linux-kernel - Re: [PATCH v4 00/40] lib/find: add atomic find

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Date: Thu, 20 Jun 2024 13:32:05 -0700
From: Linus Torvalds <torvalds@...ux-foundation.org>
To: Yury Norov <yury.norov@...il.com>
Cc: linux-kernel@...r.kernel.org, "David S. Miller" <davem@...emloft.net>, 
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Subject: Re: [PATCH v4 00/40] lib/find: add atomic find_bit() primitives

On Thu, 20 Jun 2024 at 13:20, Yury Norov <yury.norov@...il.com> wrote:
>
> FORCE_NR_CPUS helped to generate a better code for me back then. I'll
> check again against the current kernel.

Of _course_ it generates better code.

But when "better code" is a source of bugs, and isn't actually useful
in general, it's not better, is it.

> The 5d272dd1b343 is wrong. Limiting FORCE_NR_CPUS to UP case makes no
> sense because in UP case nr_cpu_ids is already a compile-time macro:

Yury, I'm very aware. That was obviously intentional. the whole point
of the commit is to just disable the the whole thing as useless and
problematic.

I could have just ripped it out entirely. I ended up doing a one-liner instead.

                Linus