Gitweb: http://git.kernel.org/linus/4995f8ef9d3aac72745e12419d7fbaa8d01b1d81
Commit: 4995f8ef9d3aac72745e12419d7fbaa8d01b1d81
Parent: ce21c7bcd796fc4f45d48781b7e85f493cc55ee5
Author: Kay Sievers <kay.sievers@vrfy.org>
AuthorDate: Mon Mar 9 14:18:52 2009 +0100
Committer: Greg Kroah-Hartman <gregkh@suse.de>
CommitDate: Tue Mar 24 16:38:26 2009 -0700
vcs: hook sysfs devices into object lifetime instead of "binding"
During bootup performance tracing I noticed many occurrences of
vca* device creation and removal, leading to the usual userspace
uevent processing, which are, in this case, rather pointless.
A simple test showing the kernel timing (not including all the
work userspace has to do), gives us these numbers:
$ time for i in `seq 1000`; do echo a > /dev/tty2; done
real 0m1.142s
user 0m0.015s
sys 0m0.540s
If we move the hook for the vcs* driver core devices from the
tty "binding" to the vc allocation/deallocation, which is what
the vcs* devices represent, we get the following numbers:
$ time for i in `seq 1000`; do echo a > /dev/tty2; done
real 0m0.152s
user 0m0.030s
sys 0m0.072s
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/char/vc_screen.c | 16 ++++++++--------
drivers/char/vt.c | 5 +++--
include/linux/console.h | 4 ++--
3 files changed, 13 insertions(+), 12 deletions(-)
diff --git a/drivers/char/vc_screen.c b/drivers/char/vc_screen.c
index 4f3b3f9..d94d25c 100644
--- a/drivers/char/vc_screen.c
+++ b/drivers/char/vc_screen.c
@@ -479,18 +479,18 @@ static const struct file_operations vcs_fops = {
static struct class *vc_class;
-void vcs_make_sysfs(struct tty_struct *tty)
+void vcs_make_sysfs(int index)
{
- device_create(vc_class, NULL, MKDEV(VCS_MAJOR, tty->index + 1), ...
