Re: [PATCH v2 10/13] mm: memcontrol: use obj_cgroup APIs to charge the LRU pages

From: kernel test robot
Date: Fri Sep 17 2021 - 12:32:24 EST

Hi Muchun,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on tj-cgroup/for-next]
[also build test WARNING on linus/master v5.15-rc1]
[cannot apply to hnaz-mm/master next-20210917]
[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/Muchun-Song/Use-obj_cgroup-APIs-to-charge-the-LRU-pages/20210916-215452
base: https://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git for-next
config: i386-randconfig-s002-20210916 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce:
# apt-get install sparse
# sparse version: v0.6.4-dirty
# https://github.com/0day-ci/linux/commit/a91949623178a5b2ef32a0842f6b6bae02a1a696
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Muchun-Song/Use-obj_cgroup-APIs-to-charge-the-LRU-pages/20210916-215452
git checkout a91949623178a5b2ef32a0842f6b6bae02a1a696
# save the attached .config to linux build tree
make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=i386

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


sparse warnings: (new ones prefixed by >>)
mm/memcontrol.c:4227:21: sparse: sparse: incompatible types in comparison expression (different address spaces):
mm/memcontrol.c:4227:21: sparse: struct mem_cgroup_threshold_ary [noderef] __rcu *
mm/memcontrol.c:4227:21: sparse: struct mem_cgroup_threshold_ary *
mm/memcontrol.c:4229:21: sparse: sparse: incompatible types in comparison expression (different address spaces):
mm/memcontrol.c:4229:21: sparse: struct mem_cgroup_threshold_ary [noderef] __rcu *
mm/memcontrol.c:4229:21: sparse: struct mem_cgroup_threshold_ary *
mm/memcontrol.c:4385:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
mm/memcontrol.c:4385:9: sparse: struct mem_cgroup_threshold_ary [noderef] __rcu *
mm/memcontrol.c:4385:9: sparse: struct mem_cgroup_threshold_ary *
mm/memcontrol.c:4479:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
mm/memcontrol.c:4479:9: sparse: struct mem_cgroup_threshold_ary [noderef] __rcu *
mm/memcontrol.c:4479:9: sparse: struct mem_cgroup_threshold_ary *
>> mm/memcontrol.c:5832:26: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct obj_cgroup *objcg @@ got struct obj_cgroup [noderef] __rcu *objcg @@
mm/memcontrol.c:5833:28: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct obj_cgroup *objcg @@ got struct obj_cgroup [noderef] __rcu *objcg @@
mm/memcontrol.c:6128:23: sparse: sparse: incompatible types in comparison expression (different address spaces):
mm/memcontrol.c:6128:23: sparse: struct task_struct [noderef] __rcu *
mm/memcontrol.c:6128:23: sparse: struct task_struct *
mm/memcontrol.c: note: in included file:
include/linux/memcontrol.h:760:9: sparse: sparse: context imbalance in 'memcg_reparent_lruvec_lock' - wrong count at exit
include/linux/memcontrol.h:760:9: sparse: sparse: context imbalance in 'memcg_reparent_lruvec_unlock' - unexpected unlock
mm/memcontrol.c: note: in included file (through include/linux/rculist.h, include/linux/pid.h, include/linux/sched.h, ...):
include/linux/rcupdate.h:718:9: sparse: sparse: context imbalance in 'lock_page_lruvec' - wrong count at exit
include/linux/rcupdate.h:718:9: sparse: sparse: context imbalance in 'lock_page_lruvec_irq' - wrong count at exit
include/linux/rcupdate.h:718:9: sparse: sparse: context imbalance in 'lock_page_lruvec_irqsave' - wrong count at exit
mm/memcontrol.c:2109:6: sparse: sparse: context imbalance in 'lock_page_memcg' - wrong count at exit
mm/memcontrol.c:2160:17: sparse: sparse: context imbalance in '__unlock_page_memcg' - unexpected unlock

vim +5832 mm/memcontrol.c

5730
5731 /**
5732 * mem_cgroup_move_account - move account of the page
5733 * @page: the page
5734 * @compound: charge the page as compound or small page
5735 * @from: mem_cgroup which the page is moved from.
5736 * @to: mem_cgroup which the page is moved to. @from != @to.
5737 *
5738 * The caller must make sure the page is not on LRU (isolate_page() is useful.)
5739 *
5740 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
5741 * from old cgroup.
5742 */
5743 static int mem_cgroup_move_account(struct page *page,
5744 bool compound,
5745 struct mem_cgroup *from,
5746 struct mem_cgroup *to)
5747 {
5748 struct lruvec *from_vec, *to_vec;
5749 struct pglist_data *pgdat;
5750 unsigned int nr_pages = compound ? thp_nr_pages(page) : 1;
5751 int ret;
5752
5753 VM_BUG_ON(from == to);
5754 VM_BUG_ON_PAGE(PageLRU(page), page);
5755 VM_BUG_ON(compound && !PageTransHuge(page));
5756
5757 /*
5758 * Prevent mem_cgroup_migrate() from looking at
5759 * page's memory cgroup of its source page while we change it.
5760 */
5761 ret = -EBUSY;
5762 if (!trylock_page(page))
5763 goto out;
5764
5765 ret = -EINVAL;
5766 if (page_memcg(page) != from)
5767 goto out_unlock;
5768
5769 pgdat = page_pgdat(page);
5770 from_vec = mem_cgroup_lruvec(from, pgdat);
5771 to_vec = mem_cgroup_lruvec(to, pgdat);
5772
5773 lock_page_memcg(page);
5774
5775 if (PageAnon(page)) {
5776 if (page_mapped(page)) {
5777 __mod_lruvec_state(from_vec, NR_ANON_MAPPED, -nr_pages);
5778 __mod_lruvec_state(to_vec, NR_ANON_MAPPED, nr_pages);
5779 if (PageTransHuge(page)) {
5780 __mod_lruvec_state(from_vec, NR_ANON_THPS,
5781 -nr_pages);
5782 __mod_lruvec_state(to_vec, NR_ANON_THPS,
5783 nr_pages);
5784 }
5785 }
5786 } else {
5787 __mod_lruvec_state(from_vec, NR_FILE_PAGES, -nr_pages);
5788 __mod_lruvec_state(to_vec, NR_FILE_PAGES, nr_pages);
5789
5790 if (PageSwapBacked(page)) {
5791 __mod_lruvec_state(from_vec, NR_SHMEM, -nr_pages);
5792 __mod_lruvec_state(to_vec, NR_SHMEM, nr_pages);
5793 }
5794
5795 if (page_mapped(page)) {
5796 __mod_lruvec_state(from_vec, NR_FILE_MAPPED, -nr_pages);
5797 __mod_lruvec_state(to_vec, NR_FILE_MAPPED, nr_pages);
5798 }
5799
5800 if (PageDirty(page)) {
5801 struct address_space *mapping = page_mapping(page);
5802
5803 if (mapping_can_writeback(mapping)) {
5804 __mod_lruvec_state(from_vec, NR_FILE_DIRTY,
5805 -nr_pages);
5806 __mod_lruvec_state(to_vec, NR_FILE_DIRTY,
5807 nr_pages);
5808 }
5809 }
5810 }
5811
5812 if (PageWriteback(page)) {
5813 __mod_lruvec_state(from_vec, NR_WRITEBACK, -nr_pages);
5814 __mod_lruvec_state(to_vec, NR_WRITEBACK, nr_pages);
5815 }
5816
5817 /*
5818 * All state has been migrated, let's switch to the new memcg.
5819 *
5820 * It is safe to change page's memcg here because the page
5821 * is referenced, charged, isolated, and locked: we can't race
5822 * with (un)charging, migration, LRU putback, or anything else
5823 * that would rely on a stable page's memory cgroup.
5824 *
5825 * Note that lock_page_memcg is a memcg lock, not a page lock,
5826 * to save space. As soon as we switch page's memory cgroup to a
5827 * new memcg that isn't locked, the above state can change
5828 * concurrently again. Make sure we're truly done with it.
5829 */
5830 smp_mb();
5831
> 5832 obj_cgroup_get(to->objcg);
5833 obj_cgroup_put(from->objcg);
5834
5835 page->memcg_data = (unsigned long)to->objcg;
5836
5837 __unlock_page_memcg(from);
5838
5839 ret = 0;
5840
5841 local_irq_disable();
5842 mem_cgroup_charge_statistics(to, page, nr_pages);
5843 memcg_check_events(to, page);
5844 mem_cgroup_charge_statistics(from, page, -nr_pages);
5845 memcg_check_events(from, page);
5846 local_irq_enable();
5847 out_unlock:
5848 unlock_page(page);
5849 out:
5850 return ret;
5851 }
5852

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

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