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Date: Wed, 13 Jun 2018 17:41:41 +1000
From: Nicholas Piggin <npiggin@gmail.com>
To: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@kernel.org>,
 "H. Peter Anvin" <hpa@zytor.com>, Andi Kleen <andi.kleen@intel.com>, Ashok
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 <tony.luck@intel.com>, "Ravi V. Shankar" <ravi.v.shankar@intel.com>,
 x86@kernel.org, sparclinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
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 Zickus <dzickus@redhat.com>, Michael Ellerman <mpe@ellerman.id.au>,
 Frederic Weisbecker <frederic@kernel.org>, Babu Moger
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 <peterz@infradead.org>, Andrew Morton <akpm@linux-foundation.org>, Philippe
 Ombredanne <pombredanne@nexb.com>, Colin Ian King
 <colin.king@canonical.com>, "Luis R. Rodriguez" <mcgrof@kernel.org>,
 iommu@lists.linux-foundation.org
Subject: Re: [RFC PATCH 12/23] kernel/watchdog: Introduce a struct for NMI
 watchdog operations
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On Tue, 12 Jun 2018 17:57:32 -0700
Ricardo Neri <ricardo.neri-calderon@linux.intel.com> wrote:

> Instead of exposing individual functions for the operations of the NMI
> watchdog, define a common interface that can be used across multiple
> implementations.
> 
> The struct nmi_watchdog_ops is defined for such operations. These initial
> definitions include the enable, disable, start, stop, and cleanup
> operations.
> 
> Only a single NMI watchdog can be used in the system. The operations of
> this NMI watchdog are accessed via the new variable nmi_wd_ops. This
> variable is set to point the operations of the first NMI watchdog that
> initializes successfully. Even though at this moment, the only available
> NMI watchdog is the perf-based hardlockup detector. More implementations
> can be added in the future.

Cool, this looks pretty nice at a quick glance. sparc and powerpc at
least have their own NMI watchdogs, it would be good to have those
converted as well.

Is hpet a cross platform thing, or just x86? We should avoid
proliferation of files under kernel/ I think, so with these watchdog
driver structs then maybe implementations could go in drivers/ or
arch/

Thanks,
Nick