linux-kernel - Re: [PATCH 6/6] x86-mce: ensure the MCP timer is not already set in the mce_timer

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Message-ID: <CAFQmdRZu8aqiDwL2aaUQUZOGxHj0qYudPz9XU06wAOfZyw3rpA@mail.gmail.com>
Date:	Wed, 9 Jul 2014 16:01:12 -0700
From:	Havard Skinnemoen <hskinnemoen@...gle.com>
To:	"Luck, Tony" <tony.luck@...el.com>
Cc:	Borislav Petkov <bp@...en8.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Ewout van Bekkum <ewout@...gle.com>
Subject: Re: [PATCH 6/6] x86-mce: ensure the MCP timer is not already set in
 the mce_timer_fn.

On Wed, Jul 9, 2014 at 2:04 PM, Luck, Tony <tony.luck@...el.com> wrote:
> +       /* Ensure a CMCI interrupt can't preempt this. */
> +       local_irq_save(flags);
>         if (mce_available(__this_cpu_ptr(&cpu_info))) {
>                 machine_check_poll(MCP_TIMESTAMP,
>                                 &__get_cpu_var(mce_poll_banks));
>
> Does this remove the problem that you fixed in part4?  If a CMCI can
> no longer interrupt a poll ... do we really need the locks you added?

It's possible this fixes part of the problem. But I still think
there's a race between multiple CPUs polling shared banks.

Havard
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