The existing clear_warn_once functionality is currently a manually issued state reset via the file /sys/kernel/debug/clear_warn_once when debugfs is mounted. The idea being that a developer would be running some tests, like LTP or similar, and want to check reproducibility without having to reboot.
But you currently can't make use of clear_warn_once unless you've got debugfs enabled and mounted - which may not be desired by some people in some deployment situations. The functionality added here allows for periodic resets in addition to the one-shot reset it already had. Then we allow for a boot-time setting of the periodic resets so it can be used even when debugfs isn't mounted. By having a periodic reset, we also open the door for having the various "once" functions act as long period ratelimited messages, where a sysadmin can pick an hour or a day reset if they are facing an issue and are wondering "did this just happen once, or am I only being informed once?" Tested with DEBUG_FS_ALLOW_ALL and DEBUG_FS_ALLOW_NONE on an otherwise defconfig. --- Cc: Andi Kleen <a...@linux.intel.com> Cc: Petr Mladek <pmla...@suse.com> Cc: Sergey Senozhatsky <sergey.senozhat...@gmail.com> Cc: Steven Rostedt <rost...@goodmis.org> Cc: John Ogness <john.ogn...@linutronix.de> Paul Gortmaker (3): clear_warn_once: expand debugfs to include read support clear_warn_once: bind a timer to written reset value clear_warn_once: add a warn_once_reset= boot parameter .../admin-guide/clearing-warn-once.rst | 9 +++ .../admin-guide/kernel-parameters.txt | 8 ++ kernel/panic.c | 78 +++++++++++++++++-- 3 files changed, 90 insertions(+), 5 deletions(-) -- 2.25.1
