[peterz-queue:sched/core 13/19] kernel/sched/fair.c:892:34: warning: variable 'stats' set but not used

From: kernel test robot
Date: Fri Sep 10 2021 - 14:22:04 EST

tree: https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git sched/core
head: 2dfdb3d20ad50e2ae2cb84cbceb0f0fc75e79e5d
commit: 445d9e8ba05d5e9e4b26956b7fe529223e29d8d1 [13/19] sched: make struct sched_statistics independent of fair sched class
config: m68k-buildonly-randconfig-r002-20210910 (attached as .config)
compiler: m68k-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://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/commit/?id=445d9e8ba05d5e9e4b26956b7fe529223e29d8d1
git remote add peterz-queue https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git
git fetch --no-tags peterz-queue sched/core
git checkout 445d9e8ba05d5e9e4b26956b7fe529223e29d8d1
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=m68k

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

kernel/sched/fair.c: In function 'update_curr':
kernel/sched/fair.c:860:42: warning: unused variable 'stats' [-Wunused-variable]
860 | struct sched_statistics *stats = __schedstats_from_se(curr);
| ^~~~~
kernel/sched/fair.c: In function 'update_stats_wait_start':
>> kernel/sched/fair.c:892:34: warning: variable 'stats' set but not used [-Wunused-but-set-variable]
892 | struct sched_statistics *stats;
| ^~~~~
kernel/sched/fair.c: In function 'update_stats_wait_end':
kernel/sched/fair.c:912:34: warning: variable 'stats' set but not used [-Wunused-but-set-variable]
912 | struct sched_statistics *stats;
| ^~~~~
kernel/sched/fair.c: In function 'update_stats_enqueue_sleeper':
kernel/sched/fair.c:956:34: warning: variable 'stats' set but not used [-Wunused-but-set-variable]
956 | struct sched_statistics *stats;
| ^~~~~
kernel/sched/fair.c: In function 'set_next_entity':
kernel/sched/fair.c:4517:42: warning: unused variable 'stats' [-Wunused-variable]
4517 | struct sched_statistics *stats = __schedstats_from_se(se);
| ^~~~~
kernel/sched/fair.c: At top level:
kernel/sched/fair.c:5505:6: warning: no previous prototype for 'init_cfs_bandwidth' [-Wmissing-prototypes]
5505 | void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
| ^~~~~~~~~~~~~~~~~~
kernel/sched/fair.c:11661:6: warning: no previous prototype for 'free_fair_sched_group' [-Wmissing-prototypes]
11661 | void free_fair_sched_group(struct task_group *tg) { }
| ^~~~~~~~~~~~~~~~~~~~~
kernel/sched/fair.c:11663:5: warning: no previous prototype for 'alloc_fair_sched_group' [-Wmissing-prototypes]
11663 | int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
| ^~~~~~~~~~~~~~~~~~~~~~
kernel/sched/fair.c:11668:6: warning: no previous prototype for 'online_fair_sched_group' [-Wmissing-prototypes]
11668 | void online_fair_sched_group(struct task_group *tg) { }
| ^~~~~~~~~~~~~~~~~~~~~~~
kernel/sched/fair.c:11670:6: warning: no previous prototype for 'unregister_fair_sched_group' [-Wmissing-prototypes]
11670 | void unregister_fair_sched_group(struct task_group *tg) { }
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/stats +892 kernel/sched/fair.c

840
841 /*
842 * Update the current task's runtime statistics.
843 */
844 static void update_curr(struct cfs_rq *cfs_rq)
845 {
846 struct sched_entity *curr = cfs_rq->curr;
847 u64 now = rq_clock_task(rq_of(cfs_rq));
848 u64 delta_exec;
849
850 if (unlikely(!curr))
851 return;
852
853 delta_exec = now - curr->exec_start;
854 if (unlikely((s64)delta_exec <= 0))
855 return;
856
857 curr->exec_start = now;
858
859 if (schedstat_enabled()) {
> 860 struct sched_statistics *stats = __schedstats_from_se(curr);
861
862 __schedstat_set(stats->exec_max,
863 max(delta_exec, stats->exec_max));
864 }
865
866 curr->sum_exec_runtime += delta_exec;
867 schedstat_add(cfs_rq->exec_clock, delta_exec);
868
869 curr->vruntime += calc_delta_fair(delta_exec, curr);
870 update_min_vruntime(cfs_rq);
871
872 if (entity_is_task(curr)) {
873 struct task_struct *curtask = task_of(curr);
874
875 trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime);
876 cgroup_account_cputime(curtask, delta_exec);
877 account_group_exec_runtime(curtask, delta_exec);
878 }
879
880 account_cfs_rq_runtime(cfs_rq, delta_exec);
881 }
882
883 static void update_curr_fair(struct rq *rq)
884 {
885 update_curr(cfs_rq_of(&rq->curr->se));
886 }
887
888 static inline void
889 update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
890 {
891 u64 wait_start, prev_wait_start;
> 892 struct sched_statistics *stats;
893
894 if (!schedstat_enabled())
895 return;
896
897 stats = __schedstats_from_se(se);
898
899 wait_start = rq_clock(rq_of(cfs_rq));
900 prev_wait_start = schedstat_val(stats->wait_start);
901
902 if (entity_is_task(se) && task_on_rq_migrating(task_of(se)) &&
903 likely(wait_start > prev_wait_start))
904 wait_start -= prev_wait_start;
905
906 __schedstat_set(stats->wait_start, wait_start);
907 }
908

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