bitkeeper revision 1.1159.1.456 (41a620473ke53REbncb8KcHcla_d3g)

time.c:
  Add per-cpu processed_system_time to get number of ticks right.

diff --git a/linux-2.6.9-xen-sparse/arch/xen/i386/kernel/time.c b/linux-2.6.9-xen-sparse/arch/xen/i386/kernel/time.c
index 58cad10c8e8b3df34390fb3aa9129f3f3a5187fd..5640ac45421160dce513249bedc25cb138f6d586 100644 (file)
--- a/linux-2.6.9-xen-sparse/arch/xen/i386/kernel/time.c
+++ b/linux-2.6.9-xen-sparse/arch/xen/i386/kernel/time.c
@@ -46,6 +46,7 @@
 #include <linux/bcd.h>
 #include <linux/efi.h>
 #include <linux/sysctl.h>
+#include <linux/percpu.h>
 
 #include <asm/io.h>
 #include <asm/smp.h>
@@ -91,7 +92,6 @@ u32 shadow_tsc_stamp;
 u64 shadow_system_time;
 static u32 shadow_time_version;
 static struct timeval shadow_tv;
-extern u64 processed_system_time;
 
 /*
  * We use this to ensure that gettimeofday() is monotonically increasing. We
@@ -109,6 +109,7 @@ static long last_update_from_xen;   /* UTC seconds when last read Xen clock. */
 
 /* Keep track of last time we did processing/updating of jiffies and xtime. */
 u64 processed_system_time;   /* System time (ns) at last processing. */
+DEFINE_PER_CPU(u64, processed_system_time);
 
 #define NS_PER_TICK (1000000000ULL/HZ)
 
@@ -719,22 +720,39 @@ void time_resume(void)
 static irqreturn_t local_timer_interrupt(int irq, void *dev_id,
                                         struct pt_regs *regs)
 {
+       s64 delta;
+       int cpu = smp_processor_id();
+
+       do {
+               __get_time_values_from_xen();
+
+               delta = (s64)(shadow_system_time +
+                             ((s64)cur_timer->get_offset() * 
+                              (s64)NSEC_PER_USEC) -
+                             per_cpu(processed_system_time, cpu));
+       }
+       while (!TIME_VALUES_UP_TO_DATE);
+
+       if (unlikely(delta < 0)) {
+               printk("Timer ISR/%d: Time went backwards: %lld %lld %lld %lld\n",
+                      cpu, delta, shadow_system_time,
+                      ((s64)cur_timer->get_offset() * (s64)NSEC_PER_USEC), 
+                      processed_system_time);
+               return IRQ_HANDLED;
+       }
+
+       /* Process elapsed jiffies since last call. */
+       while (delta >= NS_PER_TICK) {
+               delta -= NS_PER_TICK;
+               per_cpu(processed_system_time, cpu) += NS_PER_TICK;
+               if (regs)
+                       update_process_times(user_mode(regs));
 #if 0
-       static int xxx = 0;
-       if ((xxx++ % 2000) == 0)
-               printk("local_timer_interrupt %d\n", xxx);
+               if (regs)
+                       profile_tick(CPU_PROFILING, regs);
 #endif
+       }
 
-       /*
-        * update_process_times() expects us to have done irq_enter().
-        * Besides, if we don't timer interrupts ignore the global
-        * interrupt lock, which is the WrongThing (tm) to do.
-        */
-       // irq_enter();
-       /* XXX add processed_system_time loop thingy */
-       if (regs)
-               update_process_times(user_mode(regs));
-       // irq_exit();
        if (smp_processor_id() == 0) {
            xxprint("bug bug\n");
            BUG();
@@ -750,7 +768,13 @@ static struct irqaction local_irq_timer = {
 
 void local_setup_timer(void)
 {
-       int time_irq;
+       int seq, time_irq;
+       int cpu = smp_processor_id();
+
+       do {
+           seq = read_seqbegin(&xtime_lock);
+           per_cpu(processed_system_time, cpu) = shadow_system_time;
+       } while (read_seqretry(&xtime_lock, seq));
 
        time_irq = bind_virq_to_irq(VIRQ_TIMER);
        (void)setup_irq(time_irq, &local_irq_timer);