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authorFilipe David Borba Manana <fdmanana@gmail.com>2013-11-25 03:23:51 +0000
committerChris Mason <clm@fb.com>2014-01-28 13:19:48 -0800
commit32193c147f451652c6c089b5fa1c9852d53d65ee (patch)
treeece0d8e4be8b4d16d96aa6a7c45e1ad52566b805 /fs/btrfs/extent_map.c
parent68ba990f7d161c31e9eddd98727ba8393089047f (diff)
Btrfs: faster and more efficient extent map insertion
Before this change, adding an extent map to the extent map tree of an inode required 2 tree nevigations: 1) doing a tree navigation to search for an existing extent map starting at the same offset or an extent map that overlaps the extent map we want to insert; 2) Another tree navigation to add the extent map to the tree (if the former tree search didn't found anything). This change just merges these 2 steps into a single one. While running first few btrfs xfstests I had noticed these trees easily had a few hundred elements, and then with the following sysbench test it reached over 1100 elements very often. Test: sysbench --test=fileio --file-num=32 --file-total-size=10G \ --file-test-mode=seqwr --num-threads=512 --file-block-size=8192 \ --max-requests=1000000 --file-io-mode=sync [prepare|run] (fs created with mkfs.btrfs -l 4096 -f /dev/sdb3 before each sysbench prepare phase) Before this patch: run 1 - 41.894Mb/sec run 2 - 40.527Mb/sec run 3 - 40.922Mb/sec run 4 - 49.433Mb/sec run 5 - 40.959Mb/sec average - 42.75Mb/sec After this patch: run 1 - 48.036Mb/sec run 2 - 50.21Mb/sec run 3 - 50.929Mb/sec run 4 - 46.881Mb/sec run 5 - 53.192Mb/sec average - 49.85Mb/sec Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs/extent_map.c')
-rw-r--r--fs/btrfs/extent_map.c72
1 files changed, 41 insertions, 31 deletions
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index a4a7a1a8da95..b60955d4f9bf 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -79,12 +79,21 @@ void free_extent_map(struct extent_map *em)
}
}
-static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
- struct rb_node *node)
+/* simple helper to do math around the end of an extent, handling wrap */
+static u64 range_end(u64 start, u64 len)
+{
+ if (start + len < start)
+ return (u64)-1;
+ return start + len;
+}
+
+static int tree_insert(struct rb_root *root, struct extent_map *em)
{
struct rb_node **p = &root->rb_node;
struct rb_node *parent = NULL;
- struct extent_map *entry;
+ struct extent_map *entry = NULL;
+ struct rb_node *orig_parent = NULL;
+ u64 end = range_end(em->start, em->len);
while (*p) {
parent = *p;
@@ -92,19 +101,37 @@ static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
WARN_ON(!entry->in_tree);
- if (offset < entry->start)
+ if (em->start < entry->start)
p = &(*p)->rb_left;
- else if (offset >= extent_map_end(entry))
+ else if (em->start >= extent_map_end(entry))
p = &(*p)->rb_right;
else
- return parent;
+ return -EEXIST;
}
- entry = rb_entry(node, struct extent_map, rb_node);
- entry->in_tree = 1;
- rb_link_node(node, parent, p);
- rb_insert_color(node, root);
- return NULL;
+ orig_parent = parent;
+ while (parent && em->start >= extent_map_end(entry)) {
+ parent = rb_next(parent);
+ entry = rb_entry(parent, struct extent_map, rb_node);
+ }
+ if (parent)
+ if (end > entry->start && em->start < extent_map_end(entry))
+ return -EEXIST;
+
+ parent = orig_parent;
+ entry = rb_entry(parent, struct extent_map, rb_node);
+ while (parent && em->start < entry->start) {
+ parent = rb_prev(parent);
+ entry = rb_entry(parent, struct extent_map, rb_node);
+ }
+ if (parent)
+ if (end > entry->start && em->start < extent_map_end(entry))
+ return -EEXIST;
+
+ em->in_tree = 1;
+ rb_link_node(&em->rb_node, orig_parent, p);
+ rb_insert_color(&em->rb_node, root);
+ return 0;
}
/*
@@ -310,20 +337,11 @@ int add_extent_mapping(struct extent_map_tree *tree,
struct extent_map *em, int modified)
{
int ret = 0;
- struct rb_node *rb;
- struct extent_map *exist;
- exist = lookup_extent_mapping(tree, em->start, em->len);
- if (exist) {
- free_extent_map(exist);
- ret = -EEXIST;
- goto out;
- }
- rb = tree_insert(&tree->map, em->start, &em->rb_node);
- if (rb) {
- ret = -EEXIST;
+ ret = tree_insert(&tree->map, em);
+ if (ret)
goto out;
- }
+
atomic_inc(&em->refs);
em->mod_start = em->start;
@@ -337,14 +355,6 @@ out:
return ret;
}
-/* simple helper to do math around the end of an extent, handling wrap */
-static u64 range_end(u64 start, u64 len)
-{
- if (start + len < start)
- return (u64)-1;
- return start + len;
-}
-
static struct extent_map *
__lookup_extent_mapping(struct extent_map_tree *tree,
u64 start, u64 len, int strict)