Dynamic swap file allocation -> swapd

Marc MERLIN (marc_merlin@magic.metawire.com)
17 Aug 1998 22:24:28 GMT


On 16 Aug 1998 23:36:36 -0700, Rogier Wolff <wolff@dutepp0.et.tudelft.nl> wrote:
>
>In an attempt to make the people shut up that whine about a deamon
>that adds swap when things go out of and, here is a deamon that does
>that. Well, to be exact, it can be configured to do that.
>
>It is configurable. For example, you can make it do something if the
>number of errors on your ethernet interface goes above a threshold.

I had a quick look at the source.
I have however been using swapd for the last 3 years (or so).

It was written by Nick Holloway <Nick.Holloway@alfie.demon.co.uk>, but as
far as I know, the last version he put out was 1.3.
I made a port to kernels 2.x and sent him my patch for version 1.4, but I
never really heard back from him.

About 1.5y ago, we had a similar discussion here, on lk, and I posted the
patch I made against swapd and Ian T Zimmerman <itz@rahul.net> added a quick
patch to have the kernel tell swapd when it really needed more memory (by
default swapd polls, and adds swap files on the fly, as needed).
I haven't yet checked if it works as intended with 2.1.x, but I intend to
soon.

My point is that the tools are there, but hardly anyone seem to know about
it. How about choosing some daemon once and for all, and putting a reference
to it in /usr/src/linux/Documentation ?

For info, in the 3 years, I've used swap, I never had a single freeze again
(but recovering from an application that starts to eat 80Megs of ram can
take a little while since your machine gets quite slow once swapd quicks in
and starts creating lots of swap files to keep up with VM demands). If you
run out of disk space however, then you get back to square 1 :-)

Marc

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