Re: [PATCH 08/11] cgroup: rstat cpu lock indirection

kernel test robot
2025-02-19T08:51:03Z

Hi JP,

kernel test robot noticed the following build warnings:

[auto build test WARNING on tj-cgroup/for-next]
[also build test WARNING on bpf-next/master bpf/master linus/master v6.14-rc3 next-20250219]
[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/JP-Kobryn/cgroup-move-rstat-pointers-into-struct-of-their-own/20250218-111725
base: https://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git for-next
patch link: https://lore.kernel.org/r/20250218031448.46951-9-inwardvessel%40gmail.com
patch subject: [PATCH 08/11] cgroup: rstat cpu lock indirection
config: arc-randconfig-002-20250219 (https://download.01.org/0day-ci/archive/20250219/202502191619.0t8nOsuQ-lkp@intel.com/config)
compiler: arc-elf-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250219/202502191619.0t8nOsuQ-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202502191619.0t8nOsuQ-lkp@intel.com/

All warnings (new ones prefixed by >>):

kernel/cgroup/rstat.c:266: warning: Function parameter or struct member 'ops' not described in 'cgroup_rstat_push_children'
kernel/cgroup/rstat.c:326: warning: Function parameter or struct member 'ops' not described in 'cgroup_rstat_updated_list'
>> kernel/cgroup/rstat.c:326: warning: Function parameter or struct member 'cpu_lock' not described in 'cgroup_rstat_updated_list'
kernel/cgroup/rstat.c:532: warning: Function parameter or struct member 'ops' not described in '__cgroup_rstat_flush_release'
>> kernel/cgroup/rstat.c:532: warning: Function parameter or struct member 'lock' not described in '__cgroup_rstat_flush_release'
kernel/cgroup/rstat.c:532: warning: expecting prototype for cgroup_rstat_flush_release(). Prototype was for __cgroup_rstat_flush_release() instead

vim +326 kernel/cgroup/rstat.c

d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 304
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 305 /**
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 306 * cgroup_rstat_updated_list - return a list of updated cgroups to be flushed
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 307 * @root: root of the cgroup subtree to traverse
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 308 * @cpu: target cpu
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 309 * Return: A singly linked list of cgroups to be flushed
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 310 *
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 311 * Walks the updated rstat_cpu tree on @cpu from @root. During traversal,
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 312 * each returned cgroup is unlinked from the updated tree.
041cd640b2f3c5 kernel/cgroup/stat.c Tejun Heo 2017-09-25 313 *
041cd640b2f3c5 kernel/cgroup/stat.c Tejun Heo 2017-09-25 314 * The only ordering guarantee is that, for a parent and a child pair
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 315 * covered by a given traversal, the child is before its parent in
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 316 * the list.
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 317 *
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 318 * Note that updated_children is self terminated and points to a list of
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 319 * child cgroups if not empty. Whereas updated_next is like a sibling link
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 320 * within the children list and terminated by the parent cgroup. An exception
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 321 * here is the cgroup root whose updated_next can be self terminated.
041cd640b2f3c5 kernel/cgroup/stat.c Tejun Heo 2017-09-25 322 */
3d844899ba042a kernel/cgroup/rstat.c JP Kobryn 2025-02-17 323 static struct cgroup_rstat *cgroup_rstat_updated_list(
85c7ff288b9391 kernel/cgroup/rstat.c JP Kobryn 2025-02-17 324 struct cgroup_rstat *root, int cpu, struct cgroup_rstat_ops *ops,
85c7ff288b9391 kernel/cgroup/rstat.c JP Kobryn 2025-02-17 325 raw_spinlock_t *cpu_lock)
041cd640b2f3c5 kernel/cgroup/stat.c Tejun Heo 2017-09-25 @326 {
3d844899ba042a kernel/cgroup/rstat.c JP Kobryn 2025-02-17 327 struct cgroup_rstat_cpu *rstatc = rstat_cpu(root, cpu);
3d844899ba042a kernel/cgroup/rstat.c JP Kobryn 2025-02-17 328 struct cgroup_rstat *head = NULL, *parent, *child;
d67ed623c585f2 kernel/cgroup/rstat.c JP Kobryn 2025-02-17 329 struct cgroup *cgrp;
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 330 unsigned long flags;
041cd640b2f3c5 kernel/cgroup/stat.c Tejun Heo 2017-09-25 331
d67ed623c585f2 kernel/cgroup/rstat.c JP Kobryn 2025-02-17 332 cgrp = ops->cgroup_fn(root);
85c7ff288b9391 kernel/cgroup/rstat.c JP Kobryn 2025-02-17 333 flags = _cgroup_rstat_cpu_lock(cpu_lock, cpu, cgrp, false);
041cd640b2f3c5 kernel/cgroup/stat.c Tejun Heo 2017-09-25 334
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 335 /* Return NULL if this subtree is not on-list */
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 336 if (!rstatc->updated_next)
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 337 goto unlock_ret;
041cd640b2f3c5 kernel/cgroup/stat.c Tejun Heo 2017-09-25 338
041cd640b2f3c5 kernel/cgroup/stat.c Tejun Heo 2017-09-25 339 /*
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 340 * Unlink @root from its parent. As the updated_children list is
041cd640b2f3c5 kernel/cgroup/stat.c Tejun Heo 2017-09-25 341 * singly linked, we have to walk it to find the removal point.
041cd640b2f3c5 kernel/cgroup/stat.c Tejun Heo 2017-09-25 342 */
d67ed623c585f2 kernel/cgroup/rstat.c JP Kobryn 2025-02-17 343 parent = ops->parent_fn(root);
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29 344 if (parent) {
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29 345 struct cgroup_rstat_cpu *prstatc;
3d844899ba042a kernel/cgroup/rstat.c JP Kobryn 2025-02-17 346 struct cgroup_rstat **nextp;
041cd640b2f3c5 kernel/cgroup/stat.c Tejun Heo 2017-09-25 347
3d844899ba042a kernel/cgroup/rstat.c JP Kobryn 2025-02-17 348 prstatc = rstat_cpu(parent, cpu);
c58632b3631cb2 kernel/cgroup/rstat.c Tejun Heo 2018-04-26 349 nextp = &prstatc->updated_children;
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 350 while (*nextp != root) {
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29 351 struct cgroup_rstat_cpu *nrstatc;
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29 352
3d844899ba042a kernel/cgroup/rstat.c JP Kobryn 2025-02-17 353 nrstatc = rstat_cpu(*nextp, cpu);
041cd640b2f3c5 kernel/cgroup/stat.c Tejun Heo 2017-09-25 354 WARN_ON_ONCE(*nextp == parent);
c58632b3631cb2 kernel/cgroup/rstat.c Tejun Heo 2018-04-26 355 nextp = &nrstatc->updated_next;
041cd640b2f3c5 kernel/cgroup/stat.c Tejun Heo 2017-09-25 356 }
c58632b3631cb2 kernel/cgroup/rstat.c Tejun Heo 2018-04-26 357 *nextp = rstatc->updated_next;
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29 358 }
9a9e97b2f1f27e kernel/cgroup/rstat.c Tejun Heo 2018-04-26 359
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29 360 rstatc->updated_next = NULL;
e76d28bdf9ba53 kernel/cgroup/rstat.c Waiman Long 2023-11-03 361
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 362 /* Push @root to the list first before pushing the children */
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 363 head = root;
3d844899ba042a kernel/cgroup/rstat.c JP Kobryn 2025-02-17 364 root->rstat_flush_next = NULL;
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 365 child = rstatc->updated_children;
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 366 rstatc->updated_children = root;
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 367 if (child != root)
d67ed623c585f2 kernel/cgroup/rstat.c JP Kobryn 2025-02-17 368 head = cgroup_rstat_push_children(head, child, cpu, ops);
d499fd418fa159 kernel/cgroup/rstat.c Waiman Long 2023-11-30 369 unlock_ret:
85c7ff288b9391 kernel/cgroup/rstat.c JP Kobryn 2025-02-17 370 _cgroup_rstat_cpu_unlock(cpu_lock, cpu, cgrp, flags, false);
e76d28bdf9ba53 kernel/cgroup/rstat.c Waiman Long 2023-11-03 371 return head;
041cd640b2f3c5 kernel/cgroup/stat.c Tejun Heo 2017-09-25 372 }
041cd640b2f3c5 kernel/cgroup/stat.c Tejun Heo 2017-09-25 373

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