Re: Software Suspend Functionality in 2.5

[Suparna Bhattacharya <suparna@in.ibm.com>]

On Fri, Feb 28, 2003 at 02:44:06PM +0100, Pavel Machek wrote:
> > Atomic snapshots are what we'd like for dump too, since we desire 
> > accurate dumps (minimum drift), so its not a conflicting requirement. 
> > The difference is that while you could do i/o (e.g to flush pages 
> > to free up memory) before initiating an atomic snapshot, we can't.
> 
> OTOH "best-effort-atomic" is probably okay for you, while it is not
> acceptable for swsusp. Hopefully the code is not going to get too
> complicated by "must be atomic" and "must work with crashed system"
> requirements...
> 
For the kind of atomicity you need there probably are two
steps:
1) Quiesce the system - get to a point of consistency (when you
   can take a resumable snapshot)
2) Perform an atomic copy / snapshot

Step (1) would be different for swsusp and crash dump (not
intended to be common ). But for Step (2), do you think
what you need/do is complicated by crashed system requirements ?

Regards
Suparna

-- 
Suparna Bhattacharya (suparna@in.ibm.com)
Linux Technology Center
IBM Software Labs, India