Re: [PATCHv4] tty: Added a CONFIG_TTY option to allow removal of TTY

[Josh Triplett <josh@joshtriplett.org>]

On Thu, Jan 17, 2013 at 10:44:22PM -0800, Joe Millenbach wrote:
> The option allows you to remove TTY and compile without errors. This
> saves space on systems that won't support TTY interfaces anyway.
> bloat-o-meter output is below.
> 
> The bulk of this patch consists of Kconfig changes adding "depends on
> TTY" to various serial devices and similar drivers that require the TTY
> layer.  Ideally, these dependencies would occur on a common intermediate
> symbol such as SERIO, but most drivers "select SERIO" rather than
> "depends on SERIO", and "select" does not respect dependencies.
> 
> bloat-o-meter output comparing our previous minimal to new minimal by
> removing TTY.  The list is filtered to not show removed entries with awk
> '$3 != "-"' as the list was very long.
> 
> add/remove: 0/226 grow/shrink: 2/14 up/down: 6/-35356 (-35350)
> function                                     old     new   delta
> chr_dev_init                                 166     170      +4
> allow_signal                                  80      82      +2
> static.__warned                              143     142      -1
> disallow_signal                               63      62      -1
> __set_special_pids                            95      94      -1
> unregister_console                           126     121      -5
> start_kernel                                 546     541      -5
> register_console                             593     588      -5
> copy_from_user                                45      40      -5
> sys_setsid                                   128     120      -8
> sys_vhangup                                   32      19     -13
> do_exit                                     1543    1526     -17
> bitmap_zero                                   60      40     -20
> arch_local_irq_save                          137     117     -20
> release_task                                 674     652     -22
> static.spin_unlock_irqrestore                308     260     -48
> 
> Signed-off-by: Joe Millenbach <jmillenbach@gmail.com>
> Reviewed-by: Jamey Sharp <jamey@minilop.net>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>