Re: [PATCH] iov_iter: optimise iter type checking
From: Al Viro
Date: Wed Jan 27 2021 - 13:31:50 EST
On Wed, Jan 27, 2021 at 04:28:38PM +0000, David Laight wrote:
> I'd definitely leave the type as a bitmap.
What the hell for? Microoptimizations in places where we have
much heavier stuff to be done are bloody pointless.
It's already overcomplicated. And compiler is _not_ going to
be able to prove that we'll only ever have one bit set, so
you would be making it harder to optimize, not to mention
reason about.