Messages in this thread | | | Date | Wed, 28 Sep 2011 10:13:57 +0200 | From | Martin Schwidefsky <> | Subject | Re: [RFD 4/9] Make total_forks per-cgroup |
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On Wed, 28 Sep 2011 00:00:37 +0200 Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> On Fri, 2011-09-23 at 19:20 -0300, Glauber Costa wrote: > > @@ -1039,6 +1035,8 @@ static void posix_cpu_timers_init(struct task_struct *tsk) > > INIT_LIST_HEAD(&tsk->cpu_timers[2]); > > } > > > > +struct task_group *task_group(struct task_struct *p); > > That doesn't appear to be actually used in this file.. > > Also, since there's already a for_each_possible_cpu() loop in that > proc/stat function, would it yield some code improvement to make > total_forks a cpu_usage_stat? > > I guess the whole cputime64_t crap gets in the way of that being > natural... > > We could of course kill off the cputime64_t thing, its pretty pointless > and its a u64 all over the board. I think Martin or Heiko created this > stuff (although I might be wrong, my git tree doesn't go back that far).
The reason to introduce cputime_t has been that different architecture needed differently sized integers for their respective representation of cputime. On x86-32 the number of ticks is recorded in a u32, on s390 we needed a u64 for the cpu timer values. cputime64_t is needed for cpustat and other sums of cputime that would overflow a cputime_t (in particular on x86-32 with the u32 cputime_t and the u64 cputime64_t).
Now we would convert everything to u64 but that would cause x86-32 to use 64-bit arithmetic for the tick counter. If that is acceptable I can't say.
-- blue skies, Martin.
"Reality continues to ruin my life." - Calvin.
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