long state = READ_ONCE(next->__state);
  6606	
  6607		/* Don't deactivate if the state has been changed to TASK_RUNNING */
  6608		if (!state)
  6609			return false;
  6610		if (!try_to_deactivate_task(rq, next, state, true))
  6611			return false;
  6612		put_prev_task(rq, next);
  6613		rq_set_selected(rq, rq->idle);
  6614		resched_curr(rq);
  6615		return true;
  6616	}
  6617	

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