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authorEric W. Biederman <ebiederm@xmission.com>2011-12-29 20:24:29 +0400
committerEric W. Biederman <ebiederm@xmission.com>2012-01-25 04:40:29 +0400
commit7ec66d06362da7684a4948c4c2bf1f8546425df4 (patch)
treea16212ae2d23a46890c6d89068eaa9b2eb0f6e37 /include/linux/sysctl.h
parent9eb47c26f09e27506d343ef52e634b2a50ee21ef (diff)
downloadlinux-7ec66d06362da7684a4948c4c2bf1f8546425df4.tar.xz
sysctl: Stop requiring explicit management of sysctl directories
Simplify the code and the sysctl semantics by autogenerating sysctl directories when a sysctl table is registered that needs the directories and autodeleting the directories when there are no more sysctl tables registered that need them. Autogenerating directories keeps sysctl tables from depending on each other, removing all of the arcane register/unregister ordering constraints and makes it impossible to get the order wrong when reigsering and unregistering sysctl tables. Autogenerating directories yields one unique entity that dentries can point to, retaining the current effective use of the dcache. Add struct ctl_dir as the type of these new autogenerated directories. The attached_by and attached_to fields in ctl_table_header are removed as they are no longer needed. The child field in ctl_table is no longer needed by the core of the sysctl code. ctl_table.child can be removed once all of the existing users have been updated. Benchmark before: make-dummies 0 999 -> 0.7s rmmod dummy -> 0.07s make-dummies 0 9999 -> 1m10s rmmod dummy -> 0.4s Benchmark after: make-dummies 0 999 -> 0.44s rmmod dummy -> 0.065s make-dummies 0 9999 -> 1m36s rmmod dummy -> 0.4s Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Diffstat (limited to 'include/linux/sysctl.h')
-rw-r--r--include/linux/sysctl.h10
1 files changed, 7 insertions, 3 deletions
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index e73ba33cbf08..3084b624868c 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -938,6 +938,7 @@ struct ctl_table;
struct nsproxy;
struct ctl_table_root;
struct ctl_table_header;
+struct ctl_dir;
typedef struct ctl_table ctl_table;
@@ -1040,9 +1041,12 @@ struct ctl_table_header
struct ctl_table *ctl_table_arg;
struct ctl_table_root *root;
struct ctl_table_set *set;
- struct ctl_table *attached_by;
- struct ctl_table *attached_to;
- struct ctl_table_header *parent;
+ struct ctl_dir *parent;
+};
+
+struct ctl_dir {
+ /* Header must be at the start of ctl_dir */
+ struct ctl_table_header header;
};
struct ctl_table_set {