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Btrfs: extent_io and extent_state optimizations

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The end_bio routines are changed to take a pointer to the extent state
struct, and the state tree is walked in order to set/clear appropriate
bits as IO completes.  This greatly reduces the number of rbtree searches
done by the end_bio handlers, and reduces lock contention.

The extent_io releasepage function is changed to avoid expensive searches
for locked state.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
2008-01-29 09:59:12 -05:00
parent aadfeb6e39
commit 70dec8079d
4 changed files with 298 additions and 114 deletions
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15
fs/btrfs/extent_io.h
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@@ -23,19 +23,23 @@
#define EXTENT_PAGE_PRIVATE 1
#define EXTENT_PAGE_PRIVATE_FIRST_PAGE 3
struct extent_state;
struct extent_io_ops {
int (*fill_delalloc)(struct inode *inode, u64 start, u64 end);
int (*writepage_io_hook)(struct page *page, u64 start, u64 end);
int (*readpage_io_hook)(struct page *page, u64 start, u64 end);
int (*readpage_end_io_hook)(struct page *page, u64 start, u64 end);
void (*writepage_end_io_hook)(struct page *page, u64 start, u64 end);
int (*readpage_end_io_hook)(struct page *page, u64 start, u64 end,
struct extent_state *state);
void (*writepage_end_io_hook)(struct page *page, u64 start, u64 end,
struct extent_state *state);
};
struct extent_io_tree {
struct rb_root state;
struct address_space *mapping;
u64 dirty_bytes;
rwlock_t lock;
spinlock_t lock;
struct extent_io_ops *ops;
spinlock_t lru_lock;
struct list_head buffer_lru;
@@ -45,8 +49,8 @@ struct extent_io_tree {
struct extent_state {
u64 start;
u64 end; /* inclusive */
int in_tree;
struct rb_node rb_node;
struct extent_io_tree *tree;
wait_queue_head_t wq;
atomic_t refs;
unsigned long state;
@@ -82,7 +86,8 @@ void extent_io_tree_init(struct extent_io_tree *tree,
struct address_space *mapping, gfp_t mask);
void extent_io_tree_empty_lru(struct extent_io_tree *tree);
int try_release_extent_mapping(struct extent_map_tree *map,
struct extent_io_tree *tree, struct page *page);
struct extent_io_tree *tree, struct page *page,
gfp_t mask);
int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask);
int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask);
int extent_read_full_page(struct extent_io_tree *tree, struct page *page,