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SubjectRe: Updated Linux 2.4 issues page
andersen@codepoet.org (Erik Andersen)  wrote on 20.08.00 in <20000820085201.A459@codepoet.org>:

> + unsigned long mem_total = val.totalram + val.totalswap + val.totalhigh;
> +
> + /* If mem_total did not overflow. Divide all memory values by
> + * mem_unit and set mem_unit=1. This leaves things compatable with
> + * 2.2.x, and also retains compatability with earlier 2.4.x
> + * kernels... */
> + if ( !(mem_total < val.totalram || mem_total < val.totalswap ||
> + mem_total < val.totalhigh) )

This check doesn't work.

Example: assume val.totalram = val.totalswap = val.totalhigh = 2.5 GB

Then mem_total = 7.5 GB mod 4 GB = 3.5 GB

and 3.5 GB > 2.5 GB.

qed.

(More detail: for a sum of n terms, it breaks (for example) for equal
terms between max/(n-1) as lower and 2*max/n as upper bound. For n=2, this
is empty; for n=3, it's between 1/2*max and 2/3*max, for n=4 it'd be
between 1/3*max and 1/2*max, and so on.)


MfG Kai
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