Subject: Re: [RFC PATCH 2/6] jump label v3 - x86: Introduce generic jump
 patching without stop_machine
From: Steven Rostedt <rostedt@goodmis.org>
Reply-To: rostedt@goodmis.org
To: paulmck@linux.vnet.ibm.com
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
       Jason Baron <jbaron@redhat.com>, mingo@elte.hu, mhiramat@redhat.com,
       linux-kernel@vger.kernel.org, hpa@zytor.com, tglx@linutronix.de,
       andi@firstfloor.org, roland@redhat.com, rth@redhat.com
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Date: Wed, 18 Nov 2009 20:22:47 -0500
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On Wed, 2009-11-18 at 16:58 -0800, Paul E. McKenney wrote:

> I do invoke smp_send_reschedule() with irqs disabled, which did arouse my
> suspicions of late.  But this seems to bypass the smp_call_function()
> code that is most definitely illegal to invoke with irqs disabled,
> so no smoking gun.  All that aside, if invoking smp_send_reschedule()
> with irqs disabled is in any way a bad idea, please let me know so I
> can rearrange the code appropriately.

I don't think you have anything to worry about here. If calling
smp_send_reschedule was bad with keeping interrupts disabled, then we
would have a lot of problems with the scheduler. That is called with the
rq lock held and with interrupts disabled.

-- Steve


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