diff options
| author | Minchan Kim <minchan@kernel.org> | 2017-11-16 04:33:11 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-11-16 05:21:02 +0300 |
| commit | aa8d22a11da933dbf880b4933b58931f4aefe91c (patch) | |
| tree | ed7a7c1ecdfa4da6079858dfc0cfb6fbb65e3286 /include | |
| parent | 0bcac06f27d7528591c27ac2b093ccd71c5d0168 (diff) | |
| download | linux-aa8d22a11da933dbf880b4933b58931f4aefe91c.tar.xz | |
mm: swap: SWP_SYNCHRONOUS_IO: skip swapcache only if swapped page has no other reference
When SWP_SYNCHRONOUS_IO swapped-in pages are shared by several
processes, it can cause unnecessary memory wastage by skipping swap
cache. Because, with swapin fault by read, they could share a page if
the page were in swap cache. Thus, it avoids allocating same content
new pages.
This patch makes the swapcache skipping work only if the swap pte is
non-sharable.
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/1507620825-5537-1-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/swap.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h index 32c06f028c7b..8b8a6f965785 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -463,6 +463,7 @@ extern unsigned int count_swap_pages(int, int); extern sector_t map_swap_page(struct page *, struct block_device **); extern sector_t swapdev_block(int, pgoff_t); extern int page_swapcount(struct page *); +extern int __swap_count(struct swap_info_struct *si, swp_entry_t entry); extern int __swp_swapcount(swp_entry_t entry); extern int swp_swapcount(swp_entry_t entry); extern struct swap_info_struct *page_swap_info(struct page *); @@ -589,6 +590,11 @@ static inline int page_swapcount(struct page *page) return 0; } +static inline int __swap_count(struct swap_info_struct *si, swp_entry_t entry) +{ + return 0; +} + static inline int __swp_swapcount(swp_entry_t entry) { return 0; |