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Date: Thu, 24 Feb 2011 21:04:31 +0000
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>,
        Peter Zijlstra <peterz@infradead.org>,
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        Rusty Russell <rusty@rustcorp.com.au>, Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH V5 2/2] tracing, perf : add cpu hotplug trace events
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> That's the equivalent of physical hotplug, but we still have all the
> memory state around, so it is possible from idle, when we have the

All sorts of other state goes walking as well though - on die device
state for example like the GPU context may well also evaporate or
disappear except for the minimum needed for scanout.

It's not just about the CPU its a system (albeit a SoC in most cases)
going to sleep lock stock and barrel except for IRQ notifications, and in
some cases things like offloaded audio playback.

Alan