Do you know if any exist? Would it make sense to have a survey to
understand if anyone relies on it?
From what I've seen so far, drivers that were converted simply worked
with the non-managed facility and didn't have any special code for it.
Perhaps Christoph can comment as he convert most of them.
But if there aren't any drivers that absolutely rely on it, maybe its
not a bad idea to allow it by default?
Sure, I was just cautious and I have to admit that I have no insight into
the driver side details.
Christoph, feel free to chime in :)
Should I construct an email list of the driver maintainers of the
converted drivers?
* When and how is the driver informed about the change?
When:
#1 Before the core tries to move the interrupt so it can veto the
move if it cannot allocate new resources or whatever is required
to operate after the move.
What would the core do if a driver veto a move?
Return the error code from write_affinity() as it does with any other error
which fails to set the affinity.
OK, so this would mean that the driver queue no longer has a vector
correct? so is the semantics that it needs to cleanup its resources or
should it expect another callout for that?
I'm wandering in what conditions a driver will be unable to allocate
resources for move to cpu X but able to allocate for move to cpu Y.
Node affine memory allocation is the only thing which comes to my mind, or
some decision not to have a gazillion of queues on a single CPU.
Yea, makes sense.
This looks like it can work to me, but I'm probably not familiar enough
to see the full picture here.
On the interrupt core side this is workable, I just need the input from the
driver^Wsubsystem side if this can be implemented sanely.
Can you explain what do you mean by "subsystem"? I thought that the
subsystem would be the irq subsystem (which means you are the one to
provide the needed input :) ) and the driver would pass in something
like msi_irq_ops to pci_alloc_irq_vectors() if it supports the driver
requirements that you listed and NULL to tell the core to leave it alone
and do what it sees fit (or pass msi_irq_ops with flag that means that).
ops structure is a very common way for drivers to communicate with a
subsystem core.
