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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Yury Norov <yury.norov@gmail.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>
Subject: Re: [GIT PULL] Bitmap patches for v5.19-rc1
Date: Sat, 4 Jun 2022 14:24:52 -0700	[thread overview]
Message-ID: <CAHk-=wibRs6NXp1JXA58+cHcgQNDiAtdOTR7kieG5P=NOtWRGA@mail.gmail.com> (raw)
In-Reply-To: <Yppk/mN+KYTDkvz3@yury-laptop>

On Fri, Jun 3, 2022 at 12:48 PM Yury Norov <yury.norov@gmail.com> wrote:
>
>       arch/ia64: replace cpumask_weight with cpumask_empty where appropriate

As you can tell from the pr-tracker-bot reply, I've pulled this.

But I did want to point out that this patch should probably have gone further.

That first argument to per_cpu_scan_finalize() is kind of ugly, but it
should probably have been something like

    n = cpumask_weight(&early_cpu_possible_map) ? : 32;

instead of doing *both* cpumask_weight() and cpumask_empty().

The only case cpumask_empty() can be optimized if it's not entirely
empty, but that's the also the case where that code then ends up
calling cpumask_weight() to get the final result.

Note: I don't really care. This is ia64 boot-time setup code, so it's
not like performance matters. It's dead and irrelevant. I just reacted
to "that patch tries to micro-optimize the code, but is missing the
forest for the trees".

                     Linus

  parent reply	other threads:[~2022-06-04 21:25 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-03 19:46 [GIT PULL] Bitmap patches for v5.19-rc1 Yury Norov
2022-06-04 21:20 ` pr-tracker-bot
2022-06-04 21:24 ` Linus Torvalds [this message]
  -- strict thread matches above, loose matches on Subject: below --
2022-05-27 15:43 Yury Norov
2022-05-28  4:17 ` Linus Torvalds
2022-06-01  1:15   ` Yury Norov

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