linux-kernel - x86's nmi_hz wrt. oprofile's nmi_timer

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Message-Id: <20090129.155852.161923905.davem@davemloft.net>
Date:	Thu, 29 Jan 2009 15:58:52 -0800 (PST)
From:	David Miller <davem@...emloft.net>
To:	tglx@...utronix.de, mingo@...hat.com
CC:	linux-kernel@...r.kernel.org
Subject: x86's nmi_hz wrt. oprofile's nmi_timer_int.c

While working on an NMI watchdog implementation on sparc64
I noticed what seems to be a peculiar behavior of the NMI
timer int oprofile support on x86.

When the NMI watchdog tests itself at boot timer we start
with nmi_hz equal to HZ.

After the NMI watchdog self-test passes, nmi_hz is reduced
down to '1'.

The NMI timer int oprofile support simply uses DIE_NMI notifiers for
it's implementation.  But I don't see anything in the code of
arch/x86/oprofile/nmi_timer_int.c nor the NMI watchdog infrastructure
which will re-adjust nmi_hz back to HZ or something similar.

Am I missing something?
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