No surprise on memory

[Martin Langhoff]

On Thu, Dec 18, 2008 at 1:43 PM, Carol Farlow Lerche <cafl at msbit.com> wrote:
> Since Linux allows multiple swap partitions, is there anything to be gained
> by using two -- the first, a compcache swap file and the second on flash,
> perhaps with Belyakov's MTD layer.  First question is whether Linux treats
> the two swap files in an order, such that it only uses the flash swap if the
> compcache is exhausted.  If so, instrument the I/O rate to swap, first to
> study the relative sizing and second -- could the I/O rate to the flash swap
> be a signal to prune activities?

Both Belyakov and Richard Purdie seem to compress into a large-ish
buffer in RAM first, and only past a certain threshold actually put it
to NAND. This is to minimise number of erase ops, and improve
performance, so the swaponflash driver Richard's posted does exactly
what you describe.

As to treating that as a signal, I dunno.

I do think Sugar could monitor some mem stats and warn the user
_early_ when under mem pressure. If more than one activity is open, it
could sugges to close a bg activity...

cheers,



m
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