printk: refactor and rework printing logic

Browse source

Refactor/rework printing logic in order to prepare for moving to
threaded console printing.

- Move @console_seq into struct console so that the current
  "position" of each console can be tracked individually.

- Move @console_dropped into struct console so that the current drop
  count of each console can be tracked individually.

- Modify printing logic so that each console independently loads,
  prepares, and prints its next record.

- Remove exclusive_console logic. Since console positions are
  handled independently, replaying past records occurs naturally.

- Update the comments explaining why preemption is disabled while
  printing from printk() context.

With these changes, there is a change in behavior: the console
replaying the log (formerly exclusive console) will no longer block
other consoles. New messages appear on the other consoles while the
newly added console is still replaying.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220421212250.565456-10-john.ogness@linutronix.de

...

This commit is contained in:

John Ogness 2022-04-21 23:28:44 +02:06 • committed by Petr Mladek

parent 1fc0ca9e0d

commit a699449bb1

2 changed files with 230 additions and 213 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

2

include/linux/console.h

View file

443

kernel/printk/printk.c

View file