Re: memory usage at a given time

On Sat, Nov 14, 2020 at 12:30 PM Otto Moerbeek <otto@drijf.net> wrote:

> On Sat, Nov 14, 2020 at 12:21:30PM +0200, Mihai Popescu wrote:
>
> [ .. ]
> > CPU0: 22.4% user, 0.0% nice, 3.8% sys, 0.6% spin, 0.6% intr, 72.7%
> idle
> > CPU1: 21.2% user, 0.0% nice, 3.0% sys, 0.2% spin, 0.0% intr, 75.6%
> idle
> > Memory: Real: 1235M/2914M act/tot Free: 4505M Cache: 1054M Swap: 0K/7913M
>
> Cutting some corners, but the basics go like this:
>
> Currently, no swap is used.
>
> You see 4505G is free. Roughly you can use that amount more. If free
> becomes low, cache will be reduced and/or pages swapped out, making
> more pages free so they can become used and part of tot.
>
> tot + free + cache should add up to available RAM (which is a bit less
> than what you have in the machine, since the kernel also needs to fit
> somewhere and uses memory of its own).
>
> -Otto
>
>
Here is my confusion.
tot + free + cache would be:
2914M + 4505M + 1054M = 8473M

dmesg shows me this:
real mem = 8029429760 (7657MB)
avail mem = 7770787840 (7410MB)
here should be the memory for the integrated video card:
7657MB - 7410MB = 247MB <- plausible

Am I correct, or am I hit by the bit/byte units conversion.

Thank you.