linux-kernel - Re: Re [PATCH v2] lib: optimize cpumask_next

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Message-ID: <20171025155014.ppsu6hkwnhh3fjxp@yury-thinkpad>
Date:   Wed, 25 Oct 2017 18:50:14 +0300
From:   Yury Norov <ynorov@...iumnetworks.com>
To:     Clement Courbet <courbet@...gle.com>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Matthew Wilcox <mawilcox@...rosoft.com>,
        Ingo Molnar <mingo@...nel.org>, linux-arch@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: Re [PATCH v2] lib: optimize cpumask_next_and()

On Wed, Oct 25, 2017 at 05:28:41PM +0200, Clement Courbet wrote:
> Thanks for the comments Yury.
> 
> > But I'd like also to keep _find_next_bit() consistent with
> > _find_next_bit_le()
> 
> Not sure I understand what you're suggesting here: Do you want a
> find_next_and_bit_le() or do you want to make _find_next_bit_le() more
> like _find_next_bit() ? In the latter case we might just want to merge
> it with _find_next_bit() and end up with an extra is_le parameter :)

Both ways will work, but I think that extra is_le is too much.
_find_next_bit_le() should be the copy of _find_next_bit() with the
addition of swapping code.

If you don't need find_next_and_bit_le(), don't add it.
find_{first,last}_bit() doesn't have LE version, for example.

Yury