Re: [PATCH v4 1/1] sched/uclamp: add SCHED_FLAG_UTIL_CLAMP_RESET flag to reset uclamp

[kernel test robot <lkp@intel.com>]

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Hi Yun,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on tip/sched/core]
[also build test WARNING on v5.10-rc2 next-20201102]
[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/Yun-Hsiang/sched-uclamp-add-SCHED_FLAG_UTIL_CLAMP_RESET-flag-to-reset-uclamp/20201101-164635
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git d8fcb81f1acf651a0e50eacecca43d0524984f87
config: x86_64-allyesconfig (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/b705c245791a37b85013c6604ee1301022312dc5
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Yun-Hsiang/sched-uclamp-add-SCHED_FLAG_UTIL_CLAMP_RESET-flag-to-reset-uclamp/20201101-164635
        git checkout b705c245791a37b85013c6604ee1301022312dc5
        # save the attached .config to linux build tree
        make W=1 ARCH=x86_64 

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

All warnings (new ones prefixed by >>):

   kernel/sched/core.c: In function '__setscheduler_uclamp':
>> kernel/sched/core.c:1471:15: warning: variable 'clamp_value' set but not used [-Wunused-but-set-variable]
    1471 |  unsigned int clamp_value;
         |               ^~~~~~~~~~~
   kernel/sched/core.c: At top level:
   kernel/sched/core.c:2405:6: warning: no previous prototype for 'sched_set_stop_task' [-Wmissing-prototypes]
    2405 | void sched_set_stop_task(int cpu, struct task_struct *stop)
         |      ^~~~~~~~~~~~~~~~~~~

vim +/clamp_value +1471 kernel/sched/core.c

  1467	
  1468	static void __setscheduler_uclamp(struct task_struct *p,
  1469					  const struct sched_attr *attr)
  1470	{
> 1471		unsigned int clamp_value;
  1472		enum uclamp_id clamp_id;
  1473	
  1474		/*
  1475		 * Reset to default clamps on forced _UCLAMP_RESET (always) and
  1476		 * for tasks without a task-specific value (on scheduling class change).
  1477		 */
  1478		for_each_clamp_id(clamp_id) {
  1479			struct uclamp_se *uc_se = &p->uclamp_req[clamp_id];
  1480	
  1481			/* Keep using defined clamps across class changes */
  1482			if (!uclamp_reset(clamp_id, attr->sched_flags) &&
  1483					uc_se->user_defined)
  1484				continue;
  1485	
  1486			/*
  1487			 * RT by default have a 100% boost value that could be modified
  1488			 * at runtime.
  1489			 */
  1490			if (unlikely(rt_task(p) && clamp_id == UCLAMP_MIN))
  1491				clamp_value = sysctl_sched_uclamp_util_min_rt_default;
  1492			else
  1493				clamp_value = uclamp_none(clamp_id);
  1494	
  1495			uclamp_se_set(uc_se, uclamp_none(clamp_id), false);
  1496		}
  1497	
  1498		if (likely(!(attr->sched_flags && SCHED_FLAG_UTIL_CLAMP)) ||
  1499			attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_RESET)
  1500			return;
  1501	
  1502		if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN)
  1503			uclamp_se_set(&p->uclamp_req[UCLAMP_MIN],
  1504					attr->sched_util_min, true);
  1505	
  1506		if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MAX)
  1507			uclamp_se_set(&p->uclamp_req[UCLAMP_MAX],
  1508					attr->sched_util_max, true);
  1509	}
  1510	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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