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SubjectRe: [RESEND PATCH 4.0-rc7 v20 1/6] irqchip: gic: Optimize locking in gic_raise_softirq
On 10/04/15 10:51, Daniel Thompson wrote:
> Currently gic_raise_softirq() is locked using upon irq_controller_lock.
> This lock is primarily used to make register read-modify-write sequences
> atomic but gic_raise_softirq() uses it instead to ensure that the
> big.LITTLE migration logic can figure out when it is safe to migrate
> interrupts between physical cores.
>
> This is sub-optimal in closely related ways:
>
> 1. No locking at all is required on systems where the b.L switcher is
> not configured.
>
> 2. Finer grain locking can be used on systems where the b.L switcher is
> present.
>
> This patch resolves both of the above by introducing a separate finer
> grain lock and providing conditionally compiled inlines to lock/unlock
> it.
>
> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Jason Cooper <jason@lakedaemon.net>
> Cc: Russell King <linux@arm.linux.org.uk>
> Cc: Marc Zyngier <marc.zyngier@arm.com>
> Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>

Looks good to me.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>

M.
--
Jazz is not dead. It just smells funny...


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