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authorNicolas Dichtel <nicolas.dichtel@6wind.com>2014-12-10 15:45:01 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-10 17:41:09 -0800
commit710585d4922fd315f2cada8fbe550ae8ed23e994 (patch)
treedd783ed159fcf3be1463c41637b12345d60cd1de /fs/proc/internal.h
parent9edad6ea0f1416415f6fe31cc9d1dbc3817803ed (diff)
fs/proc: use a rb tree for the directory entries
When a lot of netdevices are created, one of the bottleneck is the creation of proc entries. This serie aims to accelerate this part. The current implementation for the directories in /proc is using a single linked list. This is slow when handling directories with large numbers of entries (eg netdevice-related entries when lots of tunnels are opened). This patch replaces this linked list by a red-black tree. Here are some numbers: dummy30000.batch contains 30 000 times 'link add type dummy'. Before the patch: $ time ip -b dummy30000.batch real 2m31.950s user 0m0.440s sys 2m21.440s $ time rmmod dummy real 1m35.764s user 0m0.000s sys 1m24.088s After the patch: $ time ip -b dummy30000.batch real 2m0.874s user 0m0.448s sys 1m49.720s $ time rmmod dummy real 1m13.988s user 0m0.000s sys 1m1.008s The idea of improving this part was suggested by Thierry Herbelot. [akpm@linux-foundation.org: initialise proc_root.subdir at compile time] Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Acked-by: David S. Miller <davem@davemloft.net> Cc: Thierry Herbelot <thierry.herbelot@6wind.com>. Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc/internal.h')
-rw-r--r--fs/proc/internal.h11
1 files changed, 6 insertions, 5 deletions
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index aa7a0ee182e1..7fb1a4869fd0 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -24,10 +24,9 @@ struct mempolicy;
* tree) of these proc_dir_entries, so that we can dynamically
* add new files to /proc.
*
- * The "next" pointer creates a linked list of one /proc directory,
- * while parent/subdir create the directory structure (every
- * /proc file has a parent, but "subdir" is NULL for all
- * non-directory entries).
+ * parent/subdir are used for the directory structure (every /proc file has a
+ * parent, but "subdir" is empty for all non-directory entries).
+ * subdir_node is used to build the rb tree "subdir" of the parent.
*/
struct proc_dir_entry {
unsigned int low_ino;
@@ -38,7 +37,9 @@ struct proc_dir_entry {
loff_t size;
const struct inode_operations *proc_iops;
const struct file_operations *proc_fops;
- struct proc_dir_entry *next, *parent, *subdir;
+ struct proc_dir_entry *parent;
+ struct rb_root subdir;
+ struct rb_node subdir_node;
void *data;
atomic_t count; /* use count */
atomic_t in_use; /* number of callers into module in progress; */