[Gllug] unmounting file systems

[Nix]

On Wed, 26 Jun 2002, t. clarke muttered drunkenly:
> This has long struck me as a failing of Unix/linux kernels - the inability
> to kill processes in certain states.  Maybe someone involved in kernel
> development should look at ways of killing processes from within the kernel
> by means of a system-call, rather than sending the process a signal ?

The problem is, what happens if that process has kernel locks held?
Normally things are in uninterruptible sleep for precisely that reason,
and they've normally got locks held because they're doing things to
kernel data structures that other processes would be deeply confused by
(i.e., because they're enforcing atomiticity).

So to safely kill a D-state process you'd need to snap its locks and
roll back all the changes to data structures it had made: that is, you'd
need a transaction management layer deep inside the kernel which all the
device drivers use.

Think of the performance hit. :(

-- 
`What happened?'
                 `Nick shipped buggy code!'
                                             `Oh, no dinner for him...'


-- 
Gllug mailing list  -  Gllug at linux.co.uk
http://list.ftech.net/mailman/listinfo/gllug