Hi Nicholas, I love your patch! Perhaps something to improve: [auto build test WARNING on linux/master] [also build test WARNING on linus/master hnaz-linux-mm/master v5.12-rc3 next-20210317] [cannot apply to tip/sched/core] [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/Nicholas-Piggin/Increase-page-an... base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git a74e6a014c9d4d4161061f770c9b4f98372ac778 config: x86_64-randconfig-a015-20210317 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 8ef111222a3dd12a9175f69c3bff598c46e8bdf7) 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 x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu # https://github.com/0day-ci/linux/commit/d741b0903849631440ae34fb070178e97... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Nicholas-Piggin/Increase-page-and-bit-waitqueue-hash-size/20210317-155619 git checkout d741b0903849631440ae34fb070178e9743c6928 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 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 >>): static wait_queue_head_t page_wait_table[PAGE_WAIT_TABLE_SIZE] __cacheline_aligned; ^~~~~~~~~~~~~~~~~~~~ mm/filemap.c:994:30: note: expanded from macro 'PAGE_WAIT_TABLE_SIZE' #define PAGE_WAIT_TABLE_SIZE (1 << page_wait_table_bits) ^~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/filemap.c:1018:8: error: passing 'const unsigned int *' to parameter of type 'unsigned int *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers] &page_wait_table_bits, ^~~~~~~~~~~~~~~~~~~~~ include/linux/memblock.h:579:24: note: passing argument to parameter '_hash_shift' here unsigned int *_hash_shift, ^ mm/filemap.c:1013:19: error: array type 'wait_queue_head_t [16]' is not assignable page_wait_table = alloc_large_system_hash("page waitqueue hash", ~~~~~~~~~~~~~~~ ^ 1 warning and 2 errors generated. -- static wait_queue_head_t bit_wait_table[BIT_WAIT_TABLE_SIZE] __cacheline_aligned; ^~~~~~~~~~~~~~~~~~~ kernel/sched/wait_bit.c:8:29: note: expanded from macro 'BIT_WAIT_TABLE_SIZE' #define BIT_WAIT_TABLE_SIZE (1 << bit_wait_table_bits) ^~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/sched/wait_bit.c:260:8: error: passing 'const unsigned int *' to parameter of type 'unsigned int *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers] &bit_wait_table_bits, ^~~~~~~~~~~~~~~~~~~~ include/linux/memblock.h:579:24: note: passing argument to parameter '_hash_shift' here unsigned int *_hash_shift, ^ kernel/sched/wait_bit.c:255:18: error: array type 'wait_queue_head_t [8]' is not assignable bit_wait_table = alloc_large_system_hash("bit waitqueue hash", ~~~~~~~~~~~~~~ ^ 1 warning and 2 errors generated. vim +997 mm/filemap.c 44110fe385af23 Paul Jackson 2006-03-24 983 ^1da177e4c3f41 Linus Torvalds 2005-04-16 984 /* ^1da177e4c3f41 Linus Torvalds 2005-04-16 985 * In order to wait for pages to become available there must be ^1da177e4c3f41 Linus Torvalds 2005-04-16 986 * waitqueues associated with pages. By using a hash table of ^1da177e4c3f41 Linus Torvalds 2005-04-16 987 * waitqueues where the bucket discipline is to maintain all ^1da177e4c3f41 Linus Torvalds 2005-04-16 988 * waiters on the same queue and wake all when any of the pages ^1da177e4c3f41 Linus Torvalds 2005-04-16 989 * become available, and for the woken contexts to check to be ^1da177e4c3f41 Linus Torvalds 2005-04-16 990 * sure the appropriate page became available, this saves space ^1da177e4c3f41 Linus Torvalds 2005-04-16 991 * at a cost of "thundering herd" phenomena during rare hash ^1da177e4c3f41 Linus Torvalds 2005-04-16 992 * collisions. ^1da177e4c3f41 Linus Torvalds 2005-04-16 993 */ d741b090384963 Nicholas Piggin 2021-03-17 994 #define PAGE_WAIT_TABLE_SIZE (1 << page_wait_table_bits) d741b090384963 Nicholas Piggin 2021-03-17 995 #if CONFIG_BASE_SMALL d741b090384963 Nicholas Piggin 2021-03-17 996 static const unsigned int page_wait_table_bits = 4; 62906027091f1d Nicholas Piggin 2016-12-25 @997 static wait_queue_head_t page_wait_table[PAGE_WAIT_TABLE_SIZE] __cacheline_aligned; d741b090384963 Nicholas Piggin 2021-03-17 998 #else d741b090384963 Nicholas Piggin 2021-03-17 999 static unsigned int page_wait_table_bits __ro_after_init; d741b090384963 Nicholas Piggin 2021-03-17 1000 static wait_queue_head_t *page_wait_table __ro_after_init; d741b090384963 Nicholas Piggin 2021-03-17 1001 #endif 62906027091f1d Nicholas Piggin 2016-12-25 1002 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org