* Re: [PATCH v3 01/20] mm/swap: decouple swap cache from physical swap infrastructure
[not found] <20260208215839.87595-2-nphamcs@gmail.com>
@ 2026-02-09 2:22 ` kernel test robot
0 siblings, 0 replies; only message in thread
From: kernel test robot @ 2026-02-09 2:22 UTC (permalink / raw)
To: Nhat Pham, linux-mm
Cc: llvm, oe-kbuild-all, akpm, hannes, hughd, yosry.ahmed, mhocko,
roman.gushchin, shakeel.butt, muchun.song, len.brown,
chengming.zhou, kasong, chrisl, huang.ying.caritas, ryan.roberts,
shikemeng, viro, baohua, bhe, osalvador, lorenzo.stoakes,
christophe.leroy, pavel, kernel-team, linux-kernel, cgroups,
linux-pm, peterx, riel, joshua.hahnjy
Hi Nhat,
kernel test robot noticed the following build errors:
[auto build test ERROR on linus/master]
[also build test ERROR on v6.19]
[cannot apply to akpm-mm/mm-everything tj-cgroup/for-next tip/smp/core next-20260205]
[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/Nhat-Pham/swap-rearrange-the-swap-header-file/20260209-065842
base: linus/master
patch link: https://lore.kernel.org/r/20260208215839.87595-2-nphamcs%40gmail.com
patch subject: [PATCH v3 01/20] mm/swap: decouple swap cache from physical swap infrastructure
config: x86_64-allnoconfig (https://download.01.org/0day-ci/archive/20260209/202602091044.soVrWeDA-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260209/202602091044.soVrWeDA-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/202602091044.soVrWeDA-lkp@intel.com/
All errors (new ones prefixed by >>):
>> mm/vmscan.c:715:3: error: call to undeclared function 'swap_cache_lock_irq'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
715 | swap_cache_lock_irq();
| ^
>> mm/vmscan.c:762:3: error: call to undeclared function 'swap_cache_unlock_irq'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
762 | swap_cache_unlock_irq();
| ^
mm/vmscan.c:762:3: note: did you mean 'swap_cluster_unlock_irq'?
mm/swap.h:350:20: note: 'swap_cluster_unlock_irq' declared here
350 | static inline void swap_cluster_unlock_irq(struct swap_cluster_info *ci)
| ^
mm/vmscan.c:801:3: error: call to undeclared function 'swap_cache_unlock_irq'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
801 | swap_cache_unlock_irq();
| ^
3 errors generated.
--
>> mm/shmem.c:2168:2: error: call to undeclared function 'swap_cache_lock_irq'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
2168 | swap_cache_lock_irq();
| ^
>> mm/shmem.c:2173:2: error: call to undeclared function 'swap_cache_unlock_irq'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
2173 | swap_cache_unlock_irq();
| ^
2 errors generated.
vim +/swap_cache_lock_irq +715 mm/vmscan.c
700
701 /*
702 * Same as remove_mapping, but if the folio is removed from the mapping, it
703 * gets returned with a refcount of 0.
704 */
705 static int __remove_mapping(struct address_space *mapping, struct folio *folio,
706 bool reclaimed, struct mem_cgroup *target_memcg)
707 {
708 int refcount;
709 void *shadow = NULL;
710
711 BUG_ON(!folio_test_locked(folio));
712 BUG_ON(mapping != folio_mapping(folio));
713
714 if (folio_test_swapcache(folio)) {
> 715 swap_cache_lock_irq();
716 } else {
717 spin_lock(&mapping->host->i_lock);
718 xa_lock_irq(&mapping->i_pages);
719 }
720
721 /*
722 * The non racy check for a busy folio.
723 *
724 * Must be careful with the order of the tests. When someone has
725 * a ref to the folio, it may be possible that they dirty it then
726 * drop the reference. So if the dirty flag is tested before the
727 * refcount here, then the following race may occur:
728 *
729 * get_user_pages(&page);
730 * [user mapping goes away]
731 * write_to(page);
732 * !folio_test_dirty(folio) [good]
733 * folio_set_dirty(folio);
734 * folio_put(folio);
735 * !refcount(folio) [good, discard it]
736 *
737 * [oops, our write_to data is lost]
738 *
739 * Reversing the order of the tests ensures such a situation cannot
740 * escape unnoticed. The smp_rmb is needed to ensure the folio->flags
741 * load is not satisfied before that of folio->_refcount.
742 *
743 * Note that if the dirty flag is always set via folio_mark_dirty,
744 * and thus under the i_pages lock, then this ordering is not required.
745 */
746 refcount = 1 + folio_nr_pages(folio);
747 if (!folio_ref_freeze(folio, refcount))
748 goto cannot_free;
749 /* note: atomic_cmpxchg in folio_ref_freeze provides the smp_rmb */
750 if (unlikely(folio_test_dirty(folio))) {
751 folio_ref_unfreeze(folio, refcount);
752 goto cannot_free;
753 }
754
755 if (folio_test_swapcache(folio)) {
756 swp_entry_t swap = folio->swap;
757
758 if (reclaimed && !mapping_exiting(mapping))
759 shadow = workingset_eviction(folio, target_memcg);
760 __swap_cache_del_folio(folio, swap, shadow);
761 memcg1_swapout(folio, swap);
> 762 swap_cache_unlock_irq();
763 put_swap_folio(folio, swap);
764 } else {
765 void (*free_folio)(struct folio *);
766
767 free_folio = mapping->a_ops->free_folio;
768 /*
769 * Remember a shadow entry for reclaimed file cache in
770 * order to detect refaults, thus thrashing, later on.
771 *
772 * But don't store shadows in an address space that is
773 * already exiting. This is not just an optimization,
774 * inode reclaim needs to empty out the radix tree or
775 * the nodes are lost. Don't plant shadows behind its
776 * back.
777 *
778 * We also don't store shadows for DAX mappings because the
779 * only page cache folios found in these are zero pages
780 * covering holes, and because we don't want to mix DAX
781 * exceptional entries and shadow exceptional entries in the
782 * same address_space.
783 */
784 if (reclaimed && folio_is_file_lru(folio) &&
785 !mapping_exiting(mapping) && !dax_mapping(mapping))
786 shadow = workingset_eviction(folio, target_memcg);
787 __filemap_remove_folio(folio, shadow);
788 xa_unlock_irq(&mapping->i_pages);
789 if (mapping_shrinkable(mapping))
790 inode_lru_list_add(mapping->host);
791 spin_unlock(&mapping->host->i_lock);
792
793 if (free_folio)
794 free_folio(folio);
795 }
796
797 return 1;
798
799 cannot_free:
800 if (folio_test_swapcache(folio)) {
801 swap_cache_unlock_irq();
802 } else {
803 xa_unlock_irq(&mapping->i_pages);
804 spin_unlock(&mapping->host->i_lock);
805 }
806 return 0;
807 }
808
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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