proc: use slower rb_first()
In a typical for /proc "open+read+close" usecase, dentry is looked up
successfully on open only to be killed in dput() on close. In fact
dentries which aren't /proc/*/... and /proc/sys/* were almost NEVER
CACHED. Simple printk in proc_lookup_de() shows that.
Now that ->delete hook intelligently picks which dentries should live in
dcache and which should not, rbtree caching is not necessary as dcache
does it job, at last!
As a side effect, struct proc_dir_entry shrinks by one pointer which can
go into inline name.
Link: http://lkml.kernel.org/r/20180314231032.GA15854@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 76c9964..61b7340 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -203,7 +203,7 @@ struct proc_dir_entry proc_root = {
.proc_iops = &proc_root_inode_operations,
.proc_fops = &proc_root_operations,
.parent = &proc_root,
- .subdir = RB_ROOT_CACHED,
+ .subdir = RB_ROOT,
.name = proc_root.inline_name,
.inline_name = "/proc",
};
