Btrfs: Use an array of pages in the extent buffers to reduce the cost of find_get_page
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index fad9298..0636f79 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -647,20 +647,20 @@
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 ea6ee68..7ef3397 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -1961,16 +1961,12 @@
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 @@
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 @@
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 @@
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 4ef8bdd..d74a2b3 100644
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -62,6 +62,7 @@
struct list_head list;
};
+#define EXTENT_INLINE_PAGES 32
struct extent_buffer {
u64 start;
unsigned long len;
@@ -69,13 +70,12 @@
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,