On Wed, Jul 29, 2015 at 05:01:43PM +0200, Paolo Bonzini wrote: > > > On 29/07/2015 16:56, Michael S. Tsirkin wrote: > >>>> > > > Also, document our contract with legacy userspace: when running on > >>>> > > > an > >>>> > > > old kernel, you get -1 and you can assume at least 64 slots. > >>>> > > > Since 0 > >>>> > > > value's left unused, let's make that mean that the current > >>>> > > > userspace > >>>> > > > behaviour (trial and error) is required, just in case we want it > >>>> > > > back. > >>> > > > >>> > > What's wrong with reading the module parameter value? It's there in > >>> > > sysfs ... > >> > for most cases it would work but distro doesn't have to mount > >> > sysfs under /sys > > If it wants to rewrite all userspace, sure it doesn't. > > I agree, on the other hand it doesn't seem far fetched to have a per-fd > maximum in the future. So I think this patch is more future-proof. > > Paolo
Possibly, but this calls for some kind of priveledge separation model, where a priveledged app can set the per-fd limit while regular ones can only read it. Sounds very complex. Let's see some of this code first. And I really think there are better ways to future proof it, e.g. teach userspace to do error handling, revert adding a slot if one of the components can't support it. -- MST -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
