Subject: Re: [PATCH] clocksource: Store reg field within struct clocksource
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
CC: Thomas Gleixner <tglx@linutronix.de>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        LKML <linux-kernel@vger.kernel.org>, Mans Rullgard <mans@mansr.com>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Nicolas Pitre <nico@linaro.org>, Tony Lindgren <tony@atomide.com>,
        Sebastian Frias <sebastian_frias@sigmadesigns.com>
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 <20151119112130.GY8644@n2100.arm.linux.org.uk>
From: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
Message-ID: <564DC368.2030104@sigmadesigns.com>
Date: Thu, 19 Nov 2015 13:41:12 +0100
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On 19/11/2015 12:21, Russell King wrote:

> When I wrote the MMIO clocksource implementation, there was no
> ____cacheline_aligned on struct clocksource, and the arrangement I came
> to for the structure put the 'reg' and 'read' within the same cache line
> (note that the MMIO clocksource pre-dates Thomas' rearrangement of struct
> clocksource and the addition of the cache line alignment.)  The original
> layout did not have any padding gaps.

For the record, I pointed out the chronology in a previous discussion.
But Thomas didn't comment at the time :-(

http://thread.gmane.org/gmane.linux.ports.arm.kernel/402968/focus=403604

Mason wrote:
> Oh and while I have your attention ;-) I have alignment-related
> questions about clocksource_mmio_init() (commit 442c8176d2) wrt
> Thomas Gleixner's 369db4c952 patch. (I think the two patches
> do not play nice.)

Regards.

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