Re: [PATCH 3/3] mm/lru_gen: Don't build multi-gen LRU page table walk code on architecture not supported

[kernel test robot <lkp@intel.com>]

Hi Aneesh,

kernel test robot noticed the following build warnings:

[auto build test WARNING on arm64/for-next/core]
[also build test WARNING on linus/master tip/x86/core v6.4-rc7 next-20230620]
[cannot apply to akpm-mm/mm-everything]
[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/Aneesh-Kumar-K-V/mm-lru_gen-lru_gen_look_around-simplification/20230613-200408
base:   https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core
patch link:    https://lore.kernel.org/r/20230613120047.149573-3-aneesh.kumar%40linux.ibm.com
patch subject: [PATCH 3/3] mm/lru_gen: Don't build multi-gen LRU page table walk code on architecture not supported
config: alpha-allmodconfig (https://download.01.org/0day-ci/archive/20230621/202306211018.fodsNZaR-lkp@intel.com/config)
compiler: alpha-linux-gcc (GCC) 12.3.0
reproduce: (https://download.01.org/0day-ci/archive/20230621/202306211018.fodsNZaR-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/202306211018.fodsNZaR-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> mm/vmscan.c:4564:6: warning: no previous prototype for '__try_to_inc_max_seq' [-Wmissing-prototypes]
    4564 | bool __try_to_inc_max_seq(struct lruvec *lruvec, unsigned long max_seq,
         |      ^~~~~~~~~~~~~~~~~~~~


vim +/__try_to_inc_max_seq +4564 mm/vmscan.c

  4559	
  4560	/*
  4561	 * inc_max_seq can drop the lru_lock in between. So use a waitqueue seq_update_progress
  4562	 * to allow concurrent access.
  4563	 */
> 4564	bool __try_to_inc_max_seq(struct lruvec *lruvec, unsigned long max_seq,
  4565				  bool can_swap, bool force_scan)
  4566	{
  4567		bool success = false;
  4568		struct lru_gen_folio *lrugen = &lruvec->lrugen;
  4569	
  4570		VM_WARN_ON_ONCE(max_seq > READ_ONCE(lrugen->max_seq));
  4571	
  4572		/* see the comment in iterate_mm_list() */
  4573		if (lruvec->seq_update_progress)
  4574			success = false;
  4575		else {
  4576			spin_lock_irq(&lruvec->lru_lock);
  4577	
  4578			if (max_seq != lrugen->max_seq)
  4579				goto done;
  4580	
  4581			if (lruvec->seq_update_progress)
  4582				goto done;
  4583	
  4584			success = true;
  4585			lruvec->seq_update_progress = true;
  4586	done:
  4587			spin_unlock_irq(&lruvec->lru_lock);
  4588		}
  4589	
  4590		if (success)
  4591			inc_max_seq(lruvec, can_swap, force_scan);
  4592	
  4593		return success;
  4594	}
  4595	

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