From 0e47c99d7fe25e0f3907d9f3401079169d904891 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Sat, 7 Jan 2012 23:24:30 -0800 Subject: sysctl: Replace root_list with links between sysctl_table_sets. Piecing together directories by looking first in one directory tree, than in another directory tree and finally in a third directory tree makes it hard to verify that some directory entries are not multiply defined and makes it hard to create efficient implementations the sysctl filesystem. Replace the sysctl wide list of roots with autogenerated links from the core sysctl directory tree to the other sysctl directory trees. This simplifies sysctl directory reading and lookups as now only entries in a single sysctl directory tree need to be considered. Benchmark before: make-dummies 0 999 -> 0.44s rmmod dummy -> 0.065s make-dummies 0 9999 -> 1m36s rmmod dummy -> 0.4s Benchmark after: make-dummies 0 999 -> 0.63s rmmod dummy -> 0.12s make-dummies 0 9999 -> 2m35s rmmod dummy -> 18s The slowdown is caused by the lookups used in insert_headers and put_links to see if we need to add links or remove links. Signed-off-by: Eric W. Biederman --- include/linux/sysctl.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'include/linux/sysctl.h') diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 3084b624868c..2a1446a96094 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -1051,12 +1051,11 @@ struct ctl_dir { struct ctl_table_set { struct list_head list; - struct ctl_table_root *root; int (*is_seen)(struct ctl_table_set *); + struct ctl_dir dir; }; struct ctl_table_root { - struct list_head root_list; struct ctl_table_set default_set; struct ctl_table_set *(*lookup)(struct ctl_table_root *root, struct nsproxy *namespaces); -- cgit v1.2.2