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Date: Sat, 6 Jan 2018 12:48:33 +0200
From: Konstantin Belousov <kostikbel@gmail.com>
To: Johannes Lundberg <johalun0@gmail.com>
Cc: freebsd-hackers@freebsd.org
Subject: Re: callout_reset_on() with wait?
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On Sat, Jan 06, 2018 at 09:18:32AM +0000, Johannes Lundberg wrote:
> Hi
> 
> I need to execute some code on another cpu (specified by cpu #) and wait
> for return. Is there any one function to call for this in freebsd 12
> kernel? (or example where similar is implemented?)
There is smp_rendezvous_cpus() which does exactly that, but the context
where the functions are called do not allow any synchronization, except
carefully prepared spin locks.  Your use of the word 'wait' leaves a lot
to guess.