posix-cpu-timers: Consolidate timer expiry further

With the array based samples and expiry cache, the expiry function can use
a loop to collect timers from the clock specific lists.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192922.365469982@linutronix.de

1 files changed, 30 insertions, 33 deletions

diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index cf85292575c5..caafdfdd6f0f 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -752,6 +752,18 @@ check_timers_list(struct list_head *timers,
         return U64_MAX;
 }
 
+static void collect_posix_cputimers(struct posix_cputimers *pct,
+                                    u64 *samples, struct list_head *firing)
+{
+        struct posix_cputimer_base *base = pct->bases;
+        int i;
+
+        for (i = 0; i < CPUCLOCK_MAX; i++, base++) {
+                base->nextevt = check_timers_list(&base->cpu_timers, firing,
+                                                   samples[i]);
+        }
+}
+
 static inline void check_dl_overrun(struct task_struct *tsk)
 {
         if (tsk->dl.dl_overrun) {
@@ -768,25 +780,18 @@ static inline void check_dl_overrun(struct task_struct *tsk)
 static void check_thread_timers(struct task_struct *tsk,
                                 struct list_head *firing)
 {
-        struct posix_cputimer_base *base = tsk->posix_cputimers.bases;
+        struct posix_cputimers *pct = &tsk->posix_cputimers;
+        u64 samples[CPUCLOCK_MAX];
         unsigned long soft;
-        u64 stime, utime;
 
         if (dl_task(tsk))
                 check_dl_overrun(tsk);
 
-        if (expiry_cache_is_inactive(&tsk->posix_cputimers))
+        if (expiry_cache_is_inactive(pct))
                 return;
 
-        task_cputime(tsk, &utime, &stime);
-
-        base->nextevt = check_timers_list(&base->cpu_timers, firing,
-                                          utime + stime);
-        base++;
-        base->nextevt = check_timers_list(&base->cpu_timers, firing, utime);
-        base++;
-        base->nextevt = check_timers_list(&base->cpu_timers, firing,
-                                          tsk->se.sum_exec_runtime);
+        task_sample_cputime(tsk, samples);
+        collect_posix_cputimers(pct, samples, firing);
 
         /*
          * Check for the special case thread timers.
@@ -825,7 +830,7 @@ static void check_thread_timers(struct task_struct *tsk,
                 }
         }
 
-        if (expiry_cache_is_inactive(&tsk->posix_cputimers))
+        if (expiry_cache_is_inactive(pct))
                 tick_dep_clear_task(tsk, TICK_DEP_BIT_POSIX_TIMER);
 }
 
@@ -869,15 +874,15 @@ static void check_process_timers(struct task_struct *tsk,
                                  struct list_head *firing)
 {
         struct signal_struct *const sig = tsk->signal;
-        struct posix_cputimer_base *base = sig->posix_cputimers.bases;
-        u64 virt_exp, prof_exp, sched_exp, samples[CPUCLOCK_MAX];
+        struct posix_cputimers *pct = &sig->posix_cputimers;
+        u64 samples[CPUCLOCK_MAX];
         unsigned long soft;
 
         /*
          * If cputimer is not running, then there are no active
          * process wide timers (POSIX 1.b, itimers, RLIMIT_CPU).
          */
-        if (!READ_ONCE(tsk->signal->cputimer.running))
+        if (!READ_ONCE(sig->cputimer.running))
                 return;
 
        /*
@@ -891,21 +896,17 @@ static void check_process_timers(struct task_struct *tsk,
          * so the sample can be taken directly.
          */
         proc_sample_cputime_atomic(&sig->cputimer.cputime_atomic, samples);
-
-        prof_exp = check_timers_list(&base[CPUCLOCK_PROF].cpu_timers,
-                                     firing, samples[CPUCLOCK_PROF]);
-        virt_exp = check_timers_list(&base[CPUCLOCK_VIRT].cpu_timers,
-                                     firing, samples[CPUCLOCK_VIRT]);
-        sched_exp = check_timers_list(&base[CPUCLOCK_SCHED].cpu_timers,
-                                      firing, samples[CPUCLOCK_SCHED]);
+        collect_posix_cputimers(pct, samples, firing);
 
         /*
          * Check for the special case process timers.
          */
-        check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_exp,
+        check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF],
+                         &pct->bases[CPUCLOCK_PROF].nextevt,
                          samples[CPUCLOCK_PROF], SIGPROF);
-        check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_exp,
-                         samples[CPUCLOCK_PROF], SIGVTALRM);
+        check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT],
+                         &pct->bases[CPUCLOCK_VIRT].nextevt,
+                         samples[CPUCLOCK_VIRT], SIGVTALRM);
 
         soft = task_rlimit(tsk, RLIMIT_CPU);
         if (soft != RLIM_INFINITY) {
@@ -940,15 +941,11 @@ static void check_process_timers(struct task_struct *tsk,
                         }
                 }
                 softns = soft * NSEC_PER_SEC;
-                if (softns < prof_exp)
-                        prof_exp = softns;
+                if (softns < pct->bases[CPUCLOCK_PROF].nextevt)
+                        pct->bases[CPUCLOCK_PROF].nextevt = softns;
         }
 
-        base[CPUCLOCK_PROF].nextevt = prof_exp;
-        base[CPUCLOCK_VIRT].nextevt = virt_exp;
-        base[CPUCLOCK_SCHED].nextevt = sched_exp;
-
-        if (expiry_cache_is_inactive(&sig->posix_cputimers))
+        if (expiry_cache_is_inactive(pct))
                 stop_process_timers(sig);
 
         sig->cputimer.checking_timer = false;