Re: [PATCH v5 3/9] mm/swap: Split swap cache into 64MB trunks

From: Tim Chen
Date: Thu Jan 12 2017 - 11:47:48 EST


On Wed, Jan 11, 2017 at 03:19:37PM -0800, Andi Kleen wrote:
> > Switching from a single radix-tree to an array of radix-trees to reduce
> > contention seems a bit hacky. That we can do this and have everything
> > continue to work tells me that we're simply using an inappropriate data
> > structure to hold this info.
>
> What would you use instead?

I agree that this approach is a bit hacky. However, it is pretty
effective and simple. If later on we come up with a better solution to
scale modfication of the radix tree, we can collapse the radix trees.

I think developing a scalable radix tree with write modifications will
take quite a while and is a non-trivial effort. With almost memory speed
SSDs coming on the market soon, I think having a workable solution now
and optimizing it for long term is reasonabale.

Tim

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