linux/mm/swap.h
Miaohe Lin 1baec203b7 mm/khugepaged: try to free transhuge swapcache when possible
Transhuge swapcaches won't be freed in __collapse_huge_page_copy().  It's
because release_pte_page() is not called for these pages and thus
free_page_and_swap_cache can't grab the page lock.  These pages won't be
freed from swap cache even if we are the only user until next time
reclaim.  It shouldn't hurt indeed, but we could try to free these pages
to save more memory for system.

Link: https://lkml.kernel.org/r/20220625092816.4856-8-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-03 18:08:52 -07:00

153 lines
4.0 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _MM_SWAP_H
#define _MM_SWAP_H
#ifdef CONFIG_SWAP
#include <linux/blk_types.h> /* for bio_end_io_t */
/* linux/mm/page_io.c */
int sio_pool_init(void);
struct swap_iocb;
int swap_readpage(struct page *page, bool do_poll,
struct swap_iocb **plug);
void __swap_read_unplug(struct swap_iocb *plug);
static inline void swap_read_unplug(struct swap_iocb *plug)
{
if (unlikely(plug))
__swap_read_unplug(plug);
}
void swap_write_unplug(struct swap_iocb *sio);
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);
bool add_to_swap(struct folio *folio);
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 folio *folio,
swp_entry_t entry, void *shadow);
void delete_from_swap_cache(struct folio *folio);
void clear_shadow_from_swap_cache(int type, unsigned long begin,
unsigned long end);
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 swap_iocb **plug);
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);
static inline unsigned int folio_swap_flags(struct folio *folio)
{
return page_swap_info(&folio->page)->flags;
}
#else /* CONFIG_SWAP */
struct swap_iocb;
static inline int swap_readpage(struct page *page, bool do_poll,
struct swap_iocb **plug)
{
return 0;
}
static inline void swap_write_unplug(struct swap_iocb *sio)
{
}
static inline struct address_space *swap_address_space(swp_entry_t entry)
{
return NULL;
}
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 bool add_to_swap(struct folio *folio)
{
return false;
}
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 folio *folio,
swp_entry_t entry, void *shadow)
{
}
static inline void delete_from_swap_cache(struct folio *folio)
{
}
static inline void clear_shadow_from_swap_cache(int type, unsigned long begin,
unsigned long end)
{
}
static inline unsigned int folio_swap_flags(struct folio *folio)
{
return 0;
}
#endif /* CONFIG_SWAP */
#endif /* _MM_SWAP_H */