Hi "Matthew,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on next-20210630]
[cannot apply to hnaz-linux-mm/master tip/perf/core cgroup/for-next v5.13]
[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/Matthew-Wilcox-Oracle/Folio-conversion-of-memcg/20210630-121408
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 007b350a58754a93ca9fe50c498cc27780171153
config: sparc64-randconfig-r002-20210628 (attached as .config)
compiler: sparc64-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/b527e805e7d7066a8fea14ff4a49f53454c355a1
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Matthew-Wilcox-Oracle/Folio-conversion-of-memcg/20210630-121408
        git checkout b527e805e7d7066a8fea14ff4a49f53454c355a1
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=sparc64 

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

All warnings (new ones prefixed by >>):

     403 |  VM_BUG_ON_FOLIO(folio_slab(folio), folio);
         |  ^~~~~~~~~~~~~~~
         |  VM_BUG_ON_MM
   include/linux/memcontrol.h:403:18: error: implicit declaration of function 'folio_slab' [-Werror=implicit-function-declaration]
     403 |  VM_BUG_ON_FOLIO(folio_slab(folio), folio);
         |                  ^~~~~~~~~~
   include/linux/memcontrol.h: At top level:
   include/linux/memcontrol.h:420:55: warning: 'struct folio' declared inside parameter list will not be visible outside of this definition or declaration
     420 | static inline struct obj_cgroup *__folio_objcg(struct folio *folio)
         |                                                       ^~~~~
   include/linux/memcontrol.h: In function '__folio_objcg':
   include/linux/memcontrol.h:422:34: error: dereferencing pointer to incomplete type 'struct folio'
     422 |  unsigned long memcg_data = folio->memcg_data;
         |                                  ^~
   include/linux/memcontrol.h: At top level:
   include/linux/memcontrol.h:451:53: warning: 'struct folio' declared inside parameter list will not be visible outside of this definition or declaration
     451 | static inline struct mem_cgroup *folio_memcg(struct folio *folio)
         |                                                     ^~~~~
   include/linux/memcontrol.h: In function 'folio_memcg':
   include/linux/memcontrol.h:453:23: error: passing argument 1 of 'folio_memcg_kmem' from incompatible pointer type [-Werror=incompatible-pointer-types]
     453 |  if (folio_memcg_kmem(folio))
         |                       ^~~~~
         |                       |
         |                       struct folio *
   include/linux/memcontrol.h:375:51: note: expected 'struct folio *' but argument is of type 'struct folio *'
     375 | static inline bool folio_memcg_kmem(struct folio *folio);
         |                                     ~~~~~~~~~~~~~~^~~~~
   include/linux/memcontrol.h:454:41: error: passing argument 1 of '__folio_objcg' from incompatible pointer type [-Werror=incompatible-pointer-types]
     454 |   return obj_cgroup_memcg(__folio_objcg(folio));
         |                                         ^~~~~
         |                                         |
         |                                         struct folio *
   include/linux/memcontrol.h:420:62: note: expected 'struct folio *' but argument is of type 'struct folio *'
     420 | static inline struct obj_cgroup *__folio_objcg(struct folio *folio)
         |                                                ~~~~~~~~~~~~~~^~~~~
   include/linux/memcontrol.h:456:24: error: passing argument 1 of '__folio_memcg' from incompatible pointer type [-Werror=incompatible-pointer-types]
     456 |   return __folio_memcg(folio);
         |                        ^~~~~
         |                        |
         |                        struct folio *
   include/linux/memcontrol.h:399:62: note: expected 'struct folio *' but argument is of type 'struct folio *'
     399 | static inline struct mem_cgroup *__folio_memcg(struct folio *folio)
         |                                                ~~~~~~~~~~~~~~^~~~~
   include/linux/memcontrol.h: In function 'page_memcg':
   include/linux/memcontrol.h:461:21: error: implicit declaration of function 'page_folio' [-Werror=implicit-function-declaration]
     461 |  return folio_memcg(page_folio(page));
         |                     ^~~~~~~~~~
   include/linux/memcontrol.h:461:21: warning: passing argument 1 of 'folio_memcg' makes pointer from integer without a cast [-Wint-conversion]
     461 |  return folio_memcg(page_folio(page));
         |                     ^~~~~~~~~~~~~~~~
         |                     |
         |                     int
   include/linux/memcontrol.h:451:60: note: expected 'struct folio *' but argument is of type 'int'
     451 | static inline struct mem_cgroup *folio_memcg(struct folio *folio)
         |                                              ~~~~~~~~~~~~~~^~~~~
   include/linux/memcontrol.h: At top level:
   include/linux/memcontrol.h:589:44: warning: 'struct folio' declared inside parameter list will not be visible outside of this definition or declaration
     589 | static inline bool folio_memcg_kmem(struct folio *folio)
         |                                            ^~~~~
   include/linux/memcontrol.h:589:20: error: conflicting types for 'folio_memcg_kmem'
     589 | static inline bool folio_memcg_kmem(struct folio *folio)
         |                    ^~~~~~~~~~~~~~~~
   include/linux/memcontrol.h:375:20: note: previous declaration of 'folio_memcg_kmem' was here
     375 | static inline bool folio_memcg_kmem(struct folio *folio);
         |                    ^~~~~~~~~~~~~~~~
   include/linux/memcontrol.h: In function 'PageMemcgKmem':
   include/linux/memcontrol.h:607:26: warning: passing argument 1 of 'folio_memcg_kmem' makes pointer from integer without a cast [-Wint-conversion]
     607 |  return folio_memcg_kmem(page_folio(page));
         |                          ^~~~~~~~~~~~~~~~
         |                          |
         |                          int
   include/linux/memcontrol.h:589:51: note: expected 'struct folio *' but argument is of type 'int'
     589 | static inline bool folio_memcg_kmem(struct folio *folio)
         |                                     ~~~~~~~~~~~~~~^~~~~
   include/linux/memcontrol.h: At top level:
   include/linux/memcontrol.h:708:30: warning: 'struct folio' declared inside parameter list will not be visible outside of this definition or declaration
     708 | int mem_cgroup_charge(struct folio *, struct mm_struct *, gfp_t);
         |                              ^~~~~
   include/linux/memcontrol.h:713:33: warning: 'struct folio' declared inside parameter list will not be visible outside of this definition or declaration
     713 | void mem_cgroup_uncharge(struct folio *);
         |                                 ^~~~~
   In file included from arch/sparc/include/asm/bug.h:6,
                    from include/linux/bug.h:5,
                    from include/linux/mmdebug.h:5,
                    from include/linux/mm.h:9,
                    from mm/khugepaged.c:4:
   mm/khugepaged.c: In function 'collapse_huge_page':
   mm/khugepaged.c:1091:33: warning: passing argument 1 of 'mem_cgroup_charge' makes pointer from integer without a cast [-Wint-conversion]
    1091 |  if (unlikely(mem_cgroup_charge(page_folio(new_page), mm, gfp))) {
         |                                 ^~~~~~~~~~~~~~~~~~~~
         |                                 |
         |                                 int
   include/linux/compiler.h:78:42: note: in definition of macro 'unlikely'
      78 | # define unlikely(x) __builtin_expect(!!(x), 0)
         |                                          ^
   In file included from include/linux/rmap.h:12,
                    from mm/khugepaged.c:9:
   include/linux/memcontrol.h:708:23: note: expected 'struct folio *' but argument is of type 'int'
     708 | int mem_cgroup_charge(struct folio *, struct mm_struct *, gfp_t);
         |                       ^~~~~~~~~~~~~~

quoted

mm/khugepaged.c:1215:23: warning: passing argument 1 of 'mem_cgroup_uncharge' makes pointer from integer without a cast [-Wint-conversion]

    1215 |   mem_cgroup_uncharge(page_folio(*hpage));
         |                       ^~~~~~~~~~~~~~~~~~
         |                       |
         |                       int
   In file included from include/linux/rmap.h:12,
                    from mm/khugepaged.c:9:
   include/linux/memcontrol.h:713:26: note: expected 'struct folio *' but argument is of type 'int'
     713 | void mem_cgroup_uncharge(struct folio *);
         |                          ^~~~~~~~~~~~~~
   mm/khugepaged.c: At top level:
   include/linux/memcontrol.h:375:20: warning: 'folio_memcg_kmem' used but never defined
     375 | static inline bool folio_memcg_kmem(struct folio *folio);
         |                    ^~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/mem_cgroup_uncharge +1215 mm/khugepaged.c

  1056	
  1057	static void collapse_huge_page(struct mm_struct *mm,
  1058					   unsigned long address,
  1059					   struct page **hpage,
  1060					   int node, int referenced, int unmapped)
  1061	{
  1062		LIST_HEAD(compound_pagelist);
  1063		pmd_t *pmd, _pmd;
  1064		pte_t *pte;
  1065		pgtable_t pgtable;
  1066		struct page *new_page;
  1067		spinlock_t *pmd_ptl, *pte_ptl;
  1068		int isolated = 0, result = 0;
  1069		struct vm_area_struct *vma;
  1070		struct mmu_notifier_range range;
  1071		gfp_t gfp;
  1072	
  1073		VM_BUG_ON(address & ~HPAGE_PMD_MASK);
  1074	
  1075		/* Only allocate from the target node */
  1076		gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_THISNODE;
  1077	
  1078		/*
  1079		 * Before allocating the hugepage, release the mmap_lock read lock.
  1080		 * The allocation can take potentially a long time if it involves
  1081		 * sync compaction, and we do not need to hold the mmap_lock during
  1082		 * that. We will recheck the vma after taking it again in write mode.
  1083		 */
  1084		mmap_read_unlock(mm);
  1085		new_page = khugepaged_alloc_page(hpage, gfp, node);
  1086		if (!new_page) {
  1087			result = SCAN_ALLOC_HUGE_PAGE_FAIL;
  1088			goto out_nolock;
  1089		}
  1090	
  1091		if (unlikely(mem_cgroup_charge(page_folio(new_page), mm, gfp))) {
  1092			result = SCAN_CGROUP_CHARGE_FAIL;
  1093			goto out_nolock;
  1094		}
  1095		count_memcg_page_event(new_page, THP_COLLAPSE_ALLOC);
  1096	
  1097		mmap_read_lock(mm);
  1098		result = hugepage_vma_revalidate(mm, address, &vma);
  1099		if (result) {
  1100			mmap_read_unlock(mm);
  1101			goto out_nolock;
  1102		}
  1103	
  1104		pmd = mm_find_pmd(mm, address);
  1105		if (!pmd) {
  1106			result = SCAN_PMD_NULL;
  1107			mmap_read_unlock(mm);
  1108			goto out_nolock;
  1109		}
  1110	
  1111		/*
  1112		 * __collapse_huge_page_swapin always returns with mmap_lock locked.
  1113		 * If it fails, we release mmap_lock and jump out_nolock.
  1114		 * Continuing to collapse causes inconsistency.
  1115		 */
  1116		if (unmapped && !__collapse_huge_page_swapin(mm, vma, address,
  1117							     pmd, referenced)) {
  1118			mmap_read_unlock(mm);
  1119			goto out_nolock;
  1120		}
  1121	
  1122		mmap_read_unlock(mm);
  1123		/*
  1124		 * Prevent all access to pagetables with the exception of
  1125		 * gup_fast later handled by the ptep_clear_flush and the VM
  1126		 * handled by the anon_vma lock + PG_lock.
  1127		 */
  1128		mmap_write_lock(mm);
  1129		result = hugepage_vma_revalidate(mm, address, &vma);
  1130		if (result)
  1131			goto out_up_write;
  1132		/* check if the pmd is still valid */
  1133		if (mm_find_pmd(mm, address) != pmd)
  1134			goto out_up_write;
  1135	
  1136		anon_vma_lock_write(vma->anon_vma);
  1137	
  1138		mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, mm,
  1139					address, address + HPAGE_PMD_SIZE);
  1140		mmu_notifier_invalidate_range_start(&range);
  1141	
  1142		pte = pte_offset_map(pmd, address);
  1143		pte_ptl = pte_lockptr(mm, pmd);
  1144	
  1145		pmd_ptl = pmd_lock(mm, pmd); /* probably unnecessary */
  1146		/*
  1147		 * After this gup_fast can't run anymore. This also removes
  1148		 * any huge TLB entry from the CPU so we won't allow
  1149		 * huge and small TLB entries for the same virtual address
  1150		 * to avoid the risk of CPU bugs in that area.
  1151		 */
  1152		_pmd = pmdp_collapse_flush(vma, address, pmd);
  1153		spin_unlock(pmd_ptl);
  1154		mmu_notifier_invalidate_range_end(&range);
  1155	
  1156		spin_lock(pte_ptl);
  1157		isolated = __collapse_huge_page_isolate(vma, address, pte,
  1158				&compound_pagelist);
  1159		spin_unlock(pte_ptl);
  1160	
  1161		if (unlikely(!isolated)) {
  1162			pte_unmap(pte);
  1163			spin_lock(pmd_ptl);
  1164			BUG_ON(!pmd_none(*pmd));
  1165			/*
  1166			 * We can only use set_pmd_at when establishing
  1167			 * hugepmds and never for establishing regular pmds that
  1168			 * points to regular pagetables. Use pmd_populate for that
  1169			 */
  1170			pmd_populate(mm, pmd, pmd_pgtable(_pmd));
  1171			spin_unlock(pmd_ptl);
  1172			anon_vma_unlock_write(vma->anon_vma);
  1173			result = SCAN_FAIL;
  1174			goto out_up_write;
  1175		}
  1176	
  1177		/*
  1178		 * All pages are isolated and locked so anon_vma rmap
  1179		 * can't run anymore.
  1180		 */
  1181		anon_vma_unlock_write(vma->anon_vma);
  1182	
  1183		__collapse_huge_page_copy(pte, new_page, vma, address, pte_ptl,
  1184				&compound_pagelist);
  1185		pte_unmap(pte);
  1186		/*
  1187		 * spin_lock() below is not the equivalent of smp_wmb(), but
  1188		 * the smp_wmb() inside __SetPageUptodate() can be reused to
  1189		 * avoid the copy_huge_page writes to become visible after
  1190		 * the set_pmd_at() write.
  1191		 */
  1192		__SetPageUptodate(new_page);
  1193		pgtable = pmd_pgtable(_pmd);
  1194	
  1195		_pmd = mk_huge_pmd(new_page, vma->vm_page_prot);
  1196		_pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma);
  1197	
  1198		spin_lock(pmd_ptl);
  1199		BUG_ON(!pmd_none(*pmd));
  1200		page_add_new_anon_rmap(new_page, vma, address, true);
  1201		lru_cache_add_inactive_or_unevictable(new_page, vma);
  1202		pgtable_trans_huge_deposit(mm, pmd, pgtable);
  1203		set_pmd_at(mm, address, pmd, _pmd);
  1204		update_mmu_cache_pmd(vma, address, pmd);
  1205		spin_unlock(pmd_ptl);
  1206	
  1207		*hpage = NULL;
  1208	
  1209		khugepaged_pages_collapsed++;
  1210		result = SCAN_SUCCEED;
  1211	out_up_write:
  1212		mmap_write_unlock(mm);
  1213	out_nolock:
  1214		if (!IS_ERR_OR_NULL(*hpage))

1215			mem_cgroup_uncharge(page_folio(*hpage));

  1216		trace_mm_collapse_huge_page(mm, isolated, result);
  1217		return;
  1218	}
  1219	

---
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