procfs: use faster rb_first_cached()
... such that we can avoid the tree walks to get the node with the
smallest key. Semantically the same, as the previously used rb_first(),
but O(1). The main overhead is the extra footprint for the cached rb_node
pointer, which should not matter for procfs.
Link: http://lkml.kernel.org/r/20170719014603.19029-14-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c
index d72fc40..a2bf369 100644
--- a/fs/proc/proc_net.c
+++ b/fs/proc/proc_net.c
@@ -196,7 +196,7 @@
if (!netd)
goto out;
- netd->subdir = RB_ROOT;
+ netd->subdir = RB_ROOT_CACHED;
netd->data = net;
netd->nlink = 2;
netd->namelen = 3;