Edited report from pahole on amd64 host:
struct ChannelState {
...
	ChnType                    type;                 /*    32     4 */

	/* XXX 4 bytes hole, try to pack */
...
	uint8_t                    rregs[16];            /*    66    16 */

	/* XXX 2 bytes hole, try to pack */
...
	/* size: 392, cachelines: 7 */
	/* sum members: 382, holes: 2, sum holes: 6 */
	/* padding: 4 */
	/* last cacheline: 8 bytes */
};	/* definitions: 1 */

Fix by rearranging the structure to avoid padding.

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>