From: Chris Metcalf <cmetcalf@mellanox.com>
To: Frederic Weisbecker <fweisbec@gmail.com>,
Peter Zijlstra <peterz@infradead.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Byungchul Park <byungchul.park@lge.com>,
Thomas Gleixner <tglx@linutronix.de>,
Luiz Capitulino <lcapitulino@redhat.com>,
Christoph Lameter <cl@linux.com>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
Mike Galbraith <efault@gmx.de>, Rik van Riel <riel@redhat.com>,
Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH 3/3] sched: Optimize !CONFIG_NO_HZ_COMMON cpu load updates
Date: Mon, 11 Apr 2016 10:53:01 -0400 [thread overview]
Message-ID: <570BBA4D.1060307@mellanox.com> (raw)
In-Reply-To: <20160411131814.GA22628@lerouge>
On 4/11/2016 9:18 AM, Frederic Weisbecker wrote:
> So I tried and it warns about the unused variable tickless_load, so I
> would need two scattered ifdeffery in the function:
>
> @@ -4528,7 +4529,9 @@ decay_load_missed(unsigned long load, unsigned long missed_updates, int idx)
> static void cpu_load_update(struct rq *this_rq, unsigned long this_load,
> unsigned long pending_updates)
> {
> +#ifdef CONFIG_NO_HZ_COMMON
> unsigned long tickless_load = this_rq->cpu_load[0];
> +#endif
Just move the initialization down to the first use, as a regular
assignment, and add __maybe_unused to the declaration, and the compiler
will then keep quiet (see Documentation/CodingStyle).
I have no comment on which of the approaches looks better overall,
but I think using __maybe_unused definitely improves this approach.
--
Chris Metcalf, Mellanox Technologies
http://www.mellanox.com
next prev parent reply other threads:[~2016-04-11 14:53 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-08 1:07 [PATCH 0/3] sched: Fix/improve nohz cpu load updates v2 Frederic Weisbecker
2016-04-08 1:07 ` [PATCH 1/3] sched: Gather cpu load functions under a more conventional namespace Frederic Weisbecker
2016-04-08 1:07 ` [PATCH 2/3] sched: Correctly handle nohz ticks cpu load accounting Frederic Weisbecker
2016-04-08 9:41 ` Peter Zijlstra
2016-04-08 12:53 ` Frederic Weisbecker
2016-04-08 17:40 ` Peter Zijlstra
2016-04-08 1:07 ` [PATCH 3/3] sched: Optimize !CONFIG_NO_HZ_COMMON cpu load updates Frederic Weisbecker
2016-04-08 10:48 ` Peter Zijlstra
2016-04-08 12:55 ` Frederic Weisbecker
2016-04-08 17:44 ` Peter Zijlstra
2016-04-11 13:18 ` Frederic Weisbecker
2016-04-11 14:53 ` Chris Metcalf [this message]
2016-04-11 18:21 ` Frederic Weisbecker
2016-04-12 14:23 ` Peter Zijlstra
2016-04-13 13:56 [PATCH 0/3] sched: Fix/improve nohz cpu load updates v3 Frederic Weisbecker
2016-04-13 13:56 ` [PATCH 3/3] sched: Optimize !CONFIG_NO_HZ_COMMON cpu load updates Frederic Weisbecker
2016-04-18 13:36 ` Frederic Weisbecker
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