Hi Muchun, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on next-20210813] [cannot apply to hnaz-linux-mm/master cgroup/for-next linus/master v5.14-rc5 v5.14-rc4 v5.14-rc3 v5.14-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] url: https://github.com/0day-ci/linux/commits/Muchun-Song/Use-obj_cgroup-APIs-... base: 4b358aabb93a2c654cd1dcab1a25a589f6e2b153 config: s390-randconfig-r044-20210814 (attached as .config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 1f7b25ea76a925aca690da28de9d78db7ca99d0c) 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 # install s390 cross compiling tool for clang build # apt-get install binutils-s390x-linux-gnu # https://github.com/0day-ci/linux/commit/3460bcf13b968edf6f4621c0e0dcde465... 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/20210814-132844 git checkout 3460bcf13b968edf6f4621c0e0dcde46500957e5 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=s390 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): In file included from mm/huge_memory.c:16: In file included from include/linux/rmap.h:12: In file included from include/linux/memcontrol.h:22: In file included from include/linux/writeback.h:14: In file included from include/linux/blk-cgroup.h:23: In file included from include/linux/blkdev.h:23: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:464:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __raw_readb(PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:477:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:36:59: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x)) ^ include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16' #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x)) ^ In file included from mm/huge_memory.c:16: In file included from include/linux/rmap.h:12: In file included from include/linux/memcontrol.h:22: In file included from include/linux/writeback.h:14: In file included from include/linux/blk-cgroup.h:23: In file included from include/linux/blkdev.h:23: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32' #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x)) ^ In file included from mm/huge_memory.c:16: In file included from include/linux/rmap.h:12: In file included from include/linux/memcontrol.h:22: In file included from include/linux/writeback.h:14: In file included from include/linux/blk-cgroup.h:23: In file included from include/linux/blkdev.h:23: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ struct mem_cgroup *memcg; ^ 13 warnings generated. vim +/memcg +2797 mm/huge_memory.c 2793 2794 void deferred_split_huge_page(struct page *page) 2795 { 2796 struct deferred_split *ds_queue; 2798 unsigned long flags; 2799 2800 VM_BUG_ON_PAGE(!PageTransHuge(page), page); 2801 2802 /* 2803 * The try_to_unmap() in page reclaim path might reach here too, 2804 * this may cause a race condition to corrupt deferred split queue. 2805 * And, if page reclaim is already handling the same page, it is 2806 * unnecessary to handle it again in shrinker. 2807 * 2808 * Check PageSwapCache to determine if the page is being 2809 * handled by page reclaim since THP swap would add the page into 2810 * swap cache before calling try_to_unmap(). 2811 */ 2812 if (PageSwapCache(page)) 2813 return; 2814 2815 ds_queue = folio_split_queue_lock_irqsave(page_folio(page), &flags); 2816 memcg = split_queue_memcg(ds_queue); 2817 if (list_empty(page_deferred_list(page))) { 2818 count_vm_event(THP_DEFERRED_SPLIT_PAGE); 2819 list_add_tail(page_deferred_list(page), &ds_queue->split_queue); 2820 ds_queue->split_queue_len++; 2821 #ifdef CONFIG_MEMCG 2822 if (memcg) 2823 set_shrinker_bit(memcg, page_to_nid(page), 2824 deferred_split_shrinker.id); 2825 #endif 2826 } 2827 split_queue_unlock_irqrestore(ds_queue, flags); 2828 } 2829 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org