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From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: John Ogness <john.ogness@linutronix.de>
Cc: Petr Mladek <pmladek@suse.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel@vger.kernel.org,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	Dmitry Safonov <0x7f454c46@gmail.com>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Stephen Boyd <swboyd@chromium.org>,
	Alexander Potapenko <glider@google.com>,
	"Paul E. McKenney" <paulmck@kernel.org>
Subject: Re: [PATCH next v1 1/2] dump_stack: move cpu lock to printk.c
Date: Tue, 1 Jun 2021 11:55:17 +0900	[thread overview]
Message-ID: <YLWhlZy8jQR3zpun@google.com> (raw)
In-Reply-To: <20210531162051.2325-2-john.ogness@linutronix.de>

On (21/05/31 18:20), John Ogness wrote:
> +void printk_cpu_lock(unsigned int *cpu_store, unsigned long *flags)
> +{
> +	unsigned int cpu;
> +
> +	for (;;) {
> +		cpu = get_cpu();
> +
> +		*cpu_store = atomic_read(&printk_cpulock_owner);
> +
> +		if (*cpu_store == -1) {
> +			local_irq_save(*flags);

Is there any particular reason this does

	preempt_disable();
	cpu = smp_processor_id();
	local_irq_safe();

instead of

	local_irq_safe();
	cpu = raw_smp_processor_id();

?

  parent reply	other threads:[~2021-06-01  2:55 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-31 16:20 [PATCH next v1 0/2] introduce printk cpu lock John Ogness
2021-05-31 16:20 ` [PATCH next v1 1/2] dump_stack: move cpu lock to printk.c John Ogness
2021-05-31 16:30   ` John Ogness
2021-05-31 20:04   ` kernel test robot
2021-05-31 21:49   ` kernel test robot
2021-06-01  2:55   ` Sergey Senozhatsky [this message]
2021-06-01  6:58     ` John Ogness
2021-06-01  7:37       ` John Ogness
2021-06-01 13:29         ` Petr Mladek
2021-06-01 13:59   ` Petr Mladek
2021-06-01 14:21     ` John Ogness
2021-06-03  6:33       ` Petr Mladek
2021-05-31 16:20 ` [PATCH next v1 2/2] nmi_backtrace: use the printk cpu lock for show_regs() John Ogness
2021-06-01 14:25   ` Petr Mladek

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