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authorJosef Bacik <josef@redhat.com>2011-05-13 10:32:11 -0400
committerJosef Bacik <josef@redhat.com>2011-05-23 13:03:14 -0400
commit026fd317828500524cdc7e5ff9e8e7923abb2868 (patch)
treed303bffbd895c307f49286cd90186cf58223dde2 /fs
parent589d8ade83f07c0f11c8191c0ca309f34d7a2c14 (diff)
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Btrfs: don't always do readahead
Our readahead is sort of sloppy, and really isn't always needed. For example if ls is doing a stating ls (which is the default) it's going to stat in non-disk order, so if say you have a directory with a stupid amount of files, readahead is going to do nothing but waste time in the case of doing the stat. Taking the unconditional readahead out made my test go from 57 minutes to 36 minutes. This means that everywhere we do loop through the tree we want to make sure we do set path->reada properly, so I went through and found all of the places where we loop through the path and set reada to 1. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/ctree.c2
-rw-r--r--fs/btrfs/extent-tree.c3
-rw-r--r--fs/btrfs/inode.c14
-rw-r--r--fs/btrfs/relocation.c6
4 files changed, 20 insertions, 5 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index f7a0a64..f61c16c 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -48,8 +48,6 @@ struct btrfs_path *btrfs_alloc_path(void)
{
struct btrfs_path *path;
path = kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS);
- if (path)
- path->reada = 1;
return path;
}
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 96be624..1ba2cc5 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -347,7 +347,7 @@ static int caching_kthread(void *data)
*/
path->skip_locking = 1;
path->search_commit_root = 1;
- path->reada = 2;
+ path->reada = 1;
key.objectid = last;
key.offset = 0;
@@ -8556,6 +8556,7 @@ int btrfs_read_block_groups(struct btrfs_root *root)
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
+ path->reada = 1;
cache_gen = btrfs_super_cache_generation(&root->fs_info->super_copy);
if (cache_gen != 0 &&
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index dd5938a..6228a30 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4242,7 +4242,9 @@ static int btrfs_real_readdir(struct file *filp, void *dirent,
filp->f_pos = 2;
}
path = btrfs_alloc_path();
- path->reada = 2;
+ if (!path)
+ return -ENOMEM;
+ path->reada = 1;
btrfs_set_key_type(&key, key_type);
key.offset = filp->f_pos;
@@ -5043,7 +5045,15 @@ again:
if (!path) {
path = btrfs_alloc_path();
- BUG_ON(!path);
+ if (!path) {
+ err = -ENOMEM;
+ goto out;
+ }
+ /*
+ * Chances are we'll be called again, so go ahead and do
+ * readahead
+ */
+ path->reada = 1;
}
ret = btrfs_lookup_file_extent(trans, root, path,
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 09c30d3..5872b41 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -676,6 +676,8 @@ struct backref_node *build_backref_tree(struct reloc_control *rc,
err = -ENOMEM;
goto out;
}
+ path1->reada = 1;
+ path2->reada = 2;
node = alloc_backref_node(cache);
if (!node) {
@@ -1996,6 +1998,7 @@ static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
+ path->reada = 1;
reloc_root = root->reloc_root;
root_item = &reloc_root->root_item;
@@ -3297,6 +3300,7 @@ static int find_data_references(struct reloc_control *rc,
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
+ path->reada = 1;
root = read_fs_root(rc->extent_root->fs_info, ref_root);
if (IS_ERR(root)) {
@@ -3665,6 +3669,7 @@ static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
+ path->reada = 1;
ret = prepare_to_relocate(rc);
if (ret) {
@@ -4090,6 +4095,7 @@ int btrfs_recover_relocation(struct btrfs_root *root)
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
+ path->reada = -1;
key.objectid = BTRFS_TREE_RELOC_OBJECTID;
key.type = BTRFS_ROOT_ITEM_KEY;