Messages in this thread Patch in this message | | | From | John Ogness <> | Subject | [PATCH v3] printk: do not wait for consoles when suspended | Date | Fri, 15 Jul 2022 08:16:42 +0206 |
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The console_stop() and console_start() functions call pr_flush(). When suspending, these functions are called by the serial subsystem while the serial port is suspended. In this scenario, if there are any pending messages, a call to pr_flush() will always result in a timeout because the serial port cannot make forward progress. This causes longer suspend and resume times.
Add a check in pr_flush() so that it will immediately timeout if the consoles are suspended.
Fixes: 3b604ca81202 ("printk: add pr_flush()") Reported-by: Todd Brandt <todd.e.brandt@linux.intel.com> Signed-off-by: John Ogness <john.ogness@linutronix.de> Tested-by: Todd Brandt <todd.e.brandt@linux.intel.com> --- v3: add more details to commit message and comment
v2: only avoid wait if suspended
kernel/printk/printk.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index b49c6ff6dca0..a1a81fd9889b 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -3380,6 +3380,7 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre diff = 0; console_lock(); + for_each_console(c) { if (con && con != c) continue; @@ -3389,11 +3390,19 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre if (printk_seq < seq) diff += seq - printk_seq; } - console_unlock(); - if (diff != last_diff && reset_on_progress) + /* + * If consoles are suspended, it cannot be expected that they + * make forward progress, so timeout immediately. @diff is + * still used to return a valid flush status. + */ + if (console_suspended) + remaining = 0; + else if (diff != last_diff && reset_on_progress) remaining = timeout_ms; + console_unlock(); + if (diff == 0 || remaining == 0) break; -- 2.30.2
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