Hi Rik, Thank you for the patch! Yet something to improve: [auto build test ERROR on tip/sched/core] [also build test ERROR on linux/master linus/master v5.12-rc8 next-20210416] [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] url: https://github.com/0day-ci/linux/commits/Rik-van-Riel/sched-fair-skip-new... base: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 9406415f46f6127fd31bb66f0260f7a61a8d2786 config: riscv-randconfig-r025-20210419 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 2b50f5a4343f8fb06acaa5c36355bcf58092c9cd) 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 riscv cross compiling tool for clang build # apt-get install binutils-riscv64-linux-gnu # https://github.com/0day-ci/linux/commit/3f6b55f5258c8d8d217e8b8408de056a2... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Rik-van-Riel/sched-fair-skip-newidle_balance-if-a-wakeup-is-pending/20210419-101843 git checkout 3f6b55f5258c8d8d217e8b8408de056a20745824 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=riscv 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 >>): In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/riscv/include/asm/io.h:149: include/asm-generic/io.h:564:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] return inw(addr); ^~~~~~~~~ arch/riscv/include/asm/io.h:56:76: note: expanded from macro 'inw' #define inw(c) ({ u16 __v; __io_pbr(); __v = readw_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; }) ~~~~~~~~~~ ^ arch/riscv/include/asm/mmio.h:88:76: note: expanded from macro 'readw_cpu' #define readw_cpu(c) ({ u16 __r = le16_to_cpu((__force __le16)__raw_readw(c)); __r; }) ^ include/uapi/linux/byteorder/little_endian.h:36:51: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) ((__force __u16)(__le16)(x)) ^ In file included from kernel/sched/fair.c:23: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/riscv/include/asm/io.h:149: include/asm-generic/io.h:572:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] return inl(addr); ^~~~~~~~~ arch/riscv/include/asm/io.h:57:76: note: expanded from macro 'inl' #define inl(c) ({ u32 __v; __io_pbr(); __v = readl_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; }) ~~~~~~~~~~ ^ arch/riscv/include/asm/mmio.h:89:76: note: expanded from macro 'readl_cpu' #define readl_cpu(c) ({ u32 __r = le32_to_cpu((__force __le32)__raw_readl(c)); __r; }) ^ include/uapi/linux/byteorder/little_endian.h:34:51: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) ((__force __u32)(__le32)(x)) ^ In file included from kernel/sched/fair.c:23: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/riscv/include/asm/io.h:149: include/asm-generic/io.h:580:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] outb(value, addr); ^~~~~~~~~~~~~~~~~ arch/riscv/include/asm/io.h:59:68: note: expanded from macro 'outb' #define outb(v,c) ({ __io_pbw(); writeb_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); }) ~~~~~~~~~~ ^ arch/riscv/include/asm/mmio.h:91:52: note: expanded from macro 'writeb_cpu' #define writeb_cpu(v, c) ((void)__raw_writeb((v), (c))) ^ In file included from kernel/sched/fair.c:23: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/riscv/include/asm/io.h:149: include/asm-generic/io.h:588:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] outw(value, addr); ^~~~~~~~~~~~~~~~~ arch/riscv/include/asm/io.h:60:68: note: expanded from macro 'outw' #define outw(v,c) ({ __io_pbw(); writew_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); }) ~~~~~~~~~~ ^ arch/riscv/include/asm/mmio.h:92:76: note: expanded from macro 'writew_cpu' #define writew_cpu(v, c) ((void)__raw_writew((__force u16)cpu_to_le16(v), (c))) ^ In file included from kernel/sched/fair.c:23: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/riscv/include/asm/io.h:149: include/asm-generic/io.h:596:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] outl(value, addr); ^~~~~~~~~~~~~~~~~ arch/riscv/include/asm/io.h:61:68: note: expanded from macro 'outl' #define outl(v,c) ({ __io_pbw(); writel_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); }) ~~~~~~~~~~ ^ arch/riscv/include/asm/mmio.h:93:76: note: expanded from macro 'writel_cpu' #define writel_cpu(v, c) ((void)__raw_writel((__force u32)cpu_to_le32(v), (c))) ^ In file included from kernel/sched/fair.c:23: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/riscv/include/asm/io.h:149: include/asm-generic/io.h:1005:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port; ~~~~~~~~~~ ^ kernel/sched/fair.c:637:5: warning: no previous prototype for function 'sched_update_scaling' [-Wmissing-prototypes] int sched_update_scaling(void) ^ kernel/sched/fair.c:637:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int sched_update_scaling(void) ^ static if (rq->ttwu_pending) ~~ ^ 8 warnings and 1 error generated. vim +7208 kernel/sched/fair.c 7191 7192 if (hrtick_enabled_fair(rq)) 7193 hrtick_start_fair(rq, p); 7194 7195 update_misfit_status(p, rq); 7196 7197 return p; 7198 7199 idle: 7200 if (!rf) 7201 return NULL; 7202 7203 /* 7204 * We have a woken up task pending here. No need to search for ones 7205 * elsewhere. This task will be enqueued the moment we unblock irqs 7206 * upon exiting the scheduler. 7207 */ 7209 return NULL; 7210 7211 new_tasks = newidle_balance(rq, rf); 7212 7213 /* 7214 * Because newidle_balance() releases (and re-acquires) rq->lock, it is 7215 * possible for any higher priority task to appear. In that case we 7216 * must re-start the pick_next_entity() loop. 7217 */ 7218 if (new_tasks < 0) 7219 return RETRY_TASK; 7220 7221 if (new_tasks > 0) 7222 goto again; 7223 7224 /* 7225 * rq is about to be idle, check if we need to update the 7226 * lost_idle_time of clock_pelt 7227 */ 7228 update_idle_rq_clock_pelt(rq); 7229 7230 return NULL; 7231 } 7232 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org