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

From	Tim Chen <tim.c.chen@linux.intel.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v5 3/9] mm/swap: Split swap cache into 64MB trunks
Date	2017-01-12 17:50 +0100
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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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[PATCH v5 3/9] mm/swap: Split swap cache into 64MB trunks Tim Chen <tim.c.chen@linux.intel.com> - 2017-01-11 19:00 +0100
  Re: [PATCH v5 3/9] mm/swap: Split swap cache into 64MB trunks Andrew Morton <akpm@linux-foundation.org> - 2017-01-12 00:10 +0100
    Re: [PATCH v5 3/9] mm/swap: Split swap cache into 64MB trunks Andi Kleen <ak@linux.intel.com> - 2017-01-12 00:20 +0100
      Re: [PATCH v5 3/9] mm/swap: Split swap cache into 64MB trunks Tim Chen <tim.c.chen@linux.intel.com> - 2017-01-12 17:50 +0100

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