Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon, 18 Jul 2022 23:35:39 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Yury Norov <yury.norov@gmail.com>
Cc:     linux-kernel@vger.kernel.org,
        Alexander Lobakin <alexandr.lobakin@intel.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Alexey Klimov <aklimov@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andrii Nakryiko <andrii@kernel.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Ben Segall <bsegall@google.com>,
        Christoph Lameter <cl@linux.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Dennis Zhou <dennis@kernel.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Eric Dumazet <edumazet@google.com>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Ingo Molnar <mingo@redhat.com>,
        Isabella Basso <isabbasso@riseup.net>,
        John Fastabend <john.fastabend@gmail.com>,
        Josh Poimboeuf <jpoimboe@kernel.org>,
        Juergen Gross <jgross@suse.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        KP Singh <kpsingh@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Mel Gorman <mgorman@suse.de>, Miroslav Benes <mbenes@suse.cz>,
        Nathan Chancellor <nathan@kernel.org>,
        "Paul E . McKenney" <paulmck@kernel.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Song Liu <songliubraving@fb.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Tejun Heo <tj@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Valentin Schneider <vschneid@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Vlastimil Babka <vbabka@suse.cz>, Yonghong Song <yhs@fb.com>,
        linux-mm@kvack.org, netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: Re: [PATCH 13/16] time: optimize tick_setup_device()
Message-ID: <YtXSK7qt+TuTRIbV@worktop.programming.kicks-ass.net>
References: <20220718192844.1805158-1-yury.norov@gmail.com>
 <20220718192844.1805158-14-yury.norov@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20220718192844.1805158-14-yury.norov@gmail.com>
Precedence: bulk

On Mon, Jul 18, 2022 at 12:28:41PM -0700, Yury Norov wrote:
>  kernel/time/tick-common.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
> index 7205f76f8d10..7b2da8ef09ef 100644
> --- a/kernel/time/tick-common.c
> +++ b/kernel/time/tick-common.c
> @@ -255,7 +255,7 @@ static void tick_setup_device(struct tick_device *td,
>  	 * When the device is not per cpu, pin the interrupt to the
>  	 * current cpu:
>  	 */
> -	if (!cpumask_equal(newdev->cpumask, cpumask))
> +	if (newdev->cpumask != cpumask && !cpumask_equal(newdev->cpumask, cpumask))
>  		irq_set_affinity(newdev->irq, cpumask);

This is again making a slow path harder to read for now benefit.