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

From: Josh Triplett
Date: Fri Jan 18 2013 - 12:16:59 EST


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@xxxxxxxxx>
> Reviewed-by: Jamey Sharp <jamey@xxxxxxxxxxx>
Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
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