Commit 014bb1de authored by NeilBrown's avatar NeilBrown Committed by Andrew Morton
Browse files

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.

[akpm@linux-foundation.org: mm/memory-failure.c needs mm/swap.h]
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: default avatarNeilBrown <neilb@suse.de>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Tested-by: default avatarDavid Howells <dhowells@redhat.com>
Tested-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 17de1e55

include/linux/swap.h

+0 −121
Original line number Diff line number Diff line
@@ -427,62 +427,19 @@ extern void kswapd_stop(int nid); 


#ifdef CONFIG_SWAP



#include <linux/blk_types.h> /* 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(struct swap_info_struct *si) 
}



#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(struct swap_info_struct *si) 
{

}



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_address_space(swp_entry_t entry) 
#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 page *page, swp_entry_t swp) 
{

}



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)

{

mm/huge_memory.c

+1 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ 
#include <asm/tlb.h>

#include <asm/pgalloc.h>

#include "internal.h"

#include "swap.h"



#define CREATE_TRACE_POINTS

#include <trace/events/thp.h>

mm/madvise.c

+1 −0
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ 
#include <asm/tlb.h>



#include "internal.h"

#include "swap.h"



struct madvise_walk_private {

	struct mmu_gather *tlb;

mm/memcontrol.c

+1 −0
Original line number Diff line number Diff line
@@ -67,6 +67,7 @@ 
#include <net/sock.h>

#include <net/ip.h>

#include "slab.h"

#include "swap.h"



#include <linux/uaccess.h>

mm/memory-failure.c

+1 −0
Original line number Diff line number Diff line
@@ -59,6 +59,7 @@ 
#include <linux/page-isolation.h>

#include <linux/pagewalk.h>

#include <linux/shmem_fs.h>

#include "swap.h"

#include "internal.h"

#include "ras/ras_event.h"