The patch titled Subject: mm/internal: Implement no-op mlock_page_drain() for !CONFIG_MMU has been added to the -mm tree. Its filename is mm-munlock-mlock_page-munlock_page-batch-by-pagevec-fix-2.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-munlock-mlock_page-munlock_page-batch-by-pagevec-fix-2.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-munlock-mlock_page-munlock_page-batch-by-pagevec-fix-2.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: SeongJae Park <sj@xxxxxxxxxx> Subject: mm/internal: Implement no-op mlock_page_drain() for !CONFIG_MMU Commit 4b3b8bd6c8287 ("mm/munlock: mlock_page() munlock_page() batch by pagevec") in -mm tree[1] implements 'mlock_page_drain()' under CONFIG_MMU only, but the function is used by 'lru_add_drain_cpu()', which defined outside of CONFIG_MMU. As a result, below build error occurs. /linux/mm/swap.c: In function 'lru_add_drain_cpu': /linux/mm/swap.c:637:2: error: implicit declaration of function 'mlock_page_drain' [-Werror=implicit-function-declaration] 637 | mlock_page_drain(cpu); | ^~~~~~~~~~~~~~~~ cc1: some warnings being treated as errors /linux/scripts/Makefile.build:289: recipe for target 'mm/swap.o' failed This commit fixes it by implementing no-op 'mlock_page_drain()' for !CONFIG_MMU case, similar to 'mlock_new_page()'. [1] https://www.ozlabs.org/~akpm/mmotm/broken-out/mm-munlock-mlock_page-munlock_page-batch-by-pagevec.patch [hughd: add need_mlock_page_drain() stub too] Link: https://lkml.kernel.org/r/8eae6026-098-befb-92d3-b9ad2ad57776@xxxxxxxxxx Signed-off-by: SeongJae Park <sj@xxxxxxxxxx> Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- --- a/mm/internal.h~mm-munlock-mlock_page-munlock_page-batch-by-pagevec-fix-2 +++ a/mm/internal.h @@ -508,6 +508,8 @@ static inline void mlock_vma_page(struct static inline void munlock_vma_page(struct page *page, struct vm_area_struct *vma, bool compound) { } static inline void mlock_new_page(struct page *page) { } +static inline bool need_mlock_page_drain(int cpu) { return false; } +static inline void mlock_page_drain(int cpu) { } static inline void vunmap_range_noflush(unsigned long start, unsigned long end) { } _ Patches currently in -mm which might be from sj@xxxxxxxxxx are mm-munlock-mlock_page-munlock_page-batch-by-pagevec-fix-2.patch mm-damon-dbgfs-init_regions-use-target-index-instead-of-target-id.patch docs-admin-guide-mm-damon-usage-update-for-changed-initail_regions-file-input.patch mm-damon-core-move-damon_set_targets-into-dbgfs.patch mm-damon-remove-the-target-id-concept.patch