Sergey Senozhatsky 3ac37a93fa printk: lock/unlock console only for new logbuf entries ... Prior to commit 5c2992ee7f ("printk: remove console flushing special cases for partial buffered lines") we would do console_cont_flush() for each pr_cont() to print cont fragments, so console_unlock() would actually print data: pr_cont(); console_lock(); console_unlock() console_cont_flush(); // print cont fragment ... pr_cont(); console_lock(); console_unlock() console_cont_flush(); // print cont fragment We don't do console_cont_flush() anymore, so when we do pr_cont() console_unlock() does nothing (unless we flushed the cont buffer): pr_cont(); console_lock(); console_unlock(); // noop ... pr_cont(); console_lock(); console_unlock(); // noop ... pr_cont(); cont_flush(); console_lock(); console_unlock(); // print data We also wakeup klogd purposelessly for pr_cont() output - un-flushed cont buffer is not stored in log_buf; there is nothing to pull. Thus we can console_lock()/console_unlock()/wake_up_klogd() only when we know that we log_store()-ed a message and there is something to print to the consoles/syslog. Link: http://lkml.kernel.org/r/20181002023836.4487-3-sergey.senozhatsky@gmail.com To: Steven Rostedt <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: Tejun Heo <tj@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: LKML <linux-kernel@vger.kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>		2018-10-12 10:03:39 +02:00
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braille.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
braille.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
console_cmdline.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
internal.h	printk/nmi: Prevent deadlock when accessing the main log buffer in NMI	2018-07-09 14:10:40 +02:00
Makefile	printk: introduce per-cpu safe_print seq buffer	2017-02-08 11:07:11 +01:00
printk_safe.c	printk/tracing: Do not trace printk_nmi_enter()	2018-09-06 11:24:05 -04:00
printk.c	printk: lock/unlock console only for new logbuf entries	2018-10-12 10:03:39 +02:00