From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: John Ogness <john.ogness@linutronix.de>, Petr Mladek <pmladek@suse.com>
Cc: Peter Geis <pgwipeout@gmail.com>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"open list:ARM/Rockchip SoC..."
<linux-rockchip@lists.infradead.org>
Subject: Re: [BUG] Threaded printk breaks early debugging
Date: Sun, 12 Jun 2022 12:13:36 +0900 [thread overview]
Message-ID: <YqVZ4CyWTiDgngkA@google.com> (raw)
In-Reply-To: <87y1y48spg.fsf@jogness.linutronix.de>
On (22/06/10 17:11), John Ogness wrote:
> It would be trivial to provide a boot parameter for this behavior, but I
> think we first need to see a real problem and also see if we can fix
> that problem.
John, Petr, a quick question
Should a situation when we have only one online CPU be enough of a reason
to do direct printing? Otherwise we might not have CPUs to wakeup khtread on,
e.g. when CPU that printk is in atomic section for too long.
---
@@ -480,6 +480,9 @@ static inline bool allow_direct_printing(void)
if (!printk_kthreads_available)
return true;
+ if (num_online_cpus() == 1)
+ return true;
+
/*
* Prefer direct printing when the system is in a problematic state.
* The context that sets this state will always see the updated value.
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next prev parent reply other threads:[~2022-06-12 3:13 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-10 12:48 [BUG] Threaded printk breaks early debugging Peter Geis
2022-06-10 15:05 ` John Ogness
2022-06-10 15:34 ` Peter Geis
2022-06-12 2:57 ` Sergey Senozhatsky
2022-06-12 13:30 ` Peter Geis
2022-06-12 23:08 ` John Ogness
2022-06-12 23:30 ` Peter Geis
2022-06-13 2:23 ` John Ogness
2022-06-13 15:11 ` Petr Mladek
2022-06-13 22:20 ` Peter Geis
2022-06-14 8:38 ` Petr Mladek
2022-06-13 11:24 ` Petr Mladek
2022-06-12 3:13 ` Sergey Senozhatsky [this message]
2022-06-12 23:02 ` John Ogness
2022-06-13 3:49 ` Sergey Senozhatsky
2022-06-13 8:30 ` John Ogness
2022-06-13 9:05 ` Sergey Senozhatsky
2022-06-13 10:14 ` Petr Mladek
2022-06-13 16:11 ` David Laight
2022-06-14 8:37 ` Petr Mladek
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