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| Started by | Marc Zyngier <marc.zyngier@arm.com> |
|---|---|
| First post | 2016-01-07 15:40 +0100 |
| Last post | 2016-01-07 15:40 +0100 |
| Articles | 1 — 1 participant |
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Re: [PATCH 4.4-rc5 v22 1/4] irqchip: gic: Optimize locking in gic_raise_softirq Marc Zyngier <marc.zyngier@arm.com> - 2016-01-07 15:40 +0100
| From | Marc Zyngier <marc.zyngier@arm.com> |
|---|---|
| Date | 2016-01-07 15:40 +0100 |
| Subject | Re: [PATCH 4.4-rc5 v22 1/4] irqchip: gic: Optimize locking in gic_raise_softirq |
| Message-ID | <qOjTk-SP-21@gated-at.bofh.it> |
On 20/12/15 20:52, Daniel Thompson wrote: > Currently gic_raise_softirq() is locked using 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> Acked-by: Marc Zyngier <marc.zyngier@arm.com> M. -- Jazz is not dead. It just smells funny... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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