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| author | Kay Sievers <kay.sievers@vrfy.org> | 2009-03-09 14:18:52 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-03-24 16:38:26 -0700 |
| commit | 4995f8ef9d3aac72745e12419d7fbaa8d01b1d81 (patch) | |
| tree | 32b86d8b5f5ccba8f367d3e911ba3d1e19d73729 /drivers | |
| parent | ce21c7bcd796fc4f45d48781b7e85f493cc55ee5 (diff) | |
| download | blackbird-obmc-linux-4995f8ef9d3aac72745e12419d7fbaa8d01b1d81.tar.gz blackbird-obmc-linux-4995f8ef9d3aac72745e12419d7fbaa8d01b1d81.zip | |
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')
| -rw-r--r-- | drivers/char/vc_screen.c | 16 | ||||
| -rw-r--r-- | drivers/char/vt.c | 5 |
2 files changed, 11 insertions, 10 deletions
diff --git a/drivers/char/vc_screen.c b/drivers/char/vc_screen.c index 4f3b3f95fc42..d94d25c12aa8 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 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, ¶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); } |
