Re: [PATCH] clocksource: Store reg field within struct clocksource

From: Måns Rullgård
Date: Wed Nov 18 2015 - 08:51:17 EST

Marc Gonzalez <marc_gonzalez@xxxxxxxxxxxxxxxx> writes:

> Since 'struct clocksource' is ____cacheline_aligned, gcc must insert
> a lot of padding between reg and clksrc in 'struct clocksource_mmio'
> (for example, L1_CACHE_BYTES = 64 on ARMv7).
> Storing reg within 'struct clocksource' removes unnecessary padding,
> and reg can then be grouped with other hot data.

Can you demonstrate a difference with this change? Not saying it's bad,
but it's always good to have numbers.

> A nice side-effect of this patch is making container_of() unnecessary,
> which makes the code a bit simpler.

You really need to get used to that construct.

Måns Rullgård
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