Re: [PATCH v2] consolidate WARN_...ONCE() static variables

From: Andrew Morton
Date: Mon Feb 27 2012 - 19:03:07 EST


On Mon, 27 Feb 2012 15:10:34 +0000
"Jan Beulich" <JBeulich@xxxxxxxx> wrote:

> Due to the alignment of following variables, these typically consume
> more than just the single byte that 'bool' requires, and as there are
> a few hundred instances, the cache pollution (not so much the waste of
> memory) sums up. Put these variables into their own section, outside
> of any half way frequently used memory range.
>
> v2: Do the same also to the __warned variable of rcu_lockdep_assert().
> (Don't, however, include the ones used by printk_once() and alike, as
> they can potentially be hot.)

I have a bad feeling that I still don't understand this patch. Ho hum.

What are the rules for the new .data.unlikely section? When should
people put variables into this section? Perhaps we can document this
somewhere?


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