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itimers: Simplify arm_timer() code a bit 

Don't update values in expiration cache when new ones are
equal. Add expire_le() and expire_gt() helpers to simplify the
code.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
LKML-Reference: <1248862529-6063-4-git-send-email-sgruszka@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Stanislaw Gruszka 2009-07-29 12:15:28 +02:00 committed by Ingo Molnar
parent 8356b5f9c4
commit d1e3b6d195
1 changed files with 23 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
kernel/posix-cpu-timers.c
View File

@ -541,6 +541,17 @@ static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now)
now);
}
static inline int expires_gt(cputime_t expires, cputime_t new_exp)
{
return cputime_eq(expires, cputime_zero) ||
cputime_gt(expires, new_exp);
}
static inline int expires_le(cputime_t expires, cputime_t new_exp)
{
return !cputime_eq(expires, cputime_zero) &&
cputime_le(expires, new_exp);
}
/*
* Insert the timer on the appropriate list before any timers that
* expire later. This must be called with the tasklist_lock held
@ -585,31 +596,26 @@ static void arm_timer(struct k_itimer *timer, union cpu_time_count now)
*/
if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
union cpu_time_count *exp = &nt->expires;
switch (CPUCLOCK_WHICH(timer->it_clock)) {
default:
BUG();
case CPUCLOCK_PROF:
if (cputime_eq(p->cputime_expires.prof_exp,
cputime_zero) ||
cputime_gt(p->cputime_expires.prof_exp,
nt->expires.cpu))
p->cputime_expires.prof_exp =
nt->expires.cpu;
if (expires_gt(p->cputime_expires.prof_exp,
exp->cpu))
p->cputime_expires.prof_exp = exp->cpu;
break;
case CPUCLOCK_VIRT:
if (cputime_eq(p->cputime_expires.virt_exp,
cputime_zero) ||
cputime_gt(p->cputime_expires.virt_exp,
nt->expires.cpu))
p->cputime_expires.virt_exp =
nt->expires.cpu;
if (expires_gt(p->cputime_expires.virt_exp,
exp->cpu))
p->cputime_expires.virt_exp = exp->cpu;
break;
case CPUCLOCK_SCHED:
if (p->cputime_expires.sched_exp == 0 ||
p->cputime_expires.sched_exp >
nt->expires.sched)
p->cputime_expires.sched_exp > exp->sched)
p->cputime_expires.sched_exp =
nt->expires.sched;
exp->sched;
break;
}
} else {
@ -623,17 +629,13 @@ static void arm_timer(struct k_itimer *timer, union cpu_time_count now)
default:
BUG();
case CPUCLOCK_VIRT:
if (!cputime_eq(sig->it[CPUCLOCK_VIRT].expires,
cputime_zero) &&
cputime_lt(sig->it[CPUCLOCK_VIRT].expires,
if (expires_le(sig->it[CPUCLOCK_VIRT].expires,
exp->cpu))
break;
sig->cputime_expires.virt_exp = exp->cpu;
break;
case CPUCLOCK_PROF:
if (!cputime_eq(sig->it[CPUCLOCK_PROF].expires,
cputime_zero) &&
cputime_lt(sig->it[CPUCLOCK_PROF].expires,
if (expires_le(sig->it[CPUCLOCK_PROF].expires,
exp->cpu))
break;
i = sig->rlim[RLIMIT_CPU].rlim_cur;