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cpu-timers: Simplify RLIMIT_CPU handling 

Let always set signal->cputime_expires expiration cache when setting
new itimer, POSIX 1.b timer, and RLIMIT_CPU.  Since we are
initializing prof_exp expiration cache during fork(), this allows to
remove "RLIMIT_CPU != inf" check from fastpath_timer_check() and do
some other cleanups.

Checked against regression using test cases from:
http://marc.info/?l=linux-kernel&m=123749066504641&w=4
http://marc.info/?l=linux-kernel&m=123811277916642&w=2

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Stanislaw Gruszka 2010-03-11 14:04:37 -08:00 committed by Thomas Gleixner
parent 522dba7134
commit f55db60904
1 changed files with 27 additions and 48 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

75
kernel/posix-cpu-timers.c
View File

@ -11,19 +11,18 @@
#include <trace/events/timer.h>
/*
* Called after updating RLIMIT_CPU to set timer expiration if necessary.
* Called after updating RLIMIT_CPU to run cpu timer and update
* tsk->signal->cputime_expires expiration cache if necessary. Needs
* siglock protection since other code may update expiration cache as
* well.
*/
void update_rlimit_cpu(unsigned long rlim_new)
{
cputime_t cputime = secs_to_cputime(rlim_new);
struct signal_struct *const sig = current->signal;
if (cputime_eq(sig->it[CPUCLOCK_PROF].expires, cputime_zero) ||
cputime_gt(sig->it[CPUCLOCK_PROF].expires, cputime)) {
spin_lock_irq(&current->sighand->siglock);
set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
spin_unlock_irq(&current->sighand->siglock);
}
spin_lock_irq(&current->sighand->siglock);
set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
spin_unlock_irq(&current->sighand->siglock);
}
static int check_clock(const clockid_t which_clock)
@ -564,7 +563,6 @@ static void arm_timer(struct k_itimer *timer, union cpu_time_count now)
struct list_head *head, *listpos;
struct cpu_timer_list *const nt = &timer->it.cpu;
struct cpu_timer_list *next;
unsigned long i;
head = (CPUCLOCK_PERTHREAD(timer->it_clock) ?
p->cpu_timers : p->signal->cpu_timers);
@ -630,20 +628,11 @@ static void arm_timer(struct k_itimer *timer, union cpu_time_count now)
default:
BUG();
case CPUCLOCK_VIRT:
if (expires_le(sig->it[CPUCLOCK_VIRT].expires,
exp->cpu))
break;
sig->cputime_expires.virt_exp = exp->cpu;
break;
if (expires_gt(sig->cputime_expires.virt_exp, exp->cpu))
sig->cputime_expires.virt_exp = exp->cpu;
case CPUCLOCK_PROF:
if (expires_le(sig->it[CPUCLOCK_PROF].expires,
exp->cpu))
break;
i = sig->rlim[RLIMIT_CPU].rlim_cur;
if (i != RLIM_INFINITY &&
i <= cputime_to_secs(exp->cpu))
break;
sig->cputime_expires.prof_exp = exp->cpu;
if (expires_gt(sig->cputime_expires.prof_exp, exp->cpu))
sig->cputime_expires.prof_exp = exp->cpu;
break;
case CPUCLOCK_SCHED:
sig->cputime_expires.sched_exp = exp->sched;
@ -1386,7 +1375,7 @@ static inline int fastpath_timer_check(struct task_struct *tsk)
return 1;
}
return sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY;
return 0;
}
/*
@ -1452,21 +1441,23 @@ void run_posix_cpu_timers(struct task_struct *tsk)
}
/*
* Set one of the process-wide special case CPU timers.
* Set one of the process-wide special case CPU timers or RLIMIT_CPU.
* The tsk->sighand->siglock must be held by the caller.
* The *newval argument is relative and we update it to be absolute, *oldval
* is absolute and we update it to be relative.
*/
void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
cputime_t *newval, cputime_t *oldval)
{
union cpu_time_count now;
struct list_head *head;
BUG_ON(clock_idx == CPUCLOCK_SCHED);
cpu_timer_sample_group(clock_idx, tsk, &now);
if (oldval) {
/*
* We are setting itimer. The *oldval is absolute and we update
* it to be relative, *newval argument is relative and we update
* it to be absolute.
*/
if (!cputime_eq(*oldval, cputime_zero)) {
if (cputime_le(*oldval, now.cpu)) {
/* Just about to fire. */
@ -1479,33 +1470,21 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
if (cputime_eq(*newval, cputime_zero))
return;
*newval = cputime_add(*newval, now.cpu);
/*
* If the RLIMIT_CPU timer will expire before the
* ITIMER_PROF timer, we have nothing else to do.
*/
if (tsk->signal->rlim[RLIMIT_CPU].rlim_cur
< cputime_to_secs(*newval))
return;
}
/*
* Check whether there are any process timers already set to fire
* before this one. If so, we don't have anything more to do.
* Update expiration cache if we are the earliest timer, or eventually
* RLIMIT_CPU limit is earlier than prof_exp cpu timer expire.
*/
head = &tsk->signal->cpu_timers[clock_idx];
if (list_empty(head) ||
cputime_ge(list_first_entry(head,
struct cpu_timer_list, entry)->expires.cpu,
*newval)) {
switch (clock_idx) {
case CPUCLOCK_PROF:
switch (clock_idx) {
case CPUCLOCK_PROF:
if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval))
tsk->signal->cputime_expires.prof_exp = *newval;
break;
case CPUCLOCK_VIRT:
break;
case CPUCLOCK_VIRT:
if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval))
tsk->signal->cputime_expires.virt_exp = *newval;
break;
}
break;
}
}