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Message-ID: <X8tVsaFUwAxsIVaO@jagdpanzerIV.localdomain>
Date: Sat, 5 Dec 2020 18:41:05 +0900
From: Sergey Senozhatsky <sergey.senozhatsky@...il.com>
To: Petr Mladek <pmladek@...e.com>
Cc: John Ogness <john.ogness@...utronix.de>,
Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
Steven Rostedt <rostedt@...dmis.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Thomas Gleixner <tglx@...utronix.de>,
linux-kernel@...r.kernel.org
Subject: Re: recursion handling: Re: [PATCH next v2 3/3] printk: remove
logbuf_lock, add syslog_lock
On (20/12/04 17:10), Petr Mladek wrote:
>
> One reason is the use of per-cpu variables. Alternative solution would
> be to store printk_context into task_struct.
We can keep per-CPU, disable preemption and have counters for
every context (task, soft/hard irq, NMI). Shouldn't be a problem
vprintk_emit()
{
preempt_disable()
vprintk_store()
preempt_enable()
preempt_disable()
console_unlock()
preempt_enable()
}
vprintk_store() is a small fraction of console_unlock() time wise.
-ss
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