Re: [PATCH v2 2/2] sched: Add a check for cpu unbound deferrable timers

[kbuild test robot]

Hi Prasad,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on tip/timers/core]
[also build test WARNING on tip/auto-latest tip/timers/nohz v5.7-rc3 next-20200428]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Prasad-Sodagudi/timer-make-deferrable-cpu-unbound-timers-really-not-bound-to-a-cpu/20200429-060558
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 4479730e9263befbb9ce9563a09563db2acb8f7c
config: nds32-defconfig (attached as .config)
compiler: nds32le-linux-gcc (GCC) 9.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day GCC_VERSION=9.3.0 make.cross ARCH=nds32 

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

All warnings (new ones prefixed by >>):

   In file included from ./arch/nds32/include/generated/asm/cmpxchg.h:1,
                    from include/asm-generic/atomic.h:12,
                    from ./arch/nds32/include/generated/asm/atomic.h:1,
                    from include/linux/atomic.h:7,
                    from include/asm-generic/bitops/lock.h:5,
                    from include/asm-generic/bitops.h:31,
                    from ./arch/nds32/include/generated/asm/bitops.h:1,
                    from include/linux/bitops.h:29,
                    from include/linux/kernel.h:12,
                    from include/linux/list.h:9,
                    from include/linux/smp.h:12,
                    from include/linux/kernel_stat.h:5,
                    from kernel/time/timer.c:21:
   kernel/time/timer.c: In function 'run_timer_softirq':
   kernel/time/timer.c:1828:24: error: 'deferrable_pending' undeclared (first use in this function)
    1828 |   if ((atomic_cmpxchg(&deferrable_pending, 1, 0) &&
         |                        ^~~~~~~~~~~~~~~~~~
   include/asm-generic/cmpxchg.h:97:17: note: in definition of macro 'cmpxchg_local'
      97 |  ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
         |                 ^~~
>> include/asm-generic/atomic.h:196:38: note: in expansion of macro 'cmpxchg'
     196 | #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
         |                                      ^~~~~~~
>> kernel/time/timer.c:1828:8: note: in expansion of macro 'atomic_cmpxchg'
    1828 |   if ((atomic_cmpxchg(&deferrable_pending, 1, 0) &&
         |        ^~~~~~~~~~~~~~
   kernel/time/timer.c:1828:24: note: each undeclared identifier is reported only once for each function it appears in
    1828 |   if ((atomic_cmpxchg(&deferrable_pending, 1, 0) &&
         |                        ^~~~~~~~~~~~~~~~~~
   include/asm-generic/cmpxchg.h:97:17: note: in definition of macro 'cmpxchg_local'
      97 |  ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
         |                 ^~~
>> include/asm-generic/atomic.h:196:38: note: in expansion of macro 'cmpxchg'
     196 | #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
         |                                      ^~~~~~~
>> kernel/time/timer.c:1828:8: note: in expansion of macro 'atomic_cmpxchg'
    1828 |   if ((atomic_cmpxchg(&deferrable_pending, 1, 0) &&
         |        ^~~~~~~~~~~~~~
   kernel/time/timer.c:1831:18: error: 'timer_base_deferrable' undeclared (first use in this function)
    1831 |    __run_timers(&timer_base_deferrable);
         |                  ^~~~~~~~~~~~~~~~~~~~~
   kernel/time/timer.c: In function 'init_timer_deferrable_global':
   kernel/time/timer.c:2073:2: error: 'timer_base_deferrable' undeclared (first use in this function)
    2073 |  timer_base_deferrable.cpu = nr_cpu_ids;
         |  ^~~~~~~~~~~~~~~~~~~~~

vim +/atomic_cmpxchg +1828 kernel/time/timer.c

  1817	
  1818	/*
  1819	 * This function runs timers and the timer-tq in bottom half context.
  1820	 */
  1821	static __latent_entropy void run_timer_softirq(struct softirq_action *h)
  1822	{
  1823		struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
  1824	
  1825		__run_timers(base);
  1826		if (IS_ENABLED(CONFIG_NO_HZ_COMMON)) {
  1827			__run_timers(this_cpu_ptr(&timer_bases[BASE_DEF]));
> 1828			if ((atomic_cmpxchg(&deferrable_pending, 1, 0) &&
  1829					tick_do_timer_cpu == TICK_DO_TIMER_NONE) ||
  1830					tick_do_timer_cpu == smp_processor_id())
  1831				__run_timers(&timer_base_deferrable);
  1832		}
  1833	}
  1834	

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0-DAY CI Kernel Test Service, Intel Corporation
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