Re: [PATCH v3 24/30] mm: memcontrol: prepare for reparenting LRU pages for lruvec lock

[Qi Zheng <qi.zheng@linux.dev>]

Hi,

The compilation problem I see in the report occurs under the following
configuration:

1. enable CONFIG_WARN_CONTEXT_ANALYSIS_ALL
2. make CC=clang bzImage

Could you please test whether the following fixes can resolve the
compilation issue?

Thanks!

```
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index e0b84b109b7ac..f28c5ef9bf604 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -742,15 +742,9 @@ struct mem_cgroup *get_mem_cgroup_from_current(void);
  struct mem_cgroup *get_mem_cgroup_from_folio(struct folio *folio);

  struct lruvec *folio_lruvec_lock(struct folio *folio);
-       __acquires(&lruvec->lru_lock)
-       __acquires(rcu)
  struct lruvec *folio_lruvec_lock_irq(struct folio *folio);
-       __acquires(&lruvec->lru_lock)
-       __acquires(rcu)
  struct lruvec *folio_lruvec_lock_irqsave(struct folio *folio,
                                                 unsigned long *flags);
-       __acquires(&lruvec->lru_lock)
-       __acquires(rcu)

  static inline
  struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css){
@@ -1477,38 +1471,10 @@ static inline struct lruvec 
*parent_lruvec(struct lruvec *lruvec)
         return mem_cgroup_lruvec(memcg, lruvec_pgdat(lruvec));
  }

-static inline void lruvec_lock_irq(struct lruvec *lruvec)
-       __acquires(&lruvec->lru_lock)
-       __acquires(rcu)
-{
-       rcu_read_lock();
-       spin_lock_irq(&lruvec->lru_lock);
-}
-
-static inline void lruvec_unlock(struct lruvec *lruvec)
-       __releases(&lruvec->lru_lock)
-       __releases(rcu)
-{
-       spin_unlock(&lruvec->lru_lock);
-       rcu_read_unlock();
-}
-
-static inline void lruvec_unlock_irq(struct lruvec *lruvec)
-       __releases(&lruvec->lru_lock)
-       __releases(rcu)
-{
-       spin_unlock_irq(&lruvec->lru_lock);
-       rcu_read_unlock();
-}
-
-static inline void lruvec_unlock_irqrestore(struct lruvec *lruvec,
-               unsigned long flags)
-       __releases(&lruvec->lru_lock)
-       __releases(rcu)
-{
-       spin_unlock_irqrestore(&lruvec->lru_lock, flags);
-       rcu_read_unlock();
-}
+void lruvec_lock_irq(struct lruvec *lruvec);
+void lruvec_unlock(struct lruvec *lruvec);
+void lruvec_unlock_irq(struct lruvec *lruvec);
+void lruvec_unlock_irqrestore(struct lruvec *lruvec, unsigned long flags);

  /* Test requires a stable folio->memcg binding, see folio_memcg() */
  static inline bool folio_matches_lruvec(struct folio *folio,
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 4449d1f371a56..77a6a9fa11981 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -328,9 +328,7 @@ extern unsigned long totalreserve_pages;

  /* linux/mm/swap.c */
  void lru_note_cost_unlock_irq(struct lruvec *lruvec, bool file,
-               unsigned int nr_io, unsigned int nr_rotated)
-               __releases(lruvec->lru_lock);
-               __releases(rcu)
+               unsigned int nr_io, unsigned int nr_rotated);
  void lru_note_cost_refault(struct folio *);
  void folio_add_lru(struct folio *);
  void folio_add_lru_vma(struct folio *, struct vm_area_struct *);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c303c483f55a4..8907c9ea33bbc 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1313,6 +1313,39 @@ void mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
         }
  }

+void lruvec_lock_irq(struct lruvec *lruvec)
+       __acquires(&lruvec->lru_lock)
+       __acquires(rcu)
+{
+       rcu_read_lock();
+       spin_lock_irq(&lruvec->lru_lock);
+}
+
+void lruvec_unlock(struct lruvec *lruvec)
+       __releases(&lruvec->lru_lock)
+       __releases(rcu)
+{
+       spin_unlock(&lruvec->lru_lock);
+       rcu_read_unlock();
+}
+
+void lruvec_unlock_irq(struct lruvec *lruvec)
+       __releases(&lruvec->lru_lock)
+       __releases(rcu)
+{
+       spin_unlock_irq(&lruvec->lru_lock);
+       rcu_read_unlock();
+}
+
+void lruvec_unlock_irqrestore(struct lruvec *lruvec,
+               unsigned long flags)
+       __releases(&lruvec->lru_lock)
+       __releases(rcu)
+{
+       spin_unlock_irqrestore(&lruvec->lru_lock, flags);
+       rcu_read_unlock();
+}
+
  /**
   * folio_lruvec_lock - Lock the lruvec for a folio.
   * @folio: Pointer to the folio.

```

On 1/15/26 8:34 PM, kernel test robot wrote:
> Hi Qi,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on next-20260114]
> [cannot apply to akpm-mm/mm-everything brauner-vfs/vfs.all trace/for-next linus/master dennis-percpu/for-next v6.19-rc5 v6.19-rc4 v6.19-rc3 v6.19-rc5]
> [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/Qi-Zheng/mm-memcontrol-remove-dead-code-of-checking-parent-memory-cgroup/20260114-193921
> base:   next-20260114
> patch link:    https://lore.kernel.org/r/0252f9acc29d4b1e9b8252dc003aff065c8ac1f6.1768389889.git.zhengqi.arch%40bytedance.com
> patch subject: [PATCH v3 24/30] mm: memcontrol: prepare for reparenting LRU pages for lruvec lock
> config: powerpc64-randconfig-002-20260115 (https://download.01.org/0day-ci/archive/20260115/202601152057.xgusZpKm-lkp@intel.com/config)
> compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 9b8addffa70cee5b2acc5454712d9cf78ce45710)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260115/202601152057.xgusZpKm-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/202601152057.xgusZpKm-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
>     In file included from crypto/ahash.c:26:
>     In file included from include/net/netlink.h:6:
>     In file included from include/linux/netlink.h:9:
>     In file included from include/net/scm.h:9:
>     In file included from include/linux/security.h:35:
>     In file included from include/linux/bpf.h:32:
>>> include/linux/memcontrol.h:772:14: error: use of undeclared identifier 'lruvec'
>       772 |         __acquires(&lruvec->lru_lock)
>           |                     ^~~~~~
>     include/linux/memcontrol.h:773:13: error: use of undeclared identifier 'rcu'
>       773 |         __acquires(rcu)
>           |                    ^~~
>     include/linux/memcontrol.h:775:14: error: use of undeclared identifier 'lruvec'
>       775 |         __acquires(&lruvec->lru_lock)
>           |                     ^~~~~~
>     include/linux/memcontrol.h:776:13: error: use of undeclared identifier 'rcu'
>       776 |         __acquires(rcu)
>           |                    ^~~
>     include/linux/memcontrol.h:779:14: error: use of undeclared identifier 'lruvec'
>       779 |         __acquires(&lruvec->lru_lock)
>           |                     ^~~~~~
>     include/linux/memcontrol.h:780:13: error: use of undeclared identifier 'rcu'
>       780 |         __acquires(rcu)
>           |                    ^~~
>     include/linux/memcontrol.h:1507:13: error: use of undeclared identifier 'rcu'
>      1507 |         __acquires(rcu)
>           |                    ^~~
>     include/linux/memcontrol.h:1515:13: error: use of undeclared identifier 'rcu'
>      1515 |         __releases(rcu)
>           |                    ^~~
>     include/linux/memcontrol.h:1523:13: error: use of undeclared identifier 'rcu'
>      1523 |         __releases(rcu)
>           |                    ^~~
>     include/linux/memcontrol.h:1532:13: error: use of undeclared identifier 'rcu'
>      1532 |         __releases(rcu)
>           |                    ^~~
>     In file included from crypto/ahash.c:26:
>     In file included from include/net/netlink.h:6:
>     In file included from include/linux/netlink.h:9:
>     In file included from include/net/scm.h:13:
>     In file included from include/net/compat.h:8:
>     include/linux/compat.h:454:22: warning: array index 3 is past the end of the array (that has type 'const unsigned long[1]') [-Warray-bounds]
>       454 |         case 4: v.sig[7] = (set->sig[3] >> 32); v.sig[6] = set->sig[3];
>           |                             ^        ~
>     arch/powerpc/include/uapi/asm/signal.h:18:2: note: array 'sig' declared here
>        18 |         unsigned long sig[_NSIG_WORDS];
>           |         ^
>     In file included from crypto/ahash.c:26:
>     In file included from include/net/netlink.h:6:
>     In file included from include/linux/netlink.h:9:
>     In file included from include/net/scm.h:13:
>     In file included from include/net/compat.h:8:
>     include/linux/compat.h:454:10: warning: array index 7 is past the end of the array (that has type 'compat_sigset_word[2]' (aka 'unsigned int[2]')) [-Warray-bounds]
>       454 |         case 4: v.sig[7] = (set->sig[3] >> 32); v.sig[6] = set->sig[3];
>           |                 ^     ~
>     include/linux/compat.h:130:2: note: array 'sig' declared here
>       130 |         compat_sigset_word      sig[_COMPAT_NSIG_WORDS];
>           |         ^
>     include/linux/compat.h:454:42: warning: array index 6 is past the end of the array (that has type 'compat_sigset_word[2]' (aka 'unsigned int[2]')) [-Warray-bounds]
>       454 |         case 4: v.sig[7] = (set->sig[3] >> 32); v.sig[6] = set->sig[3];
>           |                                                 ^     ~
>     include/linux/compat.h:130:2: note: array 'sig' declared here
>       130 |         compat_sigset_word      sig[_COMPAT_NSIG_WORDS];
>           |         ^
>     include/linux/compat.h:454:53: warning: array index 3 is past the end of the array (that has type 'const unsigned long[1]') [-Warray-bounds]
>       454 |         case 4: v.sig[7] = (set->sig[3] >> 32); v.sig[6] = set->sig[3];
>           |                                                            ^        ~
>     arch/powerpc/include/uapi/asm/signal.h:18:2: note: array 'sig' declared here
>        18 |         unsigned long sig[_NSIG_WORDS];
>           |         ^
>     In file included from crypto/ahash.c:26:
>     In file included from include/net/netlink.h:6:
>     In file included from include/linux/netlink.h:9:
>     In file included from include/net/scm.h:13:
>     In file included from include/net/compat.h:8:
>     include/linux/compat.h:456:22: warning: array index 2 is past the end of the array (that has type 'const unsigned long[1]') [-Warray-bounds]
>       456 |         case 3: v.sig[5] = (set->sig[2] >> 32); v.sig[4] = set->sig[2];
>           |                             ^        ~
>     arch/powerpc/include/uapi/asm/signal.h:18:2: note: array 'sig' declared here
>        18 |         unsigned long sig[_NSIG_WORDS];
>           |         ^
>     In file included from crypto/ahash.c:26:
>     In file included from include/net/netlink.h:6:
>     In file included from include/linux/netlink.h:9:
>     In file included from include/net/scm.h:13:
>     In file included from include/net/compat.h:8:
>     include/linux/compat.h:456:10: warning: array index 5 is past the end of the array (that has type 'compat_sigset_word[2]' (aka 'unsigned int[2]')) [-Warray-bounds]
>       456 |         case 3: v.sig[5] = (set->sig[2] >> 32); v.sig[4] = set->sig[2];
>           |                 ^     ~
>     include/linux/compat.h:130:2: note: array 'sig' declared here
>       130 |         compat_sigset_word      sig[_COMPAT_NSIG_WORDS];
>           |         ^
>     include/linux/compat.h:456:42: warning: array index 4 is past the end of the array (that has type 'compat_sigset_word[2]' (aka 'unsigned int[2]')) [-Warray-bounds]
>       456 |         case 3: v.sig[5] = (set->sig[2] >> 32); v.sig[4] = set->sig[2];
>           |                                                 ^     ~
>     include/linux/compat.h:130:2: note: array 'sig' declared here
>       130 |         compat_sigset_word      sig[_COMPAT_NSIG_WORDS];
>           |         ^
>     include/linux/compat.h:456:53: warning: array index 2 is past the end of the array (that has type 'const unsigned long[1]') [-Warray-bounds]
>       456 |         case 3: v.sig[5] = (set->sig[2] >> 32); v.sig[4] = set->sig[2];
>           |                                                            ^        ~
>     arch/powerpc/include/uapi/asm/signal.h:18:2: note: array 'sig' declared here
>        18 |         unsigned long sig[_NSIG_WORDS];
>           |         ^
>     In file included from crypto/ahash.c:26:
>     In file included from include/net/netlink.h:6:
>     In file included from include/linux/netlink.h:9:
> 
> 
> vim +/lruvec +772 include/linux/memcontrol.h
> 
>     770	
>     771	struct lruvec *folio_lruvec_lock(struct folio *folio);
>   > 772		__acquires(&lruvec->lru_lock)
>     773		__acquires(rcu)
>     774	struct lruvec *folio_lruvec_lock_irq(struct folio *folio);
>     775		__acquires(&lruvec->lru_lock)
>     776		__acquires(rcu)
>     777	struct lruvec *folio_lruvec_lock_irqsave(struct folio *folio,
>     778							unsigned long *flags);
>     779		__acquires(&lruvec->lru_lock)
>     780		__acquires(rcu)
>     781	
>