tree: https://github.com/rgushchin/linux.git bpfsched.rfc head: f4c466accae6c27a4fbece80f8cec431f685a20c commit: b70be3f6434db637797b13c3680a698ab96a5df3 [5/7] sched: cfs: add bpf hooks to control wakeup and tick preemption config: s390-randconfig-r033-20210915 (attached as .config) compiler: s390-linux-gcc (GCC) 11.2.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/rgushchin/linux/commit/b70be3f6434db637797b13c3680a698... git remote add rgushchin https://github.com/rgushchin/linux.git git fetch --no-tags rgushchin bpfsched.rfc git checkout b70be3f6434db637797b13c3680a698ab96a5df3 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=s390 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): kernel/sched/fair.c: In function 'check_preempt_tick': 4453 | int ret = bpf_sched_cfs_check_preempt_tick(curr, delta_exec); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/sched/fair.c: At top level: kernel/sched/fair.c:5493:6: warning: no previous prototype for 'init_cfs_bandwidth' [-Wmissing-prototypes] 5493 | void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {} | ^~~~~~~~~~~~~~~~~~ kernel/sched/fair.c: In function 'wakeup_preempt_entity': 7098 | int ret = bpf_sched_cfs_wakeup_preempt_entity(curr, se); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/sched/fair.c: In function 'check_preempt_wakeup': 7190 | int ret = bpf_sched_cfs_check_preempt_wakeup(current, p); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/sched/fair.c: At top level: kernel/sched/fair.c:11631:6: warning: no previous prototype for 'free_fair_sched_group' [-Wmissing-prototypes] 11631 | void free_fair_sched_group(struct task_group *tg) { } | ^~~~~~~~~~~~~~~~~~~~~ kernel/sched/fair.c:11633:5: warning: no previous prototype for 'alloc_fair_sched_group' [-Wmissing-prototypes] 11633 | int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) | ^~~~~~~~~~~~~~~~~~~~~~ kernel/sched/fair.c:11638:6: warning: no previous prototype for 'online_fair_sched_group' [-Wmissing-prototypes] 11638 | void online_fair_sched_group(struct task_group *tg) { } | ^~~~~~~~~~~~~~~~~~~~~~~ kernel/sched/fair.c:11640:6: warning: no previous prototype for 'unregister_fair_sched_group' [-Wmissing-prototypes] 11640 | void unregister_fair_sched_group(struct task_group *tg) { } | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ cc1: some warnings being treated as errors vim +/bpf_sched_cfs_check_preempt_tick +4453 kernel/sched/fair.c 4438 4439 /* 4440 * Preempt the current task with a newly woken task if needed: 4441 */ 4442 static void 4443 check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) 4444 { 4445 unsigned long ideal_runtime, delta_exec; 4446 struct sched_entity *se; 4447 s64 delta; 4448 4449 ideal_runtime = sched_slice(cfs_rq, curr); 4450 delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; 4451 4452 if (bpf_sched_enabled()) { 4454 4455 if (ret < 0) 4456 return; 4457 else if (ret > 0) 4458 resched_curr(rq_of(cfs_rq)); 4459 } 4460 4461 if (delta_exec > ideal_runtime) { 4462 resched_curr(rq_of(cfs_rq)); 4463 /* 4464 * The current task ran long enough, ensure it doesn't get 4465 * re-elected due to buddy favours. 4466 */ 4467 clear_buddies(cfs_rq, curr); 4468 return; 4469 } 4470 4471 /* 4472 * Ensure that a task that missed wakeup preemption by a 4473 * narrow margin doesn't have to wait for a full slice. 4474 * This also mitigates buddy induced latencies under load. 4475 */ 4476 if (delta_exec < sysctl_sched_min_granularity) 4477 return; 4478 4479 se = __pick_first_entity(cfs_rq); 4480 delta = curr->vruntime - se->vruntime; 4481 4482 if (delta < 0) 4483 return; 4484 4485 if (delta > ideal_runtime) 4486 resched_curr(rq_of(cfs_rq)); 4487 } 4488 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org