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authorKay Sievers <kay.sievers@vrfy.org>2009-03-09 16:18:52 +0300
committerGreg Kroah-Hartman <gregkh@suse.de>2009-03-25 02:38:26 +0300
commit4995f8ef9d3aac72745e12419d7fbaa8d01b1d81 (patch)
tree32b86d8b5f5ccba8f367d3e911ba3d1e19d73729 /drivers/char/vt.c
parentce21c7bcd796fc4f45d48781b7e85f493cc55ee5 (diff)
downloadlinux-4995f8ef9d3aac72745e12419d7fbaa8d01b1d81.tar.xz
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>
Diffstat (limited to 'drivers/char/vt.c')
-rw-r--r--drivers/char/vt.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/char/vt.c b/drivers/char/vt.c
index 7900bd63b36d..2c1d133819b5 100644
--- a/drivers/char/vt.c
+++ b/drivers/char/vt.c
@@ -778,6 +778,7 @@ int vc_allocate(unsigned int currcons) /* return 0 on success */
}
vc->vc_kmalloced = 1;
vc_init(vc, vc->vc_rows, vc->vc_cols, 1);
+ vcs_make_sysfs(currcons);
atomic_notifier_call_chain(&vt_notifier_list, VT_ALLOCATE, &param);
}
return 0;
@@ -987,7 +988,9 @@ void vc_deallocate(unsigned int currcons)
if (vc_cons_allocated(currcons)) {
struct vc_data *vc = vc_cons[currcons].d;
struct vt_notifier_param param = { .vc = vc };
+
atomic_notifier_call_chain(&vt_notifier_list, VT_DEALLOCATE, &param);
+ vcs_remove_sysfs(currcons);
vc->vc_sw->con_deinit(vc);
put_pid(vc->vt_pid);
module_put(vc->vc_sw->owner);
@@ -2775,7 +2778,6 @@ static int con_open(struct tty_struct *tty, struct file *filp)
tty->termios->c_iflag |= IUTF8;
else
tty->termios->c_iflag &= ~IUTF8;
- vcs_make_sysfs(tty);
release_console_sem();
return ret;
}
@@ -2795,7 +2797,6 @@ static void con_shutdown(struct tty_struct *tty)
BUG_ON(vc == NULL);
acquire_console_sem();
vc->vc_tty = NULL;
- vcs_remove_sysfs(tty);
release_console_sem();
tty_shutdown(tty);
}