Re: [PATCH 1/9] x86/intel_cqm: Modify hot cpu notification handling

From: Peter Zijlstra
Date: Wed Jul 29 2015 - 12:44:27 EST


On Wed, Jul 01, 2015 at 03:21:02PM -0700, Vikas Shivappa wrote:
> +/*
> + * Temporary cpumask used during hot cpu notificaiton handling. The usage
> + * is serialized by hot cpu locks.
> + */
> +static cpumask_t tmp_cpumask;

So the problem with this is that its 512 bytes on your general distro
config. And this patch set includes at least 3 of them

So you've just shot 1k5 bytes of .data for no reason.

I know tglx whacked you over the head for this, but is this really worth
it? I mean, nobody sane should care about hotplug performance, so who
cares if we iterate a bunch of cpus on the abysmal slow path called
hotplug.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/