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authorWang Shilong <wangsl-fnst@cn.fujitsu.com>2013-04-12 12:12:17 +0000
committerJosef Bacik <jbacik@fusionio.com>2013-05-06 15:54:44 -0400
commitf7f82b81d2c297a5864dcfd0a205917d3e753aba (patch)
treed5208b93d07ce88b5b66e646da7241fff45ce143 /fs/btrfs/ulist.h
parentc2c71324ecb471c932bc1ff59e46ffcf82f274fc (diff)
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Btrfs: add a rb_tree to improve performance of ulist search
Walking backref tree and btrfs quota rely on ulist very much. This patch tries to use rb_tree to speed up search time. The original code always checks whether an element exists before adding a new element, however it costs O(n). I try to add a rb_tree in the ulist,this is only used to speed up search. I also do some measurements with quota enabled. fsstress -p 4 -n 10000 Without this path: real 0m51.058s 2m4.745s 1m28.222s 1m5.137s user 0m0.035s 0m0.041s 0m0.105s 0m0.100s sys 0m12.009s 0m11.246s 0m10.901s 0m10.999s 0m11.287s With this path: real 0m55.295s 0m50.960s 1m2.214s 0m48.273s user 0m0.053s 0m0.095s 0m0.135s 0m0.107s sys 0m7.766s 0m6.013s 0m6.319s 0m6.030s 0m6.532s After applying the patch,the execute time is down by ~42%.(11.287s->6.532s) Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com> Reviewed-by: Miao Xie <miaox@cn.fujitsu.com> Reviewed-by: Jan Schmidt <list.btrfs@jan-o-sch.net> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Diffstat (limited to 'fs/btrfs/ulist.h')
-rw-r--r--fs/btrfs/ulist.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/btrfs/ulist.h b/fs/btrfs/ulist.h
index 21a1963439c3..fb36731074b5 100644
--- a/fs/btrfs/ulist.h
+++ b/fs/btrfs/ulist.h
@@ -8,6 +8,9 @@
#ifndef __ULIST__
#define __ULIST__
+#include <linux/list.h>
+#include <linux/rbtree.h>
+
/*
* ulist is a generic data structure to hold a collection of unique u64
* values. The only operations it supports is adding to the list and
@@ -34,6 +37,7 @@ struct ulist_iterator {
struct ulist_node {
u64 val; /* value to store */
u64 aux; /* auxiliary value saved along with the val */
+ struct rb_node rb_node; /* used to speed up search */
};
struct ulist {
@@ -54,6 +58,8 @@ struct ulist {
*/
struct ulist_node *nodes;
+ struct rb_root root;
+
/*
* inline storage space for the first ULIST_SIZE entries
*/