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Re: [SLUG] Increasing RAM


Amos Shapira <amos.shapira@xxxxxxxxx> writes:

> I used to keep around large swap partitions (that was also before the
> blissful days of LVM2) until someone on the linux-il mailing list
> convinced me that the amount of overhead for the kernel to keep track
> of large amount of swap will actually cause a slow down and reduction
> of ram utilization.

You were, I fear, convinced of something untrue.  There is no
substantial overhead to tracking a "large amount of swap", and certainly
no "reduction of ram utilization".

Linux memory management is not /that/ bad, honest. ;)


What they may have been talking about is that having swapped two or
three gigabytes of memory usually implies that you will be thrashing,
where swapping a few tens or hundreds of megabytes would, historically,
be less certain.

> Also remember that the 2X or so rule was from Unix days when the
> memory management algorithms where totally different (e.g. Each ram
> page had a shadow swap page pre-allocated for it).

Actually, this has varied across Unix implementations for a range of
reasons; under Linux it was historically that way.

> So now I stick to around .5 gig, whatever the ram size is.

*nod*  As do I, save in the one case where I want to be able to use the
"suspend to disk" functions supported by Linux.

Regards,
        Daniel