From: Denis Efremov <efremov@linux.com>
To: Julia Lawall <julia.lawall@lip6.fr>
Cc: Michal Marek <michal.lkml@markovi.net>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Nicolas Palix <nicolas.palix@imag.fr>,
linux-kernel@vger.kernel.org,
Markus Elfring <Markus.Elfring@web.de>,
Joe Perches <joe@perches.com>,
cocci@systeme.lip6.fr
Subject: Re: [Cocci] [PATCH v2] scripts: coccinelle: check for !(un)?likely usage
Date: Fri, 6 Sep 2019 23:55:39 +0300 [thread overview]
Message-ID: <3981b788-cd0b-d2c4-4585-d209f6f6a522@linux.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1909062217240.2643@hadrien>
Hi,
On 06.09.2019 23:19, Julia Lawall wrote:
>
>
> On Thu, 29 Aug 2019, Denis Efremov wrote:
>
>> This patch adds coccinelle script for detecting !likely and
>> !unlikely usage. These notations are confusing. It's better
>> to replace !likely(x) with unlikely(!x) and !unlikely(x) with
>> likely(!x) for readability.
>>
>> The rule transforms !likely(x) to unlikely(!x) based on this logic:
>> !likely(x) iff
>> !__builtin_expect(!!(x), 1) iff
>> __builtin_expect(!!!(x), 0) iff
>> unlikely(!x)
>>
>> For !unlikely(x) to likely(!x):
>> !unlikely(x) iff
>> !__builtin_expect(!!(x), 0) iff
>> __builtin_expect(!!!(x), 1) iff
>> likely(!x)
>>
>> Signed-off-by: Denis Efremov <efremov@linux.com>
>> Cc: Julia Lawall <Julia.Lawall@lip6.fr>
>> Cc: Gilles Muller <Gilles.Muller@lip6.fr>
>> Cc: Nicolas Palix <nicolas.palix@imag.fr>
>> Cc: Michal Marek <michal.lkml@markovi.net>
>> Cc: Markus Elfring <Markus.Elfring@web.de>
>> Cc: Joe Perches <joe@perches.com>
>> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
>
> Acked-by: Julia Lawall <julia.lawall@lip6.fr>
>
> A small improvement though would be to improve the explicit dependency of
> the last four python rules on r1 and r2. Those rules won't execute unless
> the inherited metavariable has a value, which makes the same dependency.
>
> julia
I think I will resend this patch as a part of patchset with all warnings fixed
in a couple of days. Hope this will help to create a discussion point with other
developers about readability of "!likely" and "!unlikely".
Thanks,
Denis
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next prev parent reply other threads:[~2019-09-06 20:56 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-25 13:05 [Cocci] [PATCH] scripts: coccinelle: check for !(un)?likely usage Denis Efremov
2019-08-25 15:30 ` Markus Elfring
2019-08-25 21:06 ` Denis Efremov
2019-08-25 15:30 ` Markus Elfring
2019-08-25 16:37 ` Joe Perches
2019-08-25 18:59 ` Denis Efremov
2019-08-25 19:19 ` Julia Lawall
2019-08-28 11:33 ` Rasmus Villemoes
2019-08-28 11:59 ` Joe Perches
2019-08-28 12:33 ` Denis Efremov
2019-08-28 12:33 ` Julia Lawall
2019-08-28 12:41 ` Denis Efremov
2019-08-28 13:57 ` Denis Efremov
2019-08-25 21:19 ` Denis Efremov
[not found] ` <20190901172403.GA1047@bug>
2019-09-01 17:39 ` Denis Efremov
2019-08-29 17:10 ` [Cocci] [PATCH v2] " Denis Efremov
2019-08-29 17:13 ` Denis Efremov
2019-08-30 0:42 ` Julia Lawall
2019-08-30 6:56 ` Denis Efremov
2019-08-30 8:06 ` Rasmus Villemoes
2019-08-29 20:07 ` Markus Elfring
2019-08-30 7:55 ` Markus Elfring
2019-09-06 20:19 ` Julia Lawall
2019-09-06 20:55 ` Denis Efremov [this message]
2019-09-07 8:05 ` [Cocci] [v2] " Markus Elfring
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