Hi Minchan, I love your patch! Perhaps something to improve:
[auto build test WARNING on linux/master] [also build test WARNING on linus/master v5.12-rc2 next-20210309] [cannot apply to hnaz-linux-mm/master] [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/Minchan-Kim/mm-disable-LRU-pagevec-during-the-migration-temporarily/20210309-131826 base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 144c79ef33536b4ecb4951e07dbc1f2b7fa99d32 config: arm64-randconfig-r023-20210308 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 820f508b08d7c94b2dd7847e9710d2bc36d3dd45) 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 arm64 cross compiling tool for clang build # apt-get install binutils-aarch64-linux-gnu # https://github.com/0day-ci/linux/commit/e746db1a2ab13441890fa2cad8604bbec190b401 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Minchan-Kim/mm-disable-LRU-pagevec-during-the-migration-temporarily/20210309-131826 git checkout e746db1a2ab13441890fa2cad8604bbec190b401 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <l...@intel.com> All warnings (new ones prefixed by >>): mm/swap.c:244:4: error: implicit declaration of function 'lru_cache_disabled' [-Werror,-Wimplicit-function-declaration] lru_cache_disabled()) ^ mm/swap.c:244:4: note: did you mean 'lru_cache_disable'? include/linux/swap.h:342:13: note: 'lru_cache_disable' declared here extern void lru_cache_disable(void); ^ >> mm/swap.c:743:6: warning: no previous prototype for function >> '__lru_add_drain_all' [-Wmissing-prototypes] void __lru_add_drain_all(bool force_all_cpus) ^ mm/swap.c:743:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __lru_add_drain_all(bool force_all_cpus) ^ static mm/swap.c:858:6: error: conflicting types for 'lru_cache_disabled' bool lru_cache_disabled(void) ^ mm/swap.c:244:4: note: previous implicit declaration is here lru_cache_disabled()) ^ 1 warning and 2 errors generated. vim +/__lru_add_drain_all +743 mm/swap.c 742 > 743 void __lru_add_drain_all(bool force_all_cpus) 744 { 745 /* 746 * lru_drain_gen - Global pages generation number 747 * 748 * (A) Definition: global lru_drain_gen = x implies that all generations 749 * 0 < n <= x are already *scheduled* for draining. 750 * 751 * This is an optimization for the highly-contended use case where a 752 * user space workload keeps constantly generating a flow of pages for 753 * each CPU. 754 */ 755 static unsigned int lru_drain_gen; 756 static struct cpumask has_work; 757 static DEFINE_MUTEX(lock); 758 unsigned cpu, this_gen; 759 760 /* 761 * Make sure nobody triggers this path before mm_percpu_wq is fully 762 * initialized. 763 */ 764 if (WARN_ON(!mm_percpu_wq)) 765 return; 766 767 /* 768 * Guarantee pagevec counter stores visible by this CPU are visible to 769 * other CPUs before loading the current drain generation. 770 */ 771 smp_mb(); 772 773 /* 774 * (B) Locally cache global LRU draining generation number 775 * 776 * The read barrier ensures that the counter is loaded before the mutex 777 * is taken. It pairs with smp_mb() inside the mutex critical section 778 * at (D). 779 */ 780 this_gen = smp_load_acquire(&lru_drain_gen); 781 782 mutex_lock(&lock); 783 784 /* 785 * (C) Exit the draining operation if a newer generation, from another 786 * lru_add_drain_all(), was already scheduled for draining. Check (A). 787 */ 788 if (unlikely(this_gen != lru_drain_gen && !force_all_cpus)) 789 goto done; 790 791 /* 792 * (D) Increment global generation number 793 * 794 * Pairs with smp_load_acquire() at (B), outside of the critical 795 * section. Use a full memory barrier to guarantee that the new global 796 * drain generation number is stored before loading pagevec counters. 797 * 798 * This pairing must be done here, before the for_each_online_cpu loop 799 * below which drains the page vectors. 800 * 801 * Let x, y, and z represent some system CPU numbers, where x < y < z. 802 * Assume CPU #z is is in the middle of the for_each_online_cpu loop 803 * below and has already reached CPU #y's per-cpu data. CPU #x comes 804 * along, adds some pages to its per-cpu vectors, then calls 805 * lru_add_drain_all(). 806 * 807 * If the paired barrier is done at any later step, e.g. after the 808 * loop, CPU #x will just exit at (C) and miss flushing out all of its 809 * added pages. 810 */ 811 WRITE_ONCE(lru_drain_gen, lru_drain_gen + 1); 812 smp_mb(); 813 814 cpumask_clear(&has_work); 815 for_each_online_cpu(cpu) { 816 struct work_struct *work = &per_cpu(lru_add_drain_work, cpu); 817 818 if (force_all_cpus || 819 pagevec_count(&per_cpu(lru_pvecs.lru_add, cpu)) || 820 data_race(pagevec_count(&per_cpu(lru_rotate.pvec, cpu))) || 821 pagevec_count(&per_cpu(lru_pvecs.lru_deactivate_file, cpu)) || 822 pagevec_count(&per_cpu(lru_pvecs.lru_deactivate, cpu)) || 823 pagevec_count(&per_cpu(lru_pvecs.lru_lazyfree, cpu)) || 824 need_activate_page_drain(cpu)) { 825 INIT_WORK(work, lru_add_drain_per_cpu); 826 queue_work_on(cpu, mm_percpu_wq, work); 827 __cpumask_set_cpu(cpu, &has_work); 828 } 829 } 830 831 for_each_cpu(cpu, &has_work) 832 flush_work(&per_cpu(lru_add_drain_work, cpu)); 833 834 done: 835 mutex_unlock(&lock); 836 } 837 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-...@lists.01.org
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