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author | Frank Rowand <frank.rowand@am.sony.com> | 2012-05-16 18:09:36 -0700 |
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committer | Steven Rostedt <rostedt@goodmis.org> | 2012-08-24 20:10:59 -0400 |
commit | 172314790a65db61c5f7d7adb91c00f67bcb2166 (patch) | |
tree | bb6d6ab78df3185f65b81191817836a83b32cda2 /localversion-rt | |
parent | 31f85ffc3a341b9377ac66702947bbc0e5ca008d (diff) |
fix printk flush of messages
Updates console-make-rt-friendly.patch
#ifdef CONFIG_PREEMPT_RT_FULL, printk() output is never flushed by
printk() because:
# some liberties taken in this pseudo-code to make it easier to follow
printk()
vprintk()
raw_spin_lock(&logbuf_lock)
# increment preempt_count():
preempt_disable()
result = console_trylock_for_printk()
retval = 0
# lock will always be false, because preempt_count() will be >= 1
lock = ... && !preempt_count()
if (lock)
retval = 1
return retval
# result will always be false since lock will always be false
if (result)
console_unlock()
# this is where the printk() output would be flushed
On system boot some printk() output is flushed because register_console()
and tty_open() call console_unlock().
This change also fixes the problem that was previously fixed by
preempt-rt-allow-immediate-magic-sysrq-output-for-preempt_rt_full.patch
Signed-off-by: Frank Rowand <frank.rowand@am.sony.com>
Cc: Frank <Frank_Rowand@sonyusa.com>
Link: http://lkml.kernel.org/r/4FB44FD0.4090800@am.sony.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'localversion-rt')
0 files changed, 0 insertions, 0 deletions