The patch titled
Subject: mm: methods for teaching filesystems about PG_swapcache pages
has been removed from the -mm tree. Its filename was
mm-methods-for-teaching-filesystems-about-pg_swapcache-pages.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxx>
Subject: 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@xxxxxxxxx>
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Eric B Munson <emunson@xxxxxxxxx>
Cc: Eric Paris <eparis@xxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Mike Christie <michaelc@xxxxxxxxxxx>
Cc: Neil Brown <neilb@xxxxxxx>
Cc: Sebastian Andrzej Siewior <sebastian@xxxxxxxxxxxxx>
Cc: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Cc: Xiaotian Feng <dfeng@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 25 +++++++++++++++++++++++++
include/linux/pagemap.h | 5 +++++
include/linux/swap.h | 1 +
mm/swapfile.c | 26 ++++++++++++++++++++++++++
4 files changed, 57 insertions(+)
diff -puN include/linux/mm.h~mm-methods-for-teaching-filesystems-about-pg_swapcache-pages include/linux/mm.h
--- a/include/linux/mm.h~mm-methods-for-teaching-filesystems-about-pg_swapcache-pages
+++ a/include/linux/mm.h
@@ -805,6 +805,17 @@ static inline void *page_rmapping(struct
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
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 -puN include/linux/pagemap.h~mm-methods-for-teaching-filesystems-about-pg_swapcache-pages include/linux/pagemap.h
--- a/include/linux/pagemap.h~mm-methods-for-teaching-filesystems-about-pg_swapcache-pages
+++ a/include/linux/pagemap.h
@@ -286,6 +286,11 @@ static inline loff_t page_offset(struct
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 -puN include/linux/swap.h~mm-methods-for-teaching-filesystems-about-pg_swapcache-pages include/linux/swap.h
--- a/include/linux/swap.h~mm-methods-for-teaching-filesystems-about-pg_swapcache-pages
+++ a/include/linux/swap.h
@@ -356,6 +356,7 @@ extern unsigned int count_swap_pages(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;
diff -puN mm/swapfile.c~mm-methods-for-teaching-filesystems-about-pg_swapcache-pages mm/swapfile.c
--- a/mm/swapfile.c~mm-methods-for-teaching-filesystems-about-pg_swapcache-pages
+++ a/mm/swapfile.c
@@ -33,6 +33,7 @@
#include <linux/oom.h>
#include <linux/frontswap.h>
#include <linux/swapfile.h>
+#include <linux/export.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
@@ -2285,6 +2286,31 @@ int swapcache_prepare(swp_entry_t entry)
return __swap_duplicate(entry, SWAP_HAS_CACHE);
}
+struct swap_info_struct *page_swap_info(struct page *page)
+{
+ swp_entry_t swap = { .val = page_private(page) };
+ BUG_ON(!PageSwapCache(page));
+ return swap_info[swp_type(swap)];
+}
+
+/*
+ * out-of-line __page_file_ methods to avoid include hell.
+ */
+struct address_space *__page_file_mapping(struct page *page)
+{
+ VM_BUG_ON(!PageSwapCache(page));
+ return page_swap_info(page)->swap_file->f_mapping;
+}
+EXPORT_SYMBOL_GPL(__page_file_mapping);
+
+pgoff_t __page_file_index(struct page *page)
+{
+ swp_entry_t swap = { .val = page_private(page) };
+ VM_BUG_ON(!PageSwapCache(page));
+ return swp_offset(swap);
+}
+EXPORT_SYMBOL_GPL(__page_file_index);
+
/*
* add_swap_count_continuation - called when a swap count is duplicated
* beyond SWAP_MAP_MAX, it allocates a new page and links that to the entry's
_
Patches currently in -mm which might be from mgorman@xxxxxxx are
origin.patch
linux-next.patch
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