Commit 09e71a32 authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Use an array of pages in the extent buffers to reduce the cost of find_get_page 



Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 14048ed0

fs/btrfs/disk-io.c

+3 −3
Original line number Diff line number Diff line
@@ -647,20 +647,20 @@ int close_ctree(struct btrfs_root *root) 


int btrfs_buffer_uptodate(struct extent_buffer *buf)

{

	struct inode *btree_inode = buf->first_page->mapping->host;

	struct inode *btree_inode = buf->pages[0]->mapping->host;

	return extent_buffer_uptodate(&BTRFS_I(btree_inode)->extent_tree, buf);

}



int btrfs_set_buffer_uptodate(struct extent_buffer *buf)

{

	struct inode *btree_inode = buf->first_page->mapping->host;

	struct inode *btree_inode = buf->pages[0]->mapping->host;

	return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->extent_tree,

					  buf);

}



void btrfs_mark_buffer_dirty(struct extent_buffer *buf)

{

	struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;

	struct btrfs_root *root = BTRFS_I(buf->pages[0]->mapping->host)->root;

	u64 transid = btrfs_header_generation(buf);

	struct inode *btree_inode = root->fs_info->btree_inode;

fs/btrfs/extent_map.c

+8 −14
Original line number Diff line number Diff line
@@ -1961,16 +1961,12 @@ static void __free_extent_buffer(struct extent_buffer *eb) 
static inline struct page *extent_buffer_page(struct extent_buffer *eb, int i)

{

	struct page *p;

	if (i == 0)

		return eb->first_page;



	if (i < EXTENT_INLINE_PAGES)

		return eb->pages[i];

	i += eb->start >> PAGE_CACHE_SHIFT;

	if (eb->last_page && eb->last_page->index == i)

		return eb->last_page;



	p = find_get_page(eb->first_page->mapping, i);

	p = find_get_page(eb->pages[0]->mapping, i);

	page_cache_release(p);

	eb->last_page = p;

	return p;

}
@@ -2012,8 +2008,8 @@ struct extent_buffer *alloc_extent_buffer(struct extent_map_tree *tree, 
			goto fail;

		}

		set_page_extent_mapped(p);

		if (i == 0)

			eb->first_page = p;

		if (i < EXTENT_INLINE_PAGES)

			eb->pages[i] = p;

		if (!PageUptodate(p))

			uptodate = 0;

		unlock_page(p);
@@ -2059,8 +2055,8 @@ struct extent_buffer *find_extent_buffer(struct extent_map_tree *tree, 
			goto fail;

		}

		set_page_extent_mapped(p);

		if (i == 0)

			eb->first_page = p;

		if (i < EXTENT_INLINE_PAGES)

			eb->pages[i] = p;

		if (!PageUptodate(p))

			uptodate = 0;

		unlock_page(p);
@@ -2087,9 +2083,7 @@ void free_extent_buffer(struct extent_buffer *eb) 


	num_pages = num_extent_pages(eb->start, eb->len);



	if (eb->first_page)

		page_cache_release(eb->first_page);

	for (i = 1; i < num_pages; i++) {

	for (i = 0; i < num_pages; i++) {

		page_cache_release(extent_buffer_page(eb, i));

	}

	__free_extent_buffer(eb);

fs/btrfs/extent_map.h

+2 −2
Original line number Diff line number Diff line
@@ -62,6 +62,7 @@ struct extent_state { 
	struct list_head list;

};



#define EXTENT_INLINE_PAGES 32

struct extent_buffer {

	u64 start;

	unsigned long len;
@@ -69,13 +70,12 @@ struct extent_buffer { 
	int flags;

	struct list_head list;

	struct list_head leak_list;

	struct page *first_page;

	struct page *last_page;

	unsigned long alloc_addr;

	char *map_token;

	char *kaddr;

	unsigned long map_start;

	unsigned long map_len;

	struct page *pages[EXTENT_INLINE_PAGES];

};



typedef struct extent_map *(get_extent_t)(struct inode *inode,