On 2022/8/17 3:55, kernel test robot wrote: > Hi Zhen, > > Thank you for the patch! Perhaps something to improve: > > [auto build test WARNING on paulmck-rcu/dev] > [also build test WARNING on linus/master v6.0-rc1 next-20220816] > [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#_base_tree_information] > > url: https://github.com/intel-lab-lkp/linux/commits/Zhen-Lei/rcu-nocb-Delete-local-variable-need_rcu_nocb_mask-in-rcu_init_nohz/20220816-205131 > base: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev > config: x86_64-randconfig-a004-20220815 (https://download.01.org/0day-ci/archive/20220817/202208170309.j1yYU9wN-lkp@xxxxxxxxx/config) > compiler: gcc-11 (Debian 11.3.0-5) 11.3.0 > reproduce (this is a W=1 build): > # https://github.com/intel-lab-lkp/linux/commit/a1d5079765918764de3ff6e3e63fa2db7f7c14df > git remote add linux-review https://github.com/intel-lab-lkp/linux > git fetch --no-tags linux-review Zhen-Lei/rcu-nocb-Delete-local-variable-need_rcu_nocb_mask-in-rcu_init_nohz/20220816-205131 > git checkout a1d5079765918764de3ff6e3e63fa2db7f7c14df > # save the config file > mkdir build_dir && cp config build_dir/.config > make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash kernel/ > > If you fix the issue, kindly add following tag where applicable > Reported-by: kernel test robot <lkp@xxxxxxxxx> > > All warnings (new ones prefixed by >>): > > In file included from kernel/rcu/tree.c:4801: > kernel/rcu/tree_nocb.h: In function 'rcu_init_nohz': >>> kernel/rcu/tree_nocb.h:1216:17: warning: assignment discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers] > 1216 | cpumask = cpu_possible_mask; > | ^ > > > vim +/const +1216 kernel/rcu/tree_nocb.h It's a shame. Sorry, I forgot to check "> error.txt". > > 1208 > 1209 void __init rcu_init_nohz(void) > 1210 { > 1211 int cpu; > 1212 struct rcu_data *rdp; > 1213 struct cpumask *cpumask = NULL; > 1214 > 1215 #if defined(CONFIG_RCU_NOCB_CPU_DEFAULT_ALL) >> 1216 cpumask = cpu_possible_mask; > 1217 #elif defined(CONFIG_NO_HZ_FULL) > 1218 if (tick_nohz_full_running && !cpumask_empty(tick_nohz_full_mask)) > 1219 cpumask = tick_nohz_full_mask; > 1220 #endif > 1221 > 1222 if (cpumask) { > 1223 if (!cpumask_available(rcu_nocb_mask)) { > 1224 if (!zalloc_cpumask_var(&rcu_nocb_mask, GFP_KERNEL)) { > 1225 pr_info("rcu_nocb_mask allocation failed, callback offloading disabled.\n"); > 1226 return; > 1227 } > 1228 } > 1229 > 1230 cpumask_or(rcu_nocb_mask, rcu_nocb_mask, cpumask); > 1231 } > 1232 > 1233 if (!cpumask_available(rcu_nocb_mask)) > 1234 return; > 1235 > 1236 if (!cpumask_subset(rcu_nocb_mask, cpu_possible_mask)) { > 1237 pr_info("\tNote: kernel parameter 'rcu_nocbs=', 'nohz_full', or 'isolcpus=' contains nonexistent CPUs.\n"); > 1238 cpumask_and(rcu_nocb_mask, cpu_possible_mask, > 1239 rcu_nocb_mask); > 1240 } > 1241 if (cpumask_empty(rcu_nocb_mask)) > 1242 pr_info("\tOffload RCU callbacks from CPUs: (none).\n"); > 1243 else > 1244 pr_info("\tOffload RCU callbacks from CPUs: %*pbl.\n", > 1245 cpumask_pr_args(rcu_nocb_mask)); > 1246 if (rcu_nocb_poll) > 1247 pr_info("\tPoll for callbacks from no-CBs CPUs.\n"); > 1248 > 1249 for_each_cpu(cpu, rcu_nocb_mask) { > 1250 rdp = per_cpu_ptr(&rcu_data, cpu); > 1251 if (rcu_segcblist_empty(&rdp->cblist)) > 1252 rcu_segcblist_init(&rdp->cblist); > 1253 rcu_segcblist_offload(&rdp->cblist, true); > 1254 rcu_segcblist_set_flags(&rdp->cblist, SEGCBLIST_KTHREAD_CB | SEGCBLIST_KTHREAD_GP); > 1255 rcu_segcblist_clear_flags(&rdp->cblist, SEGCBLIST_RCU_CORE); > 1256 } > 1257 rcu_organize_nocb_kthreads(); > 1258 } > 1259 > -- Regards, Zhen Lei