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Date: Thu, 2 Apr 2009 18:45:24 +0200
From: Ingo Molnar <mingo@...e.hu>
To: Stanislaw Gruszka <sgruszka@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Oleg Nesterov <oleg@...hat.com>
Cc: linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] itimers: merge ITIMER_VIRT and ITIMER_PROF common
code
(added more Cc:s)
* Stanislaw Gruszka <sgruszka@...hat.com> wrote:
> Both cpu itimers have same data flow in the few places, this patch make
> unification of code related with VIRT and PROF itimers.
>
> Signed-off-by: Stanislaw Gruszka <sgruszka@...hat.com>
> ---
> include/linux/sched.h | 6 +-
> kernel/fork.c | 8 +-
> kernel/itimer.c | 136 +++++++++++++++++++--------------------------
> kernel/posix-cpu-timers.c | 81 ++++++++++++++-------------
> 4 files changed, 107 insertions(+), 124 deletions(-)
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 29df637..b4c19c2 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -440,6 +440,8 @@ struct pacct_struct {
> unsigned long ac_minflt, ac_majflt;
> };
>
> +enum itimer_number {IT_VIRT = 0, IT_PROF = 1};
> +
> /**
> * struct task_cputime - collected CPU time counts
> * @utime: time spent in user mode, in &cputime_t units
> @@ -526,8 +528,8 @@ struct signal_struct {
> ktime_t it_real_incr;
>
> /* ITIMER_PROF and ITIMER_VIRTUAL timers for the process */
> - cputime_t it_prof_expires, it_virt_expires;
> - cputime_t it_prof_incr, it_virt_incr;
> + cputime_t it_expires[2];
> + cputime_t it_incr[2];
>
> /*
> * Thread group totals for process CPU timers.
> diff --git a/kernel/fork.c b/kernel/fork.c
> index 47c1584..6c7044a 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -803,10 +803,10 @@ static void posix_cpu_timers_init_group(struct signal_struct *sig)
> thread_group_cputime_init(sig);
>
> /* Expiration times and increments. */
> - sig->it_virt_expires = cputime_zero;
> - sig->it_virt_incr = cputime_zero;
> - sig->it_prof_expires = cputime_zero;
> - sig->it_prof_incr = cputime_zero;
> + sig->it_expires[IT_VIRT] = cputime_zero;
> + sig->it_expires[IT_PROF] = cputime_zero;
> + sig->it_incr[IT_VIRT] = cputime_zero;
> + sig->it_incr[IT_PROF] = cputime_zero;
>
> /* Cached expiration times. */
> sig->cputime_expires.prof_exp = cputime_zero;
> diff --git a/kernel/itimer.c b/kernel/itimer.c
> index 58762f7..ec64fea 100644
> --- a/kernel/itimer.c
> +++ b/kernel/itimer.c
> @@ -41,10 +41,34 @@ static struct timeval itimer_get_remtime(struct hrtimer *timer)
> return ktime_to_timeval(rem);
> }
>
> +static void get_cpu_itimer(struct task_struct *tsk, enum itimer_number i,
> + struct itimerval *value)
> +{
> + cputime_t cval, cinterval;
> +
> + spin_lock_irq(&tsk->sighand->siglock);
> + cval = tsk->signal->it_expires[i];
> + cinterval = tsk->signal->it_incr[i];
> + if (!cputime_eq(cval, cputime_zero)) {
> + struct task_cputime cputime;
> + cputime_t utime;
> +
> + thread_group_cputimer(tsk, &cputime);
> + utime = cputime.utime;
> + if (cputime_le(cval, utime)) { /* about to fire */
> + cval = jiffies_to_cputime(1);
> + } else {
> + cval = cputime_sub(cval, utime);
> + }
> + }
> + spin_unlock_irq(&tsk->sighand->siglock);
> + cputime_to_timeval(cval, &value->it_value);
> + cputime_to_timeval(cinterval, &value->it_interval);
> +}
> +
> int do_getitimer(int which, struct itimerval *value)
> {
> struct task_struct *tsk = current;
> - cputime_t cinterval, cval;
>
> switch (which) {
> case ITIMER_REAL:
> @@ -55,44 +79,10 @@ int do_getitimer(int which, struct itimerval *value)
> spin_unlock_irq(&tsk->sighand->siglock);
> break;
> case ITIMER_VIRTUAL:
> - spin_lock_irq(&tsk->sighand->siglock);
> - cval = tsk->signal->it_virt_expires;
> - cinterval = tsk->signal->it_virt_incr;
> - if (!cputime_eq(cval, cputime_zero)) {
> - struct task_cputime cputime;
> - cputime_t utime;
> -
> - thread_group_cputimer(tsk, &cputime);
> - utime = cputime.utime;
> - if (cputime_le(cval, utime)) { /* about to fire */
> - cval = jiffies_to_cputime(1);
> - } else {
> - cval = cputime_sub(cval, utime);
> - }
> - }
> - spin_unlock_irq(&tsk->sighand->siglock);
> - cputime_to_timeval(cval, &value->it_value);
> - cputime_to_timeval(cinterval, &value->it_interval);
> + get_cpu_itimer(tsk, IT_VIRT, value);
> break;
> case ITIMER_PROF:
> - spin_lock_irq(&tsk->sighand->siglock);
> - cval = tsk->signal->it_prof_expires;
> - cinterval = tsk->signal->it_prof_incr;
> - if (!cputime_eq(cval, cputime_zero)) {
> - struct task_cputime times;
> - cputime_t ptime;
> -
> - thread_group_cputimer(tsk, ×);
> - ptime = cputime_add(times.utime, times.stime);
> - if (cputime_le(cval, ptime)) { /* about to fire */
> - cval = jiffies_to_cputime(1);
> - } else {
> - cval = cputime_sub(cval, ptime);
> - }
> - }
> - spin_unlock_irq(&tsk->sighand->siglock);
> - cputime_to_timeval(cval, &value->it_value);
> - cputime_to_timeval(cinterval, &value->it_interval);
> + get_cpu_itimer(tsk, IT_PROF, value);
> break;
> default:
> return(-EINVAL);
> @@ -128,6 +118,35 @@ enum hrtimer_restart it_real_fn(struct hrtimer *timer)
> return HRTIMER_NORESTART;
> }
>
> +static void set_cpu_itimer(struct task_struct *tsk, enum itimer_number i,
> + struct itimerval *value, struct itimerval *ovalue)
> +{
> + cputime_t cval, cinterval, nval, ninterval;
> +
> + nval = timeval_to_cputime(&value->it_value);
> + ninterval = timeval_to_cputime(&value->it_interval);
> +
> + spin_lock_irq(&tsk->sighand->siglock);
> +
> + cval = tsk->signal->it_expires[i];
> + cinterval = tsk->signal->it_incr[i];
> + if (!cputime_eq(cval, cputime_zero) ||
> + !cputime_eq(nval, cputime_zero)) {
> + if (cputime_gt(nval, cputime_zero))
> + nval = cputime_add(nval, jiffies_to_cputime(1));
> + set_process_cpu_timer(tsk, i, &nval, &cval);
> + }
> + tsk->signal->it_expires[i] = nval;
> + tsk->signal->it_incr[i] = ninterval;
> +
> + spin_unlock_irq(&tsk->sighand->siglock);
> +
> + if (ovalue) {
> + cputime_to_timeval(cval, &ovalue->it_value);
> + cputime_to_timeval(cinterval, &ovalue->it_interval);
> + }
> +}
> +
> /*
> * Returns true if the timeval is in canonical form
> */
> @@ -139,7 +158,6 @@ int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
> struct task_struct *tsk = current;
> struct hrtimer *timer;
> ktime_t expires;
> - cputime_t cval, cinterval, nval, ninterval;
>
> /*
> * Validate the timevals in value.
> @@ -174,48 +192,10 @@ again:
> spin_unlock_irq(&tsk->sighand->siglock);
> break;
> case ITIMER_VIRTUAL:
> - nval = timeval_to_cputime(&value->it_value);
> - ninterval = timeval_to_cputime(&value->it_interval);
> - spin_lock_irq(&tsk->sighand->siglock);
> - cval = tsk->signal->it_virt_expires;
> - cinterval = tsk->signal->it_virt_incr;
> - if (!cputime_eq(cval, cputime_zero) ||
> - !cputime_eq(nval, cputime_zero)) {
> - if (cputime_gt(nval, cputime_zero))
> - nval = cputime_add(nval,
> - jiffies_to_cputime(1));
> - set_process_cpu_timer(tsk, CPUCLOCK_VIRT,
> - &nval, &cval);
> - }
> - tsk->signal->it_virt_expires = nval;
> - tsk->signal->it_virt_incr = ninterval;
> - spin_unlock_irq(&tsk->sighand->siglock);
> - if (ovalue) {
> - cputime_to_timeval(cval, &ovalue->it_value);
> - cputime_to_timeval(cinterval, &ovalue->it_interval);
> - }
> + set_cpu_itimer(tsk, IT_VIRT, value, ovalue);
> break;
> case ITIMER_PROF:
> - nval = timeval_to_cputime(&value->it_value);
> - ninterval = timeval_to_cputime(&value->it_interval);
> - spin_lock_irq(&tsk->sighand->siglock);
> - cval = tsk->signal->it_prof_expires;
> - cinterval = tsk->signal->it_prof_incr;
> - if (!cputime_eq(cval, cputime_zero) ||
> - !cputime_eq(nval, cputime_zero)) {
> - if (cputime_gt(nval, cputime_zero))
> - nval = cputime_add(nval,
> - jiffies_to_cputime(1));
> - set_process_cpu_timer(tsk, CPUCLOCK_PROF,
> - &nval, &cval);
> - }
> - tsk->signal->it_prof_expires = nval;
> - tsk->signal->it_prof_incr = ninterval;
> - spin_unlock_irq(&tsk->sighand->siglock);
> - if (ovalue) {
> - cputime_to_timeval(cval, &ovalue->it_value);
> - cputime_to_timeval(cinterval, &ovalue->it_interval);
> - }
> + set_cpu_itimer(tsk, IT_PROF, value, ovalue);
> break;
> default:
> return -EINVAL;
> diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
> index 8e5d9a6..76e125c 100644
> --- a/kernel/posix-cpu-timers.c
> +++ b/kernel/posix-cpu-timers.c
> @@ -17,8 +17,8 @@ void update_rlimit_cpu(unsigned long rlim_new)
> cputime_t cputime;
>
> cputime = secs_to_cputime(rlim_new);
> - if (cputime_eq(current->signal->it_prof_expires, cputime_zero) ||
> - cputime_lt(current->signal->it_prof_expires, cputime)) {
> + if (cputime_eq(current->signal->it_expires[IT_PROF], cputime_zero) ||
> + cputime_lt(current->signal->it_expires[IT_PROF], cputime)) {
> spin_lock_irq(¤t->sighand->siglock);
> set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
> spin_unlock_irq(¤t->sighand->siglock);
> @@ -619,18 +619,18 @@ static void arm_timer(struct k_itimer *timer, union cpu_time_count now)
> default:
> BUG();
> case CPUCLOCK_VIRT:
> - if (!cputime_eq(p->signal->it_virt_expires,
> + if (!cputime_eq(p->signal->it_expires[IT_VIRT],
> cputime_zero) &&
> - cputime_lt(p->signal->it_virt_expires,
> + cputime_lt(p->signal->it_expires[IT_VIRT],
> timer->it.cpu.expires.cpu))
> break;
> p->signal->cputime_expires.virt_exp =
> timer->it.cpu.expires.cpu;
> break;
> case CPUCLOCK_PROF:
> - if (!cputime_eq(p->signal->it_prof_expires,
> + if (!cputime_eq(p->signal->it_expires[IT_PROF],
> cputime_zero) &&
> - cputime_lt(p->signal->it_prof_expires,
> + cputime_lt(p->signal->it_expires[IT_PROF],
> timer->it.cpu.expires.cpu))
> break;
> i = p->signal->rlim[RLIMIT_CPU].rlim_cur;
> @@ -1069,6 +1069,36 @@ static void stop_process_timers(struct task_struct *tsk)
> spin_unlock_irqrestore(&cputimer->lock, flags);
> }
>
> +static cputime_t check_cpu_itimer(struct task_struct *tsk, enum itimer_number i,
> + cputime_t expires, cputime_t cur_time)
> +{
> + struct signal_struct *const sig = tsk->signal;
> +
> + if (cputime_eq(sig->it_expires[i], cputime_zero))
> + return expires;
> +
> + if (cputime_ge(cur_time, sig->it_expires[i])) {
> + int signo;
> +
> + sig->it_expires[i] = sig->it_incr[i];
> + if (!cputime_eq(sig->it_expires[i], cputime_zero)) {
> + sig->it_expires[i] = cputime_add(sig->it_expires[i],
> + cur_time);
> + }
> +
> + signo = (i == IT_VIRT) ? SIGVTALRM : SIGPROF;
> + __group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
> + }
> +
> + if (!cputime_eq(sig->it_expires[i], cputime_zero) &&
> + (cputime_eq(expires, cputime_zero) ||
> + cputime_lt(sig->it_expires[i], expires))) {
> + expires = sig->it_expires[i];
> + }
> +
> + return expires;
> +}
> +
> /*
> * Check for any per-thread CPU timers that have fired and move them
> * off the tsk->*_timers list onto the firing list. Per-thread timers
> @@ -1088,10 +1118,10 @@ static void check_process_timers(struct task_struct *tsk,
> * Don't sample the current process CPU clocks if there are no timers.
> */
> if (list_empty(&timers[CPUCLOCK_PROF]) &&
> - cputime_eq(sig->it_prof_expires, cputime_zero) &&
> + cputime_eq(sig->it_expires[IT_PROF], cputime_zero) &&
> sig->rlim[RLIMIT_CPU].rlim_cur == RLIM_INFINITY &&
> list_empty(&timers[CPUCLOCK_VIRT]) &&
> - cputime_eq(sig->it_virt_expires, cputime_zero) &&
> + cputime_eq(sig->it_expires[IT_VIRT], cputime_zero) &&
> list_empty(&timers[CPUCLOCK_SCHED])) {
> stop_process_timers(tsk);
> return;
> @@ -1151,38 +1181,9 @@ static void check_process_timers(struct task_struct *tsk,
> /*
> * Check for the special case process timers.
> */
> - if (!cputime_eq(sig->it_prof_expires, cputime_zero)) {
> - if (cputime_ge(ptime, sig->it_prof_expires)) {
> - /* ITIMER_PROF fires and reloads. */
> - sig->it_prof_expires = sig->it_prof_incr;
> - if (!cputime_eq(sig->it_prof_expires, cputime_zero)) {
> - sig->it_prof_expires = cputime_add(
> - sig->it_prof_expires, ptime);
> - }
> - __group_send_sig_info(SIGPROF, SEND_SIG_PRIV, tsk);
> - }
> - if (!cputime_eq(sig->it_prof_expires, cputime_zero) &&
> - (cputime_eq(prof_expires, cputime_zero) ||
> - cputime_lt(sig->it_prof_expires, prof_expires))) {
> - prof_expires = sig->it_prof_expires;
> - }
> - }
> - if (!cputime_eq(sig->it_virt_expires, cputime_zero)) {
> - if (cputime_ge(utime, sig->it_virt_expires)) {
> - /* ITIMER_VIRTUAL fires and reloads. */
> - sig->it_virt_expires = sig->it_virt_incr;
> - if (!cputime_eq(sig->it_virt_expires, cputime_zero)) {
> - sig->it_virt_expires = cputime_add(
> - sig->it_virt_expires, utime);
> - }
> - __group_send_sig_info(SIGVTALRM, SEND_SIG_PRIV, tsk);
> - }
> - if (!cputime_eq(sig->it_virt_expires, cputime_zero) &&
> - (cputime_eq(virt_expires, cputime_zero) ||
> - cputime_lt(sig->it_virt_expires, virt_expires))) {
> - virt_expires = sig->it_virt_expires;
> - }
> - }
> + prof_expires = check_cpu_itimer(tsk, IT_PROF, prof_expires, ptime);
> + virt_expires = check_cpu_itimer(tsk, IT_VIRT, virt_expires, utime);
> +
> if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
> unsigned long psecs = cputime_to_secs(ptime);
> cputime_t x;
> --
> 1.6.0.6
>
> --
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