From: NeilBrown Subject: mm: create new mm/swap.h header file. Patch series "MM changes to improve swap-over-NFS support". Assorted improvements for swap-via-filesystem. This is a resend of these patches, rebased on current HEAD. The only substantial changes is that swap_dirty_folio has replaced swap_set_page_dirty. Currently swap-via-fs (SWP_FS_OPS) doesn't work for any filesystem. It has previously worked for NFS but that broke a few releases back. This series changes to use a new ->swap_rw rather than ->readpage and ->direct_IO. It also makes other improvements. There is a companion series already in linux-next which fixes various issues with NFS. Once both series land, a final patch is needed which changes NFS over to use ->swap_rw. This patch (of 10): Many functions declared in include/linux/swap.h are only used within mm/ Create a new "mm/swap.h" and move some of these declarations there. Remove the redundant 'extern' from the function declarations. Link: https://lkml.kernel.org/r/164859751830.29473.5309689752169286816.stgit@noble.brown Link: https://lkml.kernel.org/r/164859778120.29473.11725907882296224053.stgit@noble.brown Signed-off-by: NeilBrown Reviewed-by: Christoph Hellwig Tested-by: David Howells Tested-by: Geert Uytterhoeven Cc: Trond Myklebust Cc: Hugh Dickins Cc: Mel Gorman Signed-off-by: Andrew Morton --- include/linux/swap.h | 121 ------------------------------------- mm/huge_memory.c | 1 mm/madvise.c | 1 mm/memcontrol.c | 1 mm/memory.c | 1 mm/mincore.c | 1 mm/page_alloc.c | 1 mm/page_io.c | 1 mm/shmem.c | 1 mm/swap.h | 133 +++++++++++++++++++++++++++++++++++++++++ mm/swap_state.c | 1 mm/swapfile.c | 1 mm/util.c | 1 mm/vmscan.c | 1 mm/zswap.c | 2 15 files changed, 147 insertions(+), 121 deletions(-) --- a/include/linux/swap.h~mm-create-new-mm-swaph-header-file +++ a/include/linux/swap.h @@ -427,62 +427,19 @@ extern void kswapd_stop(int nid); #ifdef CONFIG_SWAP -#include /* for bio_end_io_t */ - -/* linux/mm/page_io.c */ -extern int swap_readpage(struct page *page, bool do_poll); -extern int swap_writepage(struct page *page, struct writeback_control *wbc); -extern void end_swap_bio_write(struct bio *bio); -extern int __swap_writepage(struct page *page, struct writeback_control *wbc, - bio_end_io_t end_write_func); bool swap_dirty_folio(struct address_space *mapping, struct folio *folio); - int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, unsigned long nr_pages, sector_t start_block); int generic_swapfile_activate(struct swap_info_struct *, struct file *, sector_t *); -/* linux/mm/swap_state.c */ -/* One swap address space for each 64M swap space */ -#define SWAP_ADDRESS_SPACE_SHIFT 14 -#define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT) -extern struct address_space *swapper_spaces[]; -#define swap_address_space(entry) \ - (&swapper_spaces[swp_type(entry)][swp_offset(entry) \ - >> SWAP_ADDRESS_SPACE_SHIFT]) static inline unsigned long total_swapcache_pages(void) { return global_node_page_state(NR_SWAPCACHE); } -extern void show_swap_cache_info(void); -extern int add_to_swap(struct page *page); -extern void *get_shadow_from_swap_cache(swp_entry_t entry); -extern int add_to_swap_cache(struct page *page, swp_entry_t entry, - gfp_t gfp, void **shadowp); -extern void __delete_from_swap_cache(struct page *page, - swp_entry_t entry, void *shadow); -extern void delete_from_swap_cache(struct page *); -extern void clear_shadow_from_swap_cache(int type, unsigned long begin, - unsigned long end); -extern void free_swap_cache(struct page *); extern void free_page_and_swap_cache(struct page *); extern void free_pages_and_swap_cache(struct page **, int); -extern struct page *lookup_swap_cache(swp_entry_t entry, - struct vm_area_struct *vma, - unsigned long addr); -struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index); -extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, - struct vm_area_struct *vma, unsigned long addr, - bool do_poll); -extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t, - struct vm_area_struct *vma, unsigned long addr, - bool *new_page_allocated); -extern struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag, - struct vm_fault *vmf); -extern struct page *swapin_readahead(swp_entry_t entry, gfp_t flag, - struct vm_fault *vmf); - /* linux/mm/swapfile.c */ extern atomic_long_t nr_swap_pages; extern long total_swap_pages; @@ -535,12 +492,6 @@ static inline void put_swap_device(struc } #else /* CONFIG_SWAP */ - -static inline int swap_readpage(struct page *page, bool do_poll) -{ - return 0; -} - static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry) { return NULL; @@ -555,11 +506,6 @@ static inline void put_swap_device(struc { } -static inline struct address_space *swap_address_space(swp_entry_t entry) -{ - return NULL; -} - #define get_nr_swap_pages() 0L #define total_swap_pages 0L #define total_swapcache_pages() 0UL @@ -574,14 +520,6 @@ static inline struct address_space *swap #define free_pages_and_swap_cache(pages, nr) \ release_pages((pages), (nr)); -static inline void free_swap_cache(struct page *page) -{ -} - -static inline void show_swap_cache_info(void) -{ -} - /* used to sanity check ptes in zap_pte_range when CONFIG_SWAP=0 */ #define free_swap_and_cache(e) is_pfn_swap_entry(e) @@ -607,65 +545,6 @@ static inline void put_swap_page(struct { } -static inline struct page *swap_cluster_readahead(swp_entry_t entry, - gfp_t gfp_mask, struct vm_fault *vmf) -{ - return NULL; -} - -static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, - struct vm_fault *vmf) -{ - return NULL; -} - -static inline int swap_writepage(struct page *p, struct writeback_control *wbc) -{ - return 0; -} - -static inline struct page *lookup_swap_cache(swp_entry_t swp, - struct vm_area_struct *vma, - unsigned long addr) -{ - return NULL; -} - -static inline -struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index) -{ - return find_get_page(mapping, index); -} - -static inline int add_to_swap(struct page *page) -{ - return 0; -} - -static inline void *get_shadow_from_swap_cache(swp_entry_t entry) -{ - return NULL; -} - -static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, - gfp_t gfp_mask, void **shadowp) -{ - return -1; -} - -static inline void __delete_from_swap_cache(struct page *page, - swp_entry_t entry, void *shadow) -{ -} - -static inline void delete_from_swap_cache(struct page *page) -{ -} - -static inline void clear_shadow_from_swap_cache(int type, unsigned long begin, - unsigned long end) -{ -} static inline int page_swapcount(struct page *page) { --- a/mm/huge_memory.c~mm-create-new-mm-swaph-header-file +++ a/mm/huge_memory.c @@ -39,6 +39,7 @@ #include #include #include "internal.h" +#include "swap.h" #define CREATE_TRACE_POINTS #include --- a/mm/madvise.c~mm-create-new-mm-swaph-header-file +++ a/mm/madvise.c @@ -35,6 +35,7 @@ #include #include "internal.h" +#include "swap.h" struct madvise_walk_private { struct mmu_gather *tlb; --- a/mm/memcontrol.c~mm-create-new-mm-swaph-header-file +++ a/mm/memcontrol.c @@ -67,6 +67,7 @@ #include #include #include "slab.h" +#include "swap.h" #include --- a/mm/memory.c~mm-create-new-mm-swaph-header-file +++ a/mm/memory.c @@ -86,6 +86,7 @@ #include "pgalloc-track.h" #include "internal.h" +#include "swap.h" #if defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS) && !defined(CONFIG_COMPILE_TEST) #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid. --- a/mm/mincore.c~mm-create-new-mm-swaph-header-file +++ a/mm/mincore.c @@ -20,6 +20,7 @@ #include #include +#include "swap.h" static int mincore_hugetlb(pte_t *pte, unsigned long hmask, unsigned long addr, unsigned long end, struct mm_walk *walk) --- a/mm/page_alloc.c~mm-create-new-mm-swaph-header-file +++ a/mm/page_alloc.c @@ -81,6 +81,7 @@ #include "internal.h" #include "shuffle.h" #include "page_reporting.h" +#include "swap.h" /* Free Page Internal flags: for internal, non-pcp variants of free_pages(). */ typedef int __bitwise fpi_t; --- a/mm/page_io.c~mm-create-new-mm-swaph-header-file +++ a/mm/page_io.c @@ -26,6 +26,7 @@ #include #include #include +#include "swap.h" void end_swap_bio_write(struct bio *bio) { --- a/mm/shmem.c~mm-create-new-mm-swaph-header-file +++ a/mm/shmem.c @@ -38,6 +38,7 @@ #include #include #include +#include "swap.h" static struct vfsmount *shm_mnt; --- a/mm/swapfile.c~mm-create-new-mm-swaph-header-file +++ a/mm/swapfile.c @@ -44,6 +44,7 @@ #include #include #include +#include "swap.h" static bool swap_count_continued(struct swap_info_struct *, pgoff_t, unsigned char); --- /dev/null +++ a/mm/swap.h @@ -0,0 +1,133 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _MM_SWAP_H +#define _MM_SWAP_H + +#ifdef CONFIG_SWAP +#include /* for bio_end_io_t */ + +/* linux/mm/page_io.c */ +int swap_readpage(struct page *page, bool do_poll); +int swap_writepage(struct page *page, struct writeback_control *wbc); +void end_swap_bio_write(struct bio *bio); +int __swap_writepage(struct page *page, struct writeback_control *wbc, + bio_end_io_t end_write_func); + +/* linux/mm/swap_state.c */ +/* One swap address space for each 64M swap space */ +#define SWAP_ADDRESS_SPACE_SHIFT 14 +#define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT) +extern struct address_space *swapper_spaces[]; +#define swap_address_space(entry) \ + (&swapper_spaces[swp_type(entry)][swp_offset(entry) \ + >> SWAP_ADDRESS_SPACE_SHIFT]) + +void show_swap_cache_info(void); +int add_to_swap(struct page *page); +void *get_shadow_from_swap_cache(swp_entry_t entry); +int add_to_swap_cache(struct page *page, swp_entry_t entry, + gfp_t gfp, void **shadowp); +void __delete_from_swap_cache(struct page *page, + swp_entry_t entry, void *shadow); +void delete_from_swap_cache(struct page *page); +void clear_shadow_from_swap_cache(int type, unsigned long begin, + unsigned long end); +void free_swap_cache(struct page *page); +struct page *lookup_swap_cache(swp_entry_t entry, + struct vm_area_struct *vma, + unsigned long addr); +struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index); + +struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, + struct vm_area_struct *vma, + unsigned long addr, + bool do_poll); +struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, + struct vm_area_struct *vma, + unsigned long addr, + bool *new_page_allocated); +struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag, + struct vm_fault *vmf); +struct page *swapin_readahead(swp_entry_t entry, gfp_t flag, + struct vm_fault *vmf); + +#else /* CONFIG_SWAP */ +static inline int swap_readpage(struct page *page, bool do_poll) +{ + return 0; +} + +static inline struct address_space *swap_address_space(swp_entry_t entry) +{ + return NULL; +} + +static inline void free_swap_cache(struct page *page) +{ +} + +static inline void show_swap_cache_info(void) +{ +} + +static inline struct page *swap_cluster_readahead(swp_entry_t entry, + gfp_t gfp_mask, struct vm_fault *vmf) +{ + return NULL; +} + +static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, + struct vm_fault *vmf) +{ + return NULL; +} + +static inline int swap_writepage(struct page *p, struct writeback_control *wbc) +{ + return 0; +} + +static inline struct page *lookup_swap_cache(swp_entry_t swp, + struct vm_area_struct *vma, + unsigned long addr) +{ + return NULL; +} + +static inline +struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index) +{ + return find_get_page(mapping, index); +} + +static inline int add_to_swap(struct page *page) +{ + return 0; +} + +static inline void *get_shadow_from_swap_cache(swp_entry_t entry) +{ + return NULL; +} + +static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, + gfp_t gfp_mask, void **shadowp) +{ + return -1; +} + +static inline void __delete_from_swap_cache(struct page *page, + swp_entry_t entry, void *shadow) +{ +} + +static inline void delete_from_swap_cache(struct page *page) +{ +} + +static inline void clear_shadow_from_swap_cache(int type, unsigned long begin, + unsigned long end) +{ +} + +#endif /* CONFIG_SWAP */ +#endif /* _MM_SWAP_H */ --- a/mm/swap_state.c~mm-create-new-mm-swaph-header-file +++ a/mm/swap_state.c @@ -23,6 +23,7 @@ #include #include #include "internal.h" +#include "swap.h" /* * swapper_space is a fiction, retained to simplify the path through --- a/mm/util.c~mm-create-new-mm-swaph-header-file +++ a/mm/util.c @@ -27,6 +27,7 @@ #include #include "internal.h" +#include "swap.h" /** * kfree_const - conditionally free memory --- a/mm/vmscan.c~mm-create-new-mm-swaph-header-file +++ a/mm/vmscan.c @@ -59,6 +59,7 @@ #include #include "internal.h" +#include "swap.h" #define CREATE_TRACE_POINTS #include --- a/mm/zswap.c~mm-create-new-mm-swaph-header-file +++ a/mm/zswap.c @@ -36,6 +36,8 @@ #include #include +#include "swap.h" + /********************************* * statistics **********************************/ _