Subject: Re: Minimum swap size
To: <>
From: David Laight <>
List: tech-kern
Date: 05/19/2003 09:55:07
> As far as dumping goes, my understanding is that we dump to the end of the
> dumpdev, right? (so if dumping to swap, and we have 32MB of ram and 64MB of
> swap, the dump will be written to the last 32MB) correct me if i'm wrong,
> but if that is the case, then swap should (at least on systems with small
> amounts of ram) be big enough so that the system can boot up and not
> overwrite the dump if it ends up swapping during the boot process, because
> swap is activated before savecore is run. Just my two cents.

Yes, we (probably quite reasonably) don't expect the system to run
without swap while doing the fscks (etc).

But systems with >128MB of RAM are unlikely to need to swap that early on.
So any dump will (hopefully) be preserved.

I presume there needs to be space for a header on the dump?
(rounding to cylinder boundaries will probably generate it!)

A slight alternative is to dump to the start of swap, and have the system
startup code look for the signature of a valid dump and to only allocate
the latter part of 'swap' to swap if there is a dump lurking.
Once the dump has been saved the rest of the space can be given to swap.


David Laight: