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Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1g54WQ-0006IV-GI; Wed, 26 Sep 2018 07:46:24 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 449FD20289D15; Wed, 26 Sep 2018 09:46:09 +0200 (CEST) Date: Wed, 26 Sep 2018 09:46:09 +0200 From: Peter Zijlstra To: PierceGriffiths Cc: Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [PATCH] scheduler: conditional statement cleanup Message-ID: <20180926074609.GA1654@hirez.programming.kicks-ass.net> References: <20180921202205.11769-1-pierceagriffiths@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180921202205.11769-1-pierceagriffiths@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 21, 2018 at 03:22:03PM -0500, PierceGriffiths wrote: > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 625bc9897f62..443a1f235cfd 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -617,12 +617,8 @@ bool sched_can_stop_tick(struct rq *rq) > * If there are more than one RR tasks, we need the tick to effect the > * actual RR behaviour. > */ > - if (rq->rt.rr_nr_running) { > - if (rq->rt.rr_nr_running == 1) > - return true; > - else > - return false; > - } > + if (rq->rt.rr_nr_running) > + return rq->rt.rr_nr_running == 1; > > /* > * If there's no RR tasks, but FIFO tasks, we can skip the tick, no > diff --git a/kernel/sched/cpupri.c b/kernel/sched/cpupri.c > index daaadf939ccb..152c133e8247 100644 > --- a/kernel/sched/cpupri.c > +++ b/kernel/sched/cpupri.c > @@ -29,20 +29,16 @@ > #include "sched.h" > > /* Convert between a 140 based task->prio, and our 102 based cpupri */ > -static int convert_prio(int prio) > +static int convert_prio(const int prio) > { > - int cpupri; > - > if (prio == CPUPRI_INVALID) > - cpupri = CPUPRI_INVALID; > + return CPUPRI_INVALID; > else if (prio == MAX_PRIO) > - cpupri = CPUPRI_IDLE; > + return CPUPRI_IDLE; > else if (prio >= MAX_RT_PRIO) > - cpupri = CPUPRI_NORMAL; > + return CPUPRI_NORMAL; > else > - cpupri = MAX_RT_PRIO - prio + 1; > - > - return cpupri; > + return MAX_RT_PRIO - prio + 1; Code improves if you leave out the last else. > } > > /** > @@ -222,7 +216,7 @@ int cpupri_init(struct cpupri *cp) > return 0; > > cleanup: > - for (i--; i >= 0; i--) > + while (--i >= 0) > free_cpumask_var(cp->pri_to_cpu[i].mask); > return -ENOMEM; > } > diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c > index 2e2955a8cf8f..acf1b94669ad 100644 > --- a/kernel/sched/rt.c > +++ b/kernel/sched/rt.c > @@ -142,10 +142,12 @@ void free_rt_sched_group(struct task_group *tg) > destroy_rt_bandwidth(&tg->rt_bandwidth); > > for_each_possible_cpu(i) { > - if (tg->rt_rq) > - kfree(tg->rt_rq[i]); > - if (tg->rt_se) > - kfree(tg->rt_se[i]); > + /* Don't need to check if tg->rt_rq[i] > + * or tg->rt_se[i] are NULL, since kfree(NULL) > + * simply performs no operation > + */ Don't bother with the comment tho (but if you do, know this is the wrong comment style). > + kfree(tg->rt_rq[i]); > + kfree(tg->rt_se[i]); > } > > kfree(tg->rt_rq); > @@ -1393,7 +1389,7 @@ select_task_rq_rt(struct task_struct *p, int cpu, int sd_flag, int flags) > > /* For anything but wake ups, just return the task_cpu */ > if (sd_flag != SD_BALANCE_WAKE && sd_flag != SD_BALANCE_FORK) > - goto out; > + return cpu; > > rq = cpu_rq(cpu); > > @@ -1437,7 +1433,6 @@ select_task_rq_rt(struct task_struct *p, int cpu, int sd_flag, int flags) > } > rcu_read_unlock(); > > -out: > return cpu; > } > These changes are OK with minor edits, the rest just makes the code harder to read.