These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / arch / s390 / kernel / vtime.c

diff --git a/kernel/arch/s390/kernel/vtime.c b/kernel/arch/s390/kernel/vtime.c
index e53d359..dafc44f 100644 (file)
--- a/kernel/arch/s390/kernel/vtime.c
+++ b/kernel/arch/s390/kernel/vtime.c
@@ -25,9 +25,10 @@ static DEFINE_SPINLOCK(virt_timer_lock);
 static atomic64_t virt_timer_current;
 static atomic64_t virt_timer_elapsed;
 
-static DEFINE_PER_CPU(u64, mt_cycles[32]);
+DEFINE_PER_CPU(u64, mt_cycles[8]);
 static DEFINE_PER_CPU(u64, mt_scaling_mult) = { 1 };
 static DEFINE_PER_CPU(u64, mt_scaling_div) = { 1 };
+static DEFINE_PER_CPU(u64, mt_scaling_jiffies);
 
 static inline u64 get_vtimer(void)
 {
@@ -59,6 +60,34 @@ static inline int virt_timer_forward(u64 elapsed)
        return elapsed >= atomic64_read(&virt_timer_current);
 }
 
+static void update_mt_scaling(void)
+{
+       u64 cycles_new[8], *cycles_old;
+       u64 delta, fac, mult, div;
+       int i;
+
+       stcctm5(smp_cpu_mtid + 1, cycles_new);
+       cycles_old = this_cpu_ptr(mt_cycles);
+       fac = 1;
+       mult = div = 0;
+       for (i = 0; i <= smp_cpu_mtid; i++) {
+               delta = cycles_new[i] - cycles_old[i];
+               div += delta;
+               mult *= i + 1;
+               mult += delta * fac;
+               fac *= i + 1;
+       }
+       div *= fac;
+       if (div > 0) {
+               /* Update scaling factor */
+               __this_cpu_write(mt_scaling_mult, mult);
+               __this_cpu_write(mt_scaling_div, div);
+               memcpy(cycles_old, cycles_new,
+                      sizeof(u64) * (smp_cpu_mtid + 1));
+       }
+       __this_cpu_write(mt_scaling_jiffies, jiffies_64);
+}
+
 /*
  * Update process times based on virtual cpu times stored by entry.S
  * to the lowcore fields user_timer, system_timer & steal_clock.
@@ -68,7 +97,6 @@ static int do_account_vtime(struct task_struct *tsk, int hardirq_offset)
        struct thread_info *ti = task_thread_info(tsk);
        u64 timer, clock, user, system, steal;
        u64 user_scaled, system_scaled;
-       int i;
 
        timer = S390_lowcore.last_update_timer;
        clock = S390_lowcore.last_update_clock;
@@ -84,28 +112,10 @@ static int do_account_vtime(struct task_struct *tsk, int hardirq_offset)
        S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
        S390_lowcore.steal_timer += S390_lowcore.last_update_clock - clock;
 
-       /* Do MT utilization calculation */
-       if (smp_cpu_mtid) {
-               u64 cycles_new[32], *cycles_old;
-               u64 delta, mult, div;
-
-               cycles_old = this_cpu_ptr(mt_cycles);
-               if (stcctm5(smp_cpu_mtid + 1, cycles_new) < 2) {
-                       mult = div = 0;
-                       for (i = 0; i <= smp_cpu_mtid; i++) {
-                               delta = cycles_new[i] - cycles_old[i];
-                               mult += delta;
-                               div += (i + 1) * delta;
-                       }
-                       if (mult > 0) {
-                               /* Update scaling factor */
-                               __this_cpu_write(mt_scaling_mult, mult);
-                               __this_cpu_write(mt_scaling_div, div);
-                               memcpy(cycles_old, cycles_new,
-                                      sizeof(u64) * (smp_cpu_mtid + 1));
-                       }
-               }
-       }
+       /* Update MT utilization calculation */
+       if (smp_cpu_mtid &&
+           time_after64(jiffies_64, this_cpu_read(mt_scaling_jiffies)))
+               update_mt_scaling();
 
        user = S390_lowcore.user_timer - ti->user_timer;
        S390_lowcore.steal_timer -= user;
@@ -174,6 +184,11 @@ void vtime_account_irq_enter(struct task_struct *tsk)
        S390_lowcore.last_update_timer = get_vtimer();
        S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
 
+       /* Update MT utilization calculation */
+       if (smp_cpu_mtid &&
+           time_after64(jiffies_64, this_cpu_read(mt_scaling_jiffies)))
+               update_mt_scaling();
+
        system = S390_lowcore.system_timer - ti->system_timer;
        S390_lowcore.steal_timer -= system;
        ti->system_timer = S390_lowcore.system_timer;
@@ -376,4 +391,11 @@ void vtime_init(void)
 {
        /* set initial cpu timer */
        set_vtimer(VTIMER_MAX_SLICE);
+       /* Setup initial MT scaling values */
+       if (smp_cpu_mtid) {
+               __this_cpu_write(mt_scaling_jiffies, jiffies);
+               __this_cpu_write(mt_scaling_mult, 1);
+               __this_cpu_write(mt_scaling_div, 1);
+               stcctm5(smp_cpu_mtid + 1, this_cpu_ptr(mt_cycles));
+       }
 }