Re: [RFC PATCH v5 8/9] sched/fair: Steal work from an overloaded CPU when CPU goes idle

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

Hi Chen,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on v7.0-rc4]
[cannot apply to tip/sched/core peterz-queue/sched/core next-20260320]
[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/Chen-Jinghuang/sched-Provide-sparsemask-a-reduced-contention-bitmap/20260321-084706
base:   linus/master
patch link:    https://lore.kernel.org/r/20260320055920.2518389-9-chenjinghuang2%40huawei.com
patch subject: [RFC PATCH v5 8/9] sched/fair: Steal work from an overloaded CPU when CPU goes idle
config: nios2-allnoconfig (https://download.01.org/0day-ci/archive/20260322/202603222032.E2CS3R19-lkp@intel.com/config)
compiler: nios2-linux-gcc (GCC) 11.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260322/202603222032.E2CS3R19-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/202603222032.E2CS3R19-lkp@intel.com/

All error/warnings (new ones prefixed by >>):

>> kernel/sched/fair.c:13310:12: error: redefinition of 'try_steal'
   13310 | static int try_steal(struct rq *dst_rq, struct rq_flags *dst_rf)
         |            ^~~~~~~~~
   kernel/sched/fair.c:5195:19: note: previous definition of 'try_steal' with type 'int(struct rq *, struct rq_flags *)'
    5195 | static inline int try_steal(struct rq *this_rq, struct rq_flags *rf)
         |                   ^~~~~~~~~
>> kernel/sched/fair.c:13310:12: warning: 'try_steal' defined but not used [-Wunused-function]
   13310 | static int try_steal(struct rq *dst_rq, struct rq_flags *dst_rf)
         |            ^~~~~~~~~


vim +/try_steal +13310 kernel/sched/fair.c

 13303	
 13304	/*
 13305	 * Try to steal a runnable CFS task from a CPU in the same LLC as @dst_rq,
 13306	 * and migrate it to @dst_rq.  rq_lock is held on entry and return, but
 13307	 * may be dropped in between.  Return 1 on success, 0 on failure, and -1
 13308	 * if a task in a different scheduling class has become runnable on @dst_rq.
 13309	 */
 13310	static int try_steal(struct rq *dst_rq, struct rq_flags *dst_rf)
 13311	{
 13312		int src_cpu;
 13313		int dst_cpu = dst_rq->cpu;
 13314		bool locked = true;
 13315		int stolen = 0;
 13316		struct sparsemask *overload_cpus;
 13317	
 13318		if (!sched_feat(STEAL))
 13319			return 0;
 13320	
 13321		if (!cpu_active(dst_cpu))
 13322			return 0;
 13323	
 13324		if (dst_rq->avg_idle < SCHED_STEAL_COST)
 13325			return 0;
 13326	
 13327		/* Get bitmap of overloaded CPUs in the same LLC as @dst_rq */
 13328	
 13329		rcu_read_lock();
 13330		overload_cpus = rcu_dereference(dst_rq->cfs_overload_cpus);
 13331		if (!overload_cpus) {
 13332			rcu_read_unlock();
 13333			return 0;
 13334		}
 13335	

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