Cc: Luca Tettamanti <kronos.it@...>, Frans Pop <elendil@...>, Willy Tarreau <w@...>, LKML <linux-kernel@...>, Ilpo Järvinen <ilpo.jarvinen@...>, Alexander E. Patrakov <patrakov@...>, Ingo Molnar <mingo@...>
On 10/04/2007 04:00 PM, Christian Borntraeger wrote:
The code in fs/proc/array.c is... interesting.
1. task_stime() converts p->se.sum_exec_runtime to a clock_t
2. it calls task_utime() which does the same thing (can it change
between the two reads?), does some calculations that yield a
clock_t, turns the result into a cputime and returns that
3. task_stime() then converts that result back into a clock_t and
uses it!
static cputime_t task_stime(struct task_struct *p)
{
clock_t stime;
stime = nsec_to_clock_t(p->se.sum_exec_runtime) -
cputime_to_clock_t(task_utime(p));
return clock_t_to_cputime(stime);
}
static cputime_t task_utime(struct task_struct *p)
{
clock_t utime = cputime_to_clock_t(p->utime),
total = utime + cputime_to_clock_t(p->stime);
u64 temp;
temp = (u64)nsec_to_clock_t(p->se.sum_exec_runtime);
if (total) {
temp *= utime;
do_div(temp, total);
}
utime = (clock_t)temp;
return clock_t_to_cputime(utime);
}
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