From 09e71a326341f40111400c88aaf0498ef622824b Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Mon, 15 Oct 2007 16:17:04 -0400 Subject: [PATCH] Btrfs: Use an array of pages in the extent buffers to reduce the cost of find_get_page Signed-off-by: Chris Mason --- fs/btrfs/disk-io.c | 6 +++--- fs/btrfs/extent_map.c | 22 ++++++++-------------- fs/btrfs/extent_map.h | 4 ++-- 3 files changed, 13 insertions(+), 19 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index fad9298c6962..0636f79672e9 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -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; diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index ea6ee68ef53c..7ef3397a266d 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -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); diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h index 4ef8bdd68348..d74a2b3e3b5d 100644 --- a/fs/btrfs/extent_map.h +++ b/fs/btrfs/extent_map.h @@ -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, -- 2.11.0