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

2020-07-21 Thread Thomas Gleixner 
David Laight  writes:
> From: Thomas Gleixner
>> Sent: 21 July 2020 17:11
>> 
>> Frederic Weisbecker  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.

Some of it does, otherwise the booleans would have stayed, but I'm
reworking parts of it so this might change.

Thanks,

tglx

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

2020-07-21 Thread David Laight 
From: Thomas Gleixner
> Sent: 21 July 2020 17:11
> 
> Frederic Weisbecker  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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Re: [patch V2 2/5] posix-cpu-timers: Convert the flags to a bitmap

2020-07-21 Thread Thomas Gleixner 
Frederic Weisbecker  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 :)

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

2020-07-21 Thread Frederic Weisbecker 
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().

>   }
>  }