Re: [RFC] vmstat: Avoid waking up idle-cpu to service shepherd work

From: Christoph Lameter
Date: Fri Mar 27 2015 - 07:11:52 EST


On Fri, 27 Mar 2015, Peter Zijlstra wrote:

> > We could align the base on 8 bytes to gain an extra bit in the pointer
> > and use that bit to indicate the running state. Then these sites can
> > spin on that bit while we can change the actual base pointer.
>
> Even though tvec_base has ____cacheline_aligned stuck on, most are
> allocated using kzalloc_node() which does not actually respect that but
> already guarantees a minimum u64 alignment, so I think we can use that
> third bit without too much magic.

Create a new slab cache for this purpose that does the proper aligning?

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