tree 2bfffe6ab96beedc8410c70a32334951cc14ecac
parent b342dd512f7af0e0e14e29c3e1f863150cfc46ff
author Ivo Sieben <meltedpianoman@gmail.com> 1355842130 +0100
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1358319742 -0800

tty: Only wakeup the line discipline idle queue when queue is active

Before waking up the tty line discipline idle queue first check if the queue is
active (non empty). This prevents unnecessary entering the critical section in
the wake_up() function and therefore avoid needless scheduling overhead on a
PREEMPT_RT system caused by two processes being in the same critical section.

Signed-off-by: Ivo Sieben <meltedpianoman@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>