Messages in this thread | | | From | Matt Sealey <> | Date | Mon, 21 Jan 2013 17:01:30 -0600 | Subject | Re: One of these things (CONFIG_HZ) is not like the others.. |
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On Mon, Jan 21, 2013 at 4:45 PM, Russell King - ARM Linux <linux@arm.linux.org.uk> wrote: > On Mon, Jan 21, 2013 at 10:30:07PM +0000, Arnd Bergmann wrote: >> On Monday 21 January 2013, Matt Sealey wrote: >> > So is that a bug in that it is not available to ARM right now, a bug >> > in that it would be impossible for anyone on ARM to have ever tested >> > this code, or a bug in that it should NEVER be enabled for ARM for >> > some reason? John? Ingo? :) >> > >> >> I think it's a bug that it's not available. That does not look intentional. > > What's a bug? kernel/Kconfig.hz not being available? No, it's > intentional. (See my replies).
The bug I saw as real is that CONFIG_SCHED_HRTICK is defined only in kernel/Kconfig.hz (and used in kernel/sched only) - so if we want that functionality enabled we will also have to opencode it in arch/arm/Kconfig. Everyone else, by virtue of using kernel/Kconfig.hz, gets this config item enabled for free if they have hrtimers or generic smp helpers.. if I understood what John just said, this means on ARM, since we don't use kernel/Kconfig.hz and we don't also define an item for CONFIG_SCHED_HRTICK, the process scheduler is completely oblivious that we're running in HRT mode?
The thing I don't know is real is if that really matters one bit..
-- Matt Sealey <matt@genesi-usa.com> Product Development Analyst, Genesi USA, Inc.
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