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| author | Matthew Wilcox <willy@infradead.org> | 2017-11-03 13:30:42 -0400 |
|---|---|---|
| committer | Matthew Wilcox <willy@infradead.org> | 2018-09-29 22:47:49 -0400 |
| commit | 3159f943aafdbacb2f94c38fdaadabf2bbde2a14 (patch) | |
| tree | 7e06823a1ab7e90774535d17a217a939bdddda3b /mm/filemap.c | |
| parent | 66ee620f06f99d72475db6eb638559ba608c7dee (diff) | |
| download | linux-3159f943aafdbacb2f94c38fdaadabf2bbde2a14.tar.bz2 | |
xarray: Replace exceptional entries
Introduce xarray value entries and tagged pointers to replace radix
tree exceptional entries. This is a slight change in encoding to allow
the use of an extra bit (we can now store BITS_PER_LONG - 1 bits in a
value entry). It is also a change in emphasis; exceptional entries are
intimidating and different. As the comment explains, you can choose
to store values or pointers in the xarray and they are both first-class
citizens.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Diffstat (limited to 'mm/filemap.c')
| -rw-r--r-- | mm/filemap.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 52517f28e6f4..4de14e75c4ec 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -127,7 +127,7 @@ static int page_cache_tree_insert(struct address_space *mapping, p = radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock); - if (!radix_tree_exceptional_entry(p)) + if (!xa_is_value(p)) return -EEXIST; mapping->nrexceptional--; @@ -336,7 +336,7 @@ page_cache_tree_delete_batch(struct address_space *mapping, break; page = radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock); - if (radix_tree_exceptional_entry(page)) + if (xa_is_value(page)) continue; if (!tail_pages) { /* @@ -1355,7 +1355,7 @@ pgoff_t page_cache_next_hole(struct address_space *mapping, struct page *page; page = radix_tree_lookup(&mapping->i_pages, index); - if (!page || radix_tree_exceptional_entry(page)) + if (!page || xa_is_value(page)) break; index++; if (index == 0) @@ -1396,7 +1396,7 @@ pgoff_t page_cache_prev_hole(struct address_space *mapping, struct page *page; page = radix_tree_lookup(&mapping->i_pages, index); - if (!page || radix_tree_exceptional_entry(page)) + if (!page || xa_is_value(page)) break; index--; if (index == ULONG_MAX) @@ -1539,7 +1539,7 @@ struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset, repeat: page = find_get_entry(mapping, offset); - if (radix_tree_exceptional_entry(page)) + if (xa_is_value(page)) page = NULL; if (!page) goto no_page; |