linux-kernel - Re: [patch 08/15] x86/vdso: Move VDSO clocksource state tracking to callback

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Date:   Wed, 15 Jan 2020 06:56:36 +0100
From:   Jürgen Groß <jgross@...e.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, John Stultz <john.stultz@...aro.org>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        Andy Lutomirski <luto@...nel.org>,
        Christophe Leroy <christophe.leroy@....fr>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Sasha Levin <sashal@...nel.org>,
        Ralf Baechle <ralf@...ux-mips.org>,
        Paul Burton <paulburton@...nel.org>,
        James Hogan <jhogan@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Marc Zyngier <maz@...nel.org>
Subject: Re: [patch 08/15] x86/vdso: Move VDSO clocksource state tracking to
 callback

On 14.01.20 19:52, Thomas Gleixner wrote:
> All architectures which use the generic VDSO code have their own storage
> for the VDSO clock mode. That's pointless and just requires duplicate code.
> 
> X86 abuses the function which retrieves the architecture specific clock
> mode storage to mark the clocksource as used in the VDSO. That's silly
> because this is invoked on every tick when the VDSO data is updated.
> 
> Move this functionality to the clocksource::enable() callback so it gets
> invoked once when the clocksource is installed. This allows to make the
> clock mode storage generic.
> 
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>

Acked-by: Juergen Gross <jgross@...e.com> (Xen parts)


Juergen