public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: Kuan-Wei Chiu <visitorckw@gmail.com>
To: I Hsin Cheng <richard120310@gmail.com>
Cc: yury.norov@gmail.com, linux@rasmusvillemoes.dk,
	jserv@ccns.ncku.edu.tw, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] cpumask: Implement "random" version of cpumask_any_but()
Date: Mon, 13 Jan 2025 18:13:07 +0800	[thread overview]
Message-ID: <Z4TnM8jwgcMMd7Ft@visitorckw-System-Product-Name> (raw)
In-Reply-To: <20250113061839.22131-1-richard120310@gmail.com>

Hi I Hsin,

On Mon, Jan 13, 2025 at 02:18:39PM +0800, I Hsin Cheng wrote:
> Original implementation of "cpumask_any_but()" isn't actually random as
> the comment claims itself to be. It's behavior is in fact to select the
> first cpu in "mask" which isn't equal to "cpu".
> 
> Re-implement the function so we can choose a random cpu by randomly
> select the value of "n" and choose the nth cpu in "mask"
> 
This patch may slow down the efficiency of cpumask_any_but(). Are there
any in-tree users of cpumask_any_but() that require it to return a
truly random id, or benefit from such behavior?

Regards,
Kuan-Wei

  reply	other threads:[~2025-01-13 10:13 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-13  6:18 [RFC PATCH] cpumask: Implement "random" version of cpumask_any_but() I Hsin Cheng
2025-01-13 10:13 ` Kuan-Wei Chiu [this message]
2025-01-13 10:27   ` I Hsin Cheng
2025-01-13 11:09     ` Kuan-Wei Chiu
2025-01-13 11:05 ` Mark Rutland
2025-01-13 18:00   ` Yury Norov
2025-01-14  7:15     ` I Hsin Cheng
2025-01-14 15:02       ` Mark Rutland
2025-01-14 15:43       ` Yury Norov
2025-01-15  7:24         ` I Hsin Cheng

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=Z4TnM8jwgcMMd7Ft@visitorckw-System-Product-Name \
    --to=visitorckw@gmail.com \
    --cc=jserv@ccns.ncku.edu.tw \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux@rasmusvillemoes.dk \
    --cc=richard120310@gmail.com \
    --cc=yury.norov@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox