Re: [patch] context-switching overhead in X, ioport(), 2.6.8.1

["David S. Miller" <davem@redhat.com>]

FWIW, I would recommend a sparse bitmap implementation for the
ioport stuff.  Something simple like:

struct set_ent {
	u32 pos;
	u32 bits;
	struct set_ent *next;
};

static inline int is_set(struct set_ent *head, int pos)
{
	while (head != NULL) {
		if (pos >= head->pos) {
			if (pos < head->pos + 32) {
				if (head->bits &
				    (1 << (pos - head->pos)))
					return 1;
			}
			break;
		}

		head = head->next;
	}
	return 0;
}

You get the idea.