[PATCH] cpufreq: update timer notifier

- global loops_per_jiffy, x86 cpu_khz and x86
   fast_gettimeoffset_quotient can only be safely adjusted on UP
- x86 per-CPU loops_per_jiffy does not depend on TSC
- save reference values so that rounding errors do not accumulate

1 files changed, 15 insertions, 5 deletions

diff --git a/kernel/cpufreq.c b/kernel/cpufreq.c
index 5dff6da1a73f..c0be78462c81 100644
--- a/kernel/cpufreq.c
+++ b/kernel/cpufreq.c
@@ -927,17 +927,27 @@ EXPORT_SYMBOL(cpufreq_set_policy);
  * adjust_jiffies - adjust the system "loops_per_jiffy"
  *
  * This function alters the system "loops_per_jiffy" for the clock
- * speed change. Note that loops_per_jiffy is only updated if all
- * CPUs are affected - else there is a need for per-CPU loops_per_jiffy
- * values which are provided by various architectures. 
+ * speed change. Note that loops_per_jiffy cannot be updated on SMP
+ * systems as each CPU might be scaled differently. So, use the arch 
+ * per-CPU loops_per_jiffy value wherever possible.
  */
+#ifndef CONFIG_SMP
+static unsigned long l_p_j_ref = 0;
+static unsigned int  l_p_j_ref_freq = 0;
+
 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
 {
+	if (!l_p_j_ref_freq) {
+		l_p_j_ref = loops_per_jiffy;
+		l_p_j_ref_freq = ci->old;
+	}
 	if ((val == CPUFREQ_PRECHANGE  && ci->old < ci->new) ||
 	    (val == CPUFREQ_POSTCHANGE && ci->old > ci->new))
-		if (ci->cpu == CPUFREQ_ALL_CPUS)
-			loops_per_jiffy = cpufreq_scale(loops_per_jiffy, ci->old, ci->new);
+		loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, ci->new);
 }
+#else
+#define adjust_jiffies(...)
+#endif
 
 
 /**