From f7f82b81d2c297a5864dcfd0a205917d3e753aba Mon Sep 17 00:00:00 2001 From: Wang Shilong Date: Fri, 12 Apr 2013 12:12:17 +0000 Subject: 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 Reviewed-by: Miao Xie Reviewed-by: Jan Schmidt Signed-off-by: Josef Bacik --- fs/btrfs/ulist.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'fs/btrfs/ulist.h') 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 +#include + /* * 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 */ -- cgit v1.2.3