linux-kernel - Re: [PATCH] hrtimer: Avoid double reprogramming in __hrtimer_start_range

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Message-ID: <YIa0qWdxM7vIsf/4@hirez.programming.kicks-ass.net>
Date:   Mon, 26 Apr 2021 14:40:09 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Lorenzo Colitti <lorenzo@...gle.com>,
        Greg KH <gregkh@...uxfoundation.org>,
        Maciej Żenczykowski <zenczykowski@...il.com>,
        Ingo Molnar <mingo@...nel.org>,
        Anna-Maria Behnsen <anna-maria@...utronix.de>,
        lkml <linux-kernel@...r.kernel.org>,
        mikael.beckius@...driver.com,
        Maciej Żenczykowski <maze@...gle.com>,
        Will Deacon <will@...nel.org>
Subject: Re: [PATCH] hrtimer: Avoid double reprogramming in
 __hrtimer_start_range_ns()

On Mon, Apr 26, 2021 at 02:33:00PM +0200, Thomas Gleixner wrote:

> >> +	force_local = base->cpu_base == this_cpu_ptr(&hrtimer_bases);
> >> +	force_local &= base->cpu_base->next_timer == timer;
> >
> > Using bitwise ops on a bool is cute and all, but isn't that more
> > readable when written like:
> >
> > 	force_local = base->cpu_base == this_cpu_ptr(&hrtimer_bases) &&
> > 		      base->cpu_base->next_timer == timer;
> >
> 
> Which results in an extra conditional branch.

Srlsy, compiler not smart enough?