diff options
author | Mel Gorman <mgorman@suse.de> | 2012-08-01 03:44:47 +0400 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-08-01 05:42:47 +0400 |
commit | f981c5950fa85916ba49bea5d9a7a5078f47e569 (patch) | |
tree | e742598755e57e1bbed06dc90b05fe6e13091236 /include | |
parent | 6290c2c439732727899405f39fb76c2f5585b707 (diff) | |
download | linux-f981c5950fa85916ba49bea5d9a7a5078f47e569.tar.xz |
mm: methods for teaching filesystems about PG_swapcache pages
In order to teach filesystems to handle swap cache pages, three new page
functions are introduced:
pgoff_t page_file_index(struct page *);
loff_t page_file_offset(struct page *);
struct address_space *page_file_mapping(struct page *);
page_file_index() - gives the offset of this page in the file in
PAGE_CACHE_SIZE blocks. Like page->index is for mapped pages, this
function also gives the correct index for PG_swapcache pages.
page_file_offset() - uses page_file_index(), so that it will give the
expected result, even for PG_swapcache pages.
page_file_mapping() - gives the mapping backing the actual page; that is
for swap cache pages it will give swap_file->f_mapping.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Neil Brown <neilb@suse.de>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Xiaotian Feng <dfeng@redhat.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/mm.h | 25 | ||||
-rw-r--r-- | include/linux/pagemap.h | 5 | ||||
-rw-r--r-- | include/linux/swap.h | 1 |
3 files changed, 31 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 7c6dfd2faa69..7cdac1676b59 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -805,6 +805,17 @@ static inline void *page_rmapping(struct page *page) return (void *)((unsigned long)page->mapping & ~PAGE_MAPPING_FLAGS); } +extern struct address_space *__page_file_mapping(struct page *); + +static inline +struct address_space *page_file_mapping(struct page *page) +{ + if (unlikely(PageSwapCache(page))) + return __page_file_mapping(page); + + return page->mapping; +} + static inline int PageAnon(struct page *page) { return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0; @@ -821,6 +832,20 @@ static inline pgoff_t page_index(struct page *page) return page->index; } +extern pgoff_t __page_file_index(struct page *page); + +/* + * Return the file index of the page. Regular pagecache pages use ->index + * whereas swapcache pages use swp_offset(->private) + */ +static inline pgoff_t page_file_index(struct page *page) +{ + if (unlikely(PageSwapCache(page))) + return __page_file_index(page); + + return page->index; +} + /* * Return true if this page is mapped into pagetables. */ diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 7cfad3bbb0cc..e42c762f0dc7 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -286,6 +286,11 @@ static inline loff_t page_offset(struct page *page) return ((loff_t)page->index) << PAGE_CACHE_SHIFT; } +static inline loff_t page_file_offset(struct page *page) +{ + return ((loff_t)page_file_index(page)) << PAGE_CACHE_SHIFT; +} + extern pgoff_t linear_hugepage_index(struct vm_area_struct *vma, unsigned long address); diff --git a/include/linux/swap.h b/include/linux/swap.h index 9a16bb1cefd1..e62425ded2ed 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -356,6 +356,7 @@ 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 struct swap_info_struct *page_swap_info(struct page *); extern int reuse_swap_page(struct page *); extern int try_to_free_swap(struct page *); struct backing_dev_info; |