On Fri, 27 Oct 2006 23:09:05 -0600
Grant Grundler <[email protected]> wrote:
> On Fri, Oct 27, 2006 at 04:06:26PM -0700, Andrew Morton wrote:
> > On Fri, 27 Oct 2006 23:59:30 +0100
> > Alan Cox <[email protected]> wrote:
> >
> > > Ar Gwe, 2006-10-27 am 11:42 -0700, ysgrifennodd Andrew Morton:
> > > > IOW, we want to be multithreaded _within_ an initcall level, but not between
> > > > different levels.
> > >
> > > Thats actually insufficient. We have link ordered init sequences in
> > > large numbers of driver subtrees (ATA, watchdog, etc). We'll need
> > > several more initcall layers to fix that.
> > >
> >
> > It would be nice to express those dependencies in some clearer and less
> > fragile manner than link order. I guess finer-grained initcall levels
> > would do that, but it doesn't scale very well.
>
> Would making use of depmod data be a step in the right direction?
Nope. The linkage-order problem is by definition applicable to
linked-into-vmlinux code, not to modules.
> ie nic driver calls extern function (e.g. pci_enable_device())
> and therefore must depend on module which provides that function.
>
> My guess is this probably isn't 100% sufficient to replace all initcall
> levels. But likely sufficient within a given initcall level.
> My main concern are circular dependencies (which are rare).
The simplest implementation of "A needs B to have run" is for A to simply
call B, and B arranges to not allow itself to be run more than once.
But that doesn't work in the case "A needs B to be run, but only if B is
present". Resolving this one would require something like a fancy
"synchronisation object" against which dependers and dependees can register
interest, and a core engine which takes care of the case where a depender
registers against something which no dependees have registered.
The mind boggles.
> > But whatever. I think multithreaded probing just doesn't pass the
> > benefit-versus-hassle test, sorry. Make it dependent on CONFIG_GREGKH ;)
>
> Isn't already? :)
>
> I thought parallel PCI and SCSI probing on system with multiple NICs and
> "SCSI" storage requires udev to create devices with consistent naming.
For some reason people get upset when we rename all their devices. They're
a humourless lot.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
