On Tue, Nov 30, 2010 at 10:48:34AM -0800, Greg KH wrote:
On Tue, Nov 30, 2010 at 06:40:49PM +0000, Russell King - ARM Linux wrote:
There's lots of static devices, not only platform devices, in the ARM tree. It's going to be a hell of a lot of work to fix this all up properly.
I agree, it's been abused for many years this way :(
I don't agree that it is abuse - it was something explicitly allowed by the original device model design by Patrick, with the condition that such a device was never unregistered. That's exactly the way we treat these devices.
What I'm slightly concerned about is that this is going to needlessly bloat the kernel - we're going to have to find some other way to store this information, and create devices from that - which means additional code to do the creation, and data structures for it to create these from. There will be additional wastage from kmalloc as kmalloc doesn't allocate just the size you ask for, but normally a power of two which will contain the size.
That could potentially mean that as the device structure is 216 bytes, kmalloc will use the 256 byte allocation size, which means a wastage of 40 bytes per device structure. On top of that goes the size of resources with the allocation slop on top for that, and then there's another allocation for the platform data.
Has anyone considered these implications before making this choice?