Re: [RFC] VM: I have a dream...

["linux-os \(Dick Johnson\)" <linux-os@analogic.com>]

On Mon, 23 Jan 2006, Diego Calleja wrote:

> El Mon, 23 Jan 2006 09:05:41 -0600,
> Ram Gupta <ram.gupta5@gmail.com> escribió:
>
>> Linux also supports multiple swap files . But these are more
>
> There're in fact a "dynamic swap" tool which apparently
> does what mac os x do: http://dynswapd.sourceforge.net/
>
> However, I doubt the approach is really useful. If you need that much
> swap space, you're going well beyond the capabilities of the machine.
> In fact, I bet that most of the cases of machines needing too much
> memory will be because of bugs in the programs and OOM'ing would be
> a better solution.

You have roughly 2 GB of dynamic address-space avaliable to each
task (stuff that's not the kernel and not the runtime libraries).
You can easily have 500 tasks, even RedHat out-of-the-box creates
about 60 tasks. That's 1,000 GB of potential swap-space required
to support this. This is not beyond the capabilites of a 32-bit
machine with a fast front-side bus and fast I/O (like wide SCSI).
Some persons tend to forget that 32-bit address space is available
to every user, some is shared, some is not. A reasonable rule-of-
thumb is to provide enough swap-space to duplicate the address-
space of every potential task.

Cheers,
Dick Johnson
Penguin : Linux version 2.6.13.4 on an i686 machine (5589.54 BogoMips).
Warning : 98.36% of all statistics are fiction.

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