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Date: Wed, 11 May 2022 00:37:23 +0800
From: kernel test robot <lkp@...el.com>
To: Chen Yu <yu.c.chen@...el.com>
Cc: llvm@...ts.linux.dev, kbuild-all@...ts.01.org,
Chen Yu <yu.c.chen@...el.com>, linux-kernel@...r.kernel.org
Subject: [yu-chen-surf:sis 1/1] kernel/sched/fair.c:9317:12: warning:
comparison of distinct pointer types ('typeof (0) *' (aka 'int *') and
'typeof ((nr_llc * y) / (1L << 10)) *' (aka 'long *'))
tree: https://github.com/yu-chen-surf/linux.git sis
head: e99eab1b5fbda9474ad4fe9074983f2d2169923b
commit: e99eab1b5fbda9474ad4fe9074983f2d2169923b [1/1] sched/fair: Introduce SIS_UTIL to search idle CPU based on sum of util_avg
config: arm-milbeaut_m10v_defconfig (https://download.01.org/0day-ci/archive/20220511/202205110033.NNmqSG7c-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 18dd123c56754edf62c7042dcf23185c3727610f)
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
# install arm cross compiling tool for clang build
# apt-get install binutils-arm-linux-gnueabi
# https://github.com/yu-chen-surf/linux/commit/e99eab1b5fbda9474ad4fe9074983f2d2169923b
git remote add yu-chen-surf https://github.com/yu-chen-surf/linux.git
git fetch --no-tags yu-chen-surf sis
git checkout e99eab1b5fbda9474ad4fe9074983f2d2169923b
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash kernel/sched/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@...el.com>
All warnings (new ones prefixed by >>):
kernel/sched/fair.c:5530:6: warning: no previous prototype for function 'init_cfs_bandwidth' [-Wmissing-prototypes]
void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
^
kernel/sched/fair.c:5530:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
^
static
>> kernel/sched/fair.c:9317:12: warning: comparison of distinct pointer types ('typeof (0) *' (aka 'int *') and 'typeof ((nr_llc * y) / (1L << 10)) *' (aka 'long *')) [-Wcompare-distinct-pointer-types]
nr_scan = max(0, (nr_llc * y) / SCHED_CAPACITY_SCALE);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/minmax.h:52:19: note: expanded from macro 'max'
#define max(x, y) __careful_cmp(x, y, >)
^~~~~~~~~~~~~~~~~~~~~~
include/linux/minmax.h:36:24: note: expanded from macro '__careful_cmp'
__builtin_choose_expr(__safe_cmp(x, y), \
^~~~~~~~~~~~~~~~
include/linux/minmax.h:26:4: note: expanded from macro '__safe_cmp'
(__typecheck(x, y) && __no_side_effects(x, y))
^~~~~~~~~~~~~~~~~
include/linux/minmax.h:20:28: note: expanded from macro '__typecheck'
(!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~
kernel/sched/fair.c:10704:6: warning: no previous prototype for function 'nohz_balance_enter_idle' [-Wmissing-prototypes]
void nohz_balance_enter_idle(int cpu)
^
kernel/sched/fair.c:10704:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void nohz_balance_enter_idle(int cpu)
^
static
kernel/sched/fair.c:11826:6: warning: no previous prototype for function 'free_fair_sched_group' [-Wmissing-prototypes]
void free_fair_sched_group(struct task_group *tg) { }
^
kernel/sched/fair.c:11826:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void free_fair_sched_group(struct task_group *tg) { }
^
static
kernel/sched/fair.c:11828:5: warning: no previous prototype for function 'alloc_fair_sched_group' [-Wmissing-prototypes]
int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
^
kernel/sched/fair.c:11828:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
^
static
kernel/sched/fair.c:11833:6: warning: no previous prototype for function 'online_fair_sched_group' [-Wmissing-prototypes]
void online_fair_sched_group(struct task_group *tg) { }
^
kernel/sched/fair.c:11833:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void online_fair_sched_group(struct task_group *tg) { }
^
static
kernel/sched/fair.c:11835:6: warning: no previous prototype for function 'unregister_fair_sched_group' [-Wmissing-prototypes]
void unregister_fair_sched_group(struct task_group *tg) { }
^
kernel/sched/fair.c:11835:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void unregister_fair_sched_group(struct task_group *tg) { }
^
static
kernel/sched/fair.c:507:20: warning: unused function 'list_del_leaf_cfs_rq' [-Wunused-function]
static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)
^
kernel/sched/fair.c:528:19: warning: unused function 'tg_is_idle' [-Wunused-function]
static inline int tg_is_idle(struct task_group *tg)
^
kernel/sched/fair.c:5511:20: warning: unused function 'sync_throttle' [-Wunused-function]
static inline void sync_throttle(struct task_group *tg, int cpu) {}
^
kernel/sched/fair.c:5536:37: warning: unused function 'tg_cfs_bandwidth' [-Wunused-function]
static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
^
kernel/sched/fair.c:5540:20: warning: unused function 'destroy_cfs_bandwidth' [-Wunused-function]
static inline void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
^
12 warnings generated.
vim +9317 kernel/sched/fair.c
9267
9268 static inline void update_idle_cpu_scan(struct lb_env *env,
9269 unsigned long sum_util)
9270 {
9271 struct sched_domain_shared *sd_share;
9272 int nr_scan, nr_llc, x, y;
9273
9274 if (!sched_feat(SIS_UTIL))
9275 return;
9276 /*
9277 * Update the number of CPUs to scan in LLC domain, which could
9278 * be used as a hint in select_idle_cpu(). The update of this hint
9279 * occurs during periodic load balancing, rather than frequent
9280 * newidle balance.
9281 */
9282 nr_llc = per_cpu(sd_llc_size, env->dst_cpu);
9283 if (env->idle == CPU_NEWLY_IDLE ||
9284 env->sd->span_weight != nr_llc)
9285 return;
9286
9287 sd_share = rcu_dereference(per_cpu(sd_llc_shared, env->dst_cpu));
9288 if (!sd_share)
9289 return;
9290
9291 /*
9292 * The number of CPUs to search drops as sum_util increases, when
9293 * sum_util hits 85% or above, the scan stops.
9294 * The reason to choose 85% as the threshold is because this is the
9295 * imbalance_pct(117) when a LLC sched group is overloaded.
9296 *
9297 * let y = 1 - (x/0.85)^2 [1]
9298 *
9299 * y is the ratio of CPUs to be scanned in the LLC
9300 * domain, x is the ratio of sum_util compared to the
9301 * CPU capacity:
9302 *
9303 * x = sum_util / (nr_llc * SCHED_CAPACITY_SCALE) [2]
9304 *
9305 * Scale x by SCHED_CAPACITY_SCALE and [2] becomes:
9306 *
9307 * x = sum_util / nr_llc [3]
9308 *
9309 * and [1] becomes:
9310 *
9311 * y = (SCHED_CAPACITY_SCALE - (x*x)/740) / SCHED_CAPACITY_SCALE [4]
9312 *
9313 * then the number of CPUs to scan is nr_scan = nr_llc * y
9314 */
9315 x = sum_util / nr_llc;
9316 y = SCHED_CAPACITY_SCALE - (x * x) / 740;
> 9317 nr_scan = max(0, (nr_llc * y) / SCHED_CAPACITY_SCALE);
9318 WRITE_ONCE(sd_share->nr_idle_scan, nr_scan);
9319 }
9320
--
0-DAY CI Kernel Test Service
https://01.org/lkp
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