Re: Fix SWSUSP & !SWAP

[Pavel Machek <pavel@ucw.cz>]

Hi!

> >> > From: Martin J. Bligh [mailto:mbligh@aracnet.com] 
> >> > Can't you just create a pre-reserved separate swsusp area on 
> >> > disk the size 
> >> > of RAM (maybe a partition rather than a file to make things 
> >> > easier), and 
> >> > then you know you're safe (basically what Marc was 
> >> > suggesting, except pre-allocated)? Or does that make me the 
> >> > prince of all evil? ;-)
> >> > 
> >> > However much swap space you allocate, it can always all be 
> >> > used, so that seems futile ...
> >> 
> >> This is what Other OSes do, and I believe this is the correct path.
> >> Using swap for swsusp is a clever hack but not a 100% solution.
> > 
> > Well, for normal use its clearly inferior -- suspend partition is unused
> > when it could be used for speeding system up by swapping out unused
> > stuff.
> > 
> > OtherOS approach is better because it can guarantee suspend-to-disk
> > for critical situations like overheat or battery-critical.
> > 
> > But we can get best of both worlds if we OOM-kill during critical
> > suspend. [If suspend partition was not used for swapping, machine
> > would *already* OOM-killed someone, so we are only improving stuff].
> 
> OK ... but at least having the *option* to have a separate reserved
> area would be nice, no? For most people, RAM is just a tiny amount
> of their disk space ... and damn, does it make the code simpler ;-)

If it is an *option*, it does not make code simpler.

And OOM-killing during suspend is just what you want. It makes suspend
deterministic but it might kill someone. [Well, your solution would
kill him sooner than that...]
								Pavel

-- 
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]