Re: [RFC][PATCH] Faster generic_fls

[Andrew Morton]

hugang <[e-mail]> wrote:
>
> Here is table version of the fls. Yes it fast than other.

nooo..  That has a big cache footprint.  At the very least you should use
a binary search.  gcc will do it for you:

	switch (n) {
	case 0 ... 1:
		return 1;
	case 2 ... 3:
		return 2;
	case 4 ... 7:
		return 3;
	case 8 ... 15:
		return 4;

etc.