Re: Update-daemon for all FSes

[bousch@suntopo.matups.fr (Thierry Bousch)]

> On the other hand, a global update process would be nice, once that more
> advanced fs like minix fs are around. Maybe there should be a list, in which
> each filesystem could enter the drives on which a dcntl for updating makes
> sense. Some cookie maybe?!?

Having a unique "update" process would be a Good Thing (in terms of
performance) not only for file-systems, but also for device drivers; In
both cases, there are tasks which must be done (checked) periodically,
whether the device driver is called or not.  In minixfs and modm0dev,
this is accomplished by an auxiliary daemon process: this causes
significant overhead, and even more importantly, this process runs in
non-kernel mode, which forbids some functions like (*kernel->wake)()
which would be extremely handy. 

It would be nice to have a supplementary kernel function -- let's say
add_periodic_task(short period, void (*func)()) -- to register function
"func" to be executed _in kernel mode_ every "period" milliseconds. 

Any comments about this?

Thierry.