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Date: Fri, 26 Apr 2013 10:41:37 +0200
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>, RT <linux-rt-users@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Clark Williams <clark@redhat.com>, John Kacur <jkacur@redhat.com>,
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        Mauro Carvalho Chehab <mchehab@redhat.com>,
        Ingo Molnar <mingo@kernel.org>, "H. Peter Anvin" <hpa@linux.intel.com>
Subject: Re: [PATCH RT v2] x86/mce: Defer mce wakeups to threads for
 PREEMPT_RT
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* Steven Rostedt | 2013-04-11 14:33:34 [-0400]:

>As wait queue locks are notorious for long hold times, we can not
>convert them to raw_spin_locks without causing issues with -rt. But
>Thomas has created a "simple-wait" structure that uses raw spin locks
>which may have been a good fit.
>
>Unfortunately, wait queues are not the only issue, as the mce_notify_irq
>also does a schedule_work(), which grabs the workqueue spin locks that
>have the exact same issue.

mce_notify_irq() can use simple_waitqueue, no?
The other issue is that mce_report_event() is scheduling a per-cpu
workqueue (mce_schedule_work) in case of a memory fault. This has the
same issue.

Sebastian