From: John Ogness <john.ogness@linutronix.de>
To: Sergey Senozhatsky <senozhatsky@chromium.org>,
Petr Mladek <pmladek@suse.com>
Cc: Luo Jiaxing <luojiaxing@huawei.com>,
sergey.senozhatsky@gmail.com, rostedt@goodmis.org,
linux-kernel@vger.kernel.org, linuxarm@huawei.com,
bobo.shaobowang@huawei.com,
Sergey Senozhatsky <senozhatsky@chromium.org>
Subject: Re: [PATCH] printk: stop spining waiter when console resume to flush prb
Date: Thu, 06 May 2021 17:14:12 +0200 [thread overview]
Message-ID: <87h7jfzygr.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <YJP5MnkJ8pJevXM6@google.com>
On 2021-05-06, Sergey Senozhatsky <senozhatsky@chromium.org> wrote:
>> Can we count the number of lines that we print from the `current` context
>> in console_unlock() and if after N messages there is no console_lock waiter
>> waiting for the `current` to handover console lock ownership, then create
>> one: schedule IRQ work that will become a console lock owner, spin on
>> console lock and call console_unlock() once it acquired the ownership.
>> That 'artificial' console lock owner will do the same - print N
>> messages, if nothing wants to become a console lock owner then it'll
>> queue another IRQ work.
>
> Or even simpler
>
> console_unlock()
> {
> ...
>
> if (printed_messages > limit && !console_lock_spinning_disable_and_check()) {
> printk_safe_exit_irqrestore(flags);
>
> console_locked = 0;
> up_console_sem();
>
> defer_console_output();
> return;
> }
>
> ...
> }
Or instead to keep it suspend/resume related maybe...
void resume_console(void)
{
if (!console_suspend_enabled)
return;
down_console_sem();
console_suspended = 0;
- console_unlock();
+ console_locked = 0;
+ up_console_sem();
+ defer_console_output();
}
John Ogness
next prev parent reply other threads:[~2021-05-06 15:14 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-06 8:00 [PATCH] printk: stop spining waiter when console resume to flush prb Luo Jiaxing
2021-05-06 13:13 ` Steven Rostedt
2021-05-07 8:35 ` luojiaxing
2021-05-06 13:39 ` Petr Mladek
2021-05-06 14:07 ` Sergey Senozhatsky
2021-05-06 14:12 ` Sergey Senozhatsky
2021-05-06 15:14 ` John Ogness [this message]
2021-05-07 7:58 ` luojiaxing
2021-05-07 7:33 ` luojiaxing
2021-05-07 7:49 ` Sergey Senozhatsky
2021-05-07 16:36 ` Petr Mladek
2021-05-10 8:26 ` Sergey Senozhatsky
2021-05-10 10:17 ` Petr Mladek
2021-05-10 10:32 ` John Ogness
2021-05-10 11:16 ` Sergey Senozhatsky
2021-05-10 11:43 ` Sergey Senozhatsky
2021-05-07 16:13 ` Petr Mladek
2021-05-10 8:29 ` luojiaxing
2021-05-10 9:50 ` Petr Mladek
2021-05-10 12:06 ` Sergey Senozhatsky
2021-05-10 7:41 ` luojiaxing
2021-05-10 9:30 ` Petr Mladek
2021-05-11 7:32 ` luojiaxing
2021-05-11 9:08 ` Petr Mladek
2021-05-13 7:55 ` luojiaxing
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