Re: [v4 1/1] mm: Adaptive hash table scaling

[Michal Hocko]

On Sat 20-05-17 13:06:53, Pavel Tatashin wrote:
[...]
>  /*
> + * Adaptive scale is meant to reduce sizes of hash tables on large memory
> + * machines. As memory size is increased the scale is also increased but at
> + * slower pace.  Starting from ADAPT_SCALE_BASE (64G), every time memory
> + * quadruples the scale is increased by one, which means the size of hash table
> + * only doubles, instead of quadrupling as well.
> + */
> +#define ADAPT_SCALE_BASE	(64ull << 30)

I have only noticed this email today because my incoming emails stopped
syncing since Friday. But this is _definitely_ not the right approachh.
64G for 32b systems is _way_ off. We have only ~1G for the kernel. I've
already proposed scaling up to 32M for 32b systems and Andi seems to be
suggesting the same. So can we fold or apply the following instead?
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