linux-kernel - RE: [patch V2 2/5] posix-cpu-timers: Convert the flags to a bitmap

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Message-ID: <d9bb2c5f6df1471f8863f84e710e50a4@AcuMS.aculab.com>
Date:   Tue, 21 Jul 2020 16:23:01 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Thomas Gleixner' <tglx@...utronix.de>,
        Frederic Weisbecker <frederic@...nel.org>
CC:     LKML <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>, Oleg Nesterov <oleg@...hat.com>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        John Stultz <john.stultz@...aro.org>,
        Paolo Bonzini <pbonzini@...hat.com>
Subject: RE: [patch V2 2/5] posix-cpu-timers: Convert the flags to a bitmap

From: Thomas Gleixner
> Sent: 21 July 2020 17:11
> 
> Frederic Weisbecker <frederic@...nel.org> writes:
> > On Thu, Jul 16, 2020 at 10:19:25PM +0200, Thomas Gleixner wrote:
> >> --- a/kernel/time/posix-cpu-timers.c
> >> +++ b/kernel/time/posix-cpu-timers.c
> >> @@ -25,7 +25,7 @@ void posix_cputimers_group_init(struct p
> >>  	posix_cputimers_init(pct);
> >>  	if (cpu_limit != RLIM_INFINITY) {
> >>  		pct->bases[CPUCLOCK_PROF].nextevt = cpu_limit * NSEC_PER_SEC;
> >> -		pct->timers_active = true;
> >> +		set_bit(CPUTIMERS_ACTIVE, &pct->flags);
> >
> > I guess this one could be __set_bit().
> 
> True :)

Hmmm... does this code need the bit operations to be atmomic?
If not then an bitmap is completely the wrong thing to be using.

	David

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