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Subject[ammarfaizi2-block:paulmck/linux-rcu/dev 28/28] kernel/rcu/tree_nocb.h:1217:9: error: expected identifier or '(' before 'if'
tree:   https://github.com/ammarfaizi2/linux-block paulmck/linux-rcu/dev
head: ad68d8bf085421e4f22731c8b64c0b774a154e06
commit: ad68d8bf085421e4f22731c8b64c0b774a154e06 [28/28] rcu/nocb: Add an option to offload all CPUs on boot
config: x86_64-randconfig-a015 (https://download.01.org/0day-ci/archive/20220420/202204202111.gA58hkDX-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.2.0-20) 11.2.0
reproduce (this is a W=1 build):
# https://github.com/ammarfaizi2/linux-block/commit/ad68d8bf085421e4f22731c8b64c0b774a154e06
git remote add ammarfaizi2-block https://github.com/ammarfaizi2/linux-block
git fetch --no-tags ammarfaizi2-block paulmck/linux-rcu/dev
git checkout ad68d8bf085421e4f22731c8b64c0b774a154e06
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash

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

All errors (new ones prefixed by >>):

In file included from kernel/rcu/tree.c:5031:
kernel/rcu/tree_nocb.h: In function 'rcu_init_nohz':
kernel/rcu/tree_nocb.h:1211:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
1211 | if (tick_nohz_full_running && !cpumask_empty(tick_nohz_full_mask))
| ^~
kernel/rcu/tree_nocb.h:1213:17: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
1213 | offload_all = false; /* NO_HZ_FULL has its own mask. */
| ^~~~~~~~~~~
kernel/rcu/tree_nocb.h:1201:26: warning: unused variable 'rdp' [-Wunused-variable]
1201 | struct rcu_data *rdp;
| ^~~
kernel/rcu/tree_nocb.h:1200:14: warning: variable 'offload_all' set but not used [-Wunused-but-set-variable]
1200 | bool offload_all = false;
| ^~~~~~~~~~~
kernel/rcu/tree_nocb.h:1199:14: warning: variable 'need_rcu_nocb_mask' set but not used [-Wunused-but-set-variable]
1199 | bool need_rcu_nocb_mask = false;
| ^~~~~~~~~~~~~~~~~~
kernel/rcu/tree_nocb.h:1198:13: warning: unused variable 'cpu' [-Wunused-variable]
1198 | int cpu;
| ^~~
kernel/rcu/tree_nocb.h: At top level:
>> kernel/rcu/tree_nocb.h:1217:9: error: expected identifier or '(' before 'if'
1217 | if (need_rcu_nocb_mask) {
| ^~
kernel/rcu/tree_nocb.h:1227:9: error: expected identifier or '(' before 'if'
1227 | if (!rcu_state.nocb_is_setup)
| ^~
kernel/rcu/tree_nocb.h:1231:9: error: expected identifier or '(' before 'if'
1231 | if (tick_nohz_full_running)
| ^~
kernel/rcu/tree_nocb.h:1235:9: error: expected identifier or '(' before 'if'
1235 | if (offload_all)
| ^~
kernel/rcu/tree_nocb.h:1238:9: error: expected identifier or '(' before 'if'
1238 | if (!cpumask_subset(rcu_nocb_mask, cpu_possible_mask)) {
| ^~
kernel/rcu/tree_nocb.h:1243:9: error: expected identifier or '(' before 'if'
1243 | if (cpumask_empty(rcu_nocb_mask))
| ^~
In file included from include/linux/kernel.h:29,
from kernel/rcu/tree.c:21:
include/linux/printk.h:419:10: error: expected identifier or '(' before ')' token
419 | })
| ^
include/linux/printk.h:446:26: note: in expansion of macro 'printk_index_wrap'
446 | #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__)
| ^~~~~~~~~~~~~~~~~
include/linux/printk.h:519:9: note: in expansion of macro 'printk'
519 | printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
| ^~~~~~
kernel/rcu/tree_nocb.h:1244:17: note: in expansion of macro 'pr_info'
1244 | pr_info("\tOffload RCU callbacks from CPUs: (none).\n");
| ^~~~~~~
In file included from kernel/rcu/tree.c:5031:
>> kernel/rcu/tree_nocb.h:1245:9: error: expected identifier or '(' before 'else'
1245 | else
| ^~~~
In file included from include/linux/kernel.h:29,
from kernel/rcu/tree.c:21:
include/linux/printk.h:419:10: error: expected identifier or '(' before ')' token
419 | })
| ^
include/linux/printk.h:446:26: note: in expansion of macro 'printk_index_wrap'
446 | #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__)
| ^~~~~~~~~~~~~~~~~
include/linux/printk.h:519:9: note: in expansion of macro 'printk'
519 | printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
| ^~~~~~
kernel/rcu/tree_nocb.h:1246:17: note: in expansion of macro 'pr_info'
1246 | pr_info("\tOffload RCU callbacks from CPUs: %*pbl.\n",
| ^~~~~~~
In file included from kernel/rcu/tree.c:5031:
kernel/rcu/tree_nocb.h:1248:9: error: expected identifier or '(' before 'if'
1248 | if (rcu_nocb_poll)
| ^~
In file included from include/linux/kernel.h:29,
from kernel/rcu/tree.c:21:
include/linux/printk.h:419:10: error: expected identifier or '(' before ')' token
419 | })
| ^
include/linux/printk.h:446:26: note: in expansion of macro 'printk_index_wrap'
446 | #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__)
| ^~~~~~~~~~~~~~~~~
include/linux/printk.h:519:9: note: in expansion of macro 'printk'
519 | printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
| ^~~~~~
kernel/rcu/tree_nocb.h:1249:17: note: in expansion of macro 'pr_info'
1249 | pr_info("\tPoll for callbacks from no-CBs CPUs.\n");
| ^~~~~~~
In file included from arch/x86/include/asm/cpumask.h:5,
from arch/x86/include/asm/msr.h:11,
from arch/x86/include/asm/processor.h:22,
from arch/x86/include/asm/cpufeature.h:5,
from arch/x86/include/asm/thread_info.h:53,
from include/linux/thread_info.h:60,
from arch/x86/include/asm/preempt.h:7,
from include/linux/preempt.h:78,
from include/linux/spinlock.h:55,
from kernel/rcu/tree.c:23:
>> include/linux/cpumask.h:276:9: error: expected identifier or '(' before 'for'
276 | for ((cpu) = -1; \
| ^~~
kernel/rcu/tree_nocb.h:1251:9: note: in expansion of macro 'for_each_cpu'
1251 | for_each_cpu(cpu, rcu_nocb_mask) {
| ^~~~~~~~~~~~
include/linux/cpumask.h:277:17: warning: data definition has no type or storage class
277 | (cpu) = cpumask_next((cpu), (mask)), \
| ^
kernel/rcu/tree_nocb.h:1251:9: note: in expansion of macro 'for_each_cpu'
1251 | for_each_cpu(cpu, rcu_nocb_mask) {
| ^~~~~~~~~~~~
>> kernel/rcu/tree_nocb.h:1251:22: error: type defaults to 'int' in declaration of 'cpu' [-Werror=implicit-int]
1251 | for_each_cpu(cpu, rcu_nocb_mask) {
| ^~~
include/linux/cpumask.h:277:18: note: in definition of macro 'for_each_cpu'
277 | (cpu) = cpumask_next((cpu), (mask)), \
| ^~~
>> include/linux/cpumask.h:277:25: error: initializer element is not constant
277 | (cpu) = cpumask_next((cpu), (mask)), \
| ^~~~~~~~~~~~
kernel/rcu/tree_nocb.h:1251:9: note: in expansion of macro 'for_each_cpu'
1251 | for_each_cpu(cpu, rcu_nocb_mask) {
| ^~~~~~~~~~~~
>> include/linux/cpumask.h:278:23: error: expected '=', ',', ';', 'asm' or '__attribute__' before '<' token
278 | (cpu) < nr_cpu_ids;)
| ^
kernel/rcu/tree_nocb.h:1251:9: note: in expansion of macro 'for_each_cpu'
1251 | for_each_cpu(cpu, rcu_nocb_mask) {
| ^~~~~~~~~~~~
>> include/linux/cpumask.h:278:36: error: expected identifier or '(' before ')' token
278 | (cpu) < nr_cpu_ids;)
| ^
kernel/rcu/tree_nocb.h:1251:9: note: in expansion of macro 'for_each_cpu'
1251 | for_each_cpu(cpu, rcu_nocb_mask) {
| ^~~~~~~~~~~~
In file included from kernel/rcu/tree.c:5031:
kernel/rcu/tree_nocb.h:1259:9: warning: data definition has no type or storage class
1259 | rcu_organize_nocb_kthreads();
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
>> kernel/rcu/tree_nocb.h:1259:9: error: type defaults to 'int' in declaration of 'rcu_organize_nocb_kthreads' [-Werror=implicit-int]
>> kernel/rcu/tree_nocb.h:1259:9: error: function declaration isn't a prototype [-Werror=strict-prototypes]
>> kernel/rcu/tree_nocb.h:1259:9: error: conflicting types for 'rcu_organize_nocb_kthreads'; have 'int()'
In file included from kernel/rcu/tree.c:67:
kernel/rcu/tree.h:463:20: note: previous declaration of 'rcu_organize_nocb_kthreads' with type 'void(void)'
463 | static void __init rcu_organize_nocb_kthreads(void);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from kernel/rcu/tree.c:5031:
>> kernel/rcu/tree_nocb.h:1260:1: error: expected identifier or '(' before '}' token
1260 | }
| ^
>> kernel/rcu/tree_nocb.h:1339:20: error: conflicting types for 'rcu_organize_nocb_kthreads'; have 'void(void)'
1339 | static void __init rcu_organize_nocb_kthreads(void)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
kernel/rcu/tree_nocb.h:1259:9: note: previous declaration of 'rcu_organize_nocb_kthreads' with type 'int()'
1259 | rcu_organize_nocb_kthreads();
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
kernel/rcu/tree_nocb.h:1339:20: warning: 'rcu_organize_nocb_kthreads' defined but not used [-Wunused-function]
1339 | static void __init rcu_organize_nocb_kthreads(void)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors


vim +1217 kernel/rcu/tree_nocb.h

dfcb27540213e8 Frederic Weisbecker 2021-05-19 1216
a81aeaf7a1de51 Frederic Weisbecker 2021-11-23 @1217 if (need_rcu_nocb_mask) {
a81aeaf7a1de51 Frederic Weisbecker 2021-11-23 1218 if (!cpumask_available(rcu_nocb_mask)) {
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1219 if (!zalloc_cpumask_var(&rcu_nocb_mask, GFP_KERNEL)) {
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1220 pr_info("rcu_nocb_mask allocation failed, callback offloading disabled.\n");
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1221 return;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1222 }
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1223 }
8d2aaa9b7c290e Frederic Weisbecker 2022-02-14 1224 rcu_state.nocb_is_setup = true;
a81aeaf7a1de51 Frederic Weisbecker 2021-11-23 1225 }
a81aeaf7a1de51 Frederic Weisbecker 2021-11-23 1226
8d2aaa9b7c290e Frederic Weisbecker 2022-02-14 1227 if (!rcu_state.nocb_is_setup)
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1228 return;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1229
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1230 #if defined(CONFIG_NO_HZ_FULL)
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1231 if (tick_nohz_full_running)
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1232 cpumask_or(rcu_nocb_mask, rcu_nocb_mask, tick_nohz_full_mask);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1233 #endif /* #if defined(CONFIG_NO_HZ_FULL) */
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1234
ad68d8bf085421 Joel Fernandes 2022-04-19 1235 if (offload_all)
ad68d8bf085421 Joel Fernandes 2022-04-19 1236 cpumask_setall(rcu_nocb_mask);
ad68d8bf085421 Joel Fernandes 2022-04-19 1237
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1238 if (!cpumask_subset(rcu_nocb_mask, cpu_possible_mask)) {
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1239 pr_info("\tNote: kernel parameter 'rcu_nocbs=', 'nohz_full', or 'isolcpus=' contains nonexistent CPUs.\n");
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1240 cpumask_and(rcu_nocb_mask, cpu_possible_mask,
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1241 rcu_nocb_mask);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1242 }
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1243 if (cpumask_empty(rcu_nocb_mask))
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1244 pr_info("\tOffload RCU callbacks from CPUs: (none).\n");
dfcb27540213e8 Frederic Weisbecker 2021-05-19 @1245 else
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1246 pr_info("\tOffload RCU callbacks from CPUs: %*pbl.\n",
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1247 cpumask_pr_args(rcu_nocb_mask));
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1248 if (rcu_nocb_poll)
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1249 pr_info("\tPoll for callbacks from no-CBs CPUs.\n");
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1250
dfcb27540213e8 Frederic Weisbecker 2021-05-19 @1251 for_each_cpu(cpu, rcu_nocb_mask) {
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1252 rdp = per_cpu_ptr(&rcu_data, cpu);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1253 if (rcu_segcblist_empty(&rdp->cblist))
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1254 rcu_segcblist_init(&rdp->cblist);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1255 rcu_segcblist_offload(&rdp->cblist, true);
213d56bf33bdda Frederic Weisbecker 2021-10-19 1256 rcu_segcblist_set_flags(&rdp->cblist, SEGCBLIST_KTHREAD_CB | SEGCBLIST_KTHREAD_GP);
213d56bf33bdda Frederic Weisbecker 2021-10-19 1257 rcu_segcblist_clear_flags(&rdp->cblist, SEGCBLIST_RCU_CORE);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1258 }
dfcb27540213e8 Frederic Weisbecker 2021-05-19 @1259 rcu_organize_nocb_kthreads();
dfcb27540213e8 Frederic Weisbecker 2021-05-19 @1260 }
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1261
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1262 /* Initialize per-rcu_data variables for no-CBs CPUs. */
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1263 static void __init rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp)
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1264 {
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1265 init_swait_queue_head(&rdp->nocb_cb_wq);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1266 init_swait_queue_head(&rdp->nocb_gp_wq);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1267 init_swait_queue_head(&rdp->nocb_state_wq);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1268 raw_spin_lock_init(&rdp->nocb_lock);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1269 raw_spin_lock_init(&rdp->nocb_bypass_lock);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1270 raw_spin_lock_init(&rdp->nocb_gp_lock);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1271 timer_setup(&rdp->nocb_timer, do_nocb_deferred_wakeup_timer, 0);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1272 rcu_cblist_init(&rdp->nocb_bypass);
02e3024175274e Neeraj Upadhyay 2021-12-11 1273 mutex_init(&rdp->nocb_gp_kthread_mutex);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1274 }
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1275
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1276 /*
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1277 * If the specified CPU is a no-CBs CPU that does not already have its
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1278 * rcuo CB kthread, spawn it. Additionally, if the rcuo GP kthread
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1279 * for this CPU's group has not yet been created, spawn it as well.
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1280 */
10d4703154a72f Frederic Weisbecker 2021-11-23 1281 static void rcu_spawn_cpu_nocb_kthread(int cpu)
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1282 {
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1283 struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1284 struct rcu_data *rdp_gp;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1285 struct task_struct *t;
54577e23fa0791 Alison Chaiken 2022-01-11 1286 struct sched_param sp;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1287
8d2aaa9b7c290e Frederic Weisbecker 2022-02-14 1288 if (!rcu_scheduler_fully_active || !rcu_state.nocb_is_setup)
10d4703154a72f Frederic Weisbecker 2021-11-23 1289 return;
10d4703154a72f Frederic Weisbecker 2021-11-23 1290
2cf4528d6dd6f5 Frederic Weisbecker 2021-11-23 1291 /* If there already is an rcuo kthread, then nothing to do. */
2cf4528d6dd6f5 Frederic Weisbecker 2021-11-23 1292 if (rdp->nocb_cb_kthread)
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1293 return;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1294
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1295 /* If we didn't spawn the GP kthread first, reorganize! */
54577e23fa0791 Alison Chaiken 2022-01-11 1296 sp.sched_priority = kthread_prio;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1297 rdp_gp = rdp->nocb_gp_rdp;
02e3024175274e Neeraj Upadhyay 2021-12-11 1298 mutex_lock(&rdp_gp->nocb_gp_kthread_mutex);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1299 if (!rdp_gp->nocb_gp_kthread) {
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1300 t = kthread_run(rcu_nocb_gp_kthread, rdp_gp,
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1301 "rcuog/%d", rdp_gp->cpu);
02e3024175274e Neeraj Upadhyay 2021-12-11 1302 if (WARN_ONCE(IS_ERR(t), "%s: Could not start rcuo GP kthread, OOM is now expected behavior\n", __func__)) {
02e3024175274e Neeraj Upadhyay 2021-12-11 1303 mutex_unlock(&rdp_gp->nocb_gp_kthread_mutex);
3932ce26dc6822 Zqiang 2022-04-19 1304 goto end;
02e3024175274e Neeraj Upadhyay 2021-12-11 1305 }
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1306 WRITE_ONCE(rdp_gp->nocb_gp_kthread, t);
54577e23fa0791 Alison Chaiken 2022-01-11 1307 if (kthread_prio)
54577e23fa0791 Alison Chaiken 2022-01-11 1308 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1309 }
02e3024175274e Neeraj Upadhyay 2021-12-11 1310 mutex_unlock(&rdp_gp->nocb_gp_kthread_mutex);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1311
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1312 /* Spawn the kthread for this CPU. */
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1313 t = kthread_run(rcu_nocb_cb_kthread, rdp,
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1314 "rcuo%c/%d", rcu_state.abbr, cpu);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1315 if (WARN_ONCE(IS_ERR(t), "%s: Could not start rcuo CB kthread, OOM is now expected behavior\n", __func__))
3932ce26dc6822 Zqiang 2022-04-19 1316 goto end;
c8b16a65267e35 Alison Chaiken 2022-01-11 1317
c8b16a65267e35 Alison Chaiken 2022-01-11 1318 if (kthread_prio)
c8b16a65267e35 Alison Chaiken 2022-01-11 1319 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1320 WRITE_ONCE(rdp->nocb_cb_kthread, t);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1321 WRITE_ONCE(rdp->nocb_gp_kthread, rdp_gp->nocb_gp_kthread);
3932ce26dc6822 Zqiang 2022-04-19 1322 return;
3932ce26dc6822 Zqiang 2022-04-19 1323 end:
3932ce26dc6822 Zqiang 2022-04-19 1324 mutex_lock(&rcu_state.barrier_mutex);
3932ce26dc6822 Zqiang 2022-04-19 1325 if (rcu_rdp_is_offloaded(rdp)) {
3932ce26dc6822 Zqiang 2022-04-19 1326 rcu_nocb_rdp_deoffload(rdp);
3932ce26dc6822 Zqiang 2022-04-19 1327 cpumask_clear_cpu(cpu, rcu_nocb_mask);
3932ce26dc6822 Zqiang 2022-04-19 1328 }
3932ce26dc6822 Zqiang 2022-04-19 1329 mutex_unlock(&rcu_state.barrier_mutex);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1330 }
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1331
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1332 /* How many CB CPU IDs per GP kthread? Default of -1 for sqrt(nr_cpu_ids). */
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1333 static int rcu_nocb_gp_stride = -1;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1334 module_param(rcu_nocb_gp_stride, int, 0444);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1335
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1336 /*
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1337 * Initialize GP-CB relationships for all no-CBs CPU.
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1338 */
dfcb27540213e8 Frederic Weisbecker 2021-05-19 @1339 static void __init rcu_organize_nocb_kthreads(void)
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1340 {
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1341 int cpu;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1342 bool firsttime = true;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1343 bool gotnocbs = false;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1344 bool gotnocbscbs = true;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1345 int ls = rcu_nocb_gp_stride;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1346 int nl = 0; /* Next GP kthread. */
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1347 struct rcu_data *rdp;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1348 struct rcu_data *rdp_gp = NULL; /* Suppress misguided gcc warn. */
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1349
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1350 if (!cpumask_available(rcu_nocb_mask))
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1351 return;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1352 if (ls == -1) {
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1353 ls = nr_cpu_ids / int_sqrt(nr_cpu_ids);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1354 rcu_nocb_gp_stride = ls;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1355 }
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1356
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1357 /*
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1358 * Each pass through this loop sets up one rcu_data structure.
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1359 * Should the corresponding CPU come online in the future, then
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1360 * we will spawn the needed set of rcu_nocb_kthread() kthreads.
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1361 */
2cf4528d6dd6f5 Frederic Weisbecker 2021-11-23 1362 for_each_possible_cpu(cpu) {
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1363 rdp = per_cpu_ptr(&rcu_data, cpu);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1364 if (rdp->cpu >= nl) {
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1365 /* New GP kthread, set up for CBs & next GP. */
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1366 gotnocbs = true;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1367 nl = DIV_ROUND_UP(rdp->cpu + 1, ls) * ls;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1368 rdp_gp = rdp;
2ebc45c44c4f3c Frederic Weisbecker 2021-11-23 1369 INIT_LIST_HEAD(&rdp->nocb_head_rdp);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1370 if (dump_tree) {
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1371 if (!firsttime)
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1372 pr_cont("%s\n", gotnocbscbs
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1373 ? "" : " (self only)");
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1374 gotnocbscbs = false;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1375 firsttime = false;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1376 pr_alert("%s: No-CB GP kthread CPU %d:",
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1377 __func__, cpu);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1378 }
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1379 } else {
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1380 /* Another CB kthread, link to previous GP kthread. */
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1381 gotnocbscbs = true;
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1382 if (dump_tree)
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1383 pr_cont(" %d", cpu);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1384 }
2ebc45c44c4f3c Frederic Weisbecker 2021-11-23 1385 rdp->nocb_gp_rdp = rdp_gp;
2cf4528d6dd6f5 Frederic Weisbecker 2021-11-23 1386 if (cpumask_test_cpu(cpu, rcu_nocb_mask))
2ebc45c44c4f3c Frederic Weisbecker 2021-11-23 1387 list_add_tail(&rdp->nocb_entry_rdp, &rdp_gp->nocb_head_rdp);
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1388 }
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1389 if (gotnocbs && dump_tree)
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1390 pr_cont("%s\n", gotnocbscbs ? "" : " (self only)");
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1391 }
dfcb27540213e8 Frederic Weisbecker 2021-05-19 1392

:::::: The code at line 1217 was first introduced by commit
:::::: a81aeaf7a1de51400374a8e3982a3cc3ff130dd1 rcu/nocb: Optimize kthreads and rdp initialization

:::::: TO: Frederic Weisbecker <frederic@kernel.org>
:::::: CC: Paul E. McKenney <paulmck@kernel.org>

--
0-DAY CI Kernel Test Service
https://01.org/lkp

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