From 4995f8ef9d3aac72745e12419d7fbaa8d01b1d81 Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Mon, 9 Mar 2009 14:18:52 +0100 Subject: [PATCH] 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 Signed-off-by: Kay Sievers Signed-off-by: Greg Kroah-Hartman --- 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 4f3b3f95fc4..d94d25c12aa 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), NULL, - "vcs%u", tty->index + 1); - device_create(vc_class, NULL, MKDEV(VCS_MAJOR, tty->index + 129), NULL, - "vcsa%u", tty->index + 1); + device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 1), NULL, + "vcs%u", index + 1); + device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 129), NULL, + "vcsa%u", index + 1); } -void vcs_remove_sysfs(struct tty_struct *tty) +void vcs_remove_sysfs(int index) { - device_destroy(vc_class, MKDEV(VCS_MAJOR, tty->index + 1)); - device_destroy(vc_class, MKDEV(VCS_MAJOR, tty->index + 129)); + device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 1)); + device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 129)); } int __init vcs_init(void) diff --git a/drivers/char/vt.c b/drivers/char/vt.c index 7900bd63b36..2c1d133819b 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, ¶m); } 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, ¶m); + 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); } diff --git a/include/linux/console.h b/include/linux/console.h index a67a90cf826..dcca5339ceb 100644 --- a/include/linux/console.h +++ b/include/linux/console.h @@ -137,8 +137,8 @@ extern void resume_console(void); int mda_console_init(void); void prom_con_init(void); -void vcs_make_sysfs(struct tty_struct *tty); -void vcs_remove_sysfs(struct tty_struct *tty); +void vcs_make_sysfs(int index); +void vcs_remove_sysfs(int index); /* Some debug stub to catch some of the obvious races in the VT code */ #if 1