Messages in this thread Patch in this message | | | From | Stanislaw Gruszka <> | Subject | [PATCH 1/6 -mm] cpu-timers: simplify RLIMIT_CPU handling | Date | Wed, 20 Jan 2010 13:34:23 +0100 |
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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 allow 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> --- kernel/posix-cpu-timers.c | 74 ++++++++++++++++----------------------------- 1 files changed, 26 insertions(+), 48 deletions(-)
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c index 9931a64..3e31d51 100644 --- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -11,19 +11,17 @@ #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(struct task_struct *task, unsigned long rlim_new) { cputime_t cputime = secs_to_cputime(rlim_new); - struct signal_struct *const sig = task->signal; - if (cputime_eq(sig->it[CPUCLOCK_PROF].expires, cputime_zero) || - cputime_gt(sig->it[CPUCLOCK_PROF].expires, cputime)) { - spin_lock_irq(&task->sighand->siglock); - set_process_cpu_timer(task, CPUCLOCK_PROF, &cputime, NULL); - spin_unlock_irq(&task->sighand->siglock); - } + spin_lock_irq(&task->sighand->siglock); + set_process_cpu_timer(task, CPUCLOCK_PROF, &cputime, NULL); + spin_unlock_irq(&task->sighand->siglock); } static int check_clock(const clockid_t which_clock) @@ -564,7 +562,6 @@ 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 +627,11 @@ 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 +1374,7 @@ 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 +1440,23 @@ 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 +1469,21 @@ 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; } } -- 1.6.2.5
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