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printk: Tie printk_once / printk_deferred_once into .data.once for reset

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commit 3ec25826ae upstream.

In commit b1fca27d38 ("kernel debug: support resetting WARN*_ONCE")
we got the opportunity to reset state on the one shot messages,
without having to reboot.

However printk_once (printk_deferred_once) live in a different file
and didn't get the same kind of update/conversion, so they remain
unconditionally one shot, until the system is rebooted.

For example, we currently have:

  sched/rt.c: printk_deferred_once("sched: RT throttling activated\n");

..which could reasonably be tripped as someone is testing and tuning
a new system/workload and their task placements.  For consistency, and
to avoid reboots in the same vein as the original commit, we make these
two instances of _once the same as the WARN*_ONCE instances are.

Link: http://lkml.kernel.org/r/1555121491-31213-1-git-send-email-paul.gortmaker@windriver.com
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
This commit is contained in:
Paul Gortmaker 2019-04-12 22:11:31 -04:00
parent 0711a9d065
commit a57c813097
2 changed files with 3 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/clearing-warn-once.txt
View File

@ -1,5 +1,5 @@
WARN_ONCE / WARN_ON_ONCE only print a warning once.
WARN_ONCE / WARN_ON_ONCE / printk_once only emit a message once.
echo 1 > /sys/kernel/debug/clear_warn_once

4
include/linux/printk.h
View File

@ -353,7 +353,7 @@ extern int kptr_restrict;
#ifdef CONFIG_PRINTK
#define printk_once(fmt, ...) \
({ \
static bool __print_once __read_mostly; \
static bool __section(.data.once) __print_once; \
bool __ret_print_once = !__print_once; \
\
if (!__print_once) { \
@ -364,7 +364,7 @@ extern int kptr_restrict;
})
#define printk_deferred_once(fmt, ...) \
({ \
static bool __print_once __read_mostly; \
static bool __section(.data.once) __print_once; \
bool __ret_print_once = !__print_once; \
\
if (!__print_once) { \