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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Jacek Anaszewski <j.anaszewski@samsung.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	Anna-Maria Gleixner <anna-maria@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	rt@linutronix.de, Richard Cochran <rcochran@linutronix.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Paul Gortmaker <paul.gortmaker@windriver.com>,
	Richard Purdie <rpurdie@rpsys.net>,
	linux-leds@vger.kernel.org, Pawel Moll <pawel.moll@arm.com>
Subject: Re: [patch V2 43/67] leds/trigger/cpu: Convert to hotplug state machine
Date: Fri, 15 Jul 2016 16:10:26 +0200	[thread overview]
Message-ID: <20160715141026.GA16938@linutronix.de> (raw)
In-Reply-To: <57877DAE.8080401@samsung.com>

* Jacek Anaszewski | 2016-07-14 13:55:26 [+0200]:

>On 07/14/2016 01:33 PM, Thomas Gleixner wrote:
>>That does not explain WHY this needs to happen in the low level bringup phase
>>of the CPU with interrupts disabled and can't be done from the normal ONLINE
>>callbacks in thread context.
>
>It was before my time in kernel, so I can only suppose that it was
>the easiest way. Does it introduce some problems?

It was introduced by Pawel Moll in fba14ae8e924 ("ledtrig-cpu: Handle
CPU hot(un)plugging"). It does not introduce any problems but those
bring up / bring down levels are usually used by the core code. This
does not look like it needs to be done _that_ early or late during the
removal / addition of a CPU to the system.

Which means this looks like it could be moved to CPU_ONLINE /
CPU_DOWN_PREPARE which in turns means we could use dynamic IDs instead
of those hardcoded ones since the LED subsystem does not depend on other
components.

Sebastian

  reply	other threads:[~2016-07-15 14:10 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20160713153219.128052238@linutronix.de>
2016-07-13 17:16 ` [patch V2 43/67] leds/trigger/cpu: Convert to hotplug state machine Anna-Maria Gleixner
2016-07-14  7:19   ` Jacek Anaszewski
2016-07-14  7:47     ` Ingo Molnar
2016-07-14  8:10       ` Jacek Anaszewski
2016-07-14  9:41         ` Peter Zijlstra
2016-07-14 11:23           ` Jacek Anaszewski
2016-07-14 11:33             ` Thomas Gleixner
2016-07-14 11:55               ` Jacek Anaszewski
2016-07-15 14:10                 ` Sebastian Andrzej Siewior [this message]
2016-07-18  8:26                   ` Jacek Anaszewski

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